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HomeMy WebLinkAboutCT 13-03; ROBERTSON RANCH-RANCHO COSTERA; GEOTECHNICAL INVESTIGATION FOR RHE PLANNED IMPROVEMENT OF EL CAMINO REAL BETWEEN CANNON ROAD AND TAMARACK AVE; 2011-05-11I Geotechnical 'Geologic' Coastal. Environmental 5741 Palmer Way • Carlsbad, California 92010 • (760) 438-3155 • FAX (760) 931-0915 'www.geosoilsinc.com May 11, 2011 W.O. 6145-E-SC Shapell Homes 8383 Wilshire Boulevard, Suite 700 Beverly Hills, California 90211 Attention: Mr. John Butler Subject: Geotechnical Investigation for the Planned Improvement of El Camino Real, Between Cannon Road and Tamarack Avenue, Rancho Costera (Formerly Robertson Ranch West Village), Carlsbad, San Diego County, California Dear Mr. Buller: In accordance with your request, GeoSoils, Inc. (GSl) has prepared this geotechnical investigation report regarding the improvement of a portion of El Camino Real (ECR), between ECR Station 444+00 (Cannon Road), and ECR Station 494+00 (Tamarack Avenue), in the City of Carlsbad, California. The purpose of this investigation was to evaluate the various planned improvements to ECR with respect to the underlying geotechnical conditions in the vicinity, and current building codes and guidelines. This report summarizes the findings of our work. Based on our findings and analyses, recommendations for site preparation, earthwork, wall foundations, and pavement design/construction are provided for design and planning purposes. EXECUTIVE SUMMARY Based on our review of the available data (Appendix A), field exploration (Appendix B), and geologic and engineering analysis, the proposed construction appears to be feasible from a geotechnical viewpoint, provided the recommendations presented in the text of this report are property incorporated into the design and construction of the project. The most significant elements of this study are summarized below: Site exploration generally indicates that the existing pavement section within ECR consists of 6 to 8 inches of asphaltic concrete, overlying approximately 4 inches of recycled/reprocessed asphalt pavement, or R.A.P. This is in turn underlain with approximately 12 to 18 inches of a graded, sand sub-base, overlying clayey subgrade soil. Testing of representative samples of soil subgrade indicate an average resistance value (R-value) of 14. The existing pavement section shows localized areas of pavement distress, consisting predominantly of fatigue, "alligator" cracking within the wheel paths, other types of distress, such as rutting, depressions, and potholes were also noted locally. Distress appears to primarily occur within wheel paths (slow lane), and/or mirror previous utility trench backfill and patch efforts. Earth materials unsuitable for the support of structures, settlement-sensitive improvements, and/or compacted fill generally consist of surface-exposed existing roadway or undocumented artificial fill, talus deposits, colluvial soil, and near-surface alluvium. Complete removals of alluvium will be limited due to the presence of a shallow groundwater table in alluvial areas (i.e., ECR Sta. 444+00 to 451+00, and 481+00 to 488+00). Where feasible, removals of existing surface-exposed fill should minimally be completed to depths of at least 2 feet below surface grades, or at least 1 foot below the bottom of the planned surlicial improvement, whichever is deeper. Roadway perimeter removals within alluvial areas should be completed to near the groundwater table, approximately 2 to 3 feet below existing grades in alluvial areas. Other unsuitable site soils, such as talus, colluvium, etc., are anticipated to be removed during planned excavation operations during grading. In areas were removals are not feasible due to existing utilities, pavement alternatives and foundation support alternatives are provided herein. Our analysis of the planned cut slopes along ECR, indicates that these slopes are grossly stable (i.e., factor-of-safety [FOS] >1.5). Graded slopes are generally anticipated to be stable, assuming proper construction, maintenance, and normal climatic conditions. Surficial stability along portions of ECR in cut slopes exhibits continued erosion and gullying, both in descending and ascending road embankments/slopes. This appears to be due, in part, to drainage directed toward, or allowed to drain over the tops of slopes. Groundwater was encountered within some of our exploratory borings (see Appendix B, Borings B-202, B-203, B-210 and HA-9), within alluvial sediments underlying the existing alignment of ECR, in the vicinity of ECR Stations 444+00 to 452+00, and 481+50 to 488+00. In the vicinity of ECR Stations 444+00 to 452+00, the groundwater table appears to occur at an approximate elevation of 32 to 34 feet MSL, or approximately 8 to 21 feet below street grade. In the vicinity of ECR Stations 481+50 to 488+00, the groundwater table appears to occur at an approximate elevation of 42 to 43 feet MSL, or approximately 5 to 16 feet below street grades. Our review indicates that regional groundwater should not significantly affect site development provided that the recommendations presented herein are implemented. However, deeper utilities in the groundwater areas noted above will likely require dewatering to place the pipes. In general, perched groundwater conditions, along zones of contrasting permeabilities, discontinuities, or fill lifts, may not be precluded from occurring in the future due to site irrigation, poor drainage conditions, or damaged utilities. Perched groundwater should be anticipated to Shapell Homes W.O. 6145-E-SC FiIe:e:\wp9\61 OO\6145e.gif Page Two Ge,Soils9 Inc. occur after development, and may require additional mitigation when it manifests itself. A previous Liquefaction analyses (GSl, 2010) indicates that some alluvial soils are generally susceptible to liquefaction; however, given the relatively limited extent of these liquefiable zones, planned fill thicknesses, and the anticipated remediation of alluvial soils, such as removal and recompaction, the potential for damaging deformations is considered low, with the exception of areas in the vicinity of ECR Stations 444+00 to 452+00, and 481+50 to 488+00, which may exhibit dynamic settlements on the order of 1 to 4 inches, and potentially some distress on the roadway shoulder. Alluvial soils left in-place will settle due to the addition of fill loads, and seismic events. Compacted fills may also settle due to static and seismic loads. The magnitude of settlement will vary, based on the depth of fill, presence/absence of alluvium, and/or groundwater. Based on our analysis, the potential for settlement is not considered prohibitive, provided that the recommendations presented herein are properly incorporated in to the design and construction of the project. Portions of the roadway underlain by alluvium will likely require some level of increased maintenance. Our testing and experience in the site vicinity indicates that subgrade soils are generally represented by an R-value of 14. Based on a review of GSI (2010), site soils have a generally low to high expansion potential classification, but should typically be in the low to medium expansive range classification when subgrade materials are blended and/or re-worked. Site soils are anticipated to have a negligible to moderate sulfate exposure to concrete and are considered highly corrosive (when saturated) to buried metals, based on the available data. Consultation with a corrosion engineer is recommended. o Site soils are highly erosive, and will require engineered and maintained surface drainage. Foot traffic should not be allowed on natural or sandy slopes. Setbacks are discussed in the text of this report. Trenching for the deeper utility improvements within ECR will likely encounter both a shallow groundwater table and relatively soft alluvial soils. For planning purposes, trenching and shoring design/construction should be in accordance with CAL-OSHA guidelines for Type C soils. Dewatering should also be anticipated in these areas, especially ECR Stations 444+00 to 452+00, and ECR Stations 481 +50 to 488+00, where the depths of trenching extend to near, or below the groundwater surface elevations evaluated herein. Dewatering discharge may not be suitable for re-introduction into nearby habitat areas, or City storm drains, and may need to be evaluated from an environmental viewpoint. ShapeD Homes W.O. 6145-E-SC FiIe:e:\wp9\6100\6145e.gif Page Three GeoSoifls, Inc. Due to the immediate presence of existing improvements near the toe, and top, of the planned retaining wall, located in the vicinity of ECR (southbound) Stations 459+75 to 462+50, a permanent shoring wall design is recommended as an alternative to the conventional cantilevered retaining wall. The geotechnical design parameters provided herein should be considered during construction by the project structural engineer and/or architect. The opportunity to be of service is greatly appreciated. If you have any questions concerning this report or if we may be of further assistance, please do not hesitate to contact any of the undersigned. Respectfully sub mftd-. /.tAL Q. GeoSoils, Inc./ 4,Q 4c.d Robert G. Cnsm'aji Engineering Geolo 34 oAL ( , ohn P Franklin ( ' , F Engineering Geogist, E134,0 1. RGC/ATG/JPF/jh N,OP cuV Geotechnical Engineer, GE 2320 Distribution: (3) Addressee (CD also) Planning Systems, Attention: Paul Kiukas O'Day Consultants, Attention: George O'Day (2 wet signed, CD also) Shapeil Homes W.O. 6145-E-SC FiIe:e:\wp9\6100\6145e.gif Page Four GoSoils, Inc. TABLE OF CONTENTS SCOPE OF SERVICES ...................................................1 SITE DESCRIPTION .....................................................1 PROPOSED DEVELOPMENT ..............................................3 PREVIOUS WORK .......................................................3 SITE EXPLORATION .....................................................4 SITE EARTH MATERIALS .................................................4 General..........................................................4 Talus (Not Mapped) ..........................................4 Existing Fill (Map Symbol - Af) ..................................4 Colluvium (Not Mapped) .......................................5 Alluvium (Map Symbol - Qal) ...................................5 Terrace Deposits (Map Symbol - Qt) .............................5 Santiago Formation (Map Symbol - Tsa) ..........................6 Geologic Structure .................................................6 GROUNDWATER ........................................................6 MASS WASTING ........................................................7 REGIONAL FAULTING/SEISMICITY .........................................7 Regional Faulting ..................................................7 Seismicity/Seismic Design ...........................................8 SEISMIC HAZARDS ......................................................9 Liquefaction...................................................... Seismic-Induced Settlement, Liquefaction and Densification ...............10 Lateral Spreading ..................................................11 Surface Manifestation of Secondary Seismic Events .....................11 LABORATORY TESTING .................................................12 General.........................................................12 Classification ......................................................12 Field Moisture and Density ..........................................12 Laboratory Standard - Maximum Dry Density ...........................12 Expansion Index Testing ...........................................13 Direct Shear Tests ................................................13 Consolidation Testing ...............................................13 Sieve Analysis ....................................................13 Atterberg Limits .....................................................13 Geddi'Us, Inc. Resistance Value . 14 Corrosion Test Results .............................................14 SLOPE STABILITY ANALYSES ............................................14 General .........................................................14 GrossStability .....................................................15 Surficial Stability ............................................15 EXISTING PAVEMENT SECTIONS .........................................16 General.........................................................16 Pavement Distress .................................................16 As Built Sections/Subgrade .........................................17 PRELIMINARY CONCLUSIONS AND RECOMMENDATIONS ....................19 General.........................................................19 RECOMMENDATIONS-EARTHWORK CONSTRUCTION .......................20 General.........................................................20 Site Preparation ..................................................20 Removals/Ground Treatment ........................................20 Subdrains.......................................................21 Fill Placement and Suitability .........................................21 Fill Settlement ....................................................22 Erosion Control ...................................................22 Slope Considerations and Slope Design ..............................22 Graded Slopes .............................................22 Stabilization/Buttress Fill Slopes ................................22 Temporary Construction Slopes .................................23 RECOMMENDATIONS FOUNDATIONS ....................................23 WALL DESIGN PARAMETERS ............................................23 General Foundation Design .........................................23 Conventional Retaining Walls .......................................24 Restrained Walls ............................................25 Cantilevered Walls ...........................................25 Earthquake Loads (Seismic Surcharge) ................................26 Retaining Wall Backfill and Drainage ..................................26 Wall/Retaining Wall Footing Transitions ...............................30 Slope Setback Considerations for Wall Footings ........................30 TEMPORARY/PERMANENT SHORING SYSTEMS ............................31 Lateral Pressure ..................................................34 Tiebacks and Lateral Pier Loads .....................................35 Open Excavations ................................................35 ShapeH Homes Table of Contents FiIe:e:\wp9\6100\6145e.gif . 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Excavation Observation (All Excavations) . 35 Observation.....................................................36 Monitoring Existing, Offsite Improvements .............................36 SOIL NAIL WALLS ......................................................37 General.........................................................37 Preliminary Design and Construction .................................37 CIDH SUPPORTED IMPROVEMENTS ......................................38 TOP-OF-SLOPE WALLS/FENCES/IMPROVEMENTS ..........................38 SlopeCreep ......................................................38 Top of Slope Walls/Fences .........................................38 CONCRETE APRONS, SIDEWALKS; FLATWORK, AND OTHER IMPROVEMENTS .. 40 PAVEMENT REHABILITATION/PRELIMINARY PAVEMENT DESIGN ..............42 Existing Pavements ...............................................42 New Pavements ..................................................42 New Asphaltic Concrete (AC) Pavement .........................42 Alternative Pavement Section: Subgrade Enhancement Geotextile (SEG) ....................................................42 Pavement Grading Recommendations ................................43 General...................................................43 Subgrade...................................................44 Base......................................................44 Paving....................................................44 Drainage..................................................45 PERMEABLE PAVEMENT/PAVERS ........................................45 DEVELOPMENT CRITERIA ................................................45 Slope Deformation ................................................45 General...................................................45 SlopeCreep ................................................45 Lateral Fill Extension (LFE) ....................................46 Summary...................................................46 Slope Maintenance and Planting .....................................46 Drainage........................................................47 Erosion Control ....................................................47 Landscape Maintenance ...........................................47 Subsurface and Surface-Water ......................................48 Site Improvements .................................................48 Footing Trench Excavation .........................................48 Trenching.......................................................49 Utility Trench Backfill ..............................................49 Shapell Homes Table of Contents FiIe:e:\wp9\6100\6145e.gif Page iii GeoSffs, Inc. SUMMARY OF RECOMMENDATIONS REGARDING GEOTECHNICAL OBSERVATION AND TESTING.........................................................50 OTHER DESIGN PROFESSIONALS/CONSULTANTS ..........................50 PLAN REVIEW .........................................................51 LIMITATIONS..........................................................51 FIGURES: Figure 1 - Site Location Map .........................................2 Detail 1 - Typical Retaining Wall Backfill and Drainage Detail ..............27 Detail 2- Retaining Wall Backfill and Subdrain Detail Geotextile Drain .......28 Detail 3- Retaining Wall and Subdrain Detail Clean Sand Backfill .......... 29 Figure 2a - Lateral Earth Pressures for Temporary Shoring Systems ........32 Figure 2b - Lateral Earth Pressures for Permanent Shoring Systems ........33 ATTACHMENTS: Appendix A - References ...................................Rear of Text Appendix B - Boring Logs ..................................Rear of Text Appendix C - Laboratory Data ................................Rear of Text Appendix D - Slope Stability and Engineering Analysis ...........Rear of Text Appendix E - General Earthwork and Grading Guidelines .........Rear of Text Plates 1 through 5 - Geotechnical Map ........................Rear of Text Plate 6- Geologic Cross Section E-E', F-F', G-G' and H-H' Rear of Text in Folder Shapell Homes Table of Contents Fi1e:e:\wp9\6100\6145e.git Page iv Gea&üUs, Inc. GEOTECHNICAL INVESTIGATION FOR THE PLANNED IMPROVEMENT OF EL CAMINO REAL BETWEEN CANNON ROAD AND TAMARACK AVENUE RANCHO COSTERA (FORMERLY ROBERTSON RANCH WEST VILLAGE) CITY OF CARLSBAD, SAN DIEGO COUNTY, CALIFORNIA SCOPE OF SERVICES The scope of our services has included the following: Review of available soils and geologic data (Appendix A), including the findings, conclusions and recommendations presented in previous geotechnical reports for the site and vicinity. (GSI; 2010, 2004a, 2002, 2001 a, and 2001 b). Geologic reconnaissance and field mapping. Subsurface exploration consisting of 16 exploratory borings with a hollow stem auger drill rig, and an additional 11 borings with a hand auger (see Appendix B). Previous boring data, presented in GSI (2010), and considered applicable to this projeót, are also included herein as Appendix B. Boring backfill was performed in accordance with County requirements. Faulting/seismicity analysis, and seismic hazards evaluation. Laboratory testing of representative soil samples collected during our current and previous subsurface exploration program (Appendix C). Previous laboratory data, presented in GSI (2010), and considered applicable to this project, is also included herein as Appendix C. Slope Stability and Engineering Analysis (Appendix D). Pavement design/construction analysis. Retaining wall design/construction evaluations. Engineering and geologic analysis of data collected and preparation of this appropriately illustrated geotechnical report. SITE DESCRIPTION The subject site consists of the northbound portion of El Camino Real (ECR), from the intersection of Cannon Road to Tamarack Avenue (approximate Stations 444+00 to 494+00), and southbound portions of ECR, in the vicinity of a planned storm drain and retaining wall, in the general vicinity of Stations 459+50 to 468+50, located within the City of Carlsbad, California (Figure 1). GeoScifls, Inc. SITE -t ID iAgua 0 1000 2000 3000 4000 . Base Map: TOPO!f. 2003 National Geographic, U.S.G.S San Luis Rey Quadrangle, California -- San Diego Co., 7.5 Minute, dated 1997, current, 1999. 1All g y ::! ?iv At /1> a CAMINO REAL am AV W'ww _J!flS!DE . ... a::: ; PIKE ~r '10 -It :0 ,N ci AV INN '4 0 lOGO 2000 3,900 4000 Base Map: The Thomas Guide, San Diego Co., Street Guide and Directory, 2005 Edition, by Thomas Bros. Maps, pages 1106 and 1107. Reproduced with permission granted by Thomas Bros. Maps This map is copynghled by Thomas Bros Maps It is unlawful to copy or reproduce all or any part thereof, whether for personal use or resale without permission 4/i nghts reserved w.o. GeoSoUs, Inc. 6145-E-SC A S I TE LOCATION MAP NJ Figure 1 Overall relief throughout the site varies from an approximate elevation of 42 feet above Mean Sea Level (MSL) in the vicinity of ECR Station 446+00, to approximately 85 feet MSL in the vicinity of ECR Station 462+00. The approximate location of existing natural and graded slopes, as well as existing improvements are shown on the geotechnical maps (see Plates 1 through 5) included with this report. Plates 1 through 5 utilize modified improvement plans for ECR, prepared by O'Day Consultants (OC, 2010), for this project. PROPOSED DEVELOPMENT Based on a review of Plates 1 through 5, planned construction will generally consist of widening the shoulder of ECR and improving the pavement margins and medians, including an intersection for a planned entrance to the future Rancho Costera development, in the vicinity of ECR Station 463+50. Widening will result in the construction of cut slopes, and fill over cut slopes up to approximately 90 feet in height; fill slopes up to approximately 10 feet in height; and, a retaining wall up to approximately 20 feet in height near Lisa Street, and to the east. Slopes are anticipated to be constructed at gradients of 2:1 (horizontal to vertical), or flatter. Typical cut and fill grading techniques are anticipated in order to achieve the design grades shown on Plates 1 through 5, with maximum planned cut and fill thicknesses on the order of 30 feet and 10 feet, respectively. Underground utility improvements along ECR are anticipated to generally consist of shallow utilities, a proposed sewer line up to 23 feet deep from west of Crestview Drive to Cannon Road, and a new storm drain, up to about 10 feet deep, on the south side of ECR, from about Lisa Street to Julie Place. Site improvements are shown on the attached Plates 1 through 5. The need for import soils is currently unknown. The use of onsite roadway storm water treatment and retention/detention is currently in development and not available at this time. PREVIOUS WORK The findings presented in this report are based on work completed in preparation of this report and previous work performed by this office for the Robertson Ranch project (GSI, 2010). In addition to site exploration completed in preparation of this study, subsurface conditions within the project limits (see Plates 1 through 5) were previously evaluated, and presented in GSI (2010). That GSI (2010) report summarized and updated several previous reports (GSI; 2004a, 2002, 2001b), regarding the proposed development of the Rancho Costera Project (formerly Robertson Ranch West Village), generally located on the north side of ECR in the study. Logs of the borings presented in GSI (2010) and used in the preparation of this report are included in Appendix B. The approximate locations of the exploratory excavations from all current, and previous studies (used in this investigation), are indicated on Plates 1 through 5. Shapell Homes W.O. 6145-E-SC Rancho Costera, Carlsbad May 11, 2011 Fde:e:\wp9\6100\6145e.glf Page 3 Geo&ils, Inc. SITE EXPLORATION Surface observations and subsurface explorations were performed by GSI on March 28, 29, and 30, 2011, by a representative of this office. A survey of line and grade for the subject site was not conducted by this firm at the time of our site reconnaissance. Near-surface soil and geologic conditions were explored with 16 exploratory auger borings, and 11 hand auger borings within the site. The approximate locations of the exploratory borings for this study are shown on the attached Geotechnical Maps (see Plates 1 through 5). SITE EARTH MATERIALS General Earth materials within the site consist predominantly of roadway and undocumented artificial fill, surficial talus deposits, alluvium, Pleistocene-age terrace deposits, and sedimentary bedrock belonging to the Eocene-age Santiago Formation. Preliminary recommendations for site preparation and treatment of the earth materials encountered are discussed in the "Earthwork Recommendations" section of this report. The general distribution of earth materials are shown on Plates 1 through 5. Geologic cross sections, showing the spatial relationships of onsite soils/bedrock, are presented herein on Plate 6. Talus (Not Mapped) Surficial deposits of slope talus were noted along the base of existing cut slopes along the north side of ECR, and in the vicinity of the planned retaining wall on the south side of ECR. Where encountered in our exploratory excavations, these deposits consist of materials ranging from silty sand to sandy clay, and are on the order of 1 to 3 feet in thickness. These soils are loose/soft and are not considered suitable forthe support of fills and structures, and should be removed and recompacted in areas proposed for settlement-sensitive improvements. It should be noted that talus deposits will likely be removed during excavation operations when the road is widened. Therefore, special handling is not anticipated for this earth unit. Existing Fill (Map Symbol - At) Existing fills (roadway or undocumented) were encountered throughout ECR, primarily between ECR Stations 444+00 to 453+00, 464+00 to 471+00, and 481+50 to 488+50. Where observed, fills consisted of clayey/silty sand to lean clay, on the order of 5 feet to as much as 15 feet thick. The thickest fills are generally coincident with former drainages beneath ECR, and now burned. Existing fills are typically moist, stiff/medium dense to very still/dense beneath ECR. Along the un-improved margins of ECR, existing fills are generally loose to medium dense and locally bioturbated within approximately 2 to 3 feet Shapell Homes W.O. 6145-E-SC Rancho Costera, Carlsbad May 11, 2011 File:e:\wp9\610D\6145e.gif Page 4 GeaS@ils, Inc. from surface grades and where exposed at the surface (i.e., without pavement) are not considered suitable for the support of planned improvements, unless these materials are removed, moisture conditioned and recompacted. Colluvium (Not Mapped) Colluvial soils were observed within relatively undisturbed areas located outside the ECR right of way. These soils generally consist of a surficial layer of sandy clay, on the order of 2 to 3 feet in thickness. Colluvium is typically moist to wet and soft, and is not considered suitable for the support of planned improvements, unless these soils are removed, moisture conditioned and recompacted. Alluvium (Map Symbol - Qal) Where encountered, alluvial sediments consist of sandy clay and clayey/silty sand, and sand. Clayey/silty sands and sands are typically loose to medium dense, while sandy clays are stiff. Alluvium ranges from generally damp to wet above the groundwater table, to saturated near, at, and below the groundwater table. Alluvium is anticipated to be encountered at depth, during trenching operations for the planned sewer, in the vicinity of ECR Station 444+00 to 452+00, and the planned storm drain, in the vicinity of ECR Station 483+00, where trench depths up to 23 feet, and 10 feet, respectively, are anticipated. Alluvial soils are also anticipated to be encountered in the vicinity of road widening that results in the construction of new fill slopes out into alluvial areas in the vicinity of ECR, Stations 445+00 to 446+50,465+00 to 468+00,481+50 to 484+25, and 486+00 to 487+50. In areas where ECR is to be widened, near-surface alluvium above the groundwater table is not considered suitable for structural support and should be removed and recompacted. Due to the presence of groundwater, alluvial removals will be limited in depth. Complete to partial removals to saturated sediments, on the order of 2 to 6 feet, are anticipated. Alluvial materials left in place will require settlement monitoring where significant fills (>20 feet) are placed in these areas. The approximate distribution of alluvial materials, is shown on Plates 1 through 5. Terrace Deposits (Map Symbol - Qt) Mid- to late-Pleistocene terrace deposits encountered along the alignment vary from silty sand to sandy/silty clay. These sediments are typically yellowish brown to brown and olive brown, slightly moist to moist, and medium dense/stiff. Unweathered terrace deposits are generally considered suitable for the support of structures and engineered fill. Expansion testing results presented in GSI (2010), indicates that these soils range from very low to medium expansive, and potentially highly expansive. Shapell Homes W.O. 6145-E-SC Rancho Costera, Carlsbad May 11, 2011 File:e:\wp9\6100\6145e.gif Page 5 GeSoils, Inc. Santiago Formation (Map Symbol - Tsa) Sandstone, clayey siltstone, and claystone sedimentary bedrock, belonging to Eocene-age Santiago Formation, was also encountered along the alignment. Where unweathered, the Santiago Formation is considered suitable for structural support. Expansion testing results presented in GSI (2010), indicates that these soils range from very low to medium expansive, to potentially highly expansive. While the Santiago Formation occurs at/near the surface throughout the western portion of the site, it was encountered at depth in some of our exploratory borings, beneath younger terrace and alluvial deposits. The general limits of the Santiago Formation, both near the surface, and where buried, is shown on the attached Plates 1 through 5. Geologic Structure Bedding structure observed within the Pleistocene terrace deposits in our borings, and exposed in road cuts along ECR, display generally massive to thickly bedded sediments, and poorly developed sub-horizontal orientation. Within the Santiago Formation, bedding outcrops, road cuts along ECR, our exploratory excavations, and outcrops within canyon bottoms, indicate thin to thick bedding, and a general, regional trend of northerly to northeasterly, and westerly to northwesterly slight inclinations, ranging from near horizontal to about 8 degrees. Cross bedding within the Santiago Formation was generally thickly bedded, and was observed locally, trending northerly to northeasterly, with westerly to northwesterly slight to moderate inclinations, on the order of 10 to 28 degrees, and localized cross beds inclined 2 degrees southeasterly. Jointing within the Santiago Formation was typically highly inclined (65 to 89 degrees), predominately trending north to northwest,. and to a lessor extent highly inclined to the northeast. Apparent dips of regional bedding relative to the planned cut slope within the Santiago Formation are generally oriented out of slope up to 8 degrees, and have been considered in our slope stability analysis. GROUNDWATER Groundwater was encountered in some of the borings completed in preparation of this report, and may be separated into two distinct areas. The first area of groundwater occurs in the vicinity of ECR Stations 444+00 to approximately 452+00, at depths ranging from approximately 8 to 21 feet below existing street grades, or at an approximate elevation, of 32 to 34 feet Mean Sea Level (MSL). Based on our subsurface exploration, groundwater in this areas occurs within alluvial soils immediately below the ECR road fill.. The second area of groundwater generally occurs between ECR Stations 481+50 and 488+00 at depths ranging from 5 to 16 feet below existing street grades, or at an approximate elevation of 42 to 43 feet MSL. Shapell Homes W.O. 61 45-E-SC Rancho Costera, Carlsbad May 11, 2011 FiIe:e:\wp9\6100\6145e.9if Page 6 GeoScUs, mw0 Trenching for the deeper utility improvements within ECR, as well as any planned grading along the margins of the ECR in these areas, will likely encountered a shallow groundwater table. For planning purposes, dewatering during trenching operations should be anticipated, especiallywhere excavations deeperthan about 5feet occur in close proximity to known shallow groundwater. The environmental impacts of directing dewatering discharge into existing stream channels, habitat areas, or City storm drains should be considered in project planning. Regional groundwater should not adversely affect site development provided that the recommendations presented in this report are properly incorporated into the design and construction of the project. These observations reflect site conditions at the time of our field evaluation and do not preclude changes in local groundwater conditions in the future from heavy irrigation or precipitation. In general, perched groundwater conditions, along zones of contrasting permeabilities, densities, discontinuities, or fill lifts, may not be precluded from occurring in the future due to site irrigation, poor drainage conditions, or damaged utilities. Perched groundwater should be anticipated to occur after development, and may require additional mitigation when it manifests itself. Subdrains are typically used to control subsurface water in natural drainages that are proposed to be filled, and are recommended herein; however, their actual placement and location will need to be evaluated during grading. MASS WASTING Field mapping and subsurface exploration performed in preparation of this report did not indicate the presence of any deep seated Iandsliding, and these features were not noted during our review of available published documents (Appendix A). REGIONAL FAULTING/SEISMICITY Regional Faulting Our review indicates that there are no known, mapped active faults crossing the alignment within the area proposed for improvement, and the site is not located within an Alquist-Priolo Earthquake Fault Zone (Bryant and Hart, 2007; Jennings and Bryant, 2010). Faults in this area of Carlsbad are locally present, but last movement was pre-Holocene (>±1 1,000 years ago), and are thus, not considered active. However, as with most of southern California, the site is situated in an area of active as well as potentially active faulting. As noted, the possibility of ground acceleration, or shaking at the site, may be considered as approximately similar to the southern California region as a whole. A detailed discussion of faulting is presented in GSl (2010). Shapell Homes W.O. 61 45-E-SC Rancho Costera, Carlsbad May 11, 2011 File:e:\wp9\6100\6145e.gif Page 7 GedPSeils, 79w0 Seismicity/Seismic Design A detailed analysis of deterministic, historical, and probalistic site accelerations is presented in GSI (2010). Specific design criteria, as related to the evaluation of slope stability and the design/construction of retaining walls, is presented as follows. Based on the site conditions, the following table summarizes the site-specific design criteria per the 2010 CBC. The computer program Seismic Hazard Curves and Uniform Hazard Response Spectra, provided by the United States Geologic Survey (U.S.G.S.) was utilized for design. The short spectral response utilizes a period of 0.2 seconds. PARAMETEA1.. iç ' J' VALUE' - L BC.O6 REFERENCE Site Class D Table 1613.5.2 Spectral Response - (0.2 sec), S 1.188g Figure 1613.5(3) Spectral Response - (1 sec), S1 0.450g Figure 1613.5(4) Site Coefficient, Fa 1.025 Table 1613.5.3(1) Site Coefficient, F 1.55 Table 1613.5.3(2) Maximum Considered Earthquake Spectral Response Acceleration (0.2 sec), S 1.218g Section 1613.5.3 (Eqn 16-37) Maximum Considered Earthquake Spectral Response Acceleration (1 sec), SM* 0.697g Section 1613.5.3 (Eqn 16-38) 5% Damped Design Spectral Response Acceleration (0.2 sec), S 0.812g Section 1613.5.4 (Eqn 16-39) 5% Damped Design Spectral Response Acceleration (1 sec), S 0.465g Section 1613.5.4 (Eqn 16-40) .................. Distance to Seismic Source (B fault) 11 km Upper Bound Earthquake (Rose Canyon) Mw 6.9* Probabilistic Horizontal Site Acceleration ([PHSA], 10% probability of exceedance in 50 years) 0.25g PHSA (2% probability of exceeclance in 50 years) 0.45g * International Conference of Building Officials (lCBO, 2006) Conformance to the criteria above for seismic design does not constitute any kind of guarantee or assurance that significant structural damage or ground failure will not occur in the event of a significant earthquake that may affect the site. The primary goal of seismic design is to protect life, not to eliminate all damage, since such design may be economically prohibitive. Cumulative effects of low order or non-design level seismic Shapell Homes W.O. 6145-E-SC Rancho Costera, Carlsbad May 11, 2011 File:e:\wp9\6100\6145e.git Page 8 GeoSoUs, Inc. events can increase damage of the existing and proposed onsite improvements, if mitigation and repairs are not made after each significant local seismic event (M>5.5). It is important to keep in perspective that in the event of an upper bound earthquake occurring on any of the nearby major faults, strong ground shaking would occur in the subject site's general area. Potential damage to any structure(s) would likely be greatest from the vibrations and impelling force caused by the inertia of a structure's mass. This potential would be no greater than that for other existing structures and improvements in the immediate vicinity. SEISMIC HAZARDS The following list includes other seismic related hazards that have been considered during our evaluation of the site. The hazards listed are considered negligible and/or completely mitigated as a result of site location, soil characteristics, typical site development procedures, and recommendations for mitigation provided herein: Surface Fault Rupture Ground Lurching or Shallow Ground Rupture o Tsunami Seiche It is important to keep in perspective that in the event of an upper bound earthquake occurring on any of the nearby major faults, strong ground shaking would occur in the subject site's general area. Potential damage to any structure(s) would likely be greatest from the vibrations and impelling force caused by the inertia of a structure's mass, than from those induced by the hazards considered above. This potential would be no greater than that for other existing structures and improvements in the immediate vicinity. The durability of utilities embedded within the ECR roadway embankment will be dependant on the underlying lithology, composition of the utility, and orientation. The performance of each utility main line should be evaluated following significant earthquakes generating the design site accelerations presented in this report. Liquefaction Liquefaction describes a phenomenon in which cyclic stresses, produced by earthquake-induced ground motion, create excess pore pressures in relatively cohesionless soils. These soils may thereby acquire a high degree of mobility, which can lead to lateral movement, sliding, consolidation and settlement of loose sediments, sand boils and other damaging deformations. This phenomenon occurs below the water table, but after liquefaction has developed, it can propagate upward into overlying non-saturated soil as excess pore water dissipates. Shapell Homes Rancho Costera, Carlsbad File:e:\wp96100\6145e.9if Ge&ils, Kw. W.O. 6145-E-SC May 11, 2011 Page 9 One of the primary factors controlling the potential for liquefaction is the depth to groundwater. Typically, liquefaction has a relatively low potential for occurrence where the depth to groundwater is greater than 50 feet. Liquefaction is unlikely and/or will produce vertical strains well below 1 percent where the depth to groundwater is greater than 60 feet when relative soil densities are 40 to 60 percent and the effective overburden pressures are two or more atmospheres (i.e., 4,200 pounds per square foot [Moss, et al, 2005]). Uquefaction susceptibility is related to numerous factors and the following conditions should be concurrently present for liquefaction to occur: 1) sediments must be relatively young in age and not have developed a large amount of cementation; 2) sediments must generally consist of medium- to fine-grained, relatively cohesionless sands; 3) the sediments must have low relative density; 4) free groundwater must be present in the sediment; and 5) the site must experience a seismic event of a sufficient duration and magnitude, to induce straining of soil particles. The phenomenon of liquefaction has two principal effects. One is the consolidation or volumetric strain of loose sediments with potential settlement of the ground surface. The other effect is lateral deformation. Significant permanent lateral movement generally occurs only when there is significant differential geometric loading, such as fill or natural ground slopes within susceptible materials. Portions of ECR, between approximate Stations 444+00 to 452+00, and Stations 481+50 and 488+00 are underlain with alluvial soils, and relatively shallow groundwater. Based on the interbedded, granular and clayey deposits within the upper 50 feet, groundwater within the upper 15 feet, and the intermittent clay layers, liquefaction cannot be precluded, and may manifest itself as settlement. Due to the anticipated, relatively interlayered nature of these underlying soils in the vicinity, the anticipated resultant differential settlement is discussed herein. Utility trenches and manholes may be susceptible, if not properly backfilled and supported, respectively. Seismic-Induced Settlement. Liquefaction and Densification Seismic-induced ground motions from earthquakes can result in the volumetric strain caused by the excess pore pressures generated in saturated soils. This volumetric strain, in the absence of lateral flow or spreading, can result in manifestation of settlement once excess pore pressure is reduced. The same volumetric strain may also occur in unsaturated earth materials above the water table in relatively dry (well below optimum moisture as defined by ASTM D 1557) to moist, loose to medium dense granular (sandy) soils. This potential for seismic densification of dry to moist, unmitigated alluvial soil below the fill and above the groundwater is significantly lower in magnitude of settlement than that below the water table. Combined effects are anticipated to produce densification/liquefaction settlements of approximately 1 to 4 inches within the ECR right of way, with potentially (higher localized effects) adjacent to open space/habitat areas underlain with alluvial soils and a shallow Shapell Homes W.O. 6145-E-SC Rancho Costera, Carlsbad May 11, 2011 FiIe:e:\wp9\6100\6145e.git Page 10 GoSoils, Inc. groundwater table. These may result in differential settlement of ito 3 inches in 100 lateral feet in these areas (see Plates 1 through 5), and some level of increased maintenance. Lateral Spreading Lateral spread phenomenon is described as the lateral movement of stiff, surilcial, mostly intact blocks of sediment or compacted fill displaced downslope towards a free face along a shear zone that has formed within the liquefied sediment. The resulting ground deformation typically has extensional fissures atthe head of the failure, shear deformations along the side margins, and compression or buckling of the soil at the toe. The extent of lateral displacement typically ranges from less than an inch to several feet Two types of lateral spread can occur: 1) lateral spread towards a free face (e.g., river/creek channel or embankment); and 2) lateral spread down a gentle ground slope where a free face is absent. Factors such as earthquake magnitude, distance from the seismic energy source, thickness of the liquefiable layers, and the fines content and particle size of those sediments also correlate with ground displacement. Since no free face occurs on this project, no adjacent lake is present, the only lateral spread that may possibly occur would be low magnitude and due to slight elevation variations already within the established vicinity or portions of ECR adjacent to habitat/alluvial areas with shallow groundwater, which will essentially remain un-mitigated. Therefore, the margins of ECR adjacent to undeveloped wetland areas may exhibit some lateral spread movement as a result of an upper bound earthquake, and would be subject to some increased potential for additional maintenance. Our analysis of the potential for lateral spreading is provided in Appendix D (Plate 0-21). Surface Manifestation of Secondary Seismic Events The evaluation of whether or not surface manifestation of liquefaction, such as sand boils, ground fissures, foundation tilt and cracking, etc., will occur at a site is made using guidelines contained in Special Publication 117A "Guidelines for Evaluating and Mitigating Seismic Hazards in California" (California Department of Conservation, California Geological Survey [GGS], 2008). Based on the thickness of the potentially liquefiable layer(s), the thickness of the non-liquefiable soil cover, and ground acceleration for the design earthquake, an evaluation of these "liquefied" soils was made. Due to the depth of the groundwater surface (design basis elevation of approximately 8 to 12 feet below the existing ground surface), the potential for sand boils is considered low depending on the depth of groundwater, and the potential for surface soil settlement is also considered low to moderate. Utilities that are embedded in unmitigated alluvial soils, if planned, may be impacted on a moderate level. Sand boils may occur if deep (> 7 to 23 feet) manholes or utility vaults are embedded into or near the groundwater/saturated alluvium. This may be mitigated through design and planning. Planned fill slopes (planned grading) for the widening of portions of ECR will likely "toe out" into existing alluvial areas locally. Remedial plus planned fills at the site are ShapeH Homes W.O. 6145-E-SC Rancho Costera, Carlsbad May 11, 2011 flle:e:\wp9\6100\6145e.gif Page 11 GeSoils, Inc. anticipated to be on the order of 8 to 10 feet thick. On this site, the thickness of the potentially liquefiable layers is less than the overlying unsaturated alluvium and denstiled fill soils. Therefore, it is our opinion that the potential for surface manifestation of liquefaction at the site, in the event of the design earthquake, is considered low, based on the assumed design. Furthermore, based upon our analyses, it appears that a non-liquefiable soil cover consisting of unsaturated alluvium, remediated alluvium, and new fill will generally partially mitigate the surface manifestation of liquefaction and densification. The potential for distress/deformation from surface manifestations of liquefaction should be mitigated to levels similar to the existing adjacent roadway, provided our recommendations are properly adhered to during design and construction. To further reduce the potential for this distress to occur, optional ground mitigation should be considered, as discussed in the earthwork section of this report. LABORATORY TESTING General Laboratory tests were performed on representative samples of the onsite earth materials collected for the present geotechnical investigation, in order to evaluate their physical characteristics and engineering properties with respect to anticipated site development. The test procedures used and subsequent results are presented below. Classification Soils were classified visually according to the Unified Soils Classification System. The soil classification of onsite soils is provided in the exploration logs in Appendix B. Field Moisture and Density Field moisture content and dry unit weight were determined for relatively "undisturbed" samples of earth materials obtained from GSI's exploratory excavations. The dry unit weight was evaluated in general accordance with ASTM D 2937, in pounds per cubic foot (pcf), and the field moisture content was evaluated as a percentage of the dry weight. Water contents were measured in general accordance with ASTM 02216. Results of these tests are summarized on the Boring Logs (see Appendix B). Laboratory Standard - Maximum Dry Density To evaluate the compaction characteristics of representative samples of onsite soil, laboratory testing was performed in accordance with ASTM Test Method D 1557. Test results are presented in the following table: Shapell Homes W.O. 6145-E-SC Rancho Costera, Carlsbad May 11, 2011 FiIe:e:\wp96100\6145e.gIf Page 12 GeóSoU, Inc. Ik B-202@2'-4' 125.0 11.5 B-213 @ 1' 138.5 6.5 Expansion Index Testing Representative samples of soil near surface grade was tested for expansivity. The Expansion Index (E.l.) tests were performed in general accordance with ASTM Standard D 4829, and was classified according to Table 18-1-13, as outlined in Section 1803 of the 2001 California Building Code ([2001 CBC], International Conference of Building Officials [ICBO], 2001). Please note the current 2010 CBC (CBSC, 2010) does not classify an expansion potential index and as such, we have utilized these previous standards only to classify this material. The laboratory test results are presented in the following table. Direct Shear Tests Shear testing was performed on a remolded sample of site soil in general accordance with ASTM Test Method D-3080. Results of shear testing (this study and GSJ [2002, 2004a, 2004b]) are presented In Appendix C. Consolidation Testing Consolidation tests were performed on selected undisturbed samples. Testing was performed in general accordance with ASTM Test Method D-2435. Test results (this study and GSI [2002]) are presented as in Appendix C. Sieve Analysis Sample gradation for various representative samples was analyzed in general accordance with ASTM Test Method D-422. Test results are presented in Appendix C. Atterberg Limits Atterberg limits were evaluated in general accordance with ASTM Test Method D-4318. Test results for a representative sample of clayey alluvial soil evaluated a liquid limit of 34, plastic limit of 19 and a plasticity index of 24, for a sample collected from Boring B-203. Shapell Homes W.O. 6145-E-SC Rancho Costera, Carlsbad May 11, 2011 FiIe:e:\wp9\6100\6145e.gif Page 13 GeoSoiUs, Inc. Resistance Value Resistance value, or R-value, testing was performed on representative samples of road base/sub base, and subgrade soils, in general accordance with California Test Method 301. The results of this testing is presented in Appendix C. Corrosion Test Results Representative samples of the site materials has been analyzed from alluvial soils (Boring BA-1 01 [GSI, 2010]) for soluble sulfates, soil pH, and saturated resistivity. Based upon the laboratory testing, site soils are considered to present a negligible (sulfate class SO) sulfate exposure to concrete, per Table 4.2.1 and 4.3.1 of the American Concrete Institute (ACI) document 318-08 (2010 CBC [CBSC, 2010]). However, brackish conditions within adjacent wetland areas may present a higher sulfate exposure (sulfate class Si [sea water]). Soils are relatively neutral, to slightly basic with respect to soil acidity/alkalinity (pH range of 6.6 to 8.4) (Romanoff, 1989), and are very corrosive to exposed ferrous metals in a saturated state (saturated resistivity <1,100 ohm-cm). The chloride ion content in soil was also noted to generally range from below action levels (300 ppm) per Caltrans (1999), to well above action levels with chloride ion levels on the order of 910 ppm, and warrants protection of buried improvements, as provided by the corrosion consultant. SLOPE STABILITY ANALYSES General GSI performed a slope stability analysis utilizing the geologic conditions, observed in the exploratory borings completed in preparation of this study, and in GSI (2010), for planned cut slopes located along the north side of ECR, and a planned wall located on the south side of ECR hallow stem borings, exposed bluff face and earth material shear strength parameters (saturated unit weights, cohesion, friction angle) obtained from laboratory testing on this site and adjoining sites. Analyses have been performed utilizing the two-dimensional slope stability computer program "GSTABL7 v.2" (See Appendix D). The program calculates the factor-of-safety (FOS) for specified surfaces or searches for the block, or irregular slip surface having the minimum FOS using the Janbu (non-cir.cular block) method. Additional information regrading the methodology utilized in this program is included in Appendix D. Shear strength parameters used are provided in Appendix D. Representative cross sections (Sections E-E' through H-H') were prepared for analysis (see Plate 6). Our analysis utilized data from the current, and previous studies (GSI; 2010, 2004a, 2004b, 2002), with respect to the anticipated site grading, and the large, natural slopes above Tamarack Avenue, and El Camino Real. The locations of Sections E-E' through H-H' are shown on Plates 1 through 5. Shapell Homes W.O. 6145-E-SC Rancho Costera, Carlsbad May 11, 2011 File: e:\wp9\61 00\6145e.gif Page 14 GegSoils, Inc. Gross Stability Based on the available data, including a review of GSI (2010), it appears that graded fill slopes will be generally stable assuming proper construction and maintenance. Cut slopes, constructed in terrace deposits and earth materials belonging to the Santiago Formation, are anticipated to be generally stable assuming proper construction and maintenance. In order to assess the long-term gross slope stability of the planned cut slopes, three (3) geologic cross-sections (E-E,' F-F,' and H-H') were prepared (see Plate 6). A fourth section (G-G') was also prepared, to evaluate a planned retaining wall. The purpose of the cross-sections was to analyze the relationship of the planned, preliminary graded configurations shown on Plates 1 through 5, the geologic conditions observed at the surface, and at depth. The stability of the planned cut slope and fill over cut slope configurations along the north side of ECR was evaluated. These slopes vary up to approximately 90 feet in height and achieve maximum slope gradients of 2:1 (h:v). Based on our current analysis (Appendix D), using the available soil parameters, the slopes appear to be stable, possessing an adequate FOS (greater than 1.5 static and 1.1 seismic. The results of our slope stability analysis performed in preparation of this report is included as Appendix D. All cut slope construction will require observation during grading in order to evaluate the findings and conclusions presented herein and in subsequent reports. Our analysis assumes that graded slopes are designed and constructed in accordance with guidelines provided by the City, the 2010 CBC (CBSC, 2010), the 2009 "Greenbook," and recommendations provided by this office. These slopes are generally anticipated to be stable, assuming proper construction, maintenance, and normal climatic conditions. Fill slopes are also planned up to heights on the order of 50 to 60 feet (in the fill-over-cut slope), at gradients of 2:1 (h:v), or flatter, and are considered grossly stable (i.e., FOS >1.5). Graded fill slopes are generally anticipated to be stable, assuming proper construction, maintenance, and normal climatic conditions. Surficial Stability An analysis of surficial stability was performed for graded slopes constructed of compacted fills and/or formational soil. Our analysis indicates that proposed slopes exhibit an adequate FOS (i.e., > 1.5) against surficial failure, provided that the slopes are properly constructed and maintained, under normal rainfall. Terrace deposits and Santiago Formation bedrock contain granular, sandy soil. If sandy soils with a cohesion of less than 200 psf are used on slope faces derived from these deposits, the slopes may have surficial stability/erosion issues and perhaps a FOS against surficial instability of less than 1.5. Planting and management of surficial drainage is Shapell Homes W.O. 61 45-E-SC Rancho Costera, Carlsbad May 11, 2011 FiIe:e:wp9\610D\6145e.gIf Page 15 GeoSoils, ffw0 imperative to the surficial performance of slopes. Typically, similar to coastal bluff retreat, a surficial erosion rate (average) of about 11/4 inches/year for natural and unprotected sandy slopes may be assumed. Foot traffic and other activities that exacerbate surficial erosion should not be allowed to occur on slopes. Failure to adhere to these conditions may drastically increase and localize surficial erosion, requiring mitigation, so that headward erosion does not result, and impact roadways, pads, and other improvements. BUSTING PAVEMENT SECTIONS General A general overview of pavement distress was performed within the study area. Where exploratory borings were located within the existing pavement area, the pavement sections were measured, and noted on the Boring Logs (see Appendix B). A discussion of existing distress and the observed, as-built pavement sections is presented in the following sections. Pavement Distress Existing pavement distress was noted throughout the northbound pavement area, and is described as follows: Alligator (Fatigue) Cracking: The most prevalent type of pavement distress appears to be alligator, or fatigue cracking. Alligator cracking is a series of interconnected cracks caused by fatigue failure of the HMA (hot mix asphalt) surface under repeated, excessive traffic loading, due to poor drainage, weak base or subgrade (Asphalt Institute [http ://asphaltinstitute.oralpublic/engineering/index.asp]). As the number and magnitude of loads becomes too great, longitudinal cracks begin to form (usually in the wheelpaths). After repeated loading, these longitudinal cracks connect forming many-sided sharp-angled pieces that develop into a pattern resembling the skin of an alligator. Between ECR, Stations 444+00 to 455+00, moderate alligator cracks occur within the wheel paths within the slow lane, and/or the previous location of the slow lane prior to median construction. From Stations 455+00 to 459+00, alligator cracks appear within the wheel path nearest the bike lane, and along the approximate location of an approximately 6-inch wide utility trench patch. This distress may also resemble block cracking. Moderate alligatoring was again observed within the wheel path, located just outside the bike lane from approximate Stations 464+50 to 469+50, and in the vicinity of the 6-inch wide utility trench patch. Light, localized alligatoring was observed, primarily within the slow lane, from Stations 476+50 through Station 478+50. From Stations 486+50 to 491 +50, light to moderate Shapell Homes W.O. 6145-E-SC Rancho Costera, Carlsbad May 11, 2011 File: e:\wp9\61 OO\6145e.gif Page 16 Gee&pils, Inc. alligatoring was noted with the slow lane, with light cracking also observed within the fast lane. Based on our review, a greater degree of fatigue cracking appears to coincide with pavement areas underlain with alluvial soils and a relatively shallow groundwater table. Other areas of fatigue ctacking may also be associated with poor drainage along the margins of the roadway, especially in the vicinity of Stations 476+50 to 478+50. Patching: Patching, or areas of pavement that has been replaced with new material to repair the existing pavement, were observed throughout the pavement area of ECR. A patch is considered a defect, and temporary, no matter how well it performs. Depressions, or Rutting: Localized depressions, or ruts were noted within the wheel path nearest the center median in the vicinity of Stations 461+00, and between Stations 486+50 and 491+50. Pothole also appear to be forming within these areas. Other: Minor areas of polished aggregate, raveling, etc. where noted locally and are likely an indication of pavement age. Areas of water seepage were not observed within the existing northbound ECR. As Built Sections/Subgrade Where observed, the existing pavement within ECR consists of a 6-to 8-inch thick layer of asphaltic concrete (AC), overlying an approximately 4-inch thick layer of what appears to be a recycled asphalt pavement, or R.A.P. The AC/RAP section was then observed to overly a 12- to 18-inch layer of silty sand (select fill or sub base), overlying clayey subgrade. Pavement sections and the representative characteristics of the underlying soil subgrade are presented in the following table. Shapell Homes W.O. 6145-E-SC Rancho Costera, Carlsbad May 11, 2011 F1Ie:e:\wp9\6100\6145e.gif Page 17 GeoSoils, Inc. ______ _____ P-i ASpALrrHI ES qRA gEp)L eernatw i$ ESS SIR Northbound ECR Stations 444+00 to 447+50 B.O. 4.0 12.0 SM/SC, R =310) (Boring B-202) Stations 447+50 to 452+00 6.0 4.0 14.0 SC, R = 31 (Boring B-203) Stations 451 +00•to 456+00 6.0 4.0 12.0 SC, R = 14 (Boring B-2.04) Stations 456+00 to. 481+00 8.0 4.0 151/p CL, R =8 (Boring B-205) Stations 461+00 to 472+00 8.0 4.0 151/2 CL R = 15 (Boring B-206) Stations 472+00 to 481+00 6.0 4.0 1 P1 SC, R = 15 (Boring B-207) Stations 472+00 to 477+00 6.0 4.0 15 SC, R = 14 (Boring B-208) Stations 477+00 to 481+00 7.0 4.0 13 SC, R = 14 (2) (Boring B-209) Stations 481+00 to 486+00 To 4.0 16 CL, R=14 (Boring B-210) Stations 486+00 to 491+00 7.0 . 4.0 18 SC, R = '(Boring _B-211) Stations 491 +00 to 495+00 9.0 4.0 .17 CL R = 15 (Boring B-212) Southbound ECR Station 481+25 (Boring B-213) 6 0 - 40 8 SC R = Station 464+80 (Boring B-214) 70 40 13 SM. A = 26 Shapell Homes Rancho Costera, Carlsbad FiIe:e;\wp9\6100\6145e.gif GeoSoils, bw0 W.O. 6145-E-SC May 11, 2011 Page 18 4I _60 ESS AIJAI+t'3 168 4SB4BASE tzP . , i1 KESS94'- PE;(lJSCS);ANDR? J MIN Station 466+50 1 8.0 4.0 12 1 SC, R = 15 (Boring B-215) Stations 468+20 8.0 4.0 14 SC, R = 15 (Boring B-216) 0 The design TI for ECR is 9.0 and was provided by O'Day Consultants The location of each boring is shown on Plates 1 through 5. Sub base R-values have been evaluated to be in the range of 23 to 43 from representative samples obtained from Borings B-203 and B-210. A value of 30 has been assumed for planning purposes. Subgrade R-values extrapolated from adjacent borings, as tested, based on soil type. PRELIMINARY CONCLUSIONS AND RECOMMENDATIONS General Based on our field exploration, laboratory testing and geotechnical engineering analysis, it is our opinion that the subject site appears suitable for the proposed development from a geotechnical engineering and geologic viewpoint, provided that recommendations presented in the following sections are incorporated into the design and construction phases of site development. The primary geotechnical concerns with respect to the proposed development are: Earth materials characteristics and depth to competent bearing material. Slope stability and temporary slope stability. Subsurface water and potential for perched water. Excavated and saturated soils requiring drying-back to be placed as compacted fill. Corrosion and expansion potential. Uquefaction and settlement potential, and increased roadway maintenance. Proximity of existing improvements, both laterally and at depth within ECR, including the proposed retaining wall near Lisa Street. Regional seismicity and faulting. The recommendations presented herein considerthese as well as other aspects of the site. In the event that any significant changes are made to proposed site development, the conclusions and recommendations contained in this report shall not be considered valid unless the changes are reviewed and the recommendations of this report verified or modified in writing by this office. Foundation design parameters are considered preliminary until the foundation design, layout, and structural loads are provided to this office for review. Shapell Homes W.O. 6145-E-SC Rancho Costera, Carlsbad May 11, 2011 File:e:\wp9\6100\6145e.9if Page 19 GeSoils, Inc. RECOMMENDATIONS-EARTHWORK CONSTRUCTION General All earthwork should conform to the guidelines presented in the 2010 CBC, the 2009 "Greenbook," the City of Carlsbad, and as recommended herein as Appendix E (this report), except where specifically superceded in the text of this report. When code references or guidance documents are not equivalent, the more stringent code should be followed. During earthwork construction, all site preparation and the general grading procedures of the contractor should be observed and the liii selectively tested by a representative (s) of GSI. If unusual or unexpected conditions are exposed in the field, they should be reviewed by this office and, if warranted, modified and/or additional recommendations will be offered. All applicable requirements of local and national construction and general industry safety orders, the Occupational Safety and Health Act (OSHA), and the Construction Safety Act should be met. It is GSI's understanding that the site is currently at, or very near, plan grades, with respect to street surface elevations. Additional grading will likely consist of the remedial grading/processing within the undeveloped margin of the roadway, and local areas where road widening will create new slopes that "toe out" into relatively undeveloped areas to the north of ECR. During earthwork construction, all site preparation and the general grading procedures of the contractor should be observed and the fill selectively tested by a representative (s) of GSI. If unusual or unexpected conditions are exposed in the field, they should be reviewed by this office and, if warranted, modified and/or additional recommendations will be offered. All applicable requirements of local and national construction and general industry safety orders, the Occupational Safety and Health Act, and the Construction Safety Act should be met. While significant grading is not anticipated, grading along the margins of the roadway will likely occur due to the planned road widening, and resultant slope and retaining wall construction at some locations. Site Preparation Debris, vegetation, and other deleterious material should be removed from the improvement(s) area prior to the start of construction. Following removals, areas approved to receive additional fill should first be scarified and moisture conditioned (at or above the soils optimum moisture content) to a depth of 12 inches, and compacted to a minimum 90 percent relative compaction (ASTM D 1557). Removals/Ground Treatment In areas underlain with existing fills, at the surface (i.e., without pavement), or exposed during grading, the near-surface portion of the fill is considered to be loose and dry. For Shapell Homes W.O. 6145-E-SC Rancho Costera, Carlsbad May 11, 2011 FiIe:e:\wp9\6100\6145e.gif Page 20 GeoSoils, Inc. preliminary planning purposes, the upper 2 to 3 feet of existing fill (at the surface or exposed during grading) should be removed, moisture conditioned, and recompacted within a minimum of 5 horizontal feet of areas proposed for settlement-sensitive improvements. Deeper removals should not be precluded from occurring locally onsite. Actual depths of removals should be evaluated in the field during grading by the geotechnical consultant. Removals within any alluvial areas should consist of the alluvial soil to near the depth of the groundwater table, or the complete removal of alluvial soil if no water is present. Based on our observations, this depth is likely on the order of 2 to 3 feet below the ground surface within alluviated areas where shallow groundwater is present, and on the order of 5 to 10 feet where complete removals of alluvium is anticipated in the vicinity of ECR Stations 646+50 to 466+50. Placement of a geotextile fabric on the removal bottom, or a suitable rock blanket with geotextile, may be necessary in order to stabilize the area prior to the placement of additional fill in areas where partial removals are made, due to the presence of groundwater, or existing utilities. Subdrains Subdrains will be recommended behind walls, culverts, wing walls, keyways, and drainage axis, as indicated herein A subsequent review of 40-scale plans (when available) should be performed to evaluate the need for subdrainage. If encountered, local seepage along the contact between the bedrock and overburden materials, or along jointing patterns of the bedrock may require a subdrain system. Based on a review of Plates 1 through 5, subdrains are generally not anticipated within the ECR right of way due a potential lack of available fall for a drain to operate, or lack of a suitable outlet area. A subdrain and a shear key drain will be recommended for the fill over cut slope area planned above ECR Stations 474+00 to 478+00. Typical subdrain design and construction details are presented in Appendix E. Fill Placement and Suitability Subsequent to ground preparation, onsite soils may be placed in thin (6- to ±8-inch) lifts, cleaned of vegetation and debris, brought to a least optimum moisture content, and compacted to achieve a minimum relative compaction of 90 percent of the laboratory standard (ASTM Test Method D 1557). Saturated or wet soils may need to be air-dried, or dried back to be suitable for fill placement. If soil importation is planned, samples of the soil import should be evaluated by this office prior to importing in order to assure compatibility with the onsite site soils and the recommendations presented in this report. Import soils should be relatively sandy and low expansive (i.e., E.I. less than 50). Shapell Homes W.O. 6145-E-SC Rancho Costera, Carlsbad May 11, 2011 FiIe:e:\wp9\6100\6145e.gif Page 21 GeEPSOIIS, !c. Fill Settlement Following grading and placement of road widening fill, some fill may settle as a result of a newly placed fill over saturated alluvial soils. Fills recompacted on the road bed are not anticipated to settle significantly. Fills placed in deep utility trenches may be subject to settlement if they "bottom out" in alluvium. Settlements on the order of up to 1/4 inch n the road bed are possible. Fill settlement in deep utility trenches is anticipated to be up to 1/2 inch if the bottom is stabilized prior to placement of bedding and backfill. Slurry backfill in deep utilities embedded into alluvium may result in long-term settlement of up to 1 inch. For portions of the roadway extended laterally over alluvial deposits, settlement of approximately 2 inches is possible when considering long-term performance. Erosion Control Onsite soils are considered highly erosive. Use of hay bales, silt fences, and/or sand/gravel bags should be considered, as appropriate. Temporary grades should be constructed to drain at 1 to 2 percent to a suitable temporary or permanent outlet. Evaluation of cuts during grading will be necessary in order to identify any areas of loose or non-cohesive materials. Should any significant zones be encountered during earthwork construction remedial grading may be recommended; however, no remedial measures are anticipated at this time. Foot traffic should not be allowed on natural or sandy slopes. Natural slopes should not be irrigated. Slope Considerations and Slope Design Graded Slopes All slopes should be designed and constructed in accordance with the minimum requirements of City/County, the 2010 CBC (CBSC, 2010), the 2009 "Greenbok," and the recommendations in Appendix E. Slopes constructed with sand fractions of the terrace deposits or Santiago Formations are anticipated to have erosion and surficial instability issues if left unpianted, and without engineered surface drainage control, and as such, will require periodic and regular maintenance above and beyond what is normally performed for slopes in general. Stabilization/Buttress Fill Slopes The construction of stabilization and/or buttress slopes may be necessary for some west/northwest facing cut slopes. Such remedial slope construction will be recommended based upon a review of the 40-scale grading plans and/or conditions exposed in the field during grading. Shapell Homes W.O. 6145-E-SC Rancho Costera, Carlsbad May 11, 2011 Fule:e:\wp9\6100\6145e.gif Page 22 GoSils, Inc. Temporary Construction Slopes In general, temporary construction slopes may be constructed at a maximum slope ratio of 1:1 (h:v) or flatter within alluvial soils and terrace deposits, and /2:1, or flatter, for temporary slopes exposing dense sedimentary bedrock (Santiago Formation) without adverse (daylighted) bedding or fracture surfaces, and without groundwater. Otherwise Type C soils should govern. Excavations for removals, drainage devices, debris basins, and other localized conditions should be evaluated on an individual basis by the soils engineer and engineering geologist for variance from this recommendation. Due to the nature of the materials anticipated, the engineering geologist should observe all excavations and fill conditions. The geotechnical engineer should be notified of all proposed temporary construction cuts, and upon review, appropriate recommendations should be presented. Trenching for the deeper utility improvements within ECR will likely encountered both a shallow groundwater table and relatively soft alluvial soils. For planning purposes, trenching and shoring design/construction should be in accordance with CAL-OSHA guidelines for Type C soils. Dewatering should also be anticipated in these areas, especially ECR Stations 444+00 to 452+00, and ECR Stations 481+00 to 488+00. RECOMMENDATIONS - FOUNDATIONS The proposed foundation systems should be designed and constructed in accordance with current standards of practice, the guidelines contained within the 2010 CBC, the 2009 "Greenbook," the ACI (2008), and the design parameters presented herein. WALL DESIGN PARAMETERS Retaining walls should be designed using sound engineering judgement, and in accordance with the 2010 CBC, the 2009 "Greenbook," the San Diego Regional Standard Drawings cited by the City of Carlsbad, and the criteria and parameters provided below. General Foundation Design Geotechnical evaluations of these soils indicate that an allowable bearing value of 2,000 psf may be used for design of footings embedded into approved terrace deposits, Santiago Formation, or engineered fill compacted to 90 percent (ASTM D. 1557) relative compaction, placed on terrace deposits or bedrock (Santiago Formation). Footings should maintain a minimum width of 12 inches (continuous) and 24 inches square (isolated), and a minimum depth of at least 18 inches into properly compacted fill/bedrock. Isolated, square footings should extend a minimum of 24 inches into the compacted fill/bedrock. The bearing value may be increased by one-third for seismic or other temporary loads. This value may be ShapeliHomes W.O. 6145-E-SC Rancho Costera, Carlsbad May 11, 2011 File: e:\wp9\61 OO\6145e.gif Page 23 GeoSoils, Inc. increased by 20 percent for each additional 12 inches in depth to a maximum of 3,000 psf, for fill and terrace deposits, and 4,000 psf in the Santiago Formation. No increase in bearing should be used for increases in footing width. Reduction in bearing should be utilized for foundations supported by fill over left-in-place alluvium. In that case, the bearing should be used as a 1,500 psf within maximum bearing of 2,000 psf. In accordance with 2010 CBC, Section 1802.3.2, the expansive nature of the soils shall be evaluated based on Expansion Index (E.l.), if E.I. > 2001 Plasticity Index (P1)> 15, and -200 (Passing No. 200 Sieve)> 10 percent and -5J.Lm> 10 percent. For lateral sliding resistance, a 0.35 coefficient of friction may be utilized for a concrete to soil contact when multiplied by the dead load. Passive earth pressure on documented fill may be computed as an equivalent fluid having a density of 250 pounds per cubic foot (pci) with a maximum lateral earth pressure of 2,500 psf. If 2010 CBC (CBSC, 2010) restrictions on passive pressures are less for these sandy soils, those values will govern. Dense undisturbed, unweathered Santiago Formation with proper setback may utilize a 300 pcf passive pressure up to 3,000 psf for maximum later earth pressure. When combining passive pressure and frictional resistance, the passive pressure component should be reduced by one-third. All footings should maintain a minimum 7-foot horizontal distance between the base of the footing and any adjacent descending slope, and minimally comply with the guidelines depicted in Section 1805.3 as well as Figure 1805.3.1 of the 2010 CBC. Conventional Retaining Walls The design parameters provided below assume that either non expansive soils (typically Class 2 permeable filter material or Class 3 aggregate base) qr native onsite materials (up to and including an E.I. of 0 to 50, P1 <15) are used to backfill any retaining walls. The type of backfill (i.e., select or native), should be specified by the wall designer, and clearly shown on the plans. Utility vaults, or building walls below grade, should be water-proofed. The foundation system for the proposed retaining wallsshould be designed in accordance With the recommendations presented in this and preceding sections of this report, as appropriate. If walls allow water to accumulate in backfill or at their toe via a v-ditch or sloped grade, the water should be conveyed via a non-erosive device to an appropriate inlet, per the recommendations of the design civil engineer. This may require disclosure to the City, or any interested parties, so that such devices, if any, are maintained. Shapell Homes W.O. 6145-E-SC Rancho Costera, Carlsbad May 11, 2011 FiIe:e:\wp9\6100\6145e.gif Page 24 GeoSoils, Inc. Restrained Walls Any retaining walls that will be restrained prior to placing and compacting backfill material or that have re-entrant or male corners, should be designed for an at-rest equivalent fluid pressure (EFP) of 65 pcf, plus any applicable surcharge loading. For areas of male or re-entrant corners, the restrained wall design should extend a minimum distance of twice the height of the wall (21-1) laterally from the corner. Other soil parameters provided in this section should be followed in the design of restrained retaining walls. Cantilevered Walls The recommendations presented below are for cantilevered retaining walls up to 20 feet high and assume that the design conditions in front, and back of the wall, including the retaining inclination of the backfill will not be changed over the life of the project. Design parameters for walls less than 3 feet in height may be superceded by City and/or County standard design; however, the more stringent design should be followed. Active earth pressure may be used for retaining wall design, provided the top of the wall is not restrained from minor deflections (i.e., 0.002 x wall height). Passive pressure of 250 psf up to maximum lateral bearing of 2,500 psf may be used in the design of anticipated retaining walls (engineered fill, terrace deposits). Passive pressure is used to compute lateral soils resistance developed against lateral structural movement. Further, for sliding resistance, the friction coefficient of 0.35 may be used at the concrete and soil interface when considering low expansive soil, or formational earth materials. In computing the total lateral resistance, the passive pressure or the frictional resistance should be reduced by 50 percent. The total depth of retained earth for design of cantilever walls should be the vertical distance below the ground surface measured at the wall face for stem design or measured at the heel of the footing for overturning and sliding. Wall footings should be designed in accordance with structural considerations. The passive resistance value (lateral bearing) may be increased by one-third when considering loads of short duration including wind or seismic loads. The horizontal distance between foundation elements providing passive resistance should be a minimum of three times the depth of the elements to allow full development of these passive pressures. An equivalent fluid pressure approach may be used to compute the horizontal pressure against the wall. Appropriate fluid unit weights are given below for specific slope gradients of the retained material. These do not include other superimposed loading conditions due to traffic, structures, seismic events or adverse geologic conditions. These values, or those contained within Table 1610.1 of the 2010 CBC, whichever is more stringent, should be utilized. When wall configurations are finalized, the appropriate loading conditions for superimposed loads can be provided upon request. For preliminary planning purposes, traffic loads may use an active pressure of 100 psf/ft of wall in the upper 5 feet, provided the traffic area is set back from the back of the wall is 3 feet, or more. Shapell Homes W.O. 6145-E-SC Rancho Costera, Carlsbad May 11, 2011 FiIe:e:\wp9\6100\6145e.gif Page 25 GeoiJs, Inc. OEö41 tEÔU1A &iO*Eiir - fr - .d t- - r -- 4 V'. - —_ ••_ - -RErAlNED MATERIA1 P C F (SELECTPREj'PROVED P C F.(NATlV'PRE-APPRO1VED Level** 35 45 2tol 55 65 itol 95 — * These equivalent fluid weights do not include other superimposed loading conditions due to traffic, structures, seismic events or adverse geologic conditions. When wall configurations are finalized, the appropriate loading conditions for superimposed loads can be provided upon request ** Level backfill behind a retaining wall is defined as compacted earth materials, properly drained, without a slope for a distance of 2H behind the wall. *** SE - 30, P.1. <15, E. 1. <21, and < . 10% passing No. 200 sieve. E.I. <51, P.1. <15, and 115% passing No. 200 sieve. Earthquake Loads (Seismic Surcharge) In accordance with 2010 CBC, and given the granular nature of the site soils and the anticipated level of potential earthquake shaking evaluated herein, GSI recommends that for walls that retain more than, or equal to, 6 feet of retained soil and are 6 feet or less from structures, or may inhibit ingress/egress for the site roads or lots, or critical access pathways (i.e., collector streets, lire access roads, etc.), a seismic surcharge (increment) of 14H should be used where H is the height of the wall and the surcharge is applied as a uniform pressure for restrained walls. For cantilever walls, this distribution maybe taken as an inverted triangular distribution. This complies with a Probabilistic Horizontal Site Acceleration (PHSA), as previously noted in this report. The resulting wall design should be safe from seismic induced overturning with a minimum FOS of 1.1 to 1.3 should be considered and is dependant on the backfill conditions and the potential consequences of seismic induced deformations/failure. Basement walls or utility vaults, if proposed, will need to be evaluated as retaining walls, as well as part of the wall design from a seismic standpoint per the 2010 CBC. Retaining Wall Backfill and Drainage Positive drainage must be provided behind all retaining walls in the form of gravel wrapped in geofabric and outlets. A backdrain system is considered necessary for retaining walls that are 2 feet or greater in height. Details 1, 2, and 3, present the back drainage options discussed below. Backdrains should consist of a 4-inch diameter perforated PVC or ABS pipe encased in either Class 2 permeable filter material or 3/4-inch to 11/2-inch gravel wrapped in approved filter fabric (Mirafi 140 or equivalent). For very low to low expansive backfill, the filter material should extend a minimum of 1 horizontal foot behind the base of the walls and upward at least 1 foot. For native backfill that has an E.I. greater than 50, continuous Class 2 permeable drain materials should be solely used behind the wall. This material should be continuous (i.e., full height) behind the wall, and it should be constructed in accordance with the enclosed Detail 1 (Typical Retaining Wall Backfill and Drainage Detail). For limited access and confined areas, (panel) drainage behind the wall Shapell Homes W.O. 6145-E-SC Rancho Costera, Carlsbad May 11, 2011 Fi1e:e:\wp9\6100\6145e.gif Page 26 GeSeils, Inc. may be constructed in accordance with Detail 2 (Retaining Wall Backfill and Subdrain Detail Geotextile Drain). Materials with an E.I. potential of greater than 50 should not be used as backfill for retaining wails. Outlets should consist of a 4-inch diameter solid PVC or ABS pipe spaced no greater than ± 100 feet apart, with a minimum of two outlets, one on each end. The use of weep holes, only, in walls higher than 2 feet, is not recommended. The surface of the backfill should be sealed by pavement or the top 18 inches compacted with native soil (El. <50). Proper surface drainage should also be provided. For additional mitigation, consideration should be given to applying a water-proof membrane to the back of all retaining structures. The use of a waterstop should be considered for all concrete and masonry joints. Wall/Retaining Wall Footing Transitions Site wails are anticipated to be founded on footings designed in accordance with the recommendations in this report. Should wall footings transition from cut to fill, the civil designer may specify either: A minimum of a 2-foot overexcavation and recompaction of cut materials for a distance of 2H, from the point of transition. Increase of the amount of reinforcing steel and wall detailing (i.e., expansion joints or crack control joints) such that a angular distortion of 1/360 for a distance of 2H on either side of the transition may be accommodated. Expansion joints should be placed no greater than 20 feet on-center, in accordance with the structural engineer's/wall designer's recommendations, regardless of whether or not transition conditions exist. Expansion joints should be sealed with afiexible, non-shrink grout. Embed the footings entirely into native formational material (i.e., deepened footings). If transitions from cut to fill transect the wall footing alignment at an angle of less than 45 degrees (plan view), then the designer should follow recommendation 'a" (above) and until such transition is between 45 and 90 degrees to the wall alignment. Slope Setback Considerations for Wall Footings Setbacks for natural and manufactured slopes should minimally conform to 2010 CBC (CBSC, 2010) guidelines, unless specifically superceded herein. All footings should maintain a minimum horizontal setback of H/3 (H=s10pe height) from the base of the footing to the descending slope face of no less than 7 feet, nor need not be greater than 40 feet. This distance is measured from the footing face at the bearing elevation. Footings adjacent to unlined drainage swales should be deepened to a minimum of 6 inches below the invert of the adjacent unlined swale. Footings for structures adjacent to retaining walls should be deepened so as to extend below a 1:1 projection from the heel of the wall. ShapeH Homes W.O. 6145-E-SC Rancho Costera, Carlsbad May 11. 2011 FiIe:e:\wp9610O6145e.gif Page 30 GepSciJs, Inc. Alternatively, walls may be designed to accommodate structural loads from buildings or appurtenances. TEMPORARY/PERMANENT SHORING SYSTEMS The following recommendations are for the shoring of excavations up to approximately 20 feet, or less, in height. Based on the relative location(s) of existing, as well as planned improvements, a permanent shoring wall may be considered as an alternative to the construction of a typical, cantilevered retaining wall for the planned retaining wall in the vicinity of the southbound ECR, Stations 459+75 to 463+75. We recommend that permanent slopes be retained by a cantilever shoring system deriving passive support from cast-in-place soldier piles lagged with either pre-cast concrete or wood lagging (H-pile and lagging-shoring system). Based on our experience with similar projects in the San Diego area, if lateral movement of the shoring system on the order of 1 inch (permanent shoring) and 2 inches (temporary shoring) cannot be designed for ortolerated, we recommend the utilization of an internal bracing/raked shoring system, or a stiffer shoring system to limit deflection to less than 1 inch. Terzaghi and Peck (1967) suggested that shoring for excavations up to 20 feet in depth should consider settlement on the order of 0.65 percent in the backfill, or retained material, as backfill settlement. This would imply less than 1 inch of backfill or retained material settlement for a shored system retaining up to 20 feet. This is likely a conservative estimate given the depth of the formation below the surface. Locally, 0.2 percent (State of California Department of Transportation, 2000) is used for soils which would indicate approximately ½ inch of settlement. However, settlement on the order of /2 to 1½ inches should be evaluated for improvements near the rear of the wall. Shoring of excavations of this size is typically performed by specialty contractors with knowledge of the San Diego County area soil conditions. We recommend that shoring contractors provide the excavation shoring design. However, for the shoring design parameters, we provide the lateral earth pressures in Figures 2a and 2b, for both temporary and permanent shoring conditions. The use of soil anchors (tie-backs) may not be feasible on this site due to the location of adjacent residential property, or other easements. If desired, additional anchor recommendations will be provided. Since design of retaining systems is sensitive to surcharge pressures behind the excavation, we recommend that this office be consulted if unusual load conditions are anticipated. Care should be exercised when excavating into the on-site soils since caving or sloughing of these materials is possible. Observation of soldier pile excavations should be performed during construction. As an alternative to a tieback wall, a cantilever H-pile and lagging may be used. If the same system is used without tiebacks, the wall may be cost prohibitive for cantilever walls over 15 feet. Therefore, walls up to 15 feet in height may be used with a sloping backfill up to 5 feet in height, in order to achieve the same elevation of backfill. This sloping backfill should not exceed 1:1 (h:v). Earth pressures for inclined backfill up to 1:1 (h:v) are provided herein for import soils. Shapell Homes W.O. 6145-E-SC Rancho Costera, Carlsbad May 11, 2011 flle:e:\wp9\6100\6145e.gif Page 31 GeoSoUs, Inc. Cantilever Shoring System I - - Surcharge Pressure P (psf) - - Line Load 0, (pounds) '-i L A -'---- -- H(feet) - \ / .1 \ / 0.1 0.61-1 Y (feet) 0.3 6.61-1 \ / 0.5 0.56H / 0.7 0.48H I D (feet) X R 35 H (psf) (OA I I (0.4 °• ____________ 55 0 0.35 P (psf) )0.4 /0.64 0L' I '100 D (psf) - I x2+ 1 ) - Surcharge Pressure P (psf) 1 Tie-Back Shoring System P (lost) F - - Line Load QL0unc Resistance 0.2ft.) (behind this line H (feet) 7 ® Tie Back = 0.2f (ft) ® 1200 psf Bond Stress 1111111 IIlll _ — - Minimum 7' depth - ID for supporting piers 400 D (psf) 127 H (psf I® 0.35 P (psf) Y NOTES V () Include groundwater effects below groundwater level Include water effects below groundwater level. Grouted length greater than 7 feet field test anchor strength. ® Neglect passive pressure below base of excavation to a depth of one pier diameter. - - Surcharge Pressure P (psf) Cantilever Shoring System - Line Load OL(pounds) I. I H (feet) D (feet) 45 H (pat) 300 D(psf) Tie-Back Shoring System P / 0.1 0.6H Y (feet) 0.3 0.6H 0.5 0.56H 0.7 0.48H X R I - 0.35 P (pat) <04 °•550L >0.4 ( X-2- 0.64 0L'\ +l I - Surcharge Pressure P (pat) - - Line Load 0L0t13) REIM Ur 02 H (ft.) -.._.. Resistance - ç behind this line 49 H (feet) Xqn eBack 0.2 1000 ___________________ ® 1000 psf Bond Stress - I - piers Il I L1 -. - - Minimum 7' depth ¶9 for supporting . I 300 D (psf) ® I H (p I® 0.35 P (psf) gf) I NOTES Include groundwater effects below groundwater level. Include water effects below groundwater level. Grouted length greater than 7 feet; field test anchor strength. ® Neglect passive pressure below base of excavation to a depth of one pier diameter. Y Shoring of the excavation is the responsibility of the contractor. Extreme caution should be used to reduce offsite damage to existing pavement and utilities caused by settlement or reduction of lateral support. Accordingly, we recommend that adjacent improvements be surveyed prior to and during construction to evaluate the effects of shoring on these structures. Photodocumentation of pre-construction conditions is also advised. Lateral Pressure The active pressure to be utilized for trench wall shoring design may be computed by the rectangular active pressure (pst) as shown in Table 1. Passive pressure may be computed as an equivalent fluid having a given density shown in Figures 2a and 2b. The passive pressure near the bottom of the shored excavation to a depth equal to 1- to 1 '/2-pile diameters, should be reduced or ignored due to potential disturbance if the soldier beams are not embedded into formation. The lateral pressures indicated in Figures 2a and 2b assume that hydrostatic pressure is not allowed to build up behind excavation walls. If water is allowed to accumulate behind walls, an additional hydrostatic pressure surcharge should be added. These recommendations are for excavation of temporary/permanent shoring walls up to approximately 20 feet high. Active earth pressure may be used for trench wall design, provided the wall is not restrained from minor deflections. An empirical equivalent fluid pressure approach may be used to compute the horizontal pressure against the wall. Appropriate fluid unit weights are provided for specific slope gradients of the retained material: these do not include other superimposed loading conditions such as traffic, structures, seismic events, expansive soils or adverse geologic conditions. For excavation shoring walls that are to be present for more than 8 months and greater than 6 feet in height, a seismic increment of 14H (uniform pressure) may be considered for level excavation. For walls, these seismic loads should be applied at 0.6H up from the bottom of the wall to the height of retained earth materials. Due to the effects of soil movements on nearby improvements, including underground utilities, shoring lagging should be designed using a K value of 0.5 and a maximum value of 300 pounds per lineal foot. The annulus between soil and lagging should be filled with either 1/2 to 3/4 inch gravel, or 1- to 2-sack slurry, due to the potential for sloughing surlicial soils on this project, gravel, if used, will need to be separated from soil with a geotextile filter fabric to reduce the potential for piping, or migration of fines. Shapell Homes W.O. 6145-E-SC Rancho Costera, Carlsbad May 11, 2011 Fu1e:e:\wp9\6100\6145e.gif Page 34 GoSoils, Inc. If wood lagging is used, the permanent shoring wall will likely require an additional layer of steel reinforcement with panel drains using a shotcrete facing. Permanent shoring walls using tiebacks should use corrosion protection for all tendons, anchors, and anchor hardware. Refer to the structural engineer and corrosion consultant for corrosion protection recommendations. Tiebacks and Lateral Pier Loads The piles will gain there lateral support primarily from the underlying terrace deposits. The lateral pier deflection under static soil and structural loads is estimated at 1 -inch, or less. To reduce the potential for distress on the improvements above the wall, tiebacks may be added to the piers. The tiebacks will reduce the deflection of the foundation piers to less than ¼ inch. Tiebacks should have a bonded length embedded into the formation (terrace deposits) a minimum of 25 feet. For this project location, tie-backs should have a minimum batter of 20 degrees from the horizontal (2.75:1 [h:v]). It is anticipated that the tiebacks will be mounted through the piers and/or grade beams. The depth below the top of pier for this tieback connection is anticipated to be 1- to 3-pier diameters. Tieback spacing is not anticipated to be more than 10 feet laterally. Given the assumed tieback loads of 60 to 180 kips, tieback diameters are anticipated to vary based on the load but should be considered as 4 to 8 inches. Tieback static loads are assumed to be 60 to 180 kips, and the allowance for 25 percent increase for transient seismic or wind loads should be included in the seismic design of the tiebacks. Select tiebacks should be tested to a minimum of 80 percent of the design ultimate strength. Creep of the selected tiebacks should be monitored for at least 24 hours. All production tiebacks should be proof tested. All tiebacks will consist of DYWIDAG system international (DSl) anchors with Type C double-corrosion protection. Open Excavations Construction materials and/or stockpiled soil should not be stored within "H" feet of the top of any temporary slope or trench wall (where "H" equals the slope or wall height). Temporary/permanent provisions should be made to direct any potential runoff away from the top of temporary excavations. It is the responsibility of the general contractor and his subcontractor to provide a safe working environment and to protect site improvements as well as adjacent existing improvements during construction. Excavation Observation (All Excavations) Monitoring should include the measurement of any horizontal and vertical movements of both the existing structures and the shoring and/or bracing. Locations and type of the monitoring devices should be selected as soon as the total shoring system is designed Shapell Homes W.O. 6145-E-SC Rancho Costera, Carlsbad May 11, 2011 FiIe:e:wp96100\6145e.gif Page 35 GeSoUs, Inc. and approved. The program of monitoring should be agreed upon between the project team, the site surveyor and the Geotechnical Engineer of Record, prior to excavation. Reference points on the existing structures should be placed as low as possible on the exterior walls of buildings adjacent to the excavation. Exact locations may be dictated by critical points within the structure, such as bearing walls or columns for buildings; and surface points on roadways and sidewalks near the top of the excavation. The points on the shoring should be placed under or very near the points on the structures. For a survey monitoring system, an accuracy of a least 0.01 foot should be required. Reference points should be installed and read initially prior to excavation. The readings should continue until all construction below ground has been completed and the backfill has been brought up to final grade. The frequency of readings will depend upon the results of previous readings and the rate of construction. Weekly readings could be assumed throughout the duration of construction with daily readings during rapid excavation near the bottom and at critical times during the installation of shoring or support. The reading should be plotted by the Surveyor and then reviewed by the Geotechnical Engineer. In addition to the monitoring system, it would be prudent for the Geotechnical Engineer and the Contractor to make a complete inspection of the existing structures both before and after construction. The inspection should be directed toward detecting any signs of damage, particularly those caused by settlement. Notes should be made and pictures should be taken where necessary. Observation It is recommended that all excavations be observed by the Geologist or Geotechnical Engineer. Any fill which is placed should be approved, tested, and evaluated if utilized for engineered purposes. Temporary trench excavations should be observed by the Geologist or Geotechnical Engineer. Should the observation reveal any unforseen hazard, the Geologist or Geotechnical Engineer will recommend treatment. Please inform us at least 24 hours prior to any required site observation. Monitoring Existing, Offsite Improvements It is recommended that existing, offsite improvement be inspected prior to the start of earthwork and be monitored during and at the conclusion of grading to evaluate if earthwork, or shoring at the site has influenced these improvements. Shapell Homes W.O. 6145-E-SC Rancho Costera, Carlsbad May 11, 2011 FiIe:e:\wp9\6100\6145e.gif Page 36 GeoUs, Inc. SOIL NAIL WALLS General Soil nails are a passive reinforcement, usually in the form of a bar or rod of solid or hollow cross section, installed into the ground, usually at a sub horizontal angle (15 to 25 degrees) to enhance the stability of the reinforced ground mass primarily by mobilizing the axial tensile strength of the soil nail. As an alternative to a typical cantilevered retaining wall, a soil nail wall may be constructed. Soil nailing may be performed by the process of drilling and grouting, where the nail is inserted into a pre-drilled hole and then grouted into position. A bearing plate is then connected to the head of the soil nail to transfer a component of load directly to the ground surface. Each bearing plate would then be tied together with a structural concrete facing (soil nail wall). Preliminary Design and Construction The following soil parameters may be used in soil nail reinforcement design. Anchor (Bonded) Zone, (Qt) Terrace Deposits Angle of Internal Friction: 28 degrees Soil Unit Weight: 120 pcf Cohesion: 200 psf Bond Stress 1,000 psf Soil nails may be installed at a maximum spacing of 5 feet on center, both vertically and laterally across the affected area of the slope, and embedded at least 30 feet into the slope. This assumes an unbonded length of approximately 10 feet for walls up to 20 feet in exposed height. The angle of soil nail installation shall be 20 degrees from horizontal. The tendon diameter shall be at least 1 inch, with a grouted nail diameter of at least 6 inches. All soil nails will consist of DYWIDAG system international (DSl) anchors, If deemed necessary by the structural consultant, corrosion engineer, or reviewer, Type C double-corrosion protection should be provided for the DYWIDAG bar(s). Additional parameters regarding seismic design are presented in a previous section. These recommendations are meant as minimums. Soil nail design should be reviewed by the soil nail designer and modified as necessary. Final soil nail construction plans should be reviewed by this office for compliance with the intent of this report. The construction and installation of soil nails should also be observed by this office. Soil nail walls should be completed using a panel drain(s) and a shotcrete facing to improve long-term performance. Shapell Homes W.O. 6145-E-SC Rancho Costera, Carlsbad May 11, 2011 F'iIe:e:wp9\6100\6145e.gif Page 37 Inc.Geoftilsq CIDH SUPPORTED IMPROVEMENTS For light poles, sign posts, and other CIDH (cast-in-drilled-hole) supported improvements, Detail E-1 of the San Diego Regional Standards Drawings (2009) applies. There may be other standards that are applicable. Piers or CIDH foundations should be designed based on adhesion to the sides of the pier and no bearing support should be considered for the tip, due to existing till or alluvium which will likely be exposed during excavation. Skin friction for piers should be 200 psf for clayey sand/sandy clay soils. For bedrock exposures, end bearing may be taken as 3,000 psf, if the hole is cleared of loose soil. All CIDH for light standard or significant signage should be 18 inches and 12 inches in diameter, respectively. For passive pressures, referto the other section of this report. GSI will review and provide additional CIDH lateral load evaluations when the design vertical and lateral loads are provided. TOP-OF-SLOPE WALLS/FENCES/IMPROVEMENTS Slope Creep Soils at the site may be expansive and therefore, may become desiccated when allowed to div. Such soils are susceptible to surficial slope creep, especially with seasonal changes in moisture content. Typically in southern California, during the hot and dry summer period, these soils become desiccated and shrink, thereby developing surface cracks. The extent and depth of these shrinkage cracks depend on many factors such as the nature and expansivity of the soils, temperature and humidity, and extraction of moisture from surface soils by plants and roots. When seasonal rains occur, water percolates into the cracks and fissures, causing slope surfaces to expand, with a corresponding loss in soil density and shear strength near the slope surface. With the passage of time and several moisture cycles, the outer 3 to 5 feet of slope materials experience a very slow, but progressive, outward and downward movement, known as slope creep. For slope heights greater than 10 feet, this creep related soil movement will typically impact all rear yard flatwork and other secondary improvements that are located within about 15 feet from the top of slopes, concrete flatwork, etc., and in particular top of slope fences/walls. This influence is normally in the form of detrimental settlement, and tilting of the proposed improvements. The dessication/swelling and creep discussed above continues over the life of the improvements, and generally becomes progressively worse. Accordingly, the developer should provide this information to any interested/affected parties. Top of Slope Walls/Fences Due to the potential for slope creep for slopes higher than about 10 feet, some settlement and tilting of the walls/fence with the corresponding distresses, should be expected. To Shapell Homes W.O. 6145-E-SC Rancho Costera, Carlsbad May 11, 2011 FiIe:e:\wp9\6100\6145e.gif Page 38 GeoSoils, Inc. mitigate the tilting of top of slope walls/fences, we recommend that the walls/fences be constructed on deepened foundations (drilled piers) without any consideration for creep forces, where the E.I. of the materials comprising the outer 15 feet of the slope is less than 50, or a combination of grade beam and pier foundations, for expansion indices greater than 50 comprising the slope, with creep forces taken into account. The grade beam should be at a minimum of 12 inches by 12 inches in cross section, supported by drilled caissons, 12 inches minimum in diameter, placed at a maximum spacing of 6 feet on center, and with a minimum embedment length of 7 feet below the bottom of the grade beam. The strength of the concrete and grout should be evaluated by the structural engineer of record. The proper ASTM tests for the concrete and mortar should be provided along with the slump quantities. The concrete used should be appropriate to mitigate sulfate corrosion, as warranted. The design of the grade beam and caissons should be in accordance with the recommendations of the project structural engineer, and include the utilization of the following geotechnical parameters: Creep Zone: 5-foot vertical zone below the slope face and projected upward parallel to the slope face. Creep Load: The creep load projected on the area of the grade beam should be taken as an equivalent fluid approach, having a density of 60 pcf. For the caisson, it should be taken as a uniform 900 pounds per linear foot of caisson's depth, located above the creep zone. Point of Fixity: Located a distance of 1.5 times the caisson's diameter, below the creep zone. Passive Resistance: Passive earth pressure of 250 psf per foot of depth per foot of pier diameter, to a maximum value of 2,000 psf may be used to determine caisson depth and spacing, provided that they meet or exceed the minimum requirements stated above. To determine the total lateral resistance, the contribution of the creep prone zone above the point of fixity, to passive resistance, should be disregarded. Allowable Axial Capacity: Shaft capacity: 350 psf applied below the point of fixity over the surface area of the shaft, for the portion of the shaft embedded in compacted fill soil and 500 psf for the portion of the shaft embedded in bedrock or formation. Tip capacity: 2,500 in compacted fill and 3,500 psf in bedrock, or suitable formational soil, assuming loose soil is removed from the tip of all pier excavations, prior to placement of concrete. Shapell Homes W.O. 6145-E-SC Rancho Costera, Carlsbad May 11, 2011 Fite:e:\wp9\6100\6145e.gif Page 39 GeSoils, Inc. CONCRETE APRONS, SIDEWALKS, FLATWORK, AND OTHER IMPROVEMENTS The soil materials on site may be expansive. The effects of expansive soils are cumulative, and typically occur over the lifetime of any improvements: On relatively level areas, when the soils are allowed to dry, the dessication and swelling process tends to cause heaving and distress to flatwork and other improvements. The resulting potential for distress to improvements may be reduced, but not totally eliminated. To that end, it is recommended that the developer should notify any owners and/or interested/affected parties of this long-term potential for distress. To reduce the likelihood of distress, the following recommendations are presented for all exterior flatwork: The subgrade area for concrete slabs should be compacted to achieve a minimum 90 percent relative compaction, and then be presoaked to 2 to 3 percentage points above (or 125 percent of) the soils' optimum moisture content, to a depth of 18 inches below subgrade elevation. If very low expansive soils are present, only optimum moisture content, or greater, is required and specific presoaking is not warranted. The moisture content of the subgrade should be proof tested within 72 hours prior to concrete placement. Exterior concrete slabs should be cast over a non-yielding surface, consisting of a 4-inch layer of Class 2 base, crushed rock, gravel, or clean sand (or City of Carlsbad minimum, whichever is greater), that should be compacted and level prior to placement of concrete. If very low expansive soils are present, the base, rock, gravel, or sand may be deleted. The layer or subgrade should be wet-down completely prior to placement of concrete, to minimize loss of concrete moisture to the surrounding earth materials. Exterior slabs should be a minimum of 4 inches thick. Approach slabs and approaches should additionally have a thickened edge (12 inches) adjacent to all landscape areas, to help impede infiltration of landscape water under the slab. Trash disposal (dumpster) area aprons should be a minimum of 6 inches thick and meet minimum City of Carlsbad standards, as necessary. The use of transverse and longitudinal control joints are recommended to help control slab cracking due to concrete shrinkage or expansion. Two ways to mitigate such cracking are: a) add a sufficient amount of reinforcing steel, increasing tensile strength of the slab; and, b) provide an adequate amount of control and/or expansion joints to accommodate anticipated concrete shrinkage and expansion. In order to reduce the potential for unsightly cracks, exterior slabs should be reinforced at mid-height with a minimum of No. 3 bars placed at 18 inches on center, in each direction. If subgrade soils within the top 7 feet from finish grade are very low expansive soils (i.e., E.l. :g20), then 6x6-W1 .4xW1 .4 welded-wire mesh may be substituted for the rebar, provided the reinforcement is placed on chairs, at slab ShapeD Homes W.O. 6145-E-SC Rancho Costera, Carlsbad May 11, 2011 FiIe:e:\wp9\6100\6145e.gif Page 40 GoSois, Inc. mid-height. The exterior slabs should be scored or saw cut, ½ to 3/a inches deep, often enough so that no section is greater than 10 feet by 10 feet. For sidewalks or narrow slabs, control joints should be provided at intervals of every 6 feet. The slabs should be separated from the foundations and sidewalks with expansion joint filler material. The use of fiber mesh may be considered in addition to slab reinforcement to improve performance. No traffic should be allowed upon the newly placed concrete slabs until they have been properly cured to within 75 percent of design strength. Concrete compression strength should be a minimum of 2,500 psi. Driveways and sidewalks adjacent to structures should be separated from the structure with thick expansion joint filler material. In areas directly adjacent to a continuous source of moisture (i.e., irrigation, planters, etc.), all joints should be additionally sealed with flexible mastic. Planters and walls (sound walls or retaining walls) should not be tied to the structure. Overhang structures should be supported on the slabs, or structurally designed with continuous footings tied in at least two directions. If very low expansion soils are present, footings need only be tied in one direction. Any masonry landscape or sound walls that are to be constructed throughout the property should be grouted and articulated in segments no more than 20 feet long. These segments should be keyed or doweled together. If settlement concerns or expansive soils are present, utilities may be enclosed within a closed utilidor (vault) or designed with flexible connections to accommodate differential settlement and expansive soil conditions. Positive site drainage should be maintained at all times. Finish grade on the building pad should provide a minimum of 1 to 2 percent fall to the street, as indicated herein. It should be kept in mind that drainage reversals could occur, including post-construction settlement, if relatively flat drainage gradients are not periodically maintained by the owner and/or interested/affected parties. Shrinkage cracks could become excessive if proper finishing and curing practices are not followed. Finishing and curing practices should be performed per the Portland Cement Association (PCA) guidelines. Mix design should incorporate rate of curing for climate and time of year, sulfate content of soils, corrosion potential of soils, and fertilizers used on site. The use of fiber mesh may be considered to reduce to potential for shrinkage cracks. Shapell Homes W.O. 6145-E-SC Rancho Costera, Carlsbad May 11, 2011 FiIe:e:\wp9\6100\6145e.gif Page 41 GeoSoils, Inc. PAVEMENT REHABILITATION/PRELIMINARY PAVEMENT DESIGN Existing Pavements Our evaluation indicatesd that the majority of existing pavement distress generally consist of fatigue (alligator) cracking, located primarily within the slow lane wheel paths. Our analysis indicates that the existing pavement may be rehabilitated by grinding the upper 1 inch of existing pavement and placing a minimum 2- to 3-inch HMA overlay. New Pavements Pavement sections presented are based on estimated A-value data (to be evaluated by specific R-value testing at completion of grading), a range of typical design classifications, and the minimum requirements of the City of Carlsbad. For planning purposes, the following preliminary pavement sections, consisting of asphaltic concrete over base are provided in the following table. New Asphaltic Concrete (AC) Pavement LP 1~gl:t 4iTMFFiC t trR,VAthE i' J'l' I AGGEGATE,,,PI ' 'BASETHiKNESS'! CONCAETE.- , BASE'4' . riç -. . Ass medF, . Mt'riab' i41 Qncnes I t' Inc - ECA 9.0 - 14 6.0 17.0 - ECH 9.0 14 6.0 - 10.0 ECR 9.0 14 13.5 - - '"Denotes standard Caltrans Class 2 aggregate base R 78, SE .222). 11 values have been assumed for planning purposes herein and should be confirmed by the design team during future plan development. PAverage value, based on a review of Appendix C. 'Per Section 28 of Caltrans Standard Specifications (2006). It has been our experience in the City that subgrade soils with R-values less than, or equal to 12 may require additional improvement, including, but not necessarily limited to: a thickened base section, lime treatment, and/or geotextiles such as Mirafi HP 570, or equivalent. Alternative Pavement Section: Subgrade Enhancement Geotextile (SEG) In addition to a standard asphalt over aggregate base pavement section, an alternative section, using SEG's per Section 614.5 of the Highway Design Manual (State of California, 2008), and the State of California (2009) is provided. The recommended pavement Shapell Homes W.O. 6145-E-SC Rancho Costera, Carlsbad May 11, 2011 File:e:\wp9\6100\6145e.gif Page 42 GoSoils, Inc. sections, provided in general accordance with the City guidelines (City of Carlsbad, 1993), and the State of California (2008, 2009), are presented as follows: TE ir :tjg . ECR 9.0 20 6.0 15.0 Bi Per O'Day Consultants, (Improvement plans) Effective R-value when using SEG HP 570, or equivalent (State of California. 2008, 2009), on soils with A-values less than 20. Per Carlsbad (1993) Denotes Class 2 Aggregate Base A .>78, SE .?25) I (4) M Class Bi, Mirafi HP 570, or equivalent This alternative includes design pavement sections using SEG's per Section 614.5 of the Highway Design Manual (State of California, 2008), and the State of California (2009). Subgrade enhancement geotextile (SEG) used shall be either Mirali HP 570 (Class Bi), or FW500 (Class 132), or equivalent. All SEG's shall be placed per the manufacturers guidelines. The recommended pavement sections provided above are meant as minimums. If thinner or highly variable pavement sections are constructed, increased maintenance and repair could be expected. If the ADT (average daily traffic) beyond that intended, as reflected by the traffic index used for design, increased maintenance and repair could be required for the pavement section. Best management construction practices should be in effect at all times. Pavement Grading Recommendations General Subgrade preparation and aggregate base preparation should be performed in accordance with the recommendations presented below, and the minimum subgrade (upper 12 inches) and Class 2 aggregate base compaction should be 95 percent of the maximum dry density (ASTM D 1557). If adverse conditions (i.e., saturated ground, etc.) are encountered during preparation of subgrade, special construction methods may need to be employed. These recommendations should be considered preliminary. Further R-value testing and pavement design analysis should be performed upon completion of grading for the site. Shapell Homes S W.O. 6145-E-SC Rancho Costera, Carlsbad May 11, 2011 File: e:\wp9\61 OD\6145e.gif Page 4.3 GeScü, Inc. All section changes should be properly transitioned. If adverse conditions are encountered during the preparation of subgrade materials, special construction methods may need to be employed. Subgrade Within street areas, all surficial deposits of loose soil material should be removed and recompacted as recommended. After the loose soils are removed, the bottom is to be scarified to a depth of 12 inches, moisture conditioned as necessary and compacted to 95 percent of maximum laboratory density, as determined by ASTM Test Method 0 1557. Deleterious material, excessively wet or dry pockets, concentrated zones of oversized rock fragments, and any other unsuitable materials encountered during grading should be removed. The compacted fill material should then be brought to the elevation of the proposed subgrade for the pavement. The subgrade should be proof-rolled in order to ensure a uniformlyflrm and unyielding surface. All grading and fill placement should be observed by the project soil engineer and/or his representative. Base Compaction tests are required for the recommended base section. Minimum relative compaction required will be 95 percent of the maximum laboratory density as determined by ASTM Test Method D 1557. Base aggregate should be in accordance to the "Standard Specifications for Public Works Construction" (green book) current edition. Paving Prime coat may be omitted if all of the following conditions are met: The asphalt pavement layer is placed within two weeks of completion of base and/or subbase course. Traffic is not routed over completed base before paving. Construction is completed during the dry season of May through October. The base is free of dirt and debris. If construction is performed during the wet season of November through April, prime coat may be omitted if no rain occurs between completion of base course and paving and the time between completion of base and paving is reduced to three days, provided the base is free of dirt and debris. Where prime coat has been omitted and rain occurs, traffic is routed over base course, or paving is delayed, measures shall be taken to restore base Shapell Homes W.O. 6145-E-SC Rancho Costera, Carlsbad May 11, 2011 file:e:\wp9\6100\6145e.gif Page 44 Inc. course, subbase course, and subgrade to conditions that will meet specifications as directed by the soil engineer. Drainage Positive drainage should be provided for all surface water to drain towards the area swale, curb and gutter, or to an approved drainage channel. Positive site drainage should be maintained at all times. Water should not be allowed to pond or seep into the ground. If planters or landscaping are adjacent to paved areas, measures should be taken to minimize the potential for water to enter the pavement section. PERMEABLE PAVEMENT/PAVERS Should permeable payers or pavement be utilized in the median islands, thickened edges/deepened footings are recommended on the perimeter. Such improvements should be constructed per the manufacturers guidelines; however, GSI would like to point out the site soils at roadway elevations are generally anticipated to have poor infiltration. DEVELOPMENT CRITERIA Slope Deformation General Compacted fill slopes, designed using customary factors-of-safety for gross or surficial stability, and constructed in general accordance with the design specifications, should be expected to undergo some differential vertical heave, or settlement, in combination with differential lateral movement in the out-of-slope direction, after grading. This post-construction movement occurs in two forms: slope creep; and, lateral fill extension (LIFE). Slope Creep Slope creep is caused by alternate wetting and drying of the fill soils which results in slow downslope movement. This type of movement is expected to occur throughout the life of the slope, and is anticipated to potentially affect improvements or structures (i.e., separations and/or cracking), placed near the top-of-slope, generally within a horizontal distance of approximately 15 feet, measured from the outer, deepest (bottom outside) edge of the improvement, to the face of slope. The actual width of the zone affected is generally dependant upon: 1) the height of the slope: 2) the amount of irrigation/rainfall the slope receives: and, 3) the type of materials comprising the slope. This movement generally results in rotation and differential settlement of improvements located within the creep zone. Shapell Homes Rancho Costera, Carlsbad FUe:e:\wp9\6100\6145e.gif Geoftfls, Inc. W.O. 6145-E-SC May 11, 2011 Page 45 Suitable mitigative measures to reduce the potential for distress due to lateral deformation typically include: setback of improvements from the slope faces (per the 2010 CBC); positive structural separations (i.e., joints) between improvements; and, stiffening and deepening of foundations. Per Section 1805.3 of the 2010 CBC (CBSC, 2010) guidelines, unless specifically superceded herein, a horizontal setback (measured from the slope face to the outside bottom edge of the building footing) of H/3 is provided for structures, where H is the height of the fill slope in feet and 1-113 need not be greater than 40 feet. Alternatively, in consideration of the discussion presented above, site conditions and Section 1805.3 of the 2010 CBC (CBSC, 2010), H/3 generally need not be greater than 20 feet for the development. As an alternative to a deepened footing, where the adjacent slope is greater than 45 feet in height and the building/footing is within 20 feet from the slope face, a differential settlement of 0.5 inch (additional) may be applied to the design of that portion of the structure(s). Any settlement-sensitive improvements (i.e., walls ,spas, flatwork, etc.) should consider the above. Lateral Fill Extension (LFE) LFE occurs due to deep wetting from irrigation and rainfall on slopes comprised of expansive materials. Based on the generally very low expansive character of onsite soils, the potential component of slope deformation due to LFE is considered minor, but may not be totally precluded. Although some movement should be expected, long-term movement from this source may be minimized, but not eliminated, by placing the fill throughout the slope region, wet of the fill's optimum moisture content. Summary It is generally not practical to attempt to eliminate the effects of either slope creep or LFE. Suitable mitigative measures to reduce the potential of lateral deformation typically include: setback of improvements from the slope faces (per the 2010 CBC); positive structural separations (i.e., joints) between improvements; stiffening; and, deepening of foundations. All of these measures are recommended for design of structures and improvements and minimizing the placement of "dry" fills. Slope Maintenance and Planting Water has been shown to weaken the inherent strength of all earth materials. Slope stability is significantly reduced by overly wet conditions. Positive surface drainage, away from slopes, should be maintained and only the amount of irrigation necessary to sustain plant life should be provided for planted slopes. Over-watering should be avoided as it can adversely affect site improvements and cause perched groundwater conditions. Graded slopes constructed utilizing onsite materials would be erosive. Eroded debris may be minimized and surficial slope stability enhanced by establishing and maintaining a suitable vegetation cover soon after construction. Compaction to the face of fill slopes would tend to minimize short-term erosion until vegetation is established. Plants selected for landscaping should be light weight, deep rooted types that require little water and are Shapell Homes W.O. 6145-E-SC Rancho Costera, Carlsbad May 11, 2011 FiIe:e:\wp9\6100\6145e.gif Page 46 Geooils, Inc. capable of surviving the prevailing climate. Jute-type matting, or other fibrous covers, may aid in allowing the establishment of a sparse plant cover. Utilizing plants other than those recommended above will increase the potential for perched water, staining, mold, etc. to develop. A rodent control program to mitigate burrowing should be implemented. Irrigation of natural (ungraded) slope areas is not recommended. Over-steepening of slopes should be avoided during building construction activities and landscaping. Drainage Adequate lot surface drainage is a very important factor in reducing the likelihood of adverse performance of foundations, hardscape, and slopes. Surface drainage should be sufficient to mitigate ponding of water anywhere on a lot, and especially near structures and tops of slopes. Lot surface drainage should be carefully taken into consideration during fine grading, landscaping, and building construction. Therefore, care should be taken that future landscaping or construction activities do not create adverse drainage conditions. Positive site drainage within lots and common areas should be provided and maintained at all times. Drainage should not flow uncontrolled down any descending slope. Water should be directed away from foundations and not allowed to pond and/or seep into the ground. In general, the area within 3 feet around a structure should slope away from the structure. We recommend that unpaved lawn and landscape areas have a minimum gradient of 1 percent sloping away from structures, and whenever possible, should be above adjacent paved areas. Consideration should be given to avoiding construction of raised planters adjacent to structures (buildings, pools, spas, etc.). Pad drainage should be directed toward the street or other approved area(s). Although not a geotechnical requirement, roof gutters, down spouts, or other appropriate means may be utilized to control roof drainage. Down spouts, or drainage devices, should outlet a minimum of 3 feet from structures or into a subsurface drainage system. Areas of seepage may develop due to irrigation or heavy rainfall, and should be anticipated. Minimizing irrigation will lessen this potential. If areas of seepage develop, recommendations for minimizing this effect could be provided upon request. Erosion Control Cut and fill slopes will be subject to surlicial erosion during and after grading. Onsite earth materials have a moderate to high erosion potential. Consideration should be given to providing hay bales and silt fences for the temporary control of surface water, from a geotechnical viewpoint. Landscape Maintenance Only the amount of irrigation necessary to sustain plant life should be provided. Over-watering the landscape areas will adversely affect proposed site improvements. We recommend that any open-bottom, raised box planters adjacent to proposed structures be restricted for a minimum distance of 10 feet. As an alternative, closed-bottom type raised planters could be utilized. An outlet placed in the bottom of the planter could be Shapell Homes W.O. 6145-E-SC Rancho Costera, Carlsbad May 11, 2011 FiIe:e:\wp9\6100\6145e.gif Page 47 Geooüs, Inc. installed to direct drainage away from structures or any exterior concrete fiatwork. If raised box planters are constructed adjacent to structures, the sides and bottom of the planter should be provided with a moisture barrier to mitigate penetration of irrigation water into the subgrade. Provisions should be made to drain the excess irrigation water from the planters without saturating the subgrade below or adjacent to the planters. Graded slope areas should be planted with drought resistant vegetation. Consideration should be given to the type of vegetation chosen and their potential effect upon surface improvements (i.e., some trees will have an effect on concrete fiatwork with their extensive root systems). From a geotechilical standpoint, leaching is not recommended for establishing landscaping. If the surface soils are processed for the purpose of adding amendments, they should be recompacted to 90 percent minimum relative compaction. Subsurface and Surface Water Subsurface and surface water are not anticipated to affect site development, provided the recommendations contained in this report are incorporated into final design and construction, and that prudent surface and subsurface drainage practices are incorporated into the construction plans. Perched groundwater conditions, along zones of contrasting permeabilities, may not be precluded from occurring in the future due to site irrigation, poor drainage conditions, or damaged utilities, and should be anticipated. Should perched groundwater conditions develop, this office could assess the affected area(s) and provide the appropriate recommendations to mitigate the observed groundwater conditions. Groundwater conditions may change with the introduction of irrigation, rainfall, or other factors. Site Improvements If in the future, any additional improvements are planned for the site, recommendations concerning the geological or geotechnical aspects of design and construction of said improvements could be provided upon request. This office should be notified in advance of any fill placement, grading of the site, or trench backfilling after rough grading has been completed. This includes any grading, utility trench, and retaining wall backlills. Footing Trench Excavation All footing excavations should be observed by a representative of this firm subsequent to trenching and prior to concrete form and reinforcement placement. The purpose of the observations is to evaluate that the excavations are made into the recommended bearing material and to the minimum widths and depths recommended for construction. If loose or compressible materials are exposed within the footing excavation, a deeper footing or removal and recompaction of the subgrade materials would be recommended at that time. Footing trench spoil and any excess soils generated from utility trench excavations should be compacted to a minimum relative compaction of 90 percent, if not removed from the site. Shapell Homes W.O. 6145-E-SC Rancho Costera, Carlsbad May 11, 2011 FiIe:e:wp9\6100\6145e.gif Page 48 GeoSil5, Inc. Trenching Considering the nature of the onsite soils, it should be anticipated that caving or sloughing could be afactor in subsurface excavations and trenching. Shoring or excavating the trench wails at the angle of repose (typically 25 to 45 degrees) may be necessary and should be anticipated. All excavations should be observed by one of our representatives and minimally conform to CAL-OSHA and local safety codes. Trenching for the deeper utility improvements within ECR will likely encountered both a shallow groundwater table and relatively soft alluvial soils. For planning purposes, trenching and shoring design/construction should be in accordance with CAL-OSHA guidelines for type C soils. Dewatering should also be anticipated in these areas, especially ECR Stations 444+00 to 452+00, and ECR Stations 481+00 to 488+00. Dewatering Based on the depth of utility below potential groundwater elevations, some dewatering maybe necessary to construct planned utilities. The contractor should review the attached subsurface information, laboratory data, and evaluate the potential for effective dewatering. Utility Trench Backfill Pipe or utility trench backfill should adhere to all applicable OSHA regulations during installation. When designing utility backfill specifications for this project, the 2009 version of the San Diego Regional Standard Drawings, as cited by the City of Carlsbad for backfill standards, should be used. Some of the applicable backfill standards are: Storm Drains D-60 Irrigation Trench 1-26, and 1-26 ° Trench Resurfacing G-24, G-25 •Narrow Trenches G-33, M-7, M-7A, and M-8 Slurry Backfill G-36 Sewer Pipe Bedding and Backfill SP-02 Recycled and Potable Water Mains WP-02 Cutting and Abandoning Existing Sewer and Water Lines WP-03 Other standards may apply to this project and the above should only be taken as a partial listing of the applicable City standards. When considering slurry backfill as indicated by the City standard cited herein, the concern for creating a blockage of subsurface water or seepage should be considered, i.e., next to the toe of a slope that intercepts a sand layer with a gradient perpendicular to the direction of the seepage. Three-sack sand/cement slurry should be sufficient in most applications and should minimally comply with the compressive strength as indicated in Standard G-36. Shapell Homes W.O. 6145-E-SC Rancho Costera, Carlsbad May 11, 2011 Fite:e:\wp9\61006145e.gif Page 49 Gocoi9s, Inc. Trench-less technology (bore and jack) may be utilized on this project to save time and money in high traffic areas to receive deep trenches/utilities. GSl can provide supplemental recommendations including the jacking and receiving pits if this technology is to be considered. The use of geotextiles for support of weak subgrade soils at the bottom of utility trenches or to encapsulate the open-graded aggregate as specified by City standards, may be necessary. For utility trench stabilization TenCate Mirafi HP 570 may be used. For the separation of open graded aggregates from onsite soils, a TenCate Mirafi 140 or 180 N may be used. All trench excavations should conform to CAL-OSHA and local safety codes. SUMMARY OF RECOMMENDATIONS REGARDING GEOTECHNICAL OBSERVATION AND TESTING We recommend that observation and/or testing be performed by GSI at each of the following construction stages: During grading. After excavation of foundations, retaining wall footings, and free standing walls footings, prior to the placement of reinforcing steel or concrete. Prior to pouring any slabs or flatwork, after presoaki ng/presatu ration of flatwork subgrade, before the placement of concrete, reinforcing steel, capillary break (i.e., sand, pea-gravel, etc.), or vapor retarders/barriers (i.e., visqueen, etc.). During retaining wall subdrain installation, prior to backfill placement. During placement of retaining wall backfill. During slope construction/repair. When any unusual soil conditions are encountered during any construction operations, subsequent to the issuance of this report. OTHER DESIGN PROFESSIONALS/CONSULTANTS The design civil engineer, structural engineer, architect, landscape architect, wall designer, etc., should review the recommendations provided herein, incorporate those recommendations into all their respective plans, and by explicit reference, make this report part of their project plans. This report presents minimum design criteria for the design of Shapell Homes W.O. 6145-E-SC Rancho Costera, Carlsbad May 11, 2011 FiIe:e:\wp9\6100\6145e.gif Page 50 ooils, Inc. foundations and other elements possibly applicable to the project. These criena should not be considered as substitutes for actual designs by the structural engineer/designer. The structural engineer/designer should analyze actual soil-structure interaction and consider, as needed, bearing, expansive soil influence, and strength, stiffness and deflections in the various foundation, and other elements in order to develop appropriate, design-specific details. As conditions dictate, it is possible that other influences will also have to be considered. The structural engineer/designer should consider all applicable codes and authoritative sources where needed. If analyses by the structural engineer/designer result in less critical details than are provided herein as minimums, the minimums presented herein should be adopted. It is considered likely that some, more restrictive details will be required. If the structural engineer/designer has any questions or requires further assistance, they should not hesitate to call or otherwise transmit their requests to GSI. PLAN REVIEW Any additional project plans generated for this project should be reviewed by this office, prior to construction, so that construction is in accordance with the conclusions and recommendations of this report. Should grading plans change, additional review and/or investigation may be necessary. LIMITATIONS The materials encountered on the project site and utilized for our analysis are believed representative of the area; however, soil and bedrock materials vary in character between excavations and natural outcrops or conditions exposed during mass grading. Site conditions may vary due to seasonal changes or other factors. Inasmuch as our study is based upon our review and engineering analyses and laboratory data, the conclusions and recommendations are professional opinions. These opinions have been derived in accordance with current standards of practice, and no warranty is expressed or implied. Standards of practice are subjectto change with time. GSI assumes no responsibility or liability for work or testing performed by others, or their inaction; or work performed when GSI is not requested to be onsite, to evaluate if our recommendations have been properly implemented. Use of this report constitutes an agreement and consent by the user to all the limitations outlined above, notwithstanding any other agreements that may be in place. In addition, this report may be subject to review by the controlling authorities. Thus, this report brings to completion our scope of services for this project. Shapell Homes W.O. 6145-E-SC Rancho Costera, Carlsbad May 11, 2011 Fule:e:\wp9\6100\6145e.gif Page 51 Geo&ls, 19w0 I. APPENDIX A REFERENCES ACI Committee 318,2008, Building code requirements for structural concrete (ACI 318-08) and commentary, dated January. ACI Committee 360, 2006, Design of slabs-on-ground (ACI 36013-06). ACI Committee 302, 2004, Guide for concrete floor and slab construction, ACI 302.1 R-04, dated June. ACI Committee on Responsibility in Concrete Construction, 1995, Guidelines for authorities and responsibilities in concrete design and construction in Concrete International, vol 17, No. 9, dated September. Asphalt Institute, undated, [http ://asphaltinstitute.org/public/eflgifleeriflcl/ifldeX.aSP1 Bartlett, S.F. and Youd, T.L., 1995, Empirical prediction of liquefaction-induced lateral spread, Journal of Geotechnical Engineering, ASCE, Vol 121, No. 4, April. 1992, Empirical analysis of horizontal ground displacement generated by liquefaction induced lateral spreads, Tech. Rept. NCEER 92-0021, National Center for Earthquake Engineering Research, SUNY-Buffalo, Buffalo, NY. Blake, Thomas F., 2000a, EQFAULT, A computer program for the estimation of peak horizontal acceleration from 3-D fault sources; Windows 95/98 version. 2000b, EQSEARCH, A computer program for the estimation of peak horizontal acceleration from California historical earthquake catalogs; Updated to June, 2009, Windows 95/98 version. 2000c, FRISKSP, A computer program for the probabilistic estimation of peak acceleration and uniform hazard spectra using 3-D faults as earthquake sources; Windows 95/98 version. Bozorgnia, Y., Campbell K.W., and Niazi, M., 1999, Vertical ground motiOn: Characteristics, relationship with horizontal component, and building-code implications; Proceedings of the SMlP99 seminar on utilization of strong-motion data, September 15, Oakland, pp. 23-49. Bryant, W.A., and Hart, E.W., 2007, Fault-rupture hazard zones in California, Alquist-Priolo earthquake fault zoning act with index to earthquake fault zones maps; California Geological Survey, Special Publication 42, interim revision. Inc. California Building Standards Commission, 2010, California Building Code, California Code of Regulations, Title 24, Part 2, Volume 2 of 2, Based on the 2009 International Building Code, 2010 California Historical Building Code, Title 24, Part 8; 2010 California Existing Building Code, Title 24, Part 10. California Code Of Regulations, 1996, CAL-OSHA State of California Construction and Safety Orders, dated July 1. California Department of Conservation, California Geological Survey, 2008, Guidelines for evaluating and mitigating seismic hazards in California: California Geological Survey Special Publication 11 7A (revised 2008), 102 p. California Department of Conservation, Division of Mines and Geology, 1996, Probabilistic seismic hazard assessment forthe state of California, DMG Open-File Report 96-08. California Department of Transportation, 2006, Caltrans, Standard specifications, May printing. Carlsbad, City of, 1993, Standards for design and construction of public works improvements in the City of Carlsbad. Civiltech Software, 2006, LiquefyPro, liquefaction and settlement analysis; Version 5.4b and later. Fisher, P.J., and Mills, G.l., 1991, The offshore Newport-Inglewood - Rose Canyon fault zone, California: structure, segmentation, and tectonics, in Abbot, P.L., and Elliott, W.J., eds., Environmental perils - San Diego region, published by San Diego Association of Geologists. Frankel, Arthur D., Perkins, David M., and Mueller, Charles S., 1996, Preliminary and working versions of draft 1997 seismic shaking maps for the United States showing peak ground acceleration (PGA) and spectral acceleration response at 0.3 and 1.0-second site periods for the Design Basis Earthquake (10 percent chance of exceedance in 50 years) for the National Earthquake Hazards Reduction Program (NEHRP): U.S. Geological Survey, Denver, Colorado. Geopacifica Geotechnical Consultants, 2004, Geotechnical review - EIR 03-03, Robertson Ranch master plan, Carlsbad, California, No job no., dated June 19. GeoSoils, Inc., 2010, Updated geotechnical investigation for Robertson Ranch West Village, Carlsbad, San Diego County, California, W.O. 6145-A-SC, dated October 10. 2008a, Report of mass grading, Planning Area 11, Robertson Ranch Habitat Corridor and widening of El Camino Real at Cannon Road, Robertson Ranch West, Carlsbad, San Diego County, California 92010, City of Carlsbad Planning ShapeH Homes Appendix A FiIe:e:\wp9\6100\6145e.gif Page 2 Geo5eils, Inc. Department Application No. SUP 06-12/HDP 06-04, W.O. 5247-132-SC, dated July 16. 2008b, Report of mass grading, Planning Area 12 (13.44 Acres), and Planning Area 13 (6.92 Acres), Robertson Ranch West, Carlsbad, San Diego County, California 92010, City of Carlsbad Planning Department Application No. SUP 06-12/HDP 06-04, W.O. 5247-Bl-SC, dated June 5. 2004a, Updated geotechnical evaluation of the Robertson Ranch property, Carlsbad, San Diego County, California, W.O. 3098-A2-SC, dated September 20. 2004b, Unpublished large diameter bucket auger boring logs (including laboratory testing), Robertson Ranch, West Village, W.O. 3098-A2-SC. 2002, Geotechnical evaluation of the Robertson Ranch Property, City of Carlsbad, San Diego County, California, W.O. 3098-Al -SC, dated January 29. 2001a, Preliminary findings of the geotechnical evaluation, Robertson Ranch Property, City of Carlsbad, California, W.O. 3098-A-SC, dated July 31. 2001 b, Preliminary geotechnical evaluation, Calavera Hills II, College Boulevard and Cannon Road Thoroughfare, District No. 4 (B&TD), City of Carlsbad, California, W.O. 2863-A-SC, dated January 24. Greensfelder, R. W., 1974, Maximum credible rock acceleration from earthquakes in California: California Division of Mines and Geology, Map Sheet 23. Gregory, G.H., 2003, GSTABL7 with STEDwin, slope stability analysis system; Version 2.004. International Conference of Building Officials (ICBO), 1998, Maps of known active fault near-source zones in California and adjacent portions of Nevada. Ishihara, K., 1985, Stability of natural deposits during earthquakes: Proceedings of the Eleventh International Conference on Soil Mechanics and Foundation Engineering: A.A. Balkena Publishers, Rotterdam, Netherlands. Jennings, C.W., and Bryant, W.A., 2010, Fault activity map of California, scale 1:750,000, California Geological Survey, Geologic Data Map No. 6. Leighton and Associates, 1985, Geotechnical feasibility evaluation, 403.3 acres at east corner of El Camino Real and Tamarack Avenue, Carlsbad, CaJifornia, Project no. 4850555-03, dated November 15. Shapell Homes Appendix A FiIe:e:\wp9\6100\6145e.gif Page 3 GeSoils, Inc. Leighton and Associates, Inc., and David Evans and Associates, Inc., 1992, City of Carlsbad, geotechnical hazards analysis and mapping study, Carlsbad, California, dated November. Undvall, S.C., Rockwell, T.K., and Undivall, E.C., 1989, The seismic hazard of San Diego revised: new evidence for magnitude 6+ Holocene earthquakes on the Rose Canyon fault zone, in Roquemore, G., ed., Proceedings, workshop on 'The seismic risk in the San Diego region: special focus on the Rose Canyon fault system. Moss, R.E.S., Seed, R.B., Kayen, R.E., Steward, J.P., Tokimatsu, K., 2005, Probabilistic liquefaction triggering based on the cone penetration test, American Society of Civil Engineers. Naval Facilities Engineering Command, 1986a, Soil mechanics design manual 7.01, Change 1 September: U.S. Navy. 1986b, Foundations and earth structures, design manual 7.02, Change 1 September: U.S. Navy. NEWCON90, 1991 Computer program for the determination of asphalt pavement sections, dated April 30. O'Day Consultants, 2011 a, Composite grading plan, 100-scale, 1 sheet, dated April 22. 2011 b, Grading of storm drain plan for: EL Camino Real, Rancho Costera, Sheets 7 through 15, 40-scale, dated January. Petersen, Mark D., Bryant, W.A., and Cramer, C.H., 1996, Interim table of fault parameters used by the California Division of Mines and Geology to compile the probabilistic seismic hazard maps of California. Public Works Standards, Inc., 2009, "Greenbook" standard specifications for public works construction, 2009 edition (and any supplements). State of California, Department of Transportation, 2009, Guide for designing subgrade enhancement geotextiles, dated April 28. -, 2008, Highway design manual of instructions, dated July 1. Seed, H.B. and Idriss, l.M., 1982, Ground motions and soil liquefaction during earthquakes, Earthquake Engineering Research Institute. ShapeR Homes Appendix A Fu1e:e:\wp9\6100\6145egif Page 4 GeoSoils, Inc. Sowers and Sowers, 1970, Unified soil classification system (After U. S. Waterways Experiment Station and ASTM 02487-667) in Introductory Soil Mechanics, New York. State of California, 1967, Department of Water Resources, Bulletin 106-2, Groundwater occurrence and quality: San Diego Region, Vol. II: plates, dated June. Tan, S.S., and Kennedy, M.P., 1996, Geologic maps of the northwestern part of San Diego County, California, plate 2, geologic map of the Encinitas and Rancho Santa Fe 7.5' quadrangles, San Diego County, California, scale 1:24,000, DMG Open-File Report 96-02. Terzaghi, K., and Peck, R.B., 1967, Soil mechanics in engineering practice: John Wiley and Sons, New York, Second Edition. Treiman, J.A., 1993, The Rose Canyon fault zone southern California, published by the California Department of Conservation, Division of Mines and Geology, DMG Open-File Report 93-02. 1984, The Rose Canyon fault zone, a review and analysis, published by the California Department of Conservation, Division of Mines and Geology, cooperative agreement EMF-83-k-01 48. United States Department of Agriculture, 1953) Black and white aerial photographs, AXN-8M-70 and AXN-8M-71, and AXN-8M-100 to 102. Weber, F.H., 1982, Geologic map of north-central coastal area of San Diego County, California showing recent slope failures and pre-development landslides: California Department of Conservation, Division of Mines and Geology, OFR 82-12 LA. Wilson, K.L., 1972, Eocene and related geology of a portion of the San Luis Rey and Encinitas quadrangles, San Diego County, California: unpublished masters thesis, University of California, Riverside. U.S. Geological Survey, 2008, Seismic Hazard Curves and Uniform Response Spectra, Version 5.0.9. Shapell Homes Appendix A FiIe:e:\wp9\6100\6145e.gif Page 5 GeSafis, Inc. UNIFIED SOIL CLASSIFICATION SYSTEM CONSISTENCY OR RELATIVE DENSITY Major Divisions Group Typical Names CRITERIA Symbols Well-graded gravels and gravel- o a s. GW sand mixtures, lithe or no fines Standard Penetration Test > -6 ro g , .-> Penetration Poorly graded gravels and 0 • °o°O GP gravel-sand mixtures, little or no Resistance N Relative U) W E . Z fines (blows/ft) Density 8 cv 0-4 Very loose Silty gravels gravel-sand-silt o GM mixtures 4-10 Loose GC Clayey gravels, gravel-sand-day mixtures 10-30 Medium Well-graded sands and gravelly (I)! 30-50 Dense 00 SW sands, little or no lines ° c i5 C t5 > 50 Very dense Poorly graded sands and t gravelly sands, little or no lines 0 CUD, o SM Silty sands, sand-silt mixtures 0g E Q. U. Clayey sands, sand-clay (0 sc mixtures Inorganic silts, very fine sands, Standard Penetration Test ML rock flour, silty or clayey fine sands 5 Unconfined Penetration Compressive Inorganic days of low to o °IS Cr * CL medium plasticity, gravelly days. Resistance N Strength U3 CVo U) days, lean sandy clays, silty low) Consistency (tons/ft2) days CIO 6 Z 0 <2 Very Soft <0.25 Organic silts and organic silty 0)0 a) OL clays of low plasticity -3 W 2-4 Soft 0.25-.050 MH Inorganic sills, micaceous or diatomaceous fine sands or silts, (5 COL o .9 0 4-8 Medium 0.50-1.00 U.. E Q elastic silts o E B-15 Stiff 1.00-2.00 0 32 C Inorganic clays of high plasticity, U) or R CH fat days 15-30 Very Stiff 2.00 4.00 Organic clays of medium to high 0) >30 Hard >4.00 OH plasticity Highly Organic Soils PT Peat, mucic, and other highly organic soils 3' 3/4" #4 #10 #40 #200 U.S. Standard Sieve I I Unified Soil I Gravel Sand I Silt or clay Cobbles Classification coarse fine coarse medium line MOISTURE CONDITIONS MATERIAL QUANTITY OTHER SYMBOLS Dry Absence of moisture: dusty, dry to the touch trace 0-5% C Core Sample Slightly Moist Below optimum moisture content for compaction few 5-10 % S SPT Sample Moist Near optimum moisture content lithe 10-25 % B Bulk Sample Very Moist Above optimum moisture content some 25-45 % V Groundwater Wet Visible free water; below water table Op Pocket Penetrometer BASIC LOG FORMAT: Group name. Group symbol, (grain size), color, moisture, consistency or relative density. Additional comments: odor, presence of roots, mica, gypsum, coarse grained particles, etc. EXAMPLE: Sand (SP), fine to medium grained, brown, moist, loose, trace silt, little fine gravel, few cobbles up to 4" in size, some hair roots and rootlets. File:Mgr c;\SollClassif.wpd PLATE B-i BORING LOG Geoil, Inc. WO. 6145-E-SC PROJEC SI-IAPELL HOMES BORING B-201 SHEET 1 OF Rancho Costera, El Camino Real DATEE)(CAVATED 3-28-11 LOGGED BY:RGC — Sample SAMPLE METHOD: Hollow Stem Auger - - Approx. Elevation: 111f MSL FM Standard Penefration Test .5 - Gmundwater Undisluthed, Ring Sample U) a C) .! .2 co • Description of Material - - — CL COLLIJV1UM: 1- 0 © 0' SANDY CLAY, dark olive brown, wet, soft. — — — TERRACE DEPOSITS (Qfl: 4- @ 3' SILTY SAND w/CLAY, brown, moist, loose. 50 SM 110.1 10.7 56.5 ••: @ 5' Becomes SILTY SAND, brown, moist, dense; weakly developed, 6 : sub-horizontal bedding. 7- 8- - 47 SM/SC 10 98.0 10' As per 5', CLAYEY SAND interbeds. 12- 13- 14- 50+ 106.7 17.6 84.8 © 15' As per 10' SILTY SAND w/CLAYEY SAND interbeds, mottled .• olive brown and brown, moist, dense; sub-horizontal 'bedding. 17- 18- 19- 20- 50+ 107.8 16.8 83.1 © 20' As per 15'. Ti _ 25---50+ SC/Sp 108.7 iiT 57.2 @ 25' Interbedded CLAYEY SAND and fine to medium grained SAND, 26-I4 :: olive brown to brown, slightly moist to moist, dense. Geoo, Inc..FRancho'Cos'tera, El Camino Real Plate 8-2 BORING LOG Geooil, WO. 6145-E-SC PROJECT: SHAPELL HOMES BORING B-201 SHEET OF Rancho Costera, El Camino Real DATE E)(CA VA TED 3-28-11 LOGGED BY: RGC Sample . SAMPLE METHOD: Hollow Stem Auger - - ApproL Elevation: jj MSL Standaiti Penetration Test .9; . - Groundwater Undistuthed, Ring Sample (1) C D - ____________________________ - C, g Description of Material - - 45/ SP 94.7 6.2 22.0 @ 30' SAND wICLAY, moist, dense; medium grained, poorly sorted. 31 50-4" 109.8 10.3 53.9 32- 33- 34. - 50-6" SC 4o Recover © 35' CLAYEY SAND, brown to olive brown, moist, dense. 39- 40- - 50-4"SC/SP 96.6 6.1 22.5 :" 40' SAND and CLAYEY SAND interbeds, sub-horizontal bedding. 41- 42- 43- 44- -. 504" @ 45' As per 40'. Total Depth = 46' No Groundwater Encountered Backfilled 3-28-2011 - - Geo&, Inc Rancho Costera, El Camino Real Plate B-3 BORING LOG Geoil, Inc. WO. 6145-E-SC PROJECT: SHAPELL HOMES BORING 3-202 SHEET OF Rancho Costera, El Camino Real DATE EXCAVATE!) 3-28-11 LOGGED BY: RGC Sample SAMPLE METHOD: uwStemAug& - - Approx. Elevation: 4' MSL Standard Penetration Test & BE Groundwater - E >.. Undisturbed, Ring Sample ILW W 13 Cl) 0. U . U) M Description of Material D 13 C) Cl) - - - CIRA - @ 0, Asphalt -8 inches over 4 inches R.A.P. 1••- -- - sw @ 1' Base - 12 inches, dark gray brown, well graded sand with some 2 - fine gravel. . FILL: 3. @2'CLAYEY SAND, light gray, wet, medium dense. 4-. 19 99.3 19.0 CL 12 15 16' 17 18' 19 20 21 22 23 24 25 26 27 20 19 I I 112.6 I 15.2 I 85.7 11 SP 111.4 18.3 99.9 19 8 © 7' CLAY with SAND, dark brown, wet, firm. @ 8' Stabilized groundwater level. @ 12' Becomes SANDY CLAY, very dark grayish brown, wet, firm. @ 14' CLAYEY SAND and SAND, brown to dark brown, saturated (water bearing sand), medium dense. Water level in boring rose to 8'. dark gray, saturated, loose to medium dense. D and CLAYEY SAND, dark gray brown, saturated, loose. I Rancho Costera, El Camino Real Geooil, '° Plate 8-4 BORING LOG Geoils, Inc. PROJECT: SI-IAPELL HOMES Rancho Costera, El Camino Real Sample I., -g E. U) U CO 0. V 0 c .2 to ' 0 a in D m D 0 31- WO. 6145-E-SC BORING B-202 SHEET OF DATE EXCA VA TED 3-28-I1 LOGGED BY:RGC SAMPLE METHOD: Holbw Stem Auger Approx. Elevation: 42' MSL Standard Penetration Test Groundwater Undisturbed, Ring Sample cc Description of Material Total Depth =31Yz' Groundwater. Encountered @ a depth of 8' (EL = 34' MSL) Backfihled 3-28-2011 36 37 41 42 47 51 Geook, Rancho Costera, El Camino Real Plate B-5 BORING LOG Geooils, Inc. WO. 6145-E-SC PROJECT: SHAPELL HOMES BORING B-203 SHEET 1 OF Rancho Costera, El Camino Real DATEEXCAVATED 3-28-11 LOGGED BY.RGC - Sample SAMPLE METHOD: Hollow Stem Auger - - - Approx. Elevation: 4 MSL Standard Penetration Test - o - — V Groundwater Undisturbed, Ring Sample - Description of Material - - VRAI ©0' Asphalt -6 inches over 4 inchesR.A.P.. 1• - - - SW :•:• ROAD BASE: 2 @_0.83'Graded SAND with GRAVEL, dark gray, moist, dense. - - - - SM FILL :- 3- : @ 2' SILTY SAND, light gray, moist, medium dense. 4• Sr. Sr. ..iZ... - 106.7 1.7 6_ 846 Q 7' Asper 2'. a Sc 2. 7W SAND to CLAYEY SAND, dark grayish brown, moist, medium • 2• dense; few roots. 9. / 10 - - - SC/CL ALLIJVIUM(Qal): 11 @ 10' CLAYEY SAND to SANDY CLAY, dark brown, wet, loose/firm. 12- 132 - @ 13' Stabilized water level in boring. 14 - 16 CL 102.6 iT 99.9 @ 15' SANDY CLAY, dark grayish brown to dark olive brown, 16 wet/saturated, stiff; fine few water or sand grains. 17 18- 19• 106.1 21.3 100 @ 20' As per 15', soft.. 20-11 21- fl 25' As per 20'. @ 251W CLAYEY SAND, very-d, dense; interbeds of SAND (SP). 29 -J I I I I I I IFI:. Geooil, Ii©. Rancho Costera, El Camino Real Plate B BORING LOG Geoo1s, Inc. WO. 6145-E-SC PRWECT: SHAPELL HOMES BORING B-203 SHEET 2 OF Rancho Costera, El Camino Real DATE EXCA VA TED 3-28-11 LOGGED BY:RGC Sample SAMPLE METHOD: HoHow Stem Auger - - - Approx. Elevation: 4 MSL C, Standard Penetration Test .0 . - Groundwater w • E >, U) -..- C Undisturbed, Ring Sample U, C 2 0 U) CO 0 U) Description of Material o U - - Emm 19 - © 30' As per 25', interbedded SAND and CLAYEY SAND. - Total Depth 31W 71 I Groundwater Encountered @ a depth of 13' (EL = 32' MSL) 33. I Backfil!ed 3-28-2011 I 41 I 47 50 51 52 53 54 55 56 57 a I Rancho Costera, El Camino Real Geood, Inc. Plate 13-7 Sample E >. U) 0. (D 75c w 2 (I) C.) U) o co D m D 0 C/RA CL 3. BORING LOG Geoih, Inc. WO. 6145-E-SC PROJECT: SHAPELL HOMES BORING B-204 SHEET J_ OF Rancho Costera, El Camino Real DATE E)CA VA TED 3-29-11 LOGGED BY: RGC SAMPLE METHOD: Hoflgv Stem Auger Approx. Elevation: ' MSL 901 Standard Penetration Test IM - Groundwater - Undlstvthed, Ring Sample Description of Material - { © 0' Asphalt -6 inches over 4 inches RAP. ::•I ROAD BASE: @ 0.83' Well graded SAND with minor GRAVEL, gray brown, moist, - \ dense. TERRACE DEPOSITS (Qfl: @ 1.83-8' SANDY CLAY, light olive brown, moist to wet, very stiff. 36 102.2 16.9 72.5 6- 7- a- 9- 10- 11- 12- 13- 14- is- 41 102.9 19.9 85.4 16- 17- 18- 19- 20- 21- 22- 23- 24- 25- 43 92.7 27.1 91.4 I 27 © 8-15' SANDY CLAY, reddish brown, wet, stiff. Total Depth = 26' No Groundwater Encountered Backfilled 3-29-2011 @ 15-20' SANDY CLAY, light olive brown to reddish brown, wet, hard. @ 20-26' SILTY CLAY interbeds, brown to reddish brown, wet, very stiff. Rancho Costera, El Camino Real CveoSoUs,Plate B-S BORING LOG GeooilL Inc. - Wo. 6145-E-SC PRWECT. SHAPELL HOMES BORING B-205 SHEET _L OF .J_. Rancho Costera, El Camino Real DATE EXCAVATED 3-29-11 LOGGED BY: RGCIBEV - Sample - SAMPLE METhOD: Hollow StemAuger - - ApproL Elevation: i' MSL Standa,dPenet,allon Test .9: - Groundwater - V ;lt . Undisturbed, Ring Sample 5. 0 .3 Cl) - Description of Material - - - C/RA - © 0' Asphalt -8 inches over 4 inches R.A.P. SW ROAD BASE: 2 . '@ 1'SAND, light brown, moist, dense; minor gravel. - - CUML - TERRACE DEPOSITS (Qt): © 2.3' SANDY CLAY to SILTY CLAY, light brown, moist to wet, very stiff. 50 I I 102.9 I 19.9 I 86.8 9-15' SILTY SAND, light brown, moist to wet, dense. - 10 50 1101 162 855 14- LX :i 106.9 6•732•6: 17- : @ 17' SILTY SAND, orange brown, moist, dense. 18- 19- 20- 51 100.4 5.4 22.2 @ 20' SILTY SAND, light brown, moist, dense. - 23- - - CL © 23' SANDY CLAY, light brown to orange brown, moist, very stiff. 24 25- 67 91.5 258 846 Total Depth = 26' 27 No Groundwater Encountered Backfilled 3-29-2011 - Geo, hc Rancho Costera, El Camino Real Plate 8-9 BORING LOG Geooil, Ime. WO. 6145-E-SC PROJECT: SHAPELL HOMES BORING B-206 SHEET 0F1 Rancho Costera, El Camino Real DATE E)(CA VA TED 3-29-11 LOGGED BY: RGC Sample SAMPLE METHOD: Hollow Stem Auger - - - Approx. Elevation: M' MSL C. U Standard Penetration Test Groundwater E 5 /A Undisturbed, Ring Sample CI) . 0. . 0 . 2 CD .9 CI) Description of Material Q 2 U) - CIRA @ 0' Asphalt-B inches over 4 inches R.A.P. SW ROAD BASE 2 t @ 1'SAND,lightbrown,moist,dense. - . TERRACE DEPOSITS (Qt): 2.3' CLAYEY SAND, light brown to reddish brown, moist, dense. - - SM @ 41R SILTY SAND, light brown, moist, dense. 50 105.2 15.0 69.3 6- 7- 8- 9- 10- 61 lo Recover . : ... ©10'As per 5'. 11 Total Depth = 11' 12 No Groundwater Encountered Backfilled 3-29-2011 13 14 15 16 17 18 19' 20 21' 22 23 24 25 26 27 28 29 Geooil, hac0 Rancho Costera, El Camino Real Plate B-b BORING LOG Geooik, Inc. PROJECT.- SHAPELL HOMES Rancho Costera, El Camino Real Sample .;; 'a W 12 w .z V 5C 3C .2 C.) U) 0 O o 0 CIRA SIN — 2 CL 3. WO. 6145-E-SC BORING B-207 SHEET J_ OF DATE EXCA VA TED 3-29-11 LOGGED BV:RGC SAMPLE METHOD: 1101kM Stem Auger Approx. Elevation: MSL MM Standastl Penefration Test Groundwater Undisturbed, Ring Sample - - Description of Material @ 0' Asphalt -6 inches over 4 inchesR.A.P. ROAD BASE: :: t083'SAND.Iightbrown, moist, dense; minor gravel. TERRACE DEPOSITS (Qt): © 2.3' SANDY CLAY, light brown to brown, moist, very stiff. 5 67 I I 112.1 I 14.9 I 82.7 Total Depth =6' 7 No Groundwater Encountered Backfilled 3-29-2011 9 10 11 12 13 14 15 16 17 18 19 I 21 26 27 28 Geook, Rancho Costera, El Camino Real Plate B-il BORING LOG Geoo3, Inc. WO. 6145-E-SC PROJECT: SHAPELL HOMES BORING 8-208 SHEET OF Rancho Costera, El Camino Real Sample w 0 .0 E .0 U) 0. O c w 2 U) C.) U) D w D m SW 3M C/RI 50-6° 7 DATE E)(CA VA TED 3-29-11 LOGGED BY: RGC SAMPLE METHOD: Hollow Stem Auger ApproL Elevation: ' MSL Standard Penetition Test Groundwater Undist ur bed, Ring Sample Description of Material @ 0' Asphalt -6 inches over 4 inches R.A.P. ROAD BASE. : -:@ 0.83' SAND, light brown, moist, dense; minor gravels, 16 inches thick. . .:• SANTIAGO FORMATION (isa): © 2.2' SILTY SAND, light brown, moist to wet, dense. 97.3 10.8 40.7 . @ 5' SILTY SAND, light brown, moist, very dense. Total Depth =6' No Groundwater Encountered Backfilled 3-29-2011 10 11 12 13 14 15 16 17 18 19 20 21 22 23 I 27 Rancho Costera, El Camino Real GeoftUs.Plate B-12 Sample I. - I I .9 . I I . D Q. W o (DID lD 2 (D 0 U) D 0 0 CIRA --w 2 -- SM - 4 5 25/ Geooik, Inc. PROJECT: SI-IAPELL HOMES Rancho Costera, El Camino Real BORING LOG WO. 6145-E-SC BORING B-209 SHEET J_ OF J_. DATE EXCAVATED 3-29-11 LOGGED BY:RGC SAMPLE METHOD: Hoflow Stem Auger Approx. Elevation: Q' MSL Standard Penetration Test Groundwater Undisluthed, Ring Sample T Description of Material 0 0'AsDhalt -7 inchesover 4 inches R.A.P. SAND. brown, moist, dense; minor gravel. TERRACE DEPOSITS (Qt): - @ 2' SILTY SAND, light brown, moist to wet, dense to very dense. Total Depth = 6' No Groundwater Encountered Backfllled 3-29-2011 10 11 12 13 14 15 16 17 18 19 I 21 27 28 GeooI,Inc. Rancho Costera, El Camino Real Plate B-13 Sample 0 0 E >. U) a. 0 w c 2 U) O w D to 23 BORING LOG Geo©, Inc. w.o. 6145-E-SC PRWECT. SHAPELL HOMES BORING B-210 SHEET OF Rancho Costera, El Camino Real DATE E)(CA VA TED 3-29-I1 LOGGED BY: RGC SAMPLE METHOD: Hollow Stem Auger Approx.Elevation: 4 MSL Standard Penet,tion Test Groundwater Undisturbed, Ring Sample Description of Material @ 0' Asphalt -8 inches over 4 inches R.A.P. ROAD ALL: .•.• (1'SAND, brown, moist, dense, minor gravel, 20 inches thick. ALLUVIUM (Qt): @ 2.3' SANDY CLAY, brown, wet, stiff. 97.4 1 22.9 1 87.0 © 5' CLAYEY SAND, olive gray, wet, medium dense. VA @ 5' Groundwater encountered. 10- 11- 12- 13- 14- 15- 21 E 108.8 20.1 100 @ 15' SANDY CLAY, brown, saturated, very stiff. 16 Total Depth16' 17 Groundwater Encountered @ a depth of 5' (EL = 42.5' MSL) Backfilled 3-29-2011 21 29 Rancho Costera, El Camino Real Geood, Inc. Plate B-14 Sample 0 .0 w .0 >. 0 Cl) C) Cl) o Co M D CL BORING LOG Geoi, laic. WO. 6145-E-SC PROJECT: SHAPELL HOMES BORING B-211 SHEET OF Rancho Costera, El Camino Real DATECAVATED 3-29-11 LOGGED BY RGC SAMPLE METHOD: Hollow Stem Auger Approx. Elevation: 62 MSL ffln Standard Penetration Test Groundwater 5 UndLslu,bed, Ring Sample Description of Material @ 0' Asphalt -7 inches over 4 inches R.A.P. VROADSE AND, brown, moist to wet, dense; minor gravel. O FORMATION ffsa: ANDY CLAYSTONE, light brown, wet, hard/dense. 5060 108.7 I 15.7 I 79.9 Total Depth =6' No Groundwater Encountered Backfilled 3-29-2011 10 11 12 13 15- 16- 17- 18- 19- 20- 21- 221 P Rancho Costera, El Camino Real Ge©d, Me. Plate B-i 5 BORING LOG Geooik, Inc. WO. 6145-E-SC PRWECT. SHAPELL HOMES - BORING B-212 SHEET OF Rancho Costera, El Camino Real DATE S(CAVATED 3-29-11 LOGGED BY: RGC - Sample - - SAMPLE METHOD: Hollow Stem Auger - - - Approx. Elevation: ' MSL Standard Penetzatlon Test S. - Groundwater MID •E g Undisturbed, Ring Sample CL C) .! .a Description of Material - - - - C/RA - 0' Asphalt -9 inches over 4 inches R.A.P. 1• SW ROAD BASE 2 _______ :•: @ 1.1' SAND with some SILT and GRAVEL, medium gray, moist, 3. \_dense. - - 2? FILL (At): /• 4 : © 2.5' CLAYEY SAND, olive brown, moist, medium dense. 5. ----- Total Depth = 5' No Groundwater Encountered Backfilled 3-29-11 9 10 11 I 13 15- 16- 17- 18- 19-1 21 22 I 27 Geoods, . Rancho Costera, El Camino Real Plate B-16 BORING LOG Geooil, Inc. WO. 6145-E-SC PRWECT. SHAPELL HOMES BORING B-213 SHEET 1 OF Rancho Castera, El Camino Real DATE EXCAVATED 3-30-11 LOGGED BY: RGC - Sample - - SAMPLE METHOD: Hov Stem Auger - - Approx. Elevation: W MSL Standani Penetration Test -'i-Groundwater 5 Undisturbed, Ring Sample 0. Description of Material - © 0' Asphalt -7 inches thick over 4 inches R.A.P. 1• - SW ROAD BASE - 2- 0.91'SAND with SILT and GRAVEL, brown, dense. _moist, SC FILL (Af): ,i; @ 1.9' CLAYEY SAND, brown, moist, medium dense. 1004 ....4... ..222... 6 SP TERRACE DEPOSITS (Qt): @ 51W SAND, brown, dry, medium dense. 7- 8- 9- 10- 50-5" 102.8 3.0 13.2 12- 13- 14- -- GP - ° @ 13W Becomes GRAVELLY SAND, brown, dry, dense. 15 - 60 SM 100.8 4.0 16.6 SANTIAGO FORMATlON(rsa): 15' SILTY SANDSTONE, light yellowishgray,dry,dense. Total Depth = 16' 17 No Groundwater Encountered 18• , Backfihled 3-30-2011 19- I 21 Geoil, Inc. Rancho Costera, El Camino Real Plate B-17 BORING LOG Geooik, hc WO. 6145-E-SC PRWECT. SI-IAPELL. HOMES BORING B-214 SHEET J_ OF Rancho Costera, El Camino Real DATE(CAVATED 3-30-11 LOGGED BY:RGC - Sample SAMPLE METHOD: Hollow Stem Auger - - - Approx. Elevation: ' MSL 16 Standard Penetration Test — - .— -- Groundwater .2 Undisturbed, Ring Sample 5 U) — x C.) g Description of Material - - - C/R - @ 0' Asphalt - 7 inches thick over 4 inches R.A.P. SIN - ::• ROAD BASE 2-Li_- . ( 0.9' GRADED SAND with few GRAVELS. - - SM ______ - - FILL (AU: 3 @ 2.1' SILTY SAND, brown, slightly moist, dense. 4 59 110.9 11.5 61.9 @ 6' CLAYEY SAND, brown and olive gray, moist, dense. 6 SC SM SANTIAGO FORMATION (Tsa): g. : @ 8' SILTY SANDSTONE, light yellow gray, dry, dense. 10 50 114.6 11.3 67.7 13 : @ 13' As per 8', becomes very dense. 14- Q4. p Recover ________________________________________________________ 16- - Total Depth = 15W No Groundwater Encountered 17 . Backfilled 3-30-2011 29 Geoo 9 Inc. Rancho Costera, El Camino Real Plate B-18 BORING LOG Geooils, Inc. wo. 6145-E-SC PROJECT: SHAPELL HOMES BORING B-215 SHEET OF Rancho Costera, El Camino Real DATE EXCAVATED 3-30-11 LOGGED BY: RGC Sample - SAMPLE METHOD: Hollow Stem Auger - - - Approx. Elevation: 79' MSL Standam Penetration Test - Groundwater 5 Undisftirbed. Ring Sample Q. - - " Description of Material - - - ~C/RAI @ 0' Asphalt - 8 inches thick over 4 inches R.A.P. 1- - - -SIN :•:• ROAD BASE: Q 1'SILTY SAND to SAND, brown, moist, medium dense. 2--- - - SC & FILL (AO: @ 2' CLAYEY SAND, brown and light gray, moist, medium dense. 4' / ------ -_4. 5— 50-6 SM 3.5 @ 5 Becomes SILTY SAND with some angular GRAVEL. ... 10 — 44 SC 112.0 10' Becomes CLAYEY SAND, light brown to brown, moist, dense. 11- 12- 13- 1 15 - -- _____ _• I 15Asper10. — -s-- SML 123.5 _a& 14J_ ALLUVIUM (Qafl: 16 I_fl 15W SILTY SAND, very dark grayish brown, slightly moist, dense. I 17 Total Depth = 16' 18 No Groundwater Encountered Backfilled 3-30-2011 19 20 21 22 23 24 25 26 27 28 29 Geo&,ük, bic, Rantho Costera, El Camino Real Plate B-19 BORING LOG Ge@oik, b©. WO. 6145-E-SC PROJECT: SHAPELL HOMES BORING B-216 SHEET 1 OF Rancho Costera, El Camino Real DATE EXCA VATED 3-30-11 LOGGED BY:RGC Sample SAMPLE METHOD: Hollow Stem Auger — — Approx. Elevation: MSL mm Standard Penetration Test L Groundwater Undisturbed, Ring Sample 0. 0 — — Description of Material - — C/RA © 0' Asphalt - 8 inches thick over 4 inches R.A.P. — 1 —SIN ROAD BASE: 2- - — _______ . @ 1' SAND with SILT and a few angular GRAVELS, dark gray, moist, SC . \_dense./ 3. 'i. FILL (AU: 4- / @ 2.2' CLAYEY SAND, brown, moist, medium dense. 30 108.9 10.0 51.0 ./ @ 5' As per 2.2'. 7 10 — 85 SW 108.3 11.4 57.4 . @ 10' Becomes SAND, gray brown to dark gray brown, dry, dense; well 11- •:•: graded. 12- 13- 14- 15 — 64 SM 118.0 8.8 582 SANTIAGO FORMATION (Tsa): 16- - — _15'SILTY SANDSTONE, medium gray, moist, dense. Total Depth = 16' 17 No Groundwater Encountered 18- Backfllled 3-30-2011 19- 21 Geooil, Rancho Costera, El Camino Real Plate B-20 BORING LOG Geooi1 9 Inc. WO. 6145-E-SC PROJECT.- SHAPELL HOMES BORING I-IA-I SHEET OF Rancho Costera, El Camino Real DATE S(CA VA TED 3-28-11 LOGGED BY: RBBJRGC - Sample - SAMPLE METhOD: Hand Auger - - - Approx. Elevation: MSL Standard Penetration Test S Groundwater Undisturbed, Ring Sample CL - - Description of Material SW :•:• FILL : @ 0' SILTY SAND to SAND, dark gray, slightly moist, medium dense; few asphalt fragments, angular gravel. 2 - - 3CISIV TERRACE DEPOSITS (Qt): @ 2' CLAYEY SAND, brown and olive brown, moist dense; few SILTY SAND interbeds. 3, 4. - - - - IJ Total Depth 5' No Groundwater Encountered Backfllled 3-28-2011 6- 7- 8- 9, -J Geoftlls, Rancho Costera, El Camino Real Plate B-21 BORING LOG Geoo1, Inc. WO. 6145-E-SC PROJECT: SHAPELL HOMES BORING HA-2 SHEEr_L OF Rancho Costera, El Camino Real DATEEXCAVATED 3-28-11 LOGGED BY:RBB Sample SAMPLE METHOD: Hand Auger - - S Approx. Elevation: jig' MSL Standard Penetration Test -. Groundwater . Undisturbed, Ring Sample : Description of Material ;cici TALUS: @ 0' CLAYEY SAND/SANDY CLAY, brown to olive brown, wet, loose/soft; trace gravel. usr QUATERNARY TERRACE DEPOSITS (Qt): @ 1W Interbedded SANDY CLAY, CLAYEY SAND and well graded 2- SAND, brown to olive brown, wet, stiff/medium dense. LJMI 2W SILTY CLAY/CLAYEY SILT, olive brown to brownish gray, moist, very stiff. - - ii-@ 3' SILTY SAND, fine grained, reddish yellow, gray, and brown, I moist, dense. Total Depth = 4'/z' No Groundwater Encountered Backfllled 3-28-2011 9 Geooil 9 Rancho Costera, El Camino Real Plate B-22 BORING LOG eveGSOUS9 Inc. PRWECT. SHAPELL HOMES Rancho Costera, El Camino Real Sample .5 .0 tn >. U, U) P 2 0. O C3 Ad 5 co 2 M C.) U) D 0 0 1 wo. 6145-E-SC BORING HA-3 SHEET J_ OF J_ DATE E)(CA VA TED 3-28-11 LOGGED BY: RBB - S4MPLEMErHOD: Hand Auger Approx. Elevation: .' MSL Standard Penetration Test Groundwater 5 - Undisturbed, Ring Sample Description of Material TALUS: 0 SILTY SAND brown to olive brown to gray. @ 21N CLAYEY SAND, dark gray, moist, dense; slightly porous, trace root hairs. 2 SC @ 3W Interbedded CLAYEY SAND and SILTY SAND, fine grained, gray, brown, and reddish yellow, moist, very dense; moderately cemented. Total Depth =4' No Groundwater/Caving Encountered Backfilled 3-28-2011 7 B Rancho Costera, El Camino Real Plate B-23 BORING LOG Geok, Inc. wo. 6145-E-SC PRWECT. SHAPELL HOMES BORING HA-4 SHEET OF Rancho Costera, El Camino Real Sample - Li E >5 (I) C 0. Il D W Ici 2 U) o ii 0 1 12 DATE EXCAVATED 3-28-11 LOGGED BY: RBB SAMPLE MEIHOD: Hand Auger Appro)L Elevation: MSL FM Standard Penetration Test - Groundwater g . - Undisturbed, Ring Sample .2 E Description of Material TALUS: : 0' SILTY SAND with minor CLAY, fine grained, yellowish brown, -: brown, and gray, wet, loose. 5-. 1' SILTY SAND, fine grained, yellowish brown, brown, and gray, wet, : loose. -a. -S. .3'?. 3' Interbedded CLAYEY and SILTY SAND, fine grained, gray to yellowish brown, moist, dense, becoming very dense with depth; II moderately cemented. Total Depth = 31W No Groundwater/Caving Encountered Backfilled 3-28-2011 17 1 '9 4 ' III II I I II Rancho Costera, El Camino Real Geosoilsq Inc. Plate B-24 BORING LOG Geooil, Inc. PRWECT SHAPELL HOMES Rancho Costera, El Camino Real Sample 4 U, . • ' 2 0. C, c .9 0 0 is 03 D 03 D0 1 W.O. 6145-E-SC BORING HA-5 SHEET OF DATE EXCAVATED 3-28-11 LOGGED BY: RBB - SAMPLE METHOD: Hand Auger FM Approx. Elevation: 45' MSL Sffindaid Penefrabon Test V Groundwater Undisturbed, Ring Sample Description of Material - AR11FICIAL FILL (At): cl 0' SANDY CLAYICLAYEY SAND, dark brown to dark brownish gray, wet, stiff/medium dense. 7 SM -- fine brown to : gray, moist, dense. @ 3' SANDY CLAY/CLAYEY SAND, dark brown to dark gray, wet, very stiff/dense; trace asphaltic concrete fragments. Total Depth = 4' No Groundwater Encountered Backflhled 3-28-2011 Rancho Costera, El Camino Real Plate 8-25 Sample 0 E .0 >. Cl' . . Cl, Cx :5 0 c .2 Cl) /CL BORING LOG Geooik, Inc. WO. 6145-E-SC PRWECT. SHAPELL HOMES BORING HA-6 SHEET OF Rancho Costera, El Camino Real DATE E)(CA VATED 3-28-11 LOGGED BY.RBB SAMPLE METHOD: Hand Auger Approx. Elevation: 64 MSL Standard Penetration Test Groundwater Undisturbed, Ring Sample 0 co Description of Material TALUS: . © 0 SILTY SAND, CLAYEY SAND, and SANDY CLAY, fine grained, light gray to gray, wet, loose/soft. @ 1%' SILTY SANDSTONE, fine dense. Practical Refusal @ 2' No Groundwater Encountered Backfihled 3-28-2011 I WA 18 Rancho Costera, El Camino Real GeoSoHz,gco Plate B-26 BORING LOG Geoo 9 Inc. WO. 6145-E-SC PROJECT: SHAPELL HOMES BORING HA-7 SHEET 1 OF Rancho Costera, El Camino Real 17 Sample 0 0. E .0 U, 5 IiI.3 U, 0. jeII w IcI U) 0 to D to D 0 1 DATE E'XCA VA TED 3-28-11 LOGGED BY: RBB SAMPLE METHOD. Hand Auger Approx. Elevation: 54' MSL - Standard Penetration Test - Groundwater Undisturbed, Ring Sample Description of Material TALUS: I.•: @ 0' SILTY SAND to CLAYEY SAND, fine grained, light gray to gray to I.: brown, wet, loose. SM TERTIARY SANTIAGO FORMATION (isa): @ 1%' Interbedded SILTY SANDSTONE, fine to medium grained, -': yellowish brown to light gray, moist dense. .1• Practical Refusal @ 3W No Groundwater Encountered Backfllled 3-28-2011 6 7 Rancho Costera, El Camino Real Plate B-27 GeooiIs,Inc. BORING LOG Geook9 Inc. WO. 6145-E-SC PROJECT: SI-IAPELL HOMES BORING HA-8 SHEET OF Rancho Costera, El Camino Real Sample .5 U E l: u' H; II U) 0. 0 1w i2l2 Cl) ID Co :) M DID DATE E)(CA VA TED 3-28-11 LOGGED BY: RBB SAMPLE METHOD: Hand Auger Approx. Elevation: i' MSL Standard Penetration Test Groundwater Undisturbed, Ring Sample Description of Material ft.. TALUS: @ 0' SILTY SAND to pooly graded SAND, fine grained, light gray to brownish gray, moist to wet, loose. - .. TERTIARY SANTIAGO FORMATION iTsa): © 1' SANDSTONE with minor SILT, fine grained, light gray, moist, - dense becoming very dense with depth. Practical Refusal © 1W No Groundwater Encountered Backfilled 3-28-2011 1 SP 4 5 6 7 GeoiI, b. Rancho Costera, El Camino Real Plate B-28 BORING LOG Geoil, Inc. WO. 6145-E-SC PROJECT: SHAPELL HOMES BORING HA-9 SHEET OF Rancho Costera, El Camino Real DATE EXCAVATED 3-28-11 LOGGED BY: ROB Sample SAMPLE METHOD: Hand Auger - - Approx. Elevation: 46' MSL RM Standard Penetration Test V Groundwater Undisturbed, Ring Sample LU - 0• U, (I) CL - Description of Material ARTIFICIAL FILL: @ 0' SILTY to CLAYEY SAND, dark gray, light gray, and brown, wet becoming saturated at -1', loose. 2- • : @ 3W Groundwater encountered. 4- Total Depth =4W Groundwater @ a depth of 3W (EL= 42.5' MSL) 5. No Caving Encountered Backfilled 3-28-2011 6- 7- 8- 9- GeeSoUs,Plate Rancho Costera, El Camino Real B-29 BORING LOG Sample '5. ti lt~ (1) .ti •; U) .2 0. .5 0 c .2 (1) 0 C3 to D W D 0 WO. 6145-E-SC BORING HA-ID SHEE71 OF DATE EXCA VA TED 3-29-11 LOGGED BY:RBB — SAMPLE METHOD: Hand Auger Approx. Elevation: MSL NJ Standard Penebation Test NOW V Groundwater Undisturbed, Ring Sample Description of Material TALUS: 0' SANDY CLAY, dark brown and dark olive brown, wet, very soft; J trace rock fragments, trace organics. Geoi1s, I© PROJECT: SHAPELL HOMES Rancho Costera, El Camino Real CL HIGHLY WEATHERED TERRACE DEPOSITS: SANDY CLAY, dark brown to dark olive brown, wet, stiff; trace organics. Interbedded CLAYEY SAND, SILTY SAND, poorly graded SAND, and SANDY CLAY, fine to medium grained, brown to gray, moist, dense/very stiff. Total Depth = 5' No Groundwater/Caving Encountered Backfllled 3-29-2011 9 Geooils, Rancho Costera, El Camino Real Plate B-30 BORING LOG Geooi1, hc. w.o. 6145-E-SC PRWECT. SHAPELL HOMES BORING HA-Il SHEET OF Rancho Costera, El Camino Real DATE EXCAVATED 3-29.11 LOGGED BY: RBB - Sample SAMPLE METHOD: Hand Auger - - - Approx. Elevation: ' MSL FM Standard Penetion Test - V - - Gmundwater g Undisturbed, Ring Sample - - 2 . - Description of Material - - - SC ARTIFICIAL FILL (Af): - - @ 0' CLAYEY SAND, dark gray brown, wet, loose; trace organics. - SC/CL @ CLAYEY SAND/SANDY CLAY, brown to olive brown, wet, medium dense. 17 - @ 1W SANDY CLAY, reddish brown to brown, wet, stiff. 2- - - - SM/Sc § 2' SILTY to CLAYEY SAND, SANDY CLAY, and poorly graded SAND, line to medium grained, brown, olive brown, and gray, wet, CUSP • dense/very stiff. @ 21N As per 2', saturated. - -CL/SC © 3' SANDY CLAY/CLAYEY SAND, dark gray, yellowish red, and light brown, wet, very stiff. 4. Total Depth = 5' No Groundwater/Caving Encountered Possible Perched Water Seepage © 21/z' (Local Irrigation) Backfilled 3-29-2011 6- 7. 8- 9. Geooi1 Inc. Rancho Costera, El Camino Real Plate 8-31 BORING LOG Geoo1, Inc. PROJECT SI-IAPELL HOMES Robertson Ranch West Sample C. C, .9; w E S a U) 0. o c .2 C) U) o go D 0 CL/SC 3j 6 7 WO. 6145-A-SC BORING B-101 SHEET 1 OF DATE EXCAVATED 6-9-10 LOGGED BY: RBB - SAMPLE METHOD: Standard PenefralionlModlfied Cal Sampler, 140 lbs @ 3V Drop Approx. Elevation: MSL sm Standard Penetration Test - - Groundwater Undisturbed, Ring Sample 3 Description of Material QUATERNARY ALLUVIUM: @ 0' SANDY CLAY/CLAYEY SAND, dark gray, dry becoming wet at 2 feet, soft/loose becoming very stiff/medium dense at 2 feet. 3' Water seepage into boring. @ 5' No recovery. Likely as per 0'. 115.2 I 16.1 I 98.0 7' SANDY CLAY/CLAYEY SAND, dark brownish gray, saturated, hard/dense. 15.2 @ 10' SANDY CLAY to CLAYEY SAND, tan to light brownish gray, wet, very stiff/medium dense. 27 22 13 © 14' Water seepage into boring. 106.1 I 20.2 I 95.6 15' SANDY CLAY, tan, wet, hard. 22.3 @ 20' SAND, tan, saturated, medium dense; fine-.grained coarseni 21.2 downward to fine- to coarse-grained, becoming SILTY SAND at —21 25.0 feet. 21 1 SC 1 107.0 1 21.0 1 100.0 fr'/.j @ 25' CLAYEY SAND, brownish gray, saturated, medium dense. 271 I TERTIARY SANTIAGO FORMATION: 28] I I 29 usc @ 27' SANDY CLAYSTONEJCLAYEY SANDSTONE, dark gray becoming light brownish gray, moist, hard/dense. Robertson Ranch West Geoo11, Inc.Plate B-32 10 11 12 13 14 15 16 17 18 19 I 21 BORING LOG Geob, Inc. WO. 6145-A-SC PROJECT: SI-IAPELL HOMES BORING B101 SHEET 2 OF Robertson Ranch West DATE E)CCA VA TED 6-9-10 LOGGED BY: RBB Sample SAMPLE METHOD: Standard Penebationftlodified Cal Sampler, 140 lbs @ 30" DrOp - - - Approx. Elevation: ' MSL C-ME I, Standard Penetration Test V 37 Groundwater E 5 . U) e 0 VA Undisturbed, Ring Sample .. 0. 5 2 Description of Material o ED D 02 U) - i CUSC -:iyr @ 30' As per 27'. 32- 33- 34- 35- 54 107.4 19.0 93.0 @ 35' SANDY CLAYSTONEICLAYEY SANDSTONE, tan, gray, and - reddish yellow, wet, hard/dense coarsening downward to SILTY SANDSTONE, tan, wet, dense. - - - - Total Depth = 36W Perched Groundwater from 3-7' and 14-25' Backfilled 6-9-2010 39. 55- Geooh,Inc. Robertson Ranch West Plate B-33 BORING LOG Geook, Inc. WO. 6145-A-SC PRWECT. SHAPELL HOMES BORING B-102 SHEET OF Robertson Ranch West DATEB(CAVATED 6-9-10 LOGGED BY:RBB - Sample - SAMPLE METHOD: Standard PeneboniModIfied Cal Sampler, 140 WS © 30" Dmp - - - ApproL Elevation: Sr MSL Standard Penetration Test ?.. Groundwater 2 - Undisturbed, Ring Sample ;;3 U) 3 E 0. 0 . 3 - Description of Material SM : QUATERNARY ALLUVIUM: 1- 1. © 0' SILTY SAND, grayish brown, dry, loose. 2- 1 - BN 16 167 @ 5' Interbedded CLAYEY SAND to SILTY SAND to SANDY CLAY, PSI 61 Ic -.. brownish gray to grayish brown, moist, medium dense to stiff. 1II 51 L/SC 115.5 158 96.6 - QUATERNARY TERRACE DEPOSITS: 11 @ 10' SANDY CLAY, mottled grayish brown and dark brownish gray. I saturated, hard; coarsening downward to CLAYEY SAND, tan, 12 saturated, dense. 13 @ 12' Groundwater seepage into boring. 14w. 15-'33 19.4 @ 15' SANDY CLAY to CLAYEY SAND, reddish yellow to brownish 16- gray, moist to wet, very stiff/medium dense. 17- 18- 19- 20 37 104.0 22.8 99.3 @ 20' As per 15', saturated, very stiff/dense. 22- 23- 24- 24' Groundwater encountered. 25 IM15 CL 247 . TER11ARY SANTIAGO FORMATION: @ 25' SANDY CLAYSTONE, tan to dark gray, moist, stiff. 27- GOOk9 Inc. Robertson Ranch West Plate B-34 BORING LOG Gooil, Inc. WO. 6145-A-SC PROJECT: SHAPELL HOMES 80R1M B-102 SHEET 2 OF Robertson Ranch West DATE E)(CA VA TED 6-9-10 LOGGED BY: RBB - Sample SAMPLE METHOD: Standard PeiiebalionlModified Cal Sampler, 140 lbs © 30" Drop - - - Approx. Elevation: 52' MSL - Standard Penetration Test -Gmundwater g Undisturbed, Ring Sample U' Q. 0 - .2 Description of Material - - 55 L/S1' 106.2 18.8 89.4 @ 30' SANDY CLAYSTONE, brownish gray, wet, hard; becoming 31 SILTY SANDSTONE, light grayish brown, moist, dense. 32- 33- 34- 35- 17 USN 22.1 @ 35' SANDY CLAYSTONE. brownish gray, moist, very stiff, to SILTY SANDSTONE, brownish gray, wet, medium dense; to SANDY CLAYSTONE, brownish gray to reddish yellow, moist, very stiff; to SANDY CLAYSTONE, dark gray and reddish yellow, moist, very stiff. 38- 39. - 63SC/SP 109.4 18.8 97.4 @ 40' CLAYEY SANDSTONE, light brownish gray and reddish yellow, 41- saturated, dense; coarsening downward to SANDSTONE, light brownish gray, saturated, dense; fine to medium grained. 42 . Total Depth =41W 43. Perched Groundwater from 12-15' and 24-25' Backfllled 6-9-2010 44- 45- 46- 47- 48- 49- 50- 51- 52- 53- 54- 55- 55- 57- 58- 5 Geods Inc. 9 Robertson Ranch West Plate B-35 I8 9 11 12 13 14 15 16 15 BORING LOG Geoik, Inc. PROJECT: SHAPELL HOMES Robertson Ranch West Sample 0 .0 o E .0 ' >, U, . ;3 U) 0. V C.) a -1 Sc 2-I WO. 6145-A-SC BORING B-103 SHEET 0F2 DATE EXCAVATED 6-9-10 LOGGED BY: RBB - SAMPLE METHOD: Standard PenetialionlModllied Cal Sampler. 140 lbs © 30" Drop ApproL Elevation: ' MSL Standard Penefrallon Test V Groundwater C g = Undisturbed, Ring Sample 0 IWO Description of Material - QUATERNARY ALLUVIUM: 4 @ 0' CLAYEY SAND, dark gray, dry becoming wet at 3', loose '7) becoming medium dense at 3'. 64 124.6 1 9.7 1 78.6 VA @ 5' CLAYEY SAND, dark gray to dark grayish brown, wet, dense. 25.7 1 rA QUATERNARY TERRACE DEPOSITS: 10' SANDY CLAY, reddish yellow, moist, stiff. Groundwater encountered. No recovery. 20 SP 108.4 19.6 98.7 •. .• 17' SAND with minor SILT, light grayish brown, saturated, medium 18 dense; fine to medium grained. 19• 20 -24 3W/CL 23.0 @ 20' SAND, light grayish brown, saturated, medium dense; line to 21 0 coarse grained, trace SANDY CLAY interbeds, gray wet, very stiff, -- trace gravel. 46 1 SC 1 110.7 1 19.1 1 100.0 k'/A TERTiARY SAN11AGO FORMA11ON: VA @ 25' CLAYEY SANDSTONE, tan, gray, and reddish yellow, saturated, VA dense. 27 Robertson Ranch West Geoo3, Inc. Plate B-36 Sample E CD " 0. . .9 C) co 0 Go D 0 41 f L/SC 1 17.6 31 32 BORING LOG Geooil, PROJECT: SHAPELL HOMES Robertson Ranch West WO. 6145-A-SC BORING B-103 SHEET OF DATE9(CAVATED 6-9-10 LOGGED BY:RBB - SAMPLE METHOD: Standard Pe_onff4od15ed Cal Sampler, 140 lbs @ 30" Drop Approx. Elevation: 59' MSL Standard Penefration Test V Groundwater Undisturbed, Ring Sample Description of Material © 30' Interbedded SANDY CLAYSTONE, dark gray, moist, hard; and CLAYEY SANDSTONE, light brownish gray and reddish yellow, moist, -'. dense. Total Depth = 31W Perched Groundwater from 14-25' No Caving Encountered Backlilled 6-9-2010 39 40 41 42 I 47 50 51 52 53 Geooil, h© Robertson Ranch West Plate B-37 BORING LOG Geob, Inc. WO. 6145-A-SC PROJECT. SHAPELL HOMES BORING B-104 SHEET oFj_ Robertson Ranch West DATEEA'CAVATED 6-9-10 LOGGED BY:RBB Sample - SAMPLE METHOD: standard PenetJtion!Modified Cal Samplei_140 lbs @ 30" Dmp - - - Approx. Elevation: MSL FM Standard Penebelion Test .- -- Groundwater E Undisturbed, Ring Sample a - 0 D. . Description of Material LJSC QUATERNARY ALLUVIUM: 1• © 0' SANDY CLAY/CLAYEY SAND, dark gray, dry becoming moist at —2', soft/loose becoming stiff/medium dense at —2'. 2 - 32 SC 14.6 l 5' CLAYEY SAND, dark brownish gray, moist, dense. 6 - SC QUATERNARY TERRACE DEPOSITS: 7. @ 6' CLAYEY SAND, reddish yellow to brownish gray, moist, medium :2 dense. 8- :/ 116.0 15.3 94.9 @ 10' CLAYEY SAND, brownish gray, wet, dense. 10-49 12- 13- 131/2 Groundwater encountered. - 15 SMISC 16.6 : @ 15' SILTY to CLAYEY SAND, reddish yellow, wet, medium dense becoming SANDY CLAY, light brown to gray, wet, stiff at— 16'. 231 17- 18- 33 CL 106.8 23.1 99.9 TERTIARY SANTIAGO FORMATION: - l 20' SANDY CLAYSTONE, dark brownish gray to reddish yellow, 22- saturated, very stiff. 23 24 25-- 26 39 SM 20.4 •'• c 25'S ILTY SAND with minor CLAY, buff, brownish gray and redd yellow, moist, dense; fine grained. 27 Total Depth = 26W Perched Groundwater from 13Yz-20' 28- No Caving Encountered 2 - Backfilled 6-9-2010 - GeooiJRs, Robertson Ranch West Plate B-38 BORING LOG Geoo, Inc. WO. 6145-A-SC PROJECT:SHAPELL HOMES BORING BA-101 SHEET OF Robertson Ranch West DATE E)(CA VA TED 5-10-10 LOGGED BY:RBB Sample SAMPLE METHOD: Modified Cal Sampler, 140 lbs @30" Drop Approx. Elevation: 142 M SL - - Standard Penetration Test — - Groundwater Undisturbed, Ring Sample CL 0 - Description of Material - - - CL TOPSOIL 1• @ 0' SANDY CLAY, dark grayish brown, moist, stiff. 2 M1GI WEATHERED SANTIAGO FORMATION: SM 3. \ ©2' Interbedded SILTY fine SANDSTONE and SANDY CLAYSTONE, yellowish brown to brownish gray, moist, medium dense/stiff; highly fractured (infilled). TERTIARY SANTIAGO FORMATION: 5 :.: 5-9" 121.6 13.3 97.7 : @ 2W SILTY SANDSTONE, yellowish brown to buff, moist, dense; fine 6 -grained. '':• @ 3W Bedding: N30"W/5"SW. Fracture: N42°W/84"NE 7. .::@ 5' As per 2W, saturated; trace infilled fractures. @ 7' Bedding: N19"W/12"SW. 13 :• @ 12W Low angle cross-bedding. .: @ 13' Bedding: N40"E12"NW. 14- 15 @ 141W SILTY SANDSTONE, light gray; fine- to coarse-grained. 7-10" 122.7 10.2 77.4 • © 15' SILTY SANDSTONE, light gray to light brown, wet, medium 16 . dense; fine-grained. : @ 151,41 Bedding: N33"E/5"NW. 17 - LX @ 161/2' Caliche infilled fracture: N40"W/ 61 *SW. 18 17' Sub-horizontal bedding. @ 18' SILTY SANDSTONE, light gray; fine grained. 19 20- @ 20' Cross bedding (low angle). 21 : @21' SILTY SANDSTONE, gray, moist, dense. 22 .:: @ 23' Bedding: N70"W/7SW. 25 11.5 72.5 25' SILTY SANDSTONE, light gray, moist, medium dense; fine 26 - - 113.0 grained grained to CLAYEY SANDSTONE, grayish brown, moist, medium ML I ..12,t-613... 27' t26'CLAYEY SANDSTONE, grayish brown, moist,dense. - \ @26W SILTSTONE, gray to reddish yellow; slick ped surfaces. : Bedding: N76"E113"NW. @ 27' SILTY SANDSTONE, light gray; fine grained. - - - _______ : 28'As per 26W. Bedding: N42"E/7"NW. GeoSoils Inc. , Robertson Ranch West Plate B-39 BORING LOG Geooil, bac0 WO. 6145-A-SC PRWECT. SHAPELL HOMES BORING BA-101 SHEET 2 OF3 Robertson Ranch West DATE XCA VA TED 6-10-10 LOGGED BY:RBB / Sample - SAMPLE METhOD: ModUled Cal Sampler. 140 lbs @ 30" Dmp / - - - Approx. Elevation: j MSL Standard Penetration Test . VZGmuncater . Undisturbed, Ring Sample Description of Material SM :: @30'As per 26W. 31- @ 31' SILTY SANDSTONE, yellowish brown to light gray. 32 Fault N6"WNert. Bedding: N12"W/13"NE. ( 33' Concretion 34- 35- 16-13" 122.0 11.9 88.8 @ 35' SILTY SANDSTONE, light gray, wet, medium dense; fine .4 grained, near vertical fracture. 38- © 38' Bedding: W30"W14"SW. ( 39' Fault: NI"ElVert. 42- © 42' Fault N15"W/68"SW offsets SILTY fine SANDSTONE and 43- SILTY SILTY fine- to coarse-grained SANDSTONE. 44- 45- 16_11V 123.5 7.5 58.8 © 45' SILTY SANDSTONE, light gray, moist, dense; fine grained, trace 46- : coarse coarse grains. :-?-: -n. ..-: 16-11" 118.7 9.0 60.5 55' SILTY SANDSTONE, buff, moist, dense; fine grained. 58- Bedding: N7"E/4"NW. . Bedding: N30"E/15"NW. Geo&il, Robertson Ranch West Plate B-40 I. • I ira BORING LOG Geoik, Isle. WO. 6145-A-SC PROJECT: SHAPELL HOMES BORING BA-101 SHEET 3 OF Robertson Ranch West DATEE)XCAVATED 6-10-10 LOGGED BY:RBB - Sample SAMPLE METHOD: Moditied Cal Sampler, 140 lbs © 30" Drop - - - Approx. Elevation: 'MSL MM Standard Penetration Test - Groundwater g Uncilstuthed, Rfr,g Sample - C.) Description of Material SM 61 62- -a. 63- 64- 65- 24-12" 108.5 8.2 41.4 @ 65' SILTY SANDSTONE, buff to yellowish brown, damp, dense; fine 66 --: grained. : Bedding: NI0"W/10"NE. 67 © 66' Cross bedding N20"WII0°SW 73' Bedding: N51"E/10NW. 74- 75- 26-11 115.3 7.9 48.4 © 75' SILTY SANDSTONE, buff to yellowish brown, damp, dense; fine 76- -?'-: to medium grained. © 76' Bedding: NIO"E/10"NW. 77. '-S 81- -S.. .5.-'. 84 -S . 53#5 85- - T' SW 118.3 11.6 77.3 .•. @ 85' SILTY SANDSTONE, light gray, wet, dense; fine to coarse 86-- - - - _______ _____ - grained. Total Depth = 86' 87 No Groundwater/Caving Encountered 88- . Backfilled 6-10-2010 891 1 0-35' - 3 Kelly Weights; 35-65'- 2 Kelly Weights (Inner); 65-86'- 1 Kelly Weight (Innermost) Robertson Ranch West Plate B-41 BORING LOG Geooils, Inc. WO. 3098-A2-SC PROJECT: CALAVERA HILLS II, LLC BORING BA-1 SHEET OF Robertson Ranch, Carlsbad Sample 0 .0 - w E ; u U) E C) SC C 2------ 6 SM 10-1 ill is- II 5 DATE EXCAVATED 9-14-04 LOGGED BY:______ SAMPLE METHOD: 0-27' 3,500 Its; 27-55' 2,400 Its; 55-85' 1,500 lbs Approx. Elevation: j' MSL FM Standard Peneblion Test . Gmundwater Undisturbed, Ring Sample Description of Material 2 U10) • COLLUVIUM: © 0' CLAYEY SAND, dark grayish brown to grayish brown, dry, loose; few roots. /) SANTIAGO FORMATION: 2' CLAYEY SANDSTONE, brown, dry, loose to medium dense; / randomly fractured, caliche common along fractures (N70E, 85NW; N40E, BOSE; N32W, 76SW), fine grained. 114.0 __ 14.6 85.9 7 :• @ 5' Caliche less common. ____________________ © 7' SILTY SANDSTONE, yellowish brown, dry, dense; massive, : caliche generally absent .0. 125.8 10.6 88.8 -: © 12' Becomes moist. - 119.9 11.7 81.8 106.2 19.5 69.1 © 20' Bedding attitude: N30E, 2NW. . 106.4 79T IiT .7 © 25' CLAYEY SANDSTONE, brown to olive brown, slightly moist, dense; fractured (N76W, IBNE; N20E, 44SE; N40W, 60SW; N5W, 9 22NE). 30 31 32 33 8 I SC I 109.3 I 17.2 I 88.8 .TY SANDSTONE, yellowish brown, slightly moist, dense; fine grained. AVEY SANDSTONE, olive brown, moist, dense. p.. Robertson Ranch, Carlsbad 0 Gen, Inc. Plate B-42 BORING LOG Geoo1s, Inc. WO. 3098-A2-SC PROJECT: CALAVERA HILLS II, LLC BORING BA-1 SHEET OF Robertson Ranch, Carlsbad DATE E)XCA VA TED 9-14-04 LOGGED BY._______ — Sample — - SAMPLE METHOD: 0-27' 3,5001*27-55' 2400 Its; 55-851,500 lbs - — — Approx. Elevation: j MSL Standard Penetration Test a •- — -- Groundwater -E Undisturbed, Ring Sample CL Description of Material • -: — Sc10 116.3 143 89.4 - - — — SM — -:@ 36' SILTY SANDSTONE, olive brown to gray brown, moist, dense; 37- :: indurated, massive. 38- 9 — — - t39' Basal contact NIOE,4NW. © 39' SANDSTONE, grayish brown, moist, dense: massive, fine to SP 40- 17 1274 88 783 medium grained. 13 120.4 8.8 62.0 46- 47- 48- 49- so- 20 122.9 8.3 63.2 51- - — SM © 52' SILTY SANDSTONE, gray brown, moist, dense; cross-bedded : . - (N40W, 12SW; NBW, SSW), fine grained. S.-'-.. 12 119.3 12.8 87.7 -• — — — SC CLAYEY SANDSTONE, olive brown, moist, dense; bedding: — . \_N1DE,BNW, fine grained. SILTY SANDSTONE, olive brown, moist, dense; massive. • 116.6 12.9 78.2 - @ 60'As per.58'. — 61- — - — Sc — 7' © 62' CLAYEY SANDSTONE, olive brown, moist, dense; bedding: NI2E,11NW. —Sm _____ — .\ 64- \j 63'1"CLAYSTONEinterbed,N5W,7SW. @ 63 SILTY SANDSTONE, olive brown, slight moist, dense; bedding: : 30 117.7 9.6 62.7 N30E, 6NW. 3 69 0• Geoo, lime. Robertson Ranch, Carlsbad Plate 6-43 DATE EXCAVATED 9-14-04 LOGGED BY: SAMPLE METHOD: 0-2T 3,500 Ibs; 27-55' 2400 Ibs; 55-85' 1,500 lbs Approx. Elevation: 165' MSL ISM Standard Penetration Test a- - - -- Groundwater Undisturbed, Ring Sample Description of Material 115.9 8.1 50.5 @ 70' As per 63'. 114.8 8.0 48.3 '. 1g175' As per 70', cross-bedding in SANDSTONE: N5E, 4NW, basal - ______ - - : contact N40E, 5SE. • @ 77 CLAYEY SANDSTONE, grayish brown, moist, dense. © 79 SILTY SANDSTONE, light brown to grayish brown, moist, dense; 116.3 12.6 78.9 bedding: N20E, 5NW - ©80'As per 79'. 118.7 12.8 86.1 . @ 85' As per 80'. Total Depth = 86' No Groundwater Encountered Backfllled 9-14-2004 With Bentonite Chips Sample 30 77---- - SC 78- 79---- - Sm 30 30 87 88 89 90 i 91 a - a E • .0 U, 0 Cl) a 2 io 0 a 75 C 2 Cl) D BORING LOG Geooils, Inc. WO. 3098-A2-SC PRWECT. CALAVERA HILLS II, LLC BORING BA-1 SHEET OF Robertson Ranch, Carlsbad 97 99 100 101 102 103 104 GeooI, Robertson Ranch, Carlsbad Plate B-44 APPENDIX D SLOPE STABILITY ANALYSIS INTRODUCTION OF GSTABL7 v.2 COMPUTER PROGRAM Introduction GSTABL7 v.2 is a fully integrated slope stability analysis program. It permits the engineer to develop the slope geometry interactively and perform slope analysis from within a single program. The slope analysis portion of GSTABL7 v.2 uses a modified version of the popular STABL program, originally developed at Purdue University. GSTABL7 v.2 performs a two dimensional limit equilibrium analysis to compute the factor of safety (FOS) for a layered slope using the simplified Bishop or Janbu methods. This program can be used to search for the most critical surfaáe'or the FOS may be determined for specific surfaces. GSTABL7, Version 2, is programmed to handle: 1. Heterogenous soil systems 2. Anisotropic soil strength properties 3. Reinforced slopes 4. Nonlinear Mohr-Coulomb strength envelope 5. Pore water pressures for effective stress analysis using: Phreatic and piezometric surfaces Pore pressure grid Rfactor Constant pore water pressure 6. Pseudo-static earthquake loading 7. Surcharge boundary loads 8. Automatic generation and analysis of an unlimited number of circular, noncircular and block-shaped failure surfaces 9. Analysis of right-facing slopes 10. Both SI and Imperial units General Information If the reviewer wishes to obtain more information concerning slope stability analysis, the following publications may be consulted initially: The Stability of Slopes, by E.N. Bromhead, Surrey University Press, Chapman and Hall, N.Y., 411 pages, ISBN 412 01061 5, 1992. Rock Slope Engineering, by E. Hoek and J.W. Bray, Inst. of Mining and Metallurgy, London, England, Third Edition, 358 pages, ISNB 0 900488 573, 1981. Landslides: Analysis and Control, by R.L. Schuster and R.J. Knzek (editors), Special Report 176, Transportation Research Board, National Academy of Sciences, 234 pages, ISBN 0 309 02804 3, 1978. Inc. GSTABL7 v.2 Features The present version of GSTABL7 v.2 contains the following features: Allows user to calculate FOS for static stability and seismic stability evaluations. Allows user to analyze stability situations with different failure modes. Allows user to edit input for slope geometry and calculate corresponding FOS. Allows user to readily review on-screen the input slope geometry. Allows user to automatically generate and analyze defined numbers of circular, non- circular and block-shaped failure surfaces (i.e., bedding plane, slide plane, etc.). Input Data Input data includes the following items: Unit weight, residual cohesion, residual friction angle, peak cohesion, and peak friction angle of fill material, bedding plane, and bedrock, respectively. Residual cohesion and friction angle is used for static stability analysis, where as peak cohesion and friction angle is for dynamic stability analysis. Slope geometry and surcharge boundary loads. Apparent dip of bedding plane can be modeled in an anisotropic angular range (i.e., from 0 to 90 degrees. Pseudo-static earthquake loading (an earthquake loading of 0.15 iwas used in the analysis). A 20 percent (20%) increase in soil strengths to model transient seismic loading of the slope, as is customary in geotechnical practice, was used in these analyses. Seismic Discussion Seismic stability analyses were approximated using a pseudo-static approach. The major difficulty in the pseudo-static approach arises from the appropriate selection of the seismic coefficient used in the analysis. The use of a static inertia force equal to this acceleration during an earthquake (rigid-body response) would be extremely conservative for several reasons including: (1) only low height, stiff/dense embankments or embankments in confined areas may respond essentially as rigid structures; (2) an earthquake's inertiaforce is enacted on a mass for a short time period. Therefore, replacing a transient force by a pseudo-static force representing the maximum acceleration may be considered overly Shapell Homes Appendix D FiIe:e:wp9\6100\6145e.gif Page 2 GeeSefls, lime. conservative; (3) assuming that total pseudo-static loading is applied evenly throughout the embankment for an extended period of time is an incorrect assumption, as the length of the failure surface analyzed is usually much greater than the wave length of seismic waves generated by earthquakes; and (4) the seismic waves would place portions of the mass in compression and some in tension, resulting in only a limited portion of the failure surface analyzed moving in a downslope direction, at any one instant of earthquake loading. The coefficients usually suggested by regulating agencies, counties and municipalities are in the range of 0.05g to 0.25g. For example, past regulatory guidelines within the city and county of Los Angeles indicated that the slope stability pseudostatic coefficient = 0.1 to 0.151. The method developed by Krinitzsky, Gould, and Edinger (1993) which was in turn based. on Taniguchi and Sasaki (1986), was referenced. This method is based on empirical data and the performance of existing earth embankments during seismic loading. Our review of "Guidelines for Evaluating and Mitigating Seismic Hazards in California" (Davis, 1997) indicates the State of California recommends using pseudo-static coefficient of 0.15 for design earthquakes of M 8.25 or greater and using 0.1 for earthquake parameter M 6.5. Therefore, for reasonable conservatism, a seismic coefficient of 0.15 I was used in our analysis for an M6.9 event. Output Information Output information includes: All input data. FOS for the 10 most critical surfaces for static and pseudo-static stability situation. High quality plots can be generated. The plots include the slope geometry, the critical surfaces and the FOS. Note, that in the analyses, 100 to 1,000 trial surfaces were analyzed for each section for either static or pseudo-static analyses. Results of Slope Stability Calculation Attached are the soil parameters and computer print out sheets from our analyses of the existing bluff slope stability for Sections E-E' through H-H' at the site. Both static and psuedo static analysis were used to evaluate the stability of the existing slopes. The results in all cases reviewed indicated a minimum FOS of >1.5 for static and >1. 1 for psuedo static (seismic) conditions. ShapeI Homes Appendix 0 File:e:\wp9\6100\6145e.gif Page 3 Inc.Geoftilsq TABLE D-1 - SOIL PARAMETERS USED Q. wu fti r,,•,, , 4 SOILJ -4 ., e 2 1 4- j? BdIi4 i ,j. Cross-f PaIIeI * NEM 4 'Cross ' I I ,araIIeIr c n BddiIgc - -# : An = ~—~C- I .. -, Section H-H 110 125 100 22 25Afu - - 120 - - Section H-I-P/G-G' 105 125 100 Qt SPISMIQt2 33 120 37 Section H-H/"' Qt SWSC/Qt, 120 135 1,000 18 500 18 1,200 21 600 21 Section 1-1-H' Qt SM 105 125 100 30 - - 120 34 - - Section H-1-l' Clt SC 120 135 300 33 - - 360 37 - - Section E-E'/F-F'/ G-G'/H-H' 125 135 100 34 100 28 120 38 120 32 TsaSM3_- Section E-E'/F-F' 125 135 300 34 200 28 360 38 240 32 Section E-E 125 135 500 30 200 28 600 34 240 32 Section Ec' TsaCL 125 135 1,000 21 200 18 1,200 24 240 21 Section F-F 115 125 100 31 - - 120 35 - - TABLE D-2 - SWJTH PLANNED SLOPE1 -WITH P1NNEDSLOPE 1 , LOCITI 4 Eik J: TOf31 1 STATICi.' .; :.SEISMiC;;.-, cSTATIC..;:- sElSMIc.:,:.. Section E-E' 1.6 1.2 J - - Janbu Section F-F' - — L 1.8 1.4 Janbu Section G-G' - — 2.4 2.3 Janbu Section H-H' - 2.1 - 1.8 - - - - - Janbu ShapeH Homes Appendix 0 File:e:\wp9\6100\6145e.glf Page 4 Ggp&,flz, Inc. TABLE D-3 - cMAJERIA1 -c i I II.r Z - - ounruL.IMIi.o LPDILJ I T IVEN.- 4 -e-- t.j I 'j4- - yI/ C(f) Artificial Fill (Qt/Qal) 1.6 31 180 Santiago Fm. (isa, SM) 2.6 34 300 Santiago Fm. (isa, SM/SC) 2.6 32 300 Terrace Deposits (Qt) 1.7 30 200 Shapell Homes Appendix D File:e:\wp9\6100\6145e.gif Page 5 GeoSoilz, Inc. SURFICIAL SLOPE STABILITY ANALYSIS Seepage parallel to slope Tract/Project Shapell Homes Material Type: Fill _Artificial (Qt/Qal) Fs = Static Safety Factor = z (Yyw) Cos2(i) Tan + C (d)) z (y) Sin (i) Cos (I) W- 0.6145-E-SC I+- SURFICIAL SLOPE STABILITY 2: 1 SLOPE Figure D-17 Depth of Saturation (z) 4 feet Slope Angle (i) (for 2:1 slopes) 76 degrees Unit Weight of Water () 62.4 lb/ft3 Saturated Unit Weight of Soil () 125 lb/ft3 Apparent Angle of Internal Friction () 31 degrees Apparent Cohesion (C) 180 jib/f? DEPTH OF SATURATION SLOPE FACTOR OF SAFETY 4 FEET 2:1 1.61 SURFICIAL SLOPE STABILITY ANALYSIS Seepage parallel to slope Tract/Project Shapell Homes Material Type: Santiago Formation [_(TsaISM) Fs = Static Safety Factor = z (y-,) Cos2(i) Tan +C () z (y,) Sin (I) Cos (i) irL W.O. SURFICIAL SLOPE STABILITY 2: 1 SLOPE Figure D-18 Depthof Saturation (z) 4 feet Slope Angle (i)(for 2:1 slopes) 76 degrees Unit Weight of Water (Yw) lb/fl? SaturatedUnit 62.4 Weight of Soil (y) 125 lb/ft3 Apparent Angle of Internal Friction (4) 34 degrees Apparent Cohesion (C) 300 lb/ft2 DEPTH OF SATURATION SLOPE FACTOR OF SAFETY 4 FEET 2:1 2.64 SURFICIAL SLOPE STABILITY ANALYSIS Ar Seepage parallel to slope Tract/Project L Shapell Homes Material Type: Santiago Formation (Tsa/SM and SC) Fs = Static Safety Factor = z (tl'w) Cos2(i) Tan (4) +C z (y.J Sin (i) Cos (i) W.O. 6145-E-SC SURFICIAL SLOPE STABILITY 2: 1 SLOPE FigureD-19 Depth of Saturation (z) 4 feet Slope Angle (I) (for 2:1slopes) 76 degrees Unit Weight of Water (lw) 62.4 lb/ft3 Saturated Unit Weight of Soil (y,,) 125 lb/ft3 Apparent Angle of ion (4,) 32 degrees Apparent Cohesion (C) 300 1b/ft2 DEPTH OF SATURATION Internal Frict Ir SLOPE FACTOR OF SAFETY 4 FEET 2:1 2.63 SURFICIAL SLOPE STABILITY ANALYSIS ij1lel to slope Tract/Project Shapell Homes Material Type: Deposits _Terrace (Qt) Fs = Static Safety Factor = Z (Ysat) Sin (i) Cos (I) c.eoiiic. W.O. 6145-E-SC SURFICIAL SLOPE STABILITY 2: 1 SLOPE Figure 0-20 Depth of Saturation (z) 4 feet Slope Angle (I) (for 2:1 slopes) 76 degrees Unit Weight of Water (ye) 62.4 lb/ft3 Saturated Unit Weight of Soil (y) 125 The Apparent Angle of Internal Friction () 30 degrees Apparent Cohesion (C) 200 jib/f? DEPTH OF SATURATION SLOPE FACTOR OF SAFETY 4 FEET 2:1 z (t1w) Cos2(I) Tan ($) + C~N 1.78 F GENERAL EARThWORK, GRADING GUIDELINES, AND PRELIMINARY CRITERIA General These guidelines present general procedures and requirements for earthwork and grading as shown on the approved grading plans, including preparation of areas to be filled, placement of fill, installation of subdrains, excavations, and appurtenant structures or flatwork. The recommendations contained in the geotechnical report are part of these earthwork and grading guidelines and would supercede the provisions contained hereafter in the case of conflict. Evaluations performed by the consultant during the course of grading may result in new or revised recommendations which could supercede these guidelines or the recommendations contained in the geotechnical report. Generalized details follow this text. The contractor is responsible for the satisfactory completion of all earthwork in accordance with provisions of the project plans and specifications and latest adopted code. In the case of conflict, the most onerous provisions shall prevail. The project geotechnical engineer and engineering geologist (geotechnical consultant), and/or their representatives, should provide observation and testing services, and geotechnical consultation during the duration of the project. EARTHWORK OBSERVATIONS AND TESTING Geotechnical Consultant Prior to the commencement of grading, a qualified geotechnical consultant (soil engineer and engineering geologist) should be employed for the purpose of observing earthwork procedures and testing the fills for general conformance with the recommendations of the geotechnical report(s), the approved grading plans, and applicable grading codes and ordinances. The geotechnical consultant should provide testing and observation so that an evaluation may be made that the work is being accomplished as specified. It is the responsibility of the contractor to assist the consultants and keep them apprised of anticipated work schedules and changes, so that they may schedule their personnel accordingly. All remedial removals, clean-outs, prepared ground to receive fill, key excavations, and subdrain installation should be observed and documented by the geotechnical consultant prior to placing any fill. It is the contractor's responsibility to notify the geotechnical consultant when such areas are ready for observation. Laboratory and Field Tests Maximum dry density tests to determine the degree of compaction should be performed in accordance with American Standard Testing Materials test method ASTM designation D 1557. Random or representative field compaction tests should be performed in accordance with test methods ASTM designation D 1556, D 2937 or D 2922, and D 3017, oapüs, Inc. at intervals of approximately ±2 feet of fill height or approximately every 1,000 cubic yards placed. These criteria would vary depending on the soil conditions and the size of the project. The location and frequency of testing would be at the discretion of the geotechnical consultant. Contractors Responsibility All clearing, site preparation, and earthwork performed on the project should be conducted by the contractor, with observation by a geotechnical consultant, and staged approval by the governing agencies, as applicable. It is the contractor's responsibility to prepare the ground surface to receive the 1111, to the satisfaction of the geotechnical consultant, and to place, spread, moisture condition, mix, and compact the fill in accordance with the recommendations of the geotechnical consultant. The contractor should also remove all non-earth material considered unsatisfactory by the geotechnical consultant. Notwithstanding the services provided by the geotechnical consultant, it is the sole responsibility of the contractor to provide adequate equipment and methods to accomplish the earthwork in strict accordance with applicable grading guidelines, latest adopted codes or agency ordinances, geotechnical report(s), and approved grading plans. Sufficient watering apparatus and compaction equipment should be provided by the contractor with due consideration for the fill material, rate of placement, and climatic conditions. If, in the opinion of the geotechnical consultant, unsatisfactory conditions such as questionable weather, excessive oversized rock or deleterious material, insufficient support equipment, etc., are resulting in a quality of work that is not acceptable, the consultant will inform the contractor, and the contractor is expected to rectify the conditions, and if necessary, stop work until conditions are satisfactory. During construction, the contractor shall properly grade all surfaces to maintain good drainage and prevent ponding of water. The contractor shall take remedial measures to control surface water and to prevent erosion of graded areas until such time as permanent drainage and erosion control measures have been installed. SITE PREPARATION All major vegetation, including brush, trees, thick grasses, organic debris, and other deleterious material, should be removed and disposed of off-site. These removals must be concluded prior to placing fill. In-place existing fill, soil, alluvium, colluvium, or rock materials, as evaluated by the geotechnical consultant as being unsuitable, should be removed prior to any fill placement. Depending upon the soil conditions, these materials may be reused as compacted fills. Any materials incorporated as part of the compacted fills should be approved by the geotechnical consultant. Any underground structures such as cesspools, cisterns, mining shafts, tunnels, septic tanks, wells, pipelines, or other structures not located prior to grading, are to be removed or treated in a manner recommended by the geotechnical consultant. Soft, dry, spongy, Shapell Homes Appendix E F1Ie:e:\wp9\6100\6145e.gif Page 2 Go&s, Inc. highly fractured, or otherwise unsuitable ground, extending to such a depth that surface processing cannot adequately improve the condition, should be overexcavated down to firm ground and approved by the geotechnical consultant before compaction and filling operations continue. Overexcavated and processed soils, which have been properly mixed and moisture conditioned, should be re-compacted to the minimum relative compaction as specified in these guidelines. Existing ground, which is determined to be satisfactory for support of the fills, should be scarified (ripped) to a minimum depth of 6 to 8 inches, or as directed by the geotechnical consultant. After the scarified ground is brought to optimum moisture content, or greater and mixed, the materials should be compacted as specified herein. If the scarified zone is greater than 6t0 8 inches in depth, it may be necessary to remove the excess and place the material in lifts restricted to about 6 to 8 inches in compacted thickness. Existing ground which is not satisfactory to support compacted fill should be overexcavated as required in the geotechnical report, or by the on-site geotechnical consultant. Scarification, disc harrowing, or other acceptable forms of mixing should continue until the soils are broken down and free of large lumps or clods, until the working surface is reasonably uniform and free from ruts, hollows, hummocks, mounds, or other uneven features, which would inhibit compaction as described previously. Where fills are to be placed on ground with slopes steeper than 5:1 (horizontal to vertical [h:v]), the ground should be stepped or benched. The lowest bench, which will act as a key, should be a minimum of 15 feet wide and should be at least 2 feet deep into firm material, and approved by the geotechnical consultant. In fill-over-cut slope conditions, the recommended minimum width of the lowest bench or key is also 15 feet, with the key founded on firm material, as designated by the geotechnical consultant. As a general rule, unless specifically recommended otherwise by the geotechnical consultant, the minimum width of fill keys should be equal to 1/2 the height of the slope. Standard benching is generally 4 feet (minimum) vertically, exposing firm, acceptable material. Benching may be used to remove unsuitable materials, although it is understood that the vertical height of the bench may exceed 4 feet. Pre-stripping may be considered for unsuitable materials in excess of 4 feet in thickness. All areas to receive fill, including processed areas, removal areas, and the toes of fill benches, should be observed and approved by the geotechnical consultant prior to placement of fill. Fills may then be properly placed and compacted until design grades (elevations) are attained. COMPACTED FILLS Any earth materials imported or excavated on the property may be utilized in the fill provided that each material has been evaluated to be suitable by the geotechnical consultant. These materials should be free of roots, tree branches, other organic matter, Shapell Homes Appendix E Fi1e:e:\wp9\6100\6145e.gif Page 3 eSils Inc. or other deleterious materials. All unsuitable materials should be removed from the fill as directed by the geotechnical consultant. Soils of poor gradation, undesirable expansion potential, or substandard strength characteristics may be designated by the consultant as unsuitable and may require blending with other soils to serve as a satisfactory fill material. Fill materials derived from benching operations should be dispersed throughout the fill area and blended with other approved material. Benching operations should not result in the benched material being placed only within a single equipment width away from the fill/bedrock contact. Oversized materials defined as rock, or other irreducible materials, with a maximum dimension greater than 12 inches, should not be buried or placed in fills unless the location of materials and disposal methods are specifically approved by the geotechnical consultant. Oversized material should be taken offsite, or placed in accordance with recommendations of the geotechnical consultant in areas designated as suitable for rock disposal. GSl anticipates that soils to be utilized as fill material for the subject project may contain some rock. Appropriately, the need for rock disposal may. be necessary during grading operations on the site. From a geotechnical standpoint, the depth of any rocks, rock fills, or rock blankets, should be a sufficient distance from finish grade. This depth is generally the same as any overexcavation due to cut-fill transitions in hard rock areas, and generally facilitates the excavation of structural footings and substructures. Should deeper excavations be proposed (i.e., deepened footings, utility trenching, swimming pools, spas, etc.), the developer may consider increasing the hold-down depth of any rocky fills to be placed, as appropriate. In addition, some agencies/jurisdictions mandate a specific hold-down depth for oversize materials placed in fills. The hold-down depth, and potential to encounter oversize rock, both within fills, and occurring in cut or natural areas, would need to be disclosed to all interested/affected parties. Once approved by the governing agency, the hold-down depth for oversized rock (i.e., greater than 12 inches) in fills on this project is provided as 10 feet, unless specified differently in the text of this report. The governing agency may require that these materials need to be deeper, crushed, or reduced to less than 12 inches in maximum dimension, at their discretion. To facilitate future-trenching, rock (or oversized material), should not be placed within the hold-down depth feetfrom finish grade, the range of foundation excavations, future utilities, or underground construction unless specifically approved by the governing agency, the geotechnical consultant, and/or the developer's representative. If import material is required for grading, representative samples of the materials to be utilized as compacted fill should be analyzed in the laboratory by the geotechnical consultant to evaluate it's physical properties and suitability foruse onsite. Such testing should be performed three (3) days prior to importation. If any material other than that previously tested is encountered during grading, an appropriate analysis of this material should be conducted by the geotechnical consultant as soon as possible. Approved fill material should be placed in areas prepared to receive fill in near horizontal layers, that when compacted, should not exceed about 6 to 8 inches in thickness. The Shapell Homes Appendix E F1Ie:e:\wp9\6100\6145e.gif Page 4 God 9 Inc. geotechnical consultant may approve thick lifts if testing indicates the grading procedures are such that adequate compaction is being achieved with lifts of greater thickness. Each layer should be spread evenly and blended to attain uniformity of material and moisture suitable for compaction. Fill layers at a moisture content less than optimum should be watered and mixed, and wet fill layers should be aerated by scarification, or should be blended with drier material. Moisture conditioning, blending, and mixing of the fill layer should continue until the fill materials have a uniform moisture content at, or above, optimum moisture. After each layer has been evenly spread, moisture conditioned, and mixed, it should be uniformly compacted to a minimum of 90 percent of the maximum density as evaluated by ASTM test designation D 1557, or as otherwise recommended by the geotechnical consultant. Compaction equipment should be adequately sized and should be specifically designed for soil compaction, or of proven reliability to efficiently achieve the specified degree of compaction. Where tests indicate that the density of any layer of fill, or portion thereof, is below the required relative compaction, or improper moisture is in evidence, the particular layer or portion shall be re-worked until the required density and/or moisture content has been attained. No additional fill shall be placed in an area until the last placed lift of fill has been tested and found to meet the density and moisture requirements, and is approved by the geotechnical consultant. In general, per the 1997 UBC and/or latest adopted version of the California Building Code (CBC), fill slopes should be designed and constructed at a gradient of 2:1 (h:v), or flatter. Compaction of slopes should be accomplished by over-building a minimum of 3 feet horizontally, and subsequently trimming back to the design slope configuration. Testing shall be performed as the fill is elevated to evaluate compaction as the fill core is being developed. Special efforts may be necessary to attain the specified compaction in the fill slope zone. Final slope shaping should be performed by trimming and removing loose materials with appropriate equipment. A final evaluation of fill slope compaction should be based on observation and/or testing of the finished slope face. Where compacted fill slopes are designed steeper than 2:1 (h:v), prior approval from the governing agency, specific material types, a higher minimum relative compaction, special reinforcement, and special grading procedures will be recommended. If an alternative to over-building and cutting back the compacted fill slopes is selected, then special effort should be made to achieve the required compaction in the outer 10 feet of each lift of fill by undertaking the following: An extra piece of equipment consisting of a heavy, short-shanked sheepsfoot should be used to roll (horizontal) parallel to the slopes continuously as fill is placed. The sheepsfoot roller should also be used to roll perpendicular to the slopes, and extend out over the slope to provide adequate compaction to the face of the slope. Shapell Homes Appendix E FiIe:e:\wp9\61006145e.gif Page 5 Gooils, Inc. Loose fill should not be spilled out over the face of the slope as each lift is compacted. Any loose fill spilled over a previously completed slope face should be trimmed off or be subject to re-rolling. Field compaction tests will be made in the outer (horizontal) ±2 to ±8 feet of the slope at appropriate vertical intervals, subsequent to compaction operations. After completion of the slope, the slope face should be shaped with a small tractor and then re-rolled with a sheepsfoot to achieve compaction to near the slope face. Subsequent to testing to evaluate compaction, the slopes should be grid-rolled to achieve compaction to the slope face. Final testing should be used to evaluate compaction after grid rolling. Where testing indicates less than adequate compaction, the contractor will be responsible to rip, water, mix, and recompact the slope material as necessary to achieve compaction. Additional testing should be performed to evaluate compaction. SUBDRAIN INSTALLATION Subdrains should be installed in approved ground in accordance with the approximate alignment and details indicated by the geotechnical consultant. Subdrain locations or materials should not be changed or modified without approval of the geotechnical consultant. The geotechnical consultant may recommend and direct changes in subdrain line, grade, and drain material in the field, pending exposed conditions. The location of constructed subdrains, especially the outlets, should be recorded/surveyed by the project civil engineer. Drainage at the subdrain outlets should be provided by the project civil engineer. EXCAVATIONS Excavations and cut slopes should be examined during grading by the geotechnical consultant. If directed by the geotechnical consultant, further excavations or overexcavation and refilling of cut areas should be performed, and/or remedial grading of cut slopes should be performed. When fill-over-cut slopes are to be graded, unless otherwise approved, the cut portion of the slope should be observed by the geotechnical consultant prior to placement of materials for construction of the fill portion of the slope. The geotechnical consultant should observe all cut slopes, and should be notified by the contractor when excavation of cut slopes commence. If, during the course of grading, unforeseen adverse or potentially adverse geologic conditions are encountered, the geotechnical consultant should investigate, evaluate, and make appropriate recommendations for mitigation of these conditions. The need for cut ShapeD Homes Appendix E FiIe:e:\wp9\6100\6145e.gif Page 6 GeoSoiL, Z slope buttressing or stabilizing should be based on in-grading evaluation by the geotechnical consultant, whether anticipated or not. Unless otherwise specified in geotechnical and geological report(s), no cut slopes should be excavated higher or steeper than that allowed by the ordinances of controlling governmental agencies. Additionally, short-term stability of temporary cut slopes is the contractor's responsibility. Erosion control and drainage devices should be designed by the project civil engineer and should be constructed in compliance with the ordinances of the controlling governmental agencies, and/or in accordance with the recommendations of the geotechnical consultant. COMPLETION Observation, testing, and consultation by the geotéchnical consultant should be conducted during the grading operations in order to state an opinion that all cut and fill areas are graded in accordance with the approved project specifications. After completion of grading, and after the geotechnical consultant has finished observations of the work, final reports should be submitted, and may be subject to review by the controlling governmental agencies. No further excavation or filling should be undertaken without prior notification of the geotechnical consultant or approved plans. All finished cut and fill slopes should be protected from erosion and/or be planted in accordance with the project specifications and/or as recommended by a landscape architect. Such protection and/or planning should be undertaken as soon as practical after completion of grading. JOB SAFETY General At GSI, getting the job done safely is of primary concern. The following is the company's safety considerations for use by all employees on multi-employer construction sites. On-ground personnel are at highest risk of injury, and possible fatality, on grading and construction projects. GSI recognizes that construction activities will vary on each site, and that site safety is the prime responsibility of the contractor; however, everyone must be safety conscious and responsible at all times. To achieve our goal of avoiding accidents, cooperation between the client, the contractor, and GSI personnel must be maintained. In an effort to minimize risks associated with geotechnical testing and observation, the following precautions are to be implemented for the safety of field personnel on grading and construction projects: Shapell Homes Appendix E FiIe:e:wp9\6100\6145e.gif Page 7 GoSoUs, Inc. Safety Meetings: GSI field personnel are directed to attend contractor's regularly scheduled and documented safety meetings. Safety Vests: Safety vests are provided for, and are to be worn by GSI personnel, at all times, when they are working in the field. Safety Flags: Two safety flags are provided to GSI field technicians; one is to be affixed to the vehicle when on site, the other is to be placed atop the spoil pile on all test pits. Flashing Lights: All vehicles stationary in the grading area shall use rotating or flashing amber beacons, or strobe lights, on the vehicle duringall field testing. While operating a vehicle in the grading area, the emergency flasher on the vehicle shall be activated. In the event that the contractor's representative observes any of our personnel not following the above, we request that it be brought to the attention of our office. Test Pits Location, Orientation, and Clearance The technician is responsible for selecting test pit locations. A primary concern should be the technician's safety. Efforts will be made to coordinate locations with the grading contractor's authorized representative, and to select locations following or behind the established traffic pattern, preferably outside of current traffic. The contractor's authorized representative (supervisor, grade checker, dump man, operator, etc.) should direct excavation of the pit and safety during the test period. Of paramount concern should be the soil technician's safety, and obtaining enough tests to represent the fill. Test pits should be excavated so that the spoil pile is placed away from oncoming traffic, whenever possible. The technician's vehicle is to be placed next to the test pit, opposite the spoil pile. This necessitates the fill be maintained in a driveable condition. Alternatively, the contractor may wish to park a piece of equipment in front of the test holes, particularly in small fill areas or those with limited access. A zone of non-encroachment should be established for all test pits. No grading equipment should enter this zone during the testing procedure. The zone should extend approximately 50 feet outward from the center of the test pit. This zone is established for safety and to avoid excessive ground vibration, which typically decreases test results. When taking slope tests, the technician should park the vehicle directly above or below the test location. If this is not possible, a prominent flag should be placed at the top of the slope. The contractor's representative should effectively keep all equipment at a safe operational distance (e.g., 50 feet) away from the slope during this testing. The technician is directed to withdraw from the active portion of the fill as soon as possible following testing. The technician's vehicle should be parked at the perimeter of the fill in Shapell Homes Appendix E FiIe:e:\wp961 00\6145e.git Page 8 Geoils, Inc. a highly visible location, well away from the equipment traffic pattern. The contractor should inform our personnel of all changes to haul roads, cut and fill areas or other factors that may affect site access and site safety. In the event that the technician's safety is jeopardized or compromised as a result of the contractor's failure to comply with any of the above, the technician is required, by company policy, to immediately withdraw and notify his/her supervisor. The grading contractor's representative will be contacted in an effort to affect a solution. However, in the interim, no further testing will be performed until the situation is rectified. Any fill placed can be considered unacceptable and subject to reprocessing, recompaction, or removal. In the event that the soil technician does not comply with the above or other established safety guidelines, we request that the contractor bring this to the technician's attention and notify this office. Effective communication and coordination between the contractor's representative and the soil technician is strongly encouraged in order to implement the above safety plan. Trench and Vertical Excavation It is the contractor's responsibility to provide safe access into trenches where compaction testing is needed. Our personnel are directed not to enter any excavation or vertical cut which: 1) is 5 feet or deeper unless shored or laid back; 2) displays any evidence of instability, has any loose rock or other debris which could fall into the trench; or 3) displays any other evidence of any unsafe conditions regardless of depth. All trench excavations or vertical cuts in excess of 5 feet deep, which any person enters, should be shored or laid back. Trench access should be provided in accordance with Cal/OSHA and/or state and local standards. Our personnel are directed not to enter any trench by being lowered or "riding down" on the equipment. If the contractor fails to provide safe access to trenches for compaction testing, our company policy requires that the soil technician withdraw and notify his/her supervisor. The contractor's representative will be contacted in an effort to affect a solution. All backfill not tested due to safety concerns or other reasons could be subject to reprocessing and/or removal. If GSI personnel become aware of anyone working beneath an unsafe trench wall or vertical excavation, we have a legal obligation to put the contractor and owner/developer on notice to immediately correct the situation. If corrective steps are not taken, GSl then has an obligation to notify Cal/OSHA and/or the proper controlling authorities. Shapell Homes Appendix E FiIe:e:\wp9\6100\6145e.gtf Page 9 oSGP, Inc. V . ------------ .<_ —Na tur&ra—de Proposed a Colluvium and alluvium (remove) Typical benching Bedrock or approved native material -' - See Alternate Details i::;;: \. -----------e grade Colluvium and alluvium (remove .. o Typical benching Bedrock r approved native material - See Alternate Details Selection of alternate subdrain details, location, and extent of subdrains should be evaluated by the geotechnical consultant during grading. IG;H CANYON SUBDRAIN DETAIL J Plate E-1 6 1 6-incminknum B-i ALTER MATERIAL Sieve Size Percent Passin 1 inch 100 34 inch 90-100 inch 40-100 No.4 25-40 No. 8 18-33 No. 30 5-15 6-inch minimum A-2 6 Inch minimum Filter fabric 6-inch minimum 6-inch minimum ric 12-Inch minimum I I . r 6-Inch minimum 6-Inch minimum - 1..- •.•.. 6-inch minimum .00 6-Inch minimum A-i Filter material: Minimum volume of 9 cubic feet per lineal foot of pipe. Perforated pipe: 6-inch-diameter ABS or PVC pipe or approved substitute with minimum 8 perforations (Y4-inch diameter) per lineal foot in bottom half of pipe (ASTM D-2751, SDR-35, or ASTM D-1527, Schd. 40). For continuous run in excess of 500 feet, use No. 50 0-7 8-inch-diameter pipe (ASTM D-3034, SDR-35, or No. 200 0-3 ASTM D-1785, SchcL 40). ALTERNATE 1: PERFORATED PIPE AND ALTER MATERIAL \— 6-inch minimum \ 6-inch minimum 6-inch minimum Gravel Material: 9 cubic feet per lineal foot Perforated Pipe: See Alternate 1 Gravel: Clean 34-inch rock or approved substitute. Filter Fabric: Mirafi 140 or approved substitute. ALTERNATE 2: PERFORATED PIPE, GRAVEL AND ALTER FABRIC CANYON SUBDRAIN ALTERNATE DETAILS Plate E-2 Toe of slope as shown on grading plan .•—r-••- Original ground surface to be I / p..: .. . .. restored with compacted fill \ / - Compactct Fill re 2D / T '—OriginaJ ground surface D - Anticipated removal of unsuitable material sp (depth per geotechnical engineer) / / Provide 1:1 (H:V) minimum projection from toe of Back-cut varies. For deep removals, slope as shown on grading plan to the recommended backcut should be made no steeper removal depth. Slope height, site conditions, and/or than 1:1 (H:V), or flatter as necessary local conditions could dictate flatter projections. for safety considerations. ~"* C' FILL SLOPE TOEING OUT ON FLAT ALLUVIATED CANYON DETAIL Plate E-3 - Proposed grade Previously placed, temporary compacted fill for drainage only Proposed additional compacted fill Unsuitable mater.iI. Ctp.b removed) Existing compacted fill Bedrock or approved native material To be removed before placing additional compacted fill IG4"*C. I REMOVAL ADJACENT TO EXISTING FILL ADJOINING CANYON FILL DETAIL I Plate E-4 Blanket fill (if recommended by the geotechnical consultant) Design finish&o: is foot minimum' I hIML 10-foot minimum / --- ----- Drainage per design civil engineer -F --- 15-foot typical 1 t 2_ drain spacing Typical benching Buttress or stabilization fill j foot - j - - tToe,:2-P~ercen 2-Percent Gradient 2-foot minimum Heelt Grad1et—..... _ key depth _________________ 15-foot minimum or H/2 where H Is the I slope height I 4-inch--diameter non-perforated outlet pipe and backdrain (see detail Plate E-6). Outlets to be spaced at 100-foot maximum intervals and shall extend 2 feet beyond the face of slope at time of rough grading completion. At the completion of rough grading. the design civil engineer should provide recommendations to convey any outlet's discharge to a suitable conveyance, utilizing a non-erosive device. Typical benching (4-foot minimum) '- Bedrock or approved native material Subdrain as recommended by geotechnical consultant IG"lic". I TYPICAL STABILIZATION / BUTTRESS FILL DETAIL Plate E-5 1 I 2-foot I 2-toot I minimum I 2-foot mnwn 4--inch rriirftt~ 3 foot ........... pipe TimUfl'l Filter Material: Minimum of 5 cubic feet per lineal foot of pipe or 4 cubic feet per lineal feet of pipe when placed in square cut trench. Alternative in Lieu of Filter Material: Gravel may be encased in approved filter fabric. Filter fabric shall be Mirafi 140 or equivalent. Filter fabric shall be lapped a minimum of 12 inches in all joints. Minimum 4-Inch-Diameter Pipe: ABS-ASTM D-2751, SDR 35; or ASTM D-1527 Schedule 40, PVC-ASTM D-3034, SDR 35; or ASTM D-1785 Schedule 40 with a crushing strength of 1,000 pounds minimum, and a minimum of 8 uniformly-spaced perforations per foot of pipe. Must be installed with perforations down at bottom of pipe. Provide cap at upstream end of pipe. Slope at 2 percent to outlet pipe. Outlet pipe to be connected to subdrain pipe with tee or elbow. Notes: 1. Trench for outlet pipes to be backfilled and compacted with onsite soil. 2. .Backdrains and lateral drains shall be located at elevation of every bench drain. First drain located at elevation just above lower lot grade. Additional drains may be required at the discretion of the geotechnical consultant. Filter Material shall be of the following Gravel shall be of the following specification or an approved equivalent, specification or an approved equivalent. Sieve Size Percent Passing Sieve Size Percent Passing 1 inch 100 iY2 inch 100 3/4 inch 90-100 No. 4 50 % inch 40-100 No. 200 8 No. 4 25-40 No. 8 18-33 No. 30 5-15 No. 50 0-7 No. 200 0-3 1 I TYPICAL BUTTRESS SUBDRAIN DETAIL J Plate E_6] Toe of slope as shown on grading plan Proposed grade Compacted fill . •. - 4-foot rrdnImum 2-foot minimum, F ench width In bedrock or L.2may vary Bedrock or - fearth material [ approved - - - - - 2-Percent Gradient _____ native material 15-foot minimum or H/2 where H Is Subdrain as recommended by the slope height I geotechnical consultant NOTES: Where the natural slope approaches or exceeds the design slope ratio, special recommendations would be provided by the geotechnical consultant. The need for and disposition of drains should be evaluated by the geotechnical consultant, based upon exposed conditions. Go's *& FILL OVER NATURAL (SIDEHILL FILL) DETAIL Plate E-7 Natural slope to be restored with compacted fill- Backcut varies 2-percent "rent minimum__I 15-loot minimum or key depth L.._ H/2 where H Is I the elope height l\\. Bench width - may vary — I (4-loot minimum) I Subdrain as recommended by geotechnical consultant Cut/fill contact as shown on grading plan Cut/fill contact as shown on as-built plan. H - height of elope Original (existing) grade Cut slope Maintain L.inimum 15-foot liii section from backcut to face of finish elope Of Proposed grade \. Compacted fill - 4-foot minimum Bedrock or approved native material NOTE: The cut portion of the slope should be excavated and evaluated by the geotechnical consultant prior to construction of the fill portion. ... G4;c. FILL OVER CUT DETAIL Plate E-8 Natural slope Proposed finish grade '\ . ènvuitiè MateriaL A = Typical benching (4-foot minimum) H Compacted stablization fill 1-foot minimum tilt back Bedrock or other % ( approved native material - - - If recommended by the geotechnical \( consultant, the remaining cut portion of fo Y '6 2 Percent Gradient _ the slope may require removal and . \\ —--- - replacement with compacted fill. -c\*- I w Subdrain as recommended by geotechnical consultant NOTES: 1. Subdrains may be required as specified by the geotechnical consultant. 2 W shall be equipment width (15 feet) for slope heights less than 25 feet. For slopes greater than 25 feet, W shall be evaluated by the geotechnical consultant. At no time, shall W be less than H/2, where H is the height of the slope. STABLIZATION FILL FOR UNSTABLE MATERIAL EXPOSED IN CUT SLOPE DETAIL Plate E-9 J Proposed finish grade Natural grade -------------------------- L 000 H - height of elope 15- t minimum : • see Note 1) :.• . \ I -. ......-.. .. Typical benching (4-foot minimum) \\ç 3-toot minimum Bedrock or approved native material 2-Percent Qi. WA 15-fool minimum key 2-loot minimum - -' Subdrain as recommended by key depth or H/2 H)30 feet geotechnical consultant NOTES: 1. 15-foot minimum to be maintained from proposed finish slope face to backcut. The need and disposition of drains will be evaluated by the geotechnical consultant based on field conditions. Pad overexcavation and recompaction should be performed if evaluated to be necessary by the geotechnical consultant. SKIN FILL OF NATURAL GROUND DETAIL Plate E-10 _T41- x 2-foot x Y4-inch steel plate d %-inch pipe nipple to top of plate 5-foot galvanized pipe, pipe threads top and bottom; is threaded on both ends and 5-foot increments chedule 40 PVC pipe sleeve, add t increments with glue joints oposed finish grade 51eet 5feet I I I I I 5feet N. ) 1 , , —2feet ----;'..... ........ ............... - I -''J-- Provide ....................................... 7 Bottom of cleanout a minimum 1-foot f bedding of compacted sand NOTED Locations of settlement plates should be clearly marked and readily visible (red flagged) to equipment operators. Contractor should maintain clearance of a 5-foot radius of plate base and withn 5 feet (vertical) for heavy equipment. Fill within clearance area should be hand compacted to project specifications or compacted by alternative approved method by the geotechnical consultant (in writing, prior to construction). *After 5 feet (vertical) of fill is in place, contractor should maintain a 5-foot radius equipment clearance from riser. Place and mechanically hand compact initial 2 feet of fill prior to establishing the initial reading. In the event of damage to the settlement plate or extension resulting from equipment operating within the specified clearance area, contractor should immediately notify the geotechnical consultant and should be responsible for restoring the settlement plates to working order. An alternate design and method of installation may be provided at the discretion of the geotechnical consultant. SETTLEMENT PLATE AND RISER DETAIL Plate E-18 Finish grade 3/8-inch-diameter X 6-inch-long carriage bolt or equivalent II .. • 4 . I • 6-inch diameter X 3106 feet • 3Y2-inch-long hole - Concrete backfill TYPICAL SURFACE SETTLEMENT MONUMENT • Plate E-19 ] SIDE VIEW 6 Spoil pile _ Test pit TOP VIEW H - So feet • 50 feet 100 feet TEST PIT SAFETY DIAGRAM- Plate E-20 Andrew T. Guatelli, GE 2320 John P. Franklin, CEG 1340 Pavement Alternatives, El Camino FROM: SUBJECT: May 23, 2013 Shapell Homés Attention: Danus O'day Consulting, Attention: Geç 6145-E-SC .y. ./) DATE: TO: U'.. Geotechnical • Geologic • Coastal • Environmental 5741 Palmer Way • Carlsbad, California 92010 • (760) 438-3155 • FAX (760)931-0915'. ww.peosoiIsinc.com MEMORANDUM Reference: "Geotechnical Investigation for the Planned Improvement of El Camino Real, Between Cannon Road and Tamarack Avenue, Rancho Costera (Formerly Robertson Ranch West Village), Carlsbad, San Diego County, California," W.O. 6145-E-SC, dated May 11, 2011, by GeoSoils, Inc. The description of pavement distress was presented in the referenced GSI report, and is repeated below, in italics, for ease of review. Pavement Distress Existing pavement distress was noted throughout the northbound pavement area, and is déscribed as follows: Alligator (Fatigue) Cracking: The most prevalent type of pavement distress appears to be alligator, or fatigue cracking. Alligator cracking is a series of interconnected cracks caused by fatigue failure of the HMA (hot mix asphalt) surface under repeated, excessive traffic loading, dUe to poor drainage, weak base or sub grade (Asphalt Institute (http://asphaltinstitute. ora/Dubllc/enqineerinp/index.asnl). As the number and magnitude of loads becomes too great, longitudinal cracks begin to form (usually in the wheelpaths). After repeated loading, these longitudinal cracks connect forming many-sided sharp-angled pieces that develop into a pattern resembling the skin of an alligator. Between ECR, Stations 444+00 to 455+00, moderate alligator cracks occur within the wheel paths within the slow lane, and/or the previous location of the slow lane prior to median construction. From Stations 455+00 to 459+00, alligator cracks appear within the wheel path nearest the bike lane, and along the approximate location of an approximately 6-inch wide utility trench patch. This distress may also resemble block cracking. Moderate alligatoring was again observed within the wheel path, located just outside the bike lane from approximate Stations 464+50 to 469+50, and in the vicinity of the 6-inch wide utility trench patch. Light, localized alligatoring was observed, primarily within the slow lane, from Stations 476+50 through Station 478+50. From Stations 486+50 to 491+50, light to moderate alligatoring was noted with the slow lane, with light cracking also observed within the fast lane. CT Based on ourreview, a greaterdegree of fatigue cracking appears to coincide with pavement areas underlain with alluvial soils and a relatively shallow groundwater table. Other areas of fatigue cracking may also be associated with poor drainage along the margins of the roadway, especially in the vicinity of Stations 476+50 to 478+50. Patching: Patching, or areas of pavement that has been replaced with new material to repair the existing pavement, were observed throughout the pavement area of ECR. A patch is considered a defect, and temporary, no matter how well it performs. Depressions, or Rutting: Localized depressions, or ruts were noted within the wheel path nearest the center median in the vicinity of Stations 461+00, and between Stations 486 +50 and 491+50. Pothole also appear to be forming within these areas. Other: Minor areas of polished aggregate, raveling, etc. where noted locally and are likely an indication of pavement age. Areas of water seepage were not observed within the existing northbound ECR. The following alternatives may be considered for the rehabilitation of El Caminb Real between Tamarack Avenue and Cannon Road. It should be noted that the design life anticipated for these pavement repair alternatives is less than that indicated in the referenced report for the prior recommended pavement rehabilitation, and probably less than 10 years. The design civil and representatives of the City should assign the distressed locations to the categories listed below. Category 1: Existing ruts combined with alligator and large cracking - this is considered a potential subgrade failure - these areas will probably be completely rebuilt into the base section using Mirafi RS380i (or equivalent), with no paving grid or paving overlay. Category 2: Existing pavement has little or no ruts with some moderate alligator cracking - these areas potentially will replace 5-7 inches of existing AC (leaving 1 inch of existing AC in place), place a high strength PGM grid product and the 5 to 7 inches of new AC over the PGM reinforcement. GSl's concern for Category 2 is that potential damage may be caused during construction due to insufficient strength to hold equipment without "punching" the remaining pavement (1 inch thick existing AC left in-place). Consideration should be given to removing all existing AC, and use PGM-G4 with a two lift below and above "put back." Category 3: Existing AC pavement, no ruts, some small fatigue cracking, minor aggregate "pop outs" or raveling - these areas will minimally require 2 inches removal of existing AC, place a Mirapave fabric, and replace 2 inches of new AC over the Mirapave. Shapell Homes W.O. 6145-E-SC ECR Pavement Rehabilitation May 23, 2013 Fi1e:e:\wp12\6000\6145e.memo.pa Geo$ods, Inc. Page 2