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HomeMy WebLinkAboutCT 14-04; MILES BUENA VISTA; PRELIMINARY GEOTECHNICAL EVALUATION; 2014-03-17CT 4'-D4 PRELIMINARYjEOTECHNICAL EVALUATION - -,-' ,.-- PROPOSED RESIDENTIAL SUB'DIVJSION , (1833 BIJEI4A VISTA'WA -- - I 2----- ARLSBAD-SANDIEGO C -OUNTY--.CL?FORNIA 'J0 ') ('FOR '44tL. &VWIt /STA -MFLES-PACiFIC1-LiP C/O BHA, INC. 5115 AVENIDA ENCINAS, SUITE L CARLSBAD, CALIFORNIA 92008-8700 W.O. 6637-A-SC MARCH 17, 2014 RECEIVED JAN 18 2017 LAND DEVELOPMENT ENGINEERING I, ,cr14-o I I I I I I I I I I I I ~ l I l Geotechnical • Geologic• Coastal• Environmental 5741 Palmer Way •Carlsbad.California 92010 • (760) 438-3155 • FAX (760) 931-0915 • www.geoso1lsinc.corn March 17, 2014 W.O. 6637-A-SC Miles-Pacific, LP c/o BHA, Inc. 5115 Avenida Encinas, Suite L Carlsbad, California 92008-8700 Attention: Mr. Rod Bradley Subject: Preliminary Geotechnical Evaluation, Proposed Residential Subdivision, 1833 Buena Vista Way, Carlsbad, San Diego County, California Dear Mr. Bradley: In accordance with the request and authorization of Mr. Robert Miles (Client), GeoSoils, Inc. (GSI) has performed a preliminary geotechnical evaluation of the subject site with respect to the proposed residential subdivision. The purpose of the study was to evaluate the onsite soils and geologic conditions, and their effects on the proposed site development from a geotechnical viewpoint. EXECUTIVE SUMMARY Based on our review of the available data (see Appendix A), field exploration, laboratory testing, and geologic and engineering analysis, the proposed development of the property appears to be feasible from a geotechnical viewpoint, provided the recommendations presented in the text of this report are properly incorporated into the design and construction of the project. The most significant elements of this study are summarized below: • • Based on a review of the 20-scale lot study exhibit, prepared by bHA, Inc. (2013), it is our understanding that proposed site development will consist of preparing the subject site for the construction of 11 new single-family residential structures. GSI anticipates that the proposed residences will be one-to two-stories and consist of wood-frame and/or masonry construction with concrete slab-on-grade floors. Soils considered unsuitable for the support of settlement-sensitive improvements (i.e., residential structures, underground utilities, walls, pavements, etc.) and/or engineered fill include surficial undocumented artificial fill, Quaternary-age colluvium (topsoil) and, Quaternary-age colluvium (topsoil), and weathered Quaternary-age old paralic deposits. Unweathered Quaternary-age old paralic deposits are considered acceptable for the support of settlement-sensitive improvements and/or I I I I I I I I I I I I I I I I I I I • • • engineered fill in their existing state. Based on the available subsurface data, the thickness of unsuitable soils, across the subject site, ranges between approximately 3 and 3% feet below the existing grade. However, localized areas of thicker unsuitable soils cannot be precluded and should be anticipated. Slope stability analyses, performed in conjunction with this study, indicate the slope descending from the subject site to Monroe Street has an inadequate gross Factor-of-Safety (FOS) to a point located approximately ±23.8 feet from the top of the slope. For mitigation, GSI recommends stabilization or the use of structural setbacks. All vegetation and/or deleterious materials should be removed from the site and properly disposed of, where located within the influence of new settlement-sensitive improvements and/or planned fills. Undocumented artificial fill, Quaternary-age colluvium, and weathered old paralic deposits should be removed to expose suitable, unweathered old paralic deposits prior to fill placement. The removed soils may be reused as engineered fill provided that major concentrations of vegetation and/or debris have been removed prior to their placement. It should be noted, that the 2013 California Building Code ([2013 CBC], California Building Standards Commission [CBSC], 2013) indicates that removals of unsuitable soils be performed across all areas to be graded, not just within the influence of the proposed residential structures. Relatively deep removals may also necessitate a special zone of consideration, on perimeter/confining areas. This zone would be approximately equal to the depth of removals, if removals cannot be performed onsite and offsite. For this site, the width of this zone is anticipated to be approximately 3 to 3% feet, based on the available data. Any settlement-sensitive improvement (walls, brow ditches, curbs, streets, flatwork, etc.), constructed within this zone, may require deepened foundations, reinforcements, etc., or will retain some potential for settlement and associated distress. This will require proper disclosure to all interested/affected parties, should this condition exist at the conclusion of grading. • On a preliminary basis, temporary excavations greater than 4 feet, but less than 20 feet in overall height should conform to CAL-OSHA and/or OSHA requirements for Type "B" soils provided that groundwater and/or running sands are not present. All temporary excavations should be observed by a licensed engineering geologist or geotechnical engineer prior to worker entry. Although not anticipated, if temporary slopes conflict with property boundaries, shoring or alternating slot excavations may be necessary. • Expansion Index (E.1.) testing, performed on representative samples, of the onsite soils indicates non-detrimentally expansive soil conditions. As such, specialized structural design to mitigate expansive soil effects is not warranted at this time. Final foundation design will be further evaluated at the conclusion of grading. Miles-Pacific, LLC File:wp12\6600\6637a.pge GeoSoils, Inc. W.O. 6637-A-SC Page Two I I I I I I I I I I I I I I I I I I I • • Soil pH, saturated resistivity, and soluble sulfate, and chloride testing, performed on a representative sample of the onsite soils, generally indicates that the onsite soils are neutral with respect to soil acidity/alkalinity, are corrosive to exposed, buried metals when saturated, possess negligible sulfate exposure to concrete, and although not negligible, are below the action level for chloride exposure (per State of California Department of Transportation, 2003). Reinforced concrete mix design for foundations, slab-on-grade floors, and pavements should minimally conform to "Exposure Class C1" in Table 4.3.1 of ACI 318-08, as concrete would likely be exposed to moisture. GSI does not consult in corrosion engineering. Therefore, additional comments and recommendations may be obtained from a qualified corrosion engineer based on the level of corrosion protection desired or required for the project, as determined by the project architect and/or structural engineer. Regional groundwater was not encountered during our field exploration and is not expected to be a major factor during construction of the proposed improvements. Regional groundwater is anticipated to generally be coincident with Mean Sea Level (MSL) or approximately ± 185 feet below the lowest existing site elevation. However, due to the nature of the site materials, seepage and/or perched groundwater conditions may develop throughout the site in the future, both during and subsequent to development, especially along boundaries of contrasting permeabilities (i.e., clayey and sandy fill lifts, fill/old paralic deposits and old paralic deposits/Santiago Formation contacts, joints/fractures, discontinuities, etc.), and should be anticipated. Thus, more onerous slab design is considered necessary for any new slab-on-grade floor (State of California, 2014). Recommendations for reducing the amount of water and/or water vapor through slab-on-grade floors are provided in the "Soil Moisture Considerations" sections of this report. It should be noted that these recommendations should be implemented if the transmission of water or water vapor through the slab is undesirable. Should these mitigative measures not be implemented, then the potential for water or vapor to pass through the foundations and slabs and resultant distress cannot be precluded, and would need to be disclosed to all interested/affected parties. • Our evaluation and experience with similar sites indicates that the site currently has a very low potential for liquefaction, due to the relatively dense nature of the old paralic deposits and the underlying Santiago Formation, as well as the depth to the regional water table below the lowest site elevation. The potential for seismic densification to affect the planned development is considered very low, provided the recommendations in this report are properly followed. However, some seismic densification of the adjoining un-mitigated site(s) may adversely influence planned improvements at the perimeter of the site. • The seismic acceleration values and design parameters provided herein should be considered during the design of the proposed development. The adverse effects of seismic shaking on the structure(s) will likely be wall cracks, some foundation/slab distress, and some seismic settlement. However, it is anticipated M iles-Paclflc, LLC File:wp 12\6300\6324a.pge GeoSoils, Inc. W.O. 6324-A-SC Page Three I I I I I I I I I I I ] J J J J • • • that the structure will be repairable in the event of the design seismic event. This potential should be disclosed to all interested/affected parties. Our evaluation indicates there are no known active faults crossing the site. In addition, other than moderate to strong seismic shaking produced from an earthquake on a nearby active fault, other geologic and secondary seismic hazards have a very low potential to affect the proposed site development. Adverse geologic features that would preclude project feasibility were not encountered. The recommendations presented in this report should be incorporated into the design and construction considerations of the project. 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 submitted, GeoSoils, Inc. ,fU!_ Ryan 8. Boehmer Project Geologist RBB/JPF/DWS/jh Distribution: (4) Addressee ~1{1 Civil Engineer, ACE 47857 (1) Miles-Pacific, LLC, Attention: Mr. Robert Miles Miles-Pacific, LLC File:wp12\6300\6324a.pge GeoSoils, Inc. W.0. 6324-A-SC Page Four I I I I I I I I I l , ~1 I _I ] I _I TABLE OF CONTENTS SCOPE OF SERVICES ................................................... 1 SITE DESCRIPTION AND PROPOSED DEVELOPMENT ......................... 1 SITE EXPLORATION ..................................................... 3 REGIONAL GEOLOGY ................................................... 3 SITE GEOLOGIC UNITS .................................................. 4 Artificial Fill -Undocumented (Map Symbol -Afu) ........................ 4 Quaternary-age Colluvium (Not Mapped) ............................... 4 Quaternary-age Old Paralic Deposits (Map Symbol -Qop) ................. 4 Tertiary-age Santiago Formation ...................................... 5 GEOLOGIC STRUCTURE ................................................. 5 GROUNDWATER ........................................................ 5 REVIEW OF CITY OF CARLSBAD GEOTECHNICAL HAZARDS ANALYSIS AND MAPPING STUDY .......................................................... 6 MASS WASTING/LANDSLIDE SUSCEPTIBILITY/SLOPE STABILITY ............... 6 FAULTING AND REGIONAL SEISMICITY ..................................... 7 Local and Regional Faults ........................................... 7 Seismicity ........................................................ 7 Deterministic Maximum Credible Site Acceleration .................. 7 Historical Site Acceleration ..................................... 8 Seismic Shaking Parameters ................................... 8 LIQUEFACTION POTENTIAL .............................................. 9 Liquefaction ...................................................... 9 Seismic Densification .............................................. 1 O Summary ........................................................ 11 Other Geologic/Secondary Seismic Hazards ........................... 11 LABORATORY TESTING ................................................. 11 General ......................................................... 11 Classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Moisture-Density Relations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Expansion Potential ............................................... 12 Particle -Size Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Direct Shear Tests ................................................ 12 GeoSoils, Inc. I I I I I I I I I I I I I I I I I I I Saturated Resistivity, pH, and Soluble Sulfates, and Chlorides ............. 13 Corrosion Summary ......................................... 13 EMBANKMENT FACTORS (SHRINKAGE/BULKING) ........................... 13 EXCAVATION FEASIBILITY ............................................... 14 PRELIMINARY CONCLUSIONS AND RECOMMENDATIONS .................... 14 EARTHWORK CONSTRUCTION RECOMMENDATIONS ....................... 17 General ......................................................... 17 Demolition/Grubbing .............................................. 17 Remedial Removals (Removal of Potentially Compressible Surficial Materials) 18 Overexcavation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Temporary Slopes ................................................ 18 Engineered Fill Placement .......................................... 19 Graded Slopes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Offsite Easterly-Facing Slope ........................................ 19 Import Fill Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 PRELIMINARY FOUNDATION RECOMMENDATIONS .......................... 20 General ......................................................... 20 General Foundation Design ......................................... 21 Foundation Settlement ....................................... 21 PRELIMINARY FOUNDATION CONSTRUCTION RECOMMENDATIONS ........... 22 Conventional Foundations (Expansion Index of 20 or Less with a Plasticity Index Less Than 15) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 CORROSION .......................................................... 23 SOIL MOISTURE TRANSMISSION CONSIDERATIONS ........................ 23 WALL DESIGN PARAMETERS ............................................ 25 Conventional Retaining Walls ....................................... 25 Restrained Walls ............................................ 26 · Cantilevered Walls ........................................... 26 Seismic Surcharge ................................................ 27 Retaining Wall Backfill and Drainage .................................. 27 Wall/Retaining Wall Footing Transitions ............................... 31 TOP-OF-SLOPE WALLS/FENCES/IMPROVEMENTS AND EXPANSIVE SOILS ...... 32 Expansive Soils and Slope Creep .................................... 32 Top of Slope Walls/Fences ......................................... 32 M lies-Pacific, LP File:wp 12\6600\6637a.pge GeoSoils, Inc. Table of Contents Page ii I I I I ] ] J l I l ] I J J J J ! EXPANSIVE SOILS, DRIVEWAY, FLATWORK, AND OTHER IMPROVEMENTS ...... 33 PRELIMINARY PAVEMENT DESIGN ....................................... 35 New Pavements .................................................. 35 New Asphaltic Concrete (AC) Pavement ......................... 35 Pavement Grading Recommendations ................................ 36 General ................................................... 36 Subgrade .................................................. 36 Aggregate Base ............................................. 37 Paving .................................................... 37 Drainage .................................................. 37 ONSITE INFILTRATION-RUNOFF RETENTION SYSTEMS ...................... 38 General ......................................................... 38 Plan Specific ..................................................... 41 PRELIMINARY OUTDOOR POOL/SPA DESIGN RECOMMENDATIONS ........... 41 General ......................................................... 42 DEVELOPMENT CRITERIA ............................................... 47 Slope Deformation ................................................ 47 Slope Maintenance and Planting ..................................... 4 7 Drainage ........................................................ 48 Erosion Control ................................................... 48 Landscape Maintenance ........................................... 48 Gutters and Downspouts ........................................... 49 Subsurface and Surface Water ...................................... 49 Site Improvements ................................................ 49 Tile Flooring ..................................................... 50 Additional Grading ................................................ 50 Footing Trench Excavation ......................................... 50 Trenching/Temporary Construction Backcuts .......................... 50 Utility Trench Backfill .............................................. 51 SUMMARY OF RECOMMENDATIONS REGARDING GEOTECHNICAL OBSERVATION AND TESTING ........................................................ 51 OTHER DESIGN PROFESSIONALS/CONSULTANTS .......................... 52 PLAN REVIEW ......................................................... 53 LIMITATIONS .......................................................... 53 Miles-Pacific, LP File:wp12\6600\6637a.pge GeoSoils, Inc. Table of Contents Page iii I I I I I I I I I I I I I I I I I I I FIGURES: Figure 1 -Site Location Map ......................................... 2 Detail 1 -Typical Retaining Wall Backfill and Drainage Detail .............. 28 Detail 2 -Retaining Wall Backfill and Subdrain Detail Geotextile Drain ....... 29 Detail 3 -Retaining Wall and Subdrain Detail Clean Sand Backfill ........... 30 ATTACHMENTS: Appendix A -References ................................... Rear of Text Appendix B -Exploration Logs .............................. Rear of Text Appendix C -Slope Stability Analysis ......................... Rear of Text Appendix D -EQFAUL T and EQSEARCH ...................... Rear of Text Appendix E -Laboratory Data ............................... Rear of Text Appendix F -General Earthwork and Grading Guidelines ......... Rear of Text Plate 1 -Geotechnical Map . . . . . . . . . . . . . . . . . . . . . . . . . Rear of Text in Folder Plate 2 -Geologic Cross Section X-X' . . . . . . . . . . . . . . . . . Rear of Text in Folder Miles-Pacific, LP File:wp12\6600\6637a.pge GeoSoils, Inc. Table of Contents Page iv I I I I I I I I I ~ ] ] J ] J l J ] PRELIMINARY GEOTECHNICAL EVALUATION PROPOSED RESIDENTIAL SUBDIVISION 1833 BUENA VISTA WAY CARLSBAD, SAN DIEGO COUNTY, CALIFORNIA SCOPE OF SERVICES The scope of our services has included the following: 1. 2. 3. 4. 5. 6. Review of the available geologic literature for the site (see Appendix A). Geologic site reconnaissance, subsurface exploration with three hollow-stem auger borings and four hand-auger borings (see Appendix B), sampling, and mapping. Engineering and geologic analysis of data collected, including slope stability (Appendix C). General areal seismicity (see Appendix D), and geologic hazards evaluation. Appropriate laboratory testing of representative soil samples (Appendix E). Preparation of this summary report. SITE DESCRIPTION AND PROPOSED DEVELOPMENT The subject site consists of a quadrilateral-shaped property located at 1833 Buena Vista Way in Carlsbad, San Diego County, California (see Figure 1, Site Location Map). The site is bounded by existing residential development and McCauley Lane to the southeast, by steeply sloping open space and Monroe Street to the northeast, by Buena Vista Way to the northwest, and by existing residential development and agricultural land to the southwest. According to the 20-scale lot study exhibit prepared by bHA, Inc. (bHA, undated), site elevations range between approximately 185 to 196 feet (unknown datum) for an overall relief of about 10 feet. Topographically, the site is generally flat-lying to very gently sloping in both northwesterly and northeasterly directions. The overall gradient of the site is on the order of 12: 1 (horizontal:vertical [h:v]) or flatter. Near the northeasterly margin of the site, an approximately 41-foot high slope descends toward Monroe Street. The gradient of this slope varies between approximately 0.8:1 (h:v) to 2.8:1 (h:v). Existing onsite structures include a one story single-family residence and single story structures and shade canopies associated with the currently operating nursery. Based on a review of bHA, Inc. (undated), proposed development will consist of preparing the site for the construction 11 new single-family residences, with associated infrastructure (e.g., underground utilities, streets, sidewalks, etc.). Although grading plans showing design grades were not available for GSI review, cut and fill grading techniques appear GeoSoils, Inc. I I I I I I ] ] l I ] J ] 1 ] I t .._..._,,._.,,.,.~ ' -, ··--~----,-~-----'-·---~-------· Base Map: TOPO!® ©2003 National Geographic, U.S.G.S. San Luis Rey Quadrangle, California --San Diego Co., 7.5 Minute, dated 1997, current, 1999. Thia map la copyrighted by Google 2014, It i. unlawful to copy or 18ptoduc,i all or any part thel80f, whether for personal u,e or resale, without pennlsslon. All rights l'8SBIV8d. ~-\.., ' - w.o. 6637-A-SC SITE LOCATION MAP N Figure 1 I I I I I .I I I I I I I I I I I I I I necessary to achieve the planned grades. Maximum height cut and fill slopes are also assumed to be on the order of 5% feet, with maximum plan cut and fill thicknesses on the order of 5 feet. GSI anticipates that the proposed residences will be one-to two-stories and consist of wood-frame and/or masonry construction with concrete slab-on-grade floors with typical foundations. GSI assumes that the residential structure loads will be typical for this relatively light type of development. SITE EXPLORATION Surface observations and subsurface explorations were performed on December 16, 2013 and January 10, 2014, 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 three (3) hollow-stem auger borings and four (4) hand-auger borings within the site. The approximate locations of the exploratory borings are shown on the Geotechnical Map (see Plate 1) which uses bHA, Inc. (undated) as a base. Logs of the borings are presented in Appendix B. REGIONAL GEOLOGY The subject property lies within the coastal plains physiographic region of the Peninsular Ranges Geomorphic Province of southern California. This region consists of dissected, mesa-like terraces that graduate inland to rolling hills. The encompassing Peninsular Ranges Geomorphic Province is characterized as elongated mountain ranges and valleys that trend northwesterly (Norris and Webb, 1990). This geomorphic province extends from the base of the east-west aligned Santa Monica -San Gabriel Mountains, and continues south into Baja California. The mountain ranges are underlain by basement rocks consisting of pre-Cretaceous metasedimentary rocks, Jurassic metavolcanic rocks, and Cretaceous plutonic rocks of the southern California batholith. In the San Diego County region, deposition occurred during the Cretaceous Period and Cenozoic Era in the continental margin of a forearc basin. Sediments, derived from Cretaceous-age plutonic rocks and Jurassic-age volcanic rocks, were deposited into the narrow, steep, coastal plain and continental margin of the basin. These rocks have been uplifted, eroded, and deeply incised. During early Pleistocene time, a broad coastal plain was developed. During mid-to late-Pleistocene time, this plain was uplifted, eroded, and incised. Alluvial deposits have since filled the lower valleys, and young marine sediments are currently being deposited/eroded within coastal and beach areas. Regional geologic mapping by Kennedy and Tan (2005) indicates that the site is immediately underlain by Quaternary-age old paralic deposits (formerly termed terrace deposits). M lies-Pacific, LP 1833 Buena Vista Way, Carlsbad File:wp12\6600\6637a.pge GeoSoils, Inc. W.O. 6637-A-SC March 17, 2014 Page 3 1, I I I I I I I I I I I I I J J I ' SITE GEOLOGIC UNITS The site geologic units encountered during our subsurface investigation and site reconnaissance included small, localized areas undocumented artificial fill, localized Quaternary-age colluvium (topsoil), Quaternary-age old paralic deposits (weathered and unweathered), and the Tertiary-age Santiago Formation. The earth materials are generally described below from the youngest to the oldest. The distribution of the mappable units across the site is shown on Plate 1. The site geologic conditions are also shown on Plate 2 (Geologic Cross Section X-X'). Artificial Fill -Undocumented (Map Symbol -Afu) Undocumented artificial fill was encountered near the surface in Boring B-2 and is believed to also occur along the driveway, most of the westerly site boundary, and near the southeasterly corner of the site. As observed in Boring B-2, the fill generally consisted of asphaltic concrete and dark grayish brown silty sand with trace gravel. The soil fill was moist and medium dense at that location. Where directly measured in Boring B-2, the thickness of the undocumented fill was on the order of 1 % feet. Undocumented fill is considered potentially compressible in its existing state. Therefore, it is recommended that these materials be removed and reused as properly engineered fill. Quaternary-age Colluvium (Not Mapped) Quaternary-age colluvium (topsoil) was encountered at the surface in Boring B-3 and HA-1, and beneath the undocumented fill in Boring B-2. The colluvium generally consisted of dark brownish gray and grayish brown sand with local traces of silt to dark grayish brown silty sand. The colluvium was generally damp to moist and loose. As measured in these borings, the thickness of the colluvium was approximately % foot to 2 feet. All colluvium is considered potentially compressible in its existing state and therefore should be removed and recompacted. Quaternary-age Old Paralic Deposits (Map Symbol -Qop) Quaternary-age old paralic deposits were encountered at the surface in Borings 8-1 and HA-2 through HA-4, and at relatively shallow depth in the remaining subsurface explorations. As observed, the upper, approximately 1 foot to 3% feet of the old paralic deposits were weathered. Where weathered, the old paralic deposits typically consisted of dark yellowish brown, reddish yellow, and light reddish yellow silty sand and dark yellowish brown fine-grained sand with trace silt. The weathered old paralic deposits were generally dry to locally moist and loose to locally dense, with moisture and density generally increasing with depth. Above approximate elevations of 168 and 173, the unweathered old paralic deposits generally consisted of reddish yellow and grayish brown clayey sand; dark yellowish brown, dark gray, and reddish yellow silty sand; and local reddish brown sandy clay. Below the aforementioned elevations, the old paralic deposits M lies-Pacific, LP 1833 Buena Vista Way, Carlsbad File:wp12\6600\6637a.pge GeoSoils, Inc. W.O. 6637-A-SC March 17, 2014 Page 4 I I I I I I I I I I I I I I I I I I I predominately consisted of brownish gray, gray, dark yellowish brown, and grayish brown, fine-grained sand and light brownish gray, dark yellowish brown, and gray fine-to coarse-grained sand. Cobbles were locally encountered between approximate depths of 361h to 40 feet below the existing grade in Boring B-1. The unweathered old paralic deposits were typically dry to moist and medium dense to very dense/hard. Owing to their non-uniformity, weathered old paralic deposits are considered potentially compressible in their existing state and therefore should be removed and recompacted. Unweathered old paralic deposits are considered suitable for the support of settlement-sensitive improvements and/or planned fill in their existing state. Tertiary-age Santiago Formation (Map Symbol -Tsa) The Tertiary-age Santiago Formation was encountered underlying the old paralic deposits at approximately depths of 431h feet and 45 feet below the existing grades in respective Borings B-1 and B-2 (approximate elevations of 144112 feet and 148 feet). As observed in these borings, the Santiago Formation consisted of grayish brown and light grayish brown very fine-grained sandstone with local trace amounts of silt and light gray silty sandstone. These materials were dry to moist and dense to very dense. Based on our understanding of the proposed development plan, GSI does not anticipate encountering the Santiago Formation during earthwork construction. However, the Santiago Formation is considered competent bearing material. GEOLOGIC STRUCTURE Based on our regional experience, bedding within the old paralic deposits is generally flat- lying to thickly bedded. The elevation of the contact between the upper and lower members of the old paralic deposits encountered in Borings B-1 and B-2 may infer a northerly dip on the order of 1 degree. Bedding within the Santiago Formation dips 5 to as much as 15 degrees to the northwest, on a regional scale (Kennedy and Tan, 2005). Adverse geologic structures at the site, were not encountered during our field studies nor indicated on regional geologic maps. GROUNDWATER Regional groundwater was not encountered during our field exploration and is not expected to be a major factor during construction of the proposed subdivision. Regional groundwater is anticipated to generally be coincident with MSL or approximately 185 feet below the lowest existing site elevation. Due to the nature of the site earth materials, seepage and/or perched groundwater conditions may develop throughout the site in the future, both during and subsequent to development, especially along boundaries of contrasting permeabilities (i.e., sandy/clayey Miles-Pacific, LP 1833 Buena Vista Way, Carlsbad File:wp12\6600\6637a.pge GeoSoils, Inc. W.O. 6637-A-SC March 17, 2014 Page 5 I I I I I I I I I I I I I I I I I I I fill lifts, fill/old paralic deposits contact, old paralic deposits/Santiago Formation contact, bedding, joints/fractures, discontinuities, etc.), and should be anticipated. This potential should be disclosed to all interested/affected parties. Due to the potential for post-development perched water to manifest near the surface, owing to as-graded permeability contrasts, more onerous slab design is necessary for any new slab-on-grade floor (State of California, 2014). Recommendations for reducing the amount of water and/or water vapor through slab-on-grade floors are provided in the "Soil Moisture Considerations" sections of this report. It should be noted that these recommendations should be implemented if the transmission of water or water vapor through the slab is undesirable. Should these mitigative measures not be implemented, then the potential for water or vapor to pass through the foundations and slabs and resultant distress cannot be precluded, and would need to be disclosed to all interested/affected parties. REVIEW OF CITY OF CARLSBAD GEOTECHNICAL HAZARDS ANALYSIS AND MAPPING STUDY Based on our review of the geotechnical hazards analysis and mapping study prepared for the City of Carlsbad by a joint venture between Leighton and Associates, Inc. and David Evans and Associates, Inc. (1992), the subject site lies within Geotechnical Hazard Categories 51 and 53, which are considered generally stable areas posing nominal to low risk to development. MASS WASTING/LANDSLIDE SUSCEPTIBILITY /SLOPE STABILITY Mass wasting refers to the various processes by which earth materials are moved down slope in response to the force of gravity. Examples of these processes include slope creep, surficial failures, and deep-seated landslides. Creep is the slowest form of mass wasting and generally involves the outer 5 to 10 feet of a slope surface. During periods of heavy rain, such as those occurring during El Nino events, creep-affected materials may become saturated, resulting in a more rapid form of downslope movement (i.e., landslides and/or surficial failures). According to regional landslide susceptibility mapping by Tan and Giffen (1995), the site is located within landslide susceptibility Subarea 3-1 which is characterized as being 11generally susceptible11 to landsliding. However, based on our review of Kennedy and Tan (2005), landslide debris has not been mapped within the site. In addition, GSI did not observe geomorphic expressions indicative of significant past mass wasting events during our review of available stereoscopic aerial photographs (United States Department of Agriculture [USDA], 1953). Further, landslide debris or adverse geologic structure were not encountered during our field investigation. M lies-Pacific, LP 1833 Buena Vista Way, Carlsbad File:wp12\6600\6637a.pge GeoSoils, Inc. W.O. 6637-A-SC March 17, 2014 Page 6 I I I I I' I I I I I I I I I I I I I I Slope stability analyses, performed in conjunction with this study, indicates that the easterly-facing slope, descending from the project site to Monroe Street, possesses a static gross factor-of-safety (FOS) less than Code (2: 1.5 required), to a point located approximately ±23.8 feet from the top of this slope. A line of FOS = 1.5 is shown on Plate 1. Improvements constructed within this zone have the potential to be adversely affected by deep-seated slope failures. In addition, our analyses indicate that the steeper portions of this offsite slope (i.e., slope gradients greater that 2:1 [h:v]) have a surficial FOS less than 1.5. Thus, the outer portion of this slope (i.e., approximately 4 feet in from the slope face) has an inadequate FOS against surficial slope failures, locally. Slope stability analyses are included in Appendix C. FAUL TING AND REGIONAL SEISMICITY Local and Regional Faults Our review indicates that there are no known active faults crossing this site, and the site is not within an Alquist-Priolo Earthquake Fault Zone (Bryant and Hart, 2007). However, the site is situated in a region subject to strong earthquakes occurring along active faults. These faults include, but are not limited to: the San Andreas fault; the San Jacinto fault; the Elsinore fault; the Coronado Bank fault zone; and the Newport-Inglewood -Rose Canyon fault zone (NIRCFZ). The location of these, and other major faults relative to the site, are indicated on the California Fault Map in Appendix D. According to Blake (2000a), the closest known active fault to the site is the offshore segment of the Newport-Inglewood fault which located at a distance of approximately 5.8 miles [mi] (9.4 kilometers [km]). Fault splays associated with this segment have demonstrated movement in the Holocene Epoch (i.e., rupture within the last 11,000 years) and therefore, are included in an Alquist-Priolo Earthquake Fault Zone (Bryant and Hart, 2007). Cao, et al. (2003) indicate that offshore segment of the Newport-Inglewood fault is capable of producing a maximum magnitude (Mw) 7 .1 earthquake. The possibility of ground acceleration, or shaking at the site, may be considered as approximately similar to the southern California region as a whole. Major active fault zones that may have a significant affect on the site, should they experience activity, are listed in Appendix D (modified from Blake, 2000a). Seismicity Deterministic Maximum Credible Site Acceleration The acceleration-attenuation relation of Bozorgnia, Campbell, and Niazi (1999) has been incorporated into EQFAUL T (Blake, 2000a). EQFAUL Tis a computer program developed by Thomas F. Blake (2000a), which performs deterministic seismic hazard analyses using digitized California faults as earthquake sources. M if es-Pacific, LP 1833 Buena Vista Way, Carlsbad File:wp12\6600\6637a.pge GeoSoils, Inc. W.O. 6637-A-SC March 17, 2014 Page 7 I I I I I I I I I ] l l J ] _, I I. I I The program estimates the closest distance between each fault and a given site. If a fault is found to be within a user-selected radius, the program estimates peak horizontal ground acceleration that may occur at the site from an upper bound ("maximum credible") earthquake on that fault. Site acceleration (g) was computed by one user-selected acceleration-attenuation relation that is contained in EQFAUL T. Based on the EQFAUL T program, a peak horizontal ground acceleration from an upper bound event at the site may be on the order of 0.57 g. The computer printouts of pertinent portions of the EQFAULT program are included within Appendix D. Historical Site Acceleration Historical site seismicity was evaluated with the acceleration-attenuation relation of Bozorgnia, Campbell, and Niazi (1999), and the computer program EQSEARCH (Blake, 2000b). This program performs a search of the historical earthquake records for magnitude 5.0 to 9.0 seismic events within a 100-kilometer radius, between the years 1800 through December 2012. Based on the selected acceleration-attenuation relationship, a peak horizontal ground acceleration is estimated, which may have effected the site during the specific event listed. Based on the available data and the attenuation relationship used, the estimated maximum (peak) site acceleration during the period 1800 through December 2012 was 0.23 g. A historic earthquake epicenter map and a seismic recurrence curve are also estimated/generated from the historical data. Computer printouts of the EQSEARCH program are presented in Appendix D. Seismic Shaking Parameters Based on the site conditions, the following table summarizes the site-specific design criteria obtained from the 2013 CBC (CBSC, 2013), Chapter 16 Structural Design, Section 1613, Earthquake Loads. The computer program "U.S. Seismic Design Maps, provided by the United States Geologic Survey (USGS, 2013) was utilized for design (http://geohazards.usgs.gov/designmaps/us/application.php). The short spectral response utilizes a period of 0.2 seconds. ---· . -- 2013 CBC SEISMIC DESIGN PARAMETERS PARAMETER Risk Category Site Class Spectral Response -(0.2 sec), S6 Spectral Response -(1 sec), S1 Site Coefficient, Fa Site Coefficient, Fv M lies-Pacific, LP 1833 Buena Vista Way, Carlsbad File:wp12\6600\6637a.pge VALUE II D 1.125 g 0.432 g 1.050 1.568 GeoSoils, Inc. 2013 Cl::IC AND/OR REt=ERENCE _ Table 1604.5 Section 1613.3.2/ASCE 7-10 (Chapter 20) Figure 1613.3.1 (1) Figure 1613.3.1 (2) Table 1613.3.3(1) Table1613.3.3(2) W.O. 6637-A-SC March 17, 2014 Page 8 I I I I I I I I I I I I I I I I I I I 2013 CBC SEISMIC DESIGN PARAMETERS PARAMETER VALUE 2013 CBC AND/OR REFERENCE Maximum Considered Earthquake Spectral 1.181 g Section 1613.3.3 Response Acceleration (0.2 sec), SMs (Eqn 16-37) Maximum Considered Earthquake Spectral 0.678 g Section 1613.3.3 Response Acceleration (1 sec), SM1 (Eqn 16-38) 5% Damped Design Spectral Response 0.787 g Section 1613.3.4 Acceleration (0.2 sec), S08 (Eqn 16-39) 5% Damped Design Spectral Response 0.452 g Section 1613.3.4 Acceleration (1 sec), S01 (Eqn 16-40) Seismic Design Category D Section 1613.3.5/ASCE 7-10 (Table 11.6-1 or 11.6-2) PGA., 0.467 q ASCE 7-10 (Eqn 11.8.1) GENERAL SEISMIC DESIGN PARAMETERS PARAMETER VALUE Distance to Design Seismic Source (Newport-Inglewood 5.8 mi (9.4 km)(1l fault [offshore segment]) Upper Bound Earthquake (Newport-Inglewood fault Mw = 7.1(2) [offshore segment]) (l) -From Blake (2000a) (2l -Cao, et al. (2003) 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 large earthquake. 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 seismic events are not addressed in the 2013 CBC (CBSC, 2013) and regular maintenance and repair following locally significant seismic events (i.e., Mw5.5) will likely be necessary. LIQUEFACTION POTENTIAL 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 vertical deformation, lateral movement, lurching, sliding, and as a result of seismic Miles-Pacific, LP 1833 Buena Vista Way, Carlsbad File:wp12\6600\6637a.pge GeoSoils, Inc. W.O. 6637-A-SC March 17, 2014 Page 9 I I I I I I I I I I I I I I I 1. I I I loading, volumetric strain and manifestation in surface settlement of loose sediments, sand boils and other damaging lateral deformations. This phenomenon occurs only below the water table, but after liquefaction has developed, it can propagate upward into overlying non-saturated soil as excess pore water dissipates. One of the primary factors controlling the potential for liquefaction is depth to groundwater. Typically, liquefaction has a relatively low potential at depths greater than 50 feet and is unlikely and/or will produce vertical strains well below 1 percent for depths below 60 feet when relative densities are 40 to 60 percent and effective overburden pressures are two or more atmospheres (i.e., 4,232 psf [Seed, 2005]). The condition of liquefaction has two principal effects. One is the consolidation of loose sediments with resultant settlement of the ground surface. The other effect is lateral sliding. Significant permanent lateral movement generally occurs only when there is significant differential loading, such as fill or natural ground slopes within susceptible materials. No such loading conditions exist at the site. Liquefaction susceptibility is related to numerous factors and the following five 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. Only about one to perhaps two of these concurrently required conditions have the potential to affect the site. Seismic Densification Seismic densification is a phenomenon that typically occurs in low relative density granular soils (i.e., United States Soil Classification System [USCS] soil types SP, SM, and SC) that are above the groundwater table. These unsaturated granular soils are susceptible if left in the original density (unmitigated), and are generally dry of the optimum moisture content (as defined by the ASTM D 1557). During seismic-induced ground shaking, these natural or artificial soils deform under loading and volumetrically strain, potentially resulting in ground surface settlements. Some densification of the adjoining un-mitigated properties may influence improvements at the perimeter of the site. Special setbacks and/or foundations may be utilized if significant structures/improvements are placed close to the perimeter of the site. Typically, this setback would be equal to the depth of the remedial grading excavations performed near the site boundary. Our evaluation assumed that the current offsite conditions will not be significantly modified by future grading at the time of the design earthquake, which is a reasonably conservative assumption. Miles-Pacific, LP 1833 Buena Vista Way, Carlsbad File:wp12\6600\6637a.pge GeoSoils, Inc. W.O. 6637-A-SC March 17, 2014 Page 10 I I I I I I I I I I I I I I I I I I Summary It is the opinion of GSI that the susceptibility of the site to experience damaging deformations from seismically-induced liquefaction and densification is relatively low owing to the dense, nature of the old paralic deposits that underlie the site in the near-surface and the depth to the regional water table. In addition, the recommendations for remedial earthwork and foundations would further reduce any significant liquefaction/densification potential. Some seismic densification of the adjoining un-mitigated site(s) may adversely influence planned improvements at the perimeter of the site. However, given the recommendations provided herein, the potential for the planned buildings to be affected by significant seismic densification or liquefaction of offsite soils may be considered low. Other Geologic/Secondary Seismic Hazards The following list includes other geologic/seismic related hazards that have been considered during our evaluation of the site. The hazards listed are considered negligible and/or mitigated as a result of site location, soil characteristics, and typical site development procedures: • Subsidence • Dynamic Settlement • Surface Fault Rupture • Ground Lurching or Shallow Ground Rupture • Tsunami • Seiche It is important to keep in perspective that in the event of an upper bound or maximum credible 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. Following implementation of remedial earthwork and design of foundations described herein, this potential would be no greater than that for other existing structures and improvements in the immediate vicinity that comply with current and adopted building standards. LABORATORY TESTING General Laboratory tests were performed on representative samples of the onsite earth materials in order to evaluate their physical characteristics. The test procedures used and results obtained are presented below. Miles-Pacific, LP 1833 Buena Vista Way, Carlsbad File:wp 12\6600\6637a.pge GeoSoils, Inc. W.O. 6637-A-SC March 17, 2014 Page 11 I I I I I I· I I I I I. I I I I I I I I Classification Soils were classified visually according to the Unified Soils Classification System (Sowers and Sowers, 1979). The soil classifications are shown on the Exploration Logs in Appendix B. Moisture-Density Relations The field moisture contents and field dry densities of relatively undisturbed soil samples were evaluated in the laboratory, in general accordance with ASTM D 2216 and ASTM D 2937. The results of these tests are shown on the Exploration Logs in Appendix B. Expansion Potential Expansion Index (E.1.) testing and expansion potential classification were performed in general accordance with ASTM Standard D 4829 on representative samples of the onsite soils collected from the field exploration. The results of the expansion testing are presented in the following table. SAMPLE LOCATION EXPANSION INDEX EXPANSION POTENTIAL* AND DEPTH (FTI I B-1 @ 0-31h I <5 I Very Low I B-3@ 0-5 <5 Ver'f_ Low Particle -Size Analysis An evaluation was performed on a representative, soil sample in general accordance with ASTM D 422-63. The grain-size distribution curve is presented in Appendix E. The testing was utilized to evaluate the soil classification in accordance with the Unified Soil Classification System (USCS). The results of the particle size analysis indicate that the tested soil is a clayey sand (SC) (Appendix E). Direct Shear Tests Shear testing was performed on relatively undisturbed samples of site earth materials collected from the borings in general accordance with ASTM D 3080. The shear testing results are provided in the following table and are presented in Appendix E. Miles-Pacific, LP 1833 Buena Vista Way, Carlsbad File:wp 12\6600\6637a.pge GeoSoils, Inc. W.O. 6637-A-SC March 17, 2014 Page 12 I I I I I I I I I I I I I I I I I I I PRIMARY RESIDUAL SAMPLE LOCATION AND DEPTH (FT) COHESION FRICTION ANGLE COHESION FRICTION ANGLE (PSF) (DEGREES) (PSF) {DEGREES) 8-3@ 15 200 32 150 29 B-1@ 42% 345 34 98 35 8-2@ 45 320 32 247 33 Saturated Resistivity, pH, and Soluble Sulfates, and Chlorides GSI conducted general soil corrosivity and soluble sulfates, and chlorides testing on a representative sample of the onsite soils. The testing included evaluation of soil pH, soluble sulfates, chlorides, and saturated resistivity. Test results are presented in Appendix E and the following table: SAMPLE LOCATION SATURATED SOLUBLE SOLUBLE AND DEPTH (FT) pH RESISTIVITY SULFATES CHLORIDES {ohm-cm) {ppm) . foam) I B-3@ 0-5 I 7.04 I 1,800 I 0.0130 I 103 I Corrosion Summary Laboratory testing indicates that the tested sample of the on site soils is neutral with respect to soil acidity/alkalinity, is corrosive to exposed, buried metals when saturated, presents negligible sulfate exposure to concrete (SO), and although not negligible, is below the action level for chloride exposure (per State of California Department of Transportation, 2003). Reinforced concrete mix design for foundations, slab-on-grade floors, and pavements should minimally conform to "Exposure Class C1" in Table 4.3.1 of ACI 318-08, as concrete would likely be exposed to moisture. It should be noted that GSI does not consult in the field of corrosion engineering. Therefore, additional comments and recommendations may be obtained from a qualified corrosion engineer based on the level of corrosion protection required for the project, as determined by the project architect and/or structural engineer. EMBANKMENT FACTORS (SHRINKAGE/BULKING) The volume change of excavated materials upon compaction as engineered fill is anticipated to vary with material type and location. The overall earthwork shrinkage and bulking may be approximated by using the following parameters: Miles-Pacific, LP 1833 Buena Vista Way, Carlsbad File:wp 12\6600\6637a.pge GeoSoils, Inc. W.0. 6637-A-SC March 17, 2014 Page 13 I I I I I I I I I I I I I I I I I I I Undocumented Artificial Fill . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5% to 10% shrinkage Quaternary Colluvium . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10% to 15% shrinkage Weathered Old Paralic Deposits . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0% to 5% shrinkage Unweathered Old Paralic Deposits .................... 2% to 3% shrinkage/bulking It should be noted that the above factors are estimates only, based on preliminary data. Colluvium may achieve higher shrinkage if organics or clay content is higher than anticipated. Final earthwork balance factors could vary. In this regard, it is recommended that balance areas be reserved where grades could be adjusted up or down near the completion of grading in order to accommodate any yardage imbalance for the project. EXCAVATION FEASIBILITY Based on our experience with sites underlain by similar deposits, GSI anticipates that excavations into the onsite soils will range from easy to moderately difficult, assuming the use of a Caterpillar D-9L bulldozer and a Caterpillar 235 track excavator. However, localized cemented zones may be encountered and result in difficult excavation, especially if lightweight excavation equipment (i.e., backhoe, mini-excavator, etc.) is used. Excavation equipment should be appropriately sized to complete the planned excavation tasks. PRELIMINARY CONCLUSIONS AND RECOMMENDATIONS Based on our field exploration, laboratory testing, and geotechnical engineering analysis, it is our opinion that the site appears suitable for the proposed development from a geotechnical engineering and geologic viewpoint, provided that the recommendations presented in the following sections are properly incorporated into the design and construction phases of site development. The primary geotechnical concerns with respect to the currently proposed development are: • • • • • • • • Earth materials characteristics and depth to competent bearing material. On-going expansion/corrosion potentials of site soils . Stability of the offsite easterly-facing slope descending from the project site to Monroe Avenue. Potential for distress to settlement-sensitive improvements located in close proximity to this slope (see Plate 1 ). Potential for perched groundwater to occur during and after development. Non-structural zone on un-mitigated perimeter conditions (improvements subject to distress). Temporary and permanent slope stability . Regional seismic activity . Miles-Pacific, LP W.O. 6637-A-SC March 17, 2014 Page 14 1833 Buena Vista Way, Carlsbad File:wp12\6600\6637a.pge GeoSoils, Inc. I I I I I I I I I I I I I I I I I I I The recommendations presented herein consider these as well as other aspects of the site. The engineering analyses, performed, concerning site preparation and the recommendations presented herein have been completed using the information provided and obtained during our field work. 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 are evaluated 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. 1. 2. 3. 4. Geotechnical observation, and testing services should be provided during earthwork to aid the contractor in removing unsuitable soils and in his effort to compact the fill. Geologic observations should be performed during any grading to verify and/or further evaluate geologic conditions. Although unlikely, if adverse geologic structures are encountered, supplemental recommendations and earthwork may be warranted. All undocumented fill, colluvium, and weathered portions of the old paralic deposits are considered potentially compressible in their existing state and therefore, should not be relied upon for the support of planned settlement-sensitive improvements (i.e., residential structures, underground utilities, walls, pavements, swimming pools/spas, etc.) and/or planned fills. These soils should be removed and re-used as properly compacted fill during grading. In general, remedial grading excavations for the removal and re-compaction of potentially compressible, near-surface soils are anticipated to be on the order of 3 to 3112 feet across a majority of the site. However, local deeper remedial grading excavations cannot be precluded and should be anticipated. Remedial grading excavations should be completed below a 1 :1 (h:v) projection down from the bottom, outermost edge of proposed settlement-sensitive improvements and/or limits of planned fills unless constrained by property lines or existing structures to remain. 5. Laboratory testing indicates that the expansion indices of representative samples of the onsite earth materials are less than 5 which correlates to very low expansion potential. As such, these soil samples are not detrimentally expansive as defined in Section 1803.5.3 of the 2013 CBC. On a preliminary basis, conventional-type foundation and slab-on-grade floor systems may be incorporated into the construction of the proposed residential structures. 6. Slope stability analyses, performed in conjunction with this study, indicate that the offsite easterly-facing slope, descending from the project site to Monroe Street, does not have an adequate FOS against deep-seated and surficial slope failures. Miles-Pacific, LP 1833 Buena Vista Way, Carlsbad File:wp 12\6600\6637a.pge GeoSoils, Inc. W.O. 6637-A-SC March 17, 2014 Page 15 I I I I I I I I I I I I I I I I I I I Failures of this slope may effect onsite improvements, if the slope is not properly maintained or repaired. 7. Soil pH, saturated resistivity, soluble sulfate, and chloride testing indicates that a representative sample of the onsite soils is neutral with respect to soil acidity/alkalinity, is corrosive to exposed, buried metals when saturated, presents negligible sulfate exposure to concrete (SO), and although not negligible, is below the action level for chloride exposure (per State of California Department of Transportation, 2003). Reinforced concrete mix design for foundations, slab-on-grade floors, and pavements should minimally conform to "Exposure Class C1" in Table 4.3.1 of ACI 318-08, as concrete would likely be exposed to moisture. It should be noted that GSI does not consult in the field of corrosion engineering. Therefore, additional comments and recommendations may be obtained from a qualified corrosion engineer based on the level of corrosion protection required for the project, as determined by the project architect and/or structural engineer. 8. In general and based upon the available data to date, the regional groundwater table is not expected to be encountered during construction of the proposed site improvements nor is it anticipated to adversely affect site development. However, there is potential for perched water conditions to manifest along zones of contrasting permeabilities (i.e., sandy/clayey fill lifts, fill/old paralic deposit contacts, old paralic deposit/Santiago Formation contacts, bedding, discontinuities, etc.) during and after construction. The potential for perched water to occur should be disclosed to all interested/affected parties. 9. It should be noted, that the 2013 CBC (CBSC, 2013) indicates that removals of unsuitable soils be performed across all areas to be graded under the purview of a grading permit, and not just within the influence of the proposed residential structures. Relatively deep removals may also necessitate a special zone of consideration, on perimeter/confining areas. This zone would be approximately equal to the depth of remedial grading excavations, if remedial grading cannot be performed onsite and offsite. For this site, the width of this zone is anticipated to be on the order of 3 to 3112 feet, based on the available data. Any settlement-sensitive improvement, constructed within this zone, may require deepened foundations, reinforcements, etc., or will retain some potential for settlement and associated distress. This will require proper disclosure to all interested/affected parties, should this condition exist at the conclusion of grading. 10. On a preliminary basis, unsupported temporary excavation walls ranging between 4 and 20 feet in gross overall height should be constructed in accordance with CAL-OSHA guidelines for Type B soils (i.e., 1 :1 [h:v] slope), provided groundwater or running sands are not present. Miles-Pacific, LP 1833 Buena Vista Way, Carlsbad File:wp12\6600\6637a.pge GeoSoils, Inc. W.0. 6637-A-SC March 17, 2014 Page 16 I I I I I I I I I I I I I I I I I I I 11. The seismicity-acceleration values provided herein should be considered during the design and construction of the proposed development. 12. General Earthwork and Grading Guidelines are provided at the end of this report as Appendix F. Specific recommendations are provided below. EARTHWORK CONSTRUCTION RECOMMENDATIONS General Remedial earthwork will be necessary for the support of the planned settlement-sensitive improvements (i.e., residential structures, walls, underground utilities, pavements, etc.). Remedial grading should conform to the guidelines presented in Section 1804 of the 2013 CBC, the requirements of the City of Carlsbad, and the Grading Guidelines presented in Appendix F, except where specifically superceded in the text of this report. In case of conflict, the more onerous code or recommendations should govern. Prior to grading, a GSI representative should be present at the pre-construction meeting to provide additional grading guidelines, if needed, and review the earthwork schedule. 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 (OSHA), and the Construction Safety Act should be met. It is the onsite general contractor's and individual subcontractors' responsibility to provide a safe working environment for our field staff who are onsite. GSI does not consult in the area of safety engineering. GSI also recommends that the contractor(s) take precautionary measure to protect work, especially during the rainy season. Failure to do so may result in additional remedial earthwork. Demolition/Grubbing 1. Vegetation, and any miscellaneous deleterious debris generated from the demolition of existing site improvements should be removed from the areas of proposed grading/earthwork. 2. Cavities or loose soils remaining after demolition and site clearance should be cleaned out and observed by the geotechnical consultant. The cavities should be replaced with fill materials that have been moisture conditioned to at least optimum moisture content and compacted to at least 90 percent of the laboratory standard. M lies-Pacific, LP 1833 Buena Vista Way, Carlsbad File:wp12\6600\6637a.pge GeoSoils, Inc. W.O. 6637-A-SC March 17, 2014 Page 17 I I I I I I I I I I I I I I I I I I I 3. Any buried septic systems encountered during grading should be observed by the geotechnical consultant. Recommendations for the removal/mitigation of septic structures will then be provided based on the conditions exposed. Remedial Removals (Removal of Potentially Compressible Surficial Materials) Where planned fills or settlement-sensitive improvements are proposed, potentially compressible undocumented artificial fill, Quaternary colluvium, and weathered old paralic deposits should be removed to expose unweathered old paralic deposits. Removed soils may be reused as properly engineered fill provided that major concentrations of organic and/or deleterious materials have been removed prior to placement. In general, the remedial grading excavations to remove potentially compressible soils are anticipated to be on the order of 3 to 3% feet across a majority of the site. However, local deeper rem dial excavations cannot be precluded and should be anticipated. The removal of potentially compressible soils should be performed below a 1 :1 (h:v) projection down from the bottom, outermost edge of proposed settlement-sensitive improvements and/or limits of planned fills. Once the unsuitable soils have been removed, the exposed unweathered old paralic deposits should be scarified approximately 6 to 8 inches, moisture conditioned as necessary to achieve the soil's optimum moisture content and then be re-compacted to at least 90 percent of the laboratory standard prior to fill placement. All remedial removal excavations should be observed by the geotechnical consultant prior to scarification. Overexcavation Uniform support of foundations should be provided by overexcavating the cut portion of cut/fill transition lots or building pad areas where the planned plus remedial fill thickness does not allow for 42 inches of engineered fill below finish grade or 2 feet of engineered fill beneath the lowest foundation element. This would require that all old paralic deposits exposed within 42 inches of finish grade or 2 feet from the bottom of the lowest foundation element, following the removal of potentially compressible soils, be overexcavated to allow for the aforementioned minimum engineered fill cap. The bottom of the overexcavation should be sloped toward street areas, scarified at least 6 to 8 inches, moisture-conditioned as necessary to achieve the soil's optimum moisture content, and then be recompacted to at least 90 percent of the laboratory standard (ASTM D 1557) prior to fill placement. Overexcavation should be performed across the entire lot. Otherwise, there would be an increased potential for post-development perched water conditions to manifest. Overexcavation bottoms should be observed by the geotechnical consultant prior to scarification. The maximum to minimum fill thickness across building pads should not exceed a ratio of 3:1 (maximum:minimum). Overexcavation need not be performed in street areas. Temporary Slopes Temporary slopes for excavations greater than 4 feet but less than 20 feet in overall height should conform to CAL-OSHA and/or OSHA requirements for Type "8" soils. Temporary Miles-Pacific, LP 1833 Buena Vista Way, Carlsbad File:wp12\6600\6637a.pge GeoSoils, Inc. W.O. 6637-A-SC March 17, 2014 Page 18 I I I I I I I I I I I I I I I I I I I slopes, up to a maximum height of ±20 feet, may be excavated at a 1 :1 (h:v) gradient, or flatter, provided groundwater and/or running sands are not exposed. Construction equipment, building materials, or soil stockpiles should not be placed within 'H' of any temporary slope where 'H' equals the height of the temporary slope. All temporary slopes should be observed by a licensed engineering geologist and/or geotechnical engineer prior to worker entry into the excavation. Based on the exposed field conditions, inclining temporary slopes to flatter gradients or the use of shoring may be necessary if adverse conditions are observed. If temporary slopes conflict with property boundaries, shoring or alternating slot excavations may be necessary. The need for shoring or alternating slot excavations could be further evaluated during the grading plan review stage, but is considered likely on the eastern and northern property lines. Engineered Fill Placement Engineered fill should be well blended, placed in thin lifts, moisture conditioned, and mixed to achieve 1.1 to 1.2 times the soil's optimum moisture content, and then be mechanically compacted to at least 90 percent of the laboratory standard (ASTM D 1557). Engineered fill placement should be observed and selectively tested for moisture content and compaction by the geotechnical consultant. Graded Slopes Plans showing graded slope construction are currently unavailable. However, based on site relief, GSI does not anticipated graded cut and fill slopes to exceed about 5% feet in overall height. Graded fill slopes should be properly keyed and benched, and be compacted to at least 90 percent relative compaction throughout, including the slope face. All graded cut slopes should be observed by this office following construction. If adverse geologic conditions (daylighted, out-of-slope bedding and/or joints/fractures, highly weathered old paralic deposits, thick unsuitable soils, etc.) are noted in the slope face, GSI would provide recommendations for mitigation. Mitigation measures may include, but not necessarily be limited to: inclining the slope to gradients flatter than any adverse geologic structure; stabilization fills; or the use of an erosion control mat. Offsite Easterly-Facing Slope It is important to control pedestrian traffic and drainage in the adjoining area, so that the stability of the slope is not affected. Should failures occur on the slope, they will need to be mitigated so that they do not affect the project site. Import Fill Materials Any import fill materials used on this project should possess an E. I. of 20 or less with a P. I. not exceeding 15. All import fill material should be tested by GSI prior to placement within M Hes-Pacific, LP 1833 Buena Vista Way, Carlsbad File:wp 12\6600\6637a.pge GeoSoils, Inc. W.0. 6637-A-SC March 17, 2014 Page 19 I I I I I I I I I I I I I I I I I I I the site. GSI would also request environmental documentation (e.g., Phase I Environmental Site Assessment) pertaining to offsite export site, to evaluate if the proposed import could present an environmental risk to the planned residential development. At least three (3) business days of lead time will be necessary for the required laboratory testing and document review. PRELIMINARY FOUNDATION RECOMMENDATIONS General The foundation design and construction recommendations are based on laboratory testing and engineering evaluations of onsite earth materials by GSI. The following preliminary foundation construction recommendations are presented as a minimum criteria from a geotechnical engineering viewpoint. Testing indicates that the expansion indices of representative samples of the onsite soils is <5. This correlates to very low expansion potential. As such, the onsite soils are considered non-detrimentally expansive as defined in Section 1803.5.3 of the 2013 CBC. On a preliminary basis, conventional-type foundation and slab-on-grade floor systems may be incorporated into the construction of the proposed residential structures. Final foundation design should be based on the expansion index of soils exposed near finish grade. This report presents minimum design criteria for the design of foundations, concrete slab-on-grade floors, and other elements possibly applicable to the project. These criteria should not be considered as substitutes for actual designs by the structural engineer. Recommendations by the project's design-structural engineer or architect, which may exceed the geotechnical consultant's recommendations, should take precedence over the following minimum requirements. The foundation systems recommended herein may be used to support the proposed residences provided they are entirely founded into non- detrimentally expansive (i.e., expansion index< 21 and plasticity index< 15) engineered fill tested and approved by GSI. The proposed foundation systems should be designed and constructed in accordance with the guidelines contained in the 2013 CBC and indicated herein. In the event that the information concerning the proposed development plan is not correct, or any changes in the design, location or loading conditions of the proposed structure are made, the conclusions and recommendations contained in this report shall not be considered valid unless the changes are reviewed and conclusions of this report are modified or approved in writing by this office. The information and recommendations presented in this section are not meant to supercede design by the project structural engineer or civil engineer specializing in structural design. Upon request, GSI could provide additional input/consultation regarding soil parameters, as they relate to foundation design. Miles-Pacific, LP 1833 Buena Vista Way, Carlsbad File:wp12\6600\6637a.pge GeoSoils, Inc. W.O. 6637-A-SC March 17, 2014 Page 20 I I I I I I I I I I I I I I I I I I I General Foundation Design 1. The foundation systems should be designed and constructed in accordance with guidelines presented in the 2013 CBC. 2. 3. 4. 5. 6. 7. An allowable bearing value of 2,000 pounds per square foot (psf) may be used for the design of footings that maintain a minimum width of 12 inches and a minimum depth of 12 inches (below the lowest adjacent grade) and are founded into properly engineered fill. This value may be increased by 20 percent for each additional 12 inches in footing depth to a maximum value of 3,000 psf. These values may be increased by one-third when considering short duration seismic or wind loads. Isolated pad footings should have a minimum dimension of at least 24 inches square and a minimum embedment of 24 inches below the lowest adjacent grade into properly engineered fill. Foundation embedment excludes any landscaped zone, topsoil/colluvium, weathered paralic deposits, concrete slabs-on-grade, and/or slab underlayment. Passive earth pressure may be computed as an equivalent fluid having a density of 250 pcf, with a maximum earth pressure of 2,500 psf for footings founded into properly engineered fill. Lateral passive pressures for shallow foundations within 2013 CBC setback zones should be reduced following a review by the geotechnical engineer unless proper setback can be established. 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. When combining passive pressure and frictional resistance, the passive pressure component should be reduced by one-third. All footing setbacks from slopes should comply with Figure 1808.7.1 of the 2013 CBC. GSI recommends a minimum horizontal setback distance of 7 feet as measured from the bottom, outboard edge of the footing to the slope face. 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. Alternatively, walls may be designed to accommodate structural loads from buildings or appurtenances .. Foundation Settlement Provided the recommendations in this report are properly followed, foundation systems should be minimally designed to accommodate a differential static and seismic settlement of at least 1 inch in a 40-foot horizontal span (angular distortion= 1/480). Miles-Pacific, LP 1833 Buena Vista Way, Carlsbad File:wp 12\6600\6637a.pge GeoSoils, Inc. W.O. 6637-A-SC March 17, 2014 Page 21 I I I I I I I I I I I I I I I I I I I PRELIMINARY FOUNDATION CONSTRUCTION RECOMMENDATIONS The following foundation construction recommendations are presented as a minimum criteria from a soils engineering viewpoint. Conventional foundations and slab-on-grade floors may be into the construction of the planned residential structures provided the soils within the upper 7 feet of pad grade possess an expansion index of 20 or less and a plasticity index less than 15. Otherwise, specialized foundation systems would be necessary to mitigate expansive soil effects in accordance with Sections 1808.6.1 or 1808.6.2 of the 2013 CBC. Conventional Foundations (Expansion Index of 20 or Less with a Plasticity Index Less Than 15) 1. Exterior and interior footings should be founded into approved engineered fill at a minimum depth of 12 or 18 inches below the lowest adjacent grade for one-or two-story floor loads, respectively. For one-and two-story floor loads, footing widths should be 12 and 15 inches, respectively. Isolated, exterior column and panel pads, or wall footings, should be at least 24 inches, square, and founded at a minimum depth of 18 inches into properly compacted fill (this excludes the landscape zone [top 6 inches]). And be connected in at least one direction. All footings should be minimally reinforced with four No. 4 reinforcing bars, two placed near the top and two placed near the bottom of the footing. 2. 3. 4. 5. All interior and exterior column footings, and perimeter wall footings, should be tied together via grade beams in at least one direction. The grade beam should be at least 12 inches square in cross section, and should be provided with a minimum of one No.4 reinforcing bar at the top, and one No.4 reinforcing bar at the bottom of the grade beam. The base of the reinforced grade beam should be at the same elevation as the adjoining footings. A grade beam, reinforced as previously recommended and at least 12 inches square, should be provided across large (garage) entrances. The base of the reinforced grade beam should be at the same elevation as the adjoining footings. A minimum concrete slab-on-grade thickness of 5 inches is recommended. This includes the garage slabs-on-grade. Concrete slabs should be reinforced with a minimum of No. 3 reinforcement bars placed at 18-inch on centers, in two horizontally perpendicular directions (i.e., long axis and short axis). 6. All slab reinforcement should be supported to ensure proper mid-slab height positioning during placement of the concrete. 1Hooking11 of reinforcement is not an acceptable method of positioning. MIies-Pacific, LP 1833 Buena Vista Way, Carlsbad File:wp 12\6600\6637a.pge GeoSoils, Inc. W.O. 6637-A-SC March 17, 2014 Page 22 I I I I I I I I I I I I I I I I I I I 7. 8. Specific slab subgrade pre-soaking is not required for these soil conditions. However, moisture conditioning the upper 12 inches of the slab subgrade to at least optimum moisture should be considered. Soils generated from footing excavations to be used onsite should be compacted to a minimum relative compaction of 90 percent of the laboratory standard (ASTM D 1557), whether the soils are to be placed inside the foundation perimeter or in the yard/right-of-way areas. This material must not alter positive drainage patterns that direct drainage away from the structural areas and toward the street. 9. Reinforced concrete mix design should minimally conform to "Exposure Class C1" in Table 4.3.1 of ACl-318-08 since concrete would likely be exposed to moisture. CORROSION Upon completion of grading, additional testing of soils (including import materials) for corrosion to concrete and metals should be performed prior to the construction of utilities and foundations. SOIL MOISTURE TRANSMISSION CONSIDERATIONS GSI has evaluated the potential for vapor or water transmission through the concrete floor slabs, in light of typical floor coverings and improvements. Please note that slab moisture emission rates range from about 2 to 27 lbs/24 hours/1,000 square feet from a typical slab (Kanare, 2005), while floor covering manufacturers generally recommend about 3 lbs/24 hours as an upper limit. The recommendations in this section are not intended to preclude the transmission of water or vapor through the foundation or slabs. Foundation systems and slabs shall not allow water or water vapor to enter into the structure so as to cause damage to another building component or to limit the installation of the type of flooring materials typically used for the particular application (State of California, 2014). These recommendations may be exceeded or supplemented by a water "proofing" specialist, project architect, or structural consultant. Thus, the client will need to evaluate the following in light of a cost vs. benefit analysis (owner expectations and repairs/replacement), along with disclosure to all interested/affected parties. It should also be noted that vapor transmission will occur in new slab-on-grade floors as a result of chemical reactions taking place within the curing concrete. Vapor transmission through concrete floor slabs as a result of concrete curing has the potential to adversely affect sensitive floor coverings depending on the thickness of the concrete floor slab and the duration of time between the placement of concrete, and the installation of the floor covering. It is possible that a slab moisture sealant may be needed prior to the placement of sensitive floor coverings if a thick slab-on-grade floor is used and the time frame between concrete and floor covering placement is relatively short. Miles-Pacific, LP 1833 Buena Vista Way, Carlsbad File:wp 12\6600\6637a.pge GeoSoils, Inc. W.O. 6637-A-SC March 17, 2014 Page 23 I I I I I I I I I I I I I I I I I I I Considering the E.1. test results presented herein, and known soil conditions in the region, the anticipated typical water vapor transmission rates, floor coverings, and improvements (to be chosen by the Client and/or project architect) that can tolerate vapor transmission rates without significant distress, the following alternatives are provided: • Concrete slabs (including garage slabs) should be a minimum of 5 inches thick. • • • • Concrete slab underlayment should consist of a 10 to 15-mil vapor retarder, or equivalent, with all laps and penetrations (i.e., piping, ducting, reinforcing bars, etc.) sealed per the manufacturer's recommendation. The vapor retarder should comply with the ASTM E 17 45 -Class A or B criteria, and be installed in accordance with ACI 302.1 R-04, ASTM E 1643, and the manufacturer's specifications. The manufacturer shall provide instructions for lap sealing, including minimum width of lap, method of sealing, and either supply or specify suitable products for lap sealing (ASTM E 17 45), and per code. Concrete slabs, including the garage areas, should be underlain by 2 inches of clean, washed sand (SE> 30) above a 15 mil vapor retarder (ASTM E-1745 -Class A or Class B, per Engineering Bulletin 119 [Kanare, 2005]). ACI 302.1 R-04 (2004) states "If a cushion or sand layer is desired between the vapor retarder and the slab, care must be taken to protect the sand layer from taking on additional water from a source such as rain, curing, cutting, or cleaning. Wet cushion or sand layer has been directly linked in the past to significant lengthening of time required for a slab to reach an acceptable level of dryness for floor covering applications." Therefore, additional observation and/or testing will be necessary for the cushion or sand layer for moisture content, and relatively uniform thicknesses, prior to the placement of concrete. The vapor retarder shall be underlain by 2 inches of sand (SE > 30) placed directly on the properly prepared, moisture conditioned, subgrade and should be sealed to provide a continuous retarder under the entire slab, as discussed above. Concrete should have a maximum water/cement ratio of 0.50. This does not supercede Table 4.3.1 of Chapter 4 of the ACI (2008) for corrosion or other corrosive requirements. Additional concrete mix design recommendations should be provided by the structural consultant and/or waterproofing specialist. Concrete finishing and workablity should be addressed by the structural consultant and a waterproofing specialist. • Where slab water/cement ratios are as indicated herein, and/or admixtures used, the structural consultant should also make changes to the concrete in the grade beams and footings in kind, so that the concrete used in the foundation and slabs are designed and/or treated for more uniform moisture protection. Miles-Pacific, LP 1833 Buena Vista Way, Carlsbad File:wp12\6600\6637a.pge GeoSoils, Inc. W.O. 6637-A-SC March 17, 2014 Page 24 I I I I I I I I I I I I I I I I I I I • • The owner(s) should be specifically advised which areas are suitable for tile flooring, vinyl flooring, or other types of water/vapor-sensitive flooring and which are not suitable. In all planned floor areas, flooring shall be installed per the manufactures specifications. Additional recommendations regarding water or vapor transmission should be provided by the architect/structural engineer/slab or foundation designer, or waterproofing consultant, and should be consistent with the specified floor coverings indicated by the architect. Regardless of the mitigation, some limited moisture/moisture vapor transmission through the slab should be anticipated. Construction crews may require special training for installation of certain product(s), as well as concrete finishing techniques. The use of specialized product(s) should be approved by the slab designer and water-proofing consultant. A technical representative of the flooring contractor should review the slab and moisture retarder plans and provide comment prior to the construction of the foundations or improvements. The vapor retarder contractor should have representatives onsite during the initial installation. WALL DESIGN PARAMETERS Conventional Retaining Walls The design parameters provided below assume that either very low expansive soils (typically Class 2 permeable filter material or Class 3 aggregate base) or native onsite materials with an expansion index less than 21 and a plasticity index less than 15 are used to backfill any retaining wall. The type of backfill (i.e., select or native), should be specified by the wall designer, and clearly shown on the plans. Building walls, below grade, should be water-proofed. The foundation system for the proposed retaining walls should be designed in accordance with the recommendations presented in this and preceding sections of this report, as appropriate. Footings should be embedded a minimum of 18 inches below the lowest adjacent grade (excluding landscape layer, 6 inches) and should be 24 inches in width. An increase in maximum allowable bearing value for footing width may be used, only in the case of retaining wall footings. The increase should be limited to 100 psf for each additional foot of width to a maximum allowable bearing of 3,000psf, on a preliminary basis. Planned retaining wall footings near the perimeter of the site will likely need to be deepened into unweathered old paralic deposits for adequate vertical and lateral bearing support. Recommendations for specialty walls (i.e., crib, earthstone, geogrid, etc.) can be provided upon request, and would be based on site specific conditions. Miles-Pacific, LP 1833 Buena Vista Way, Carlsbad File:wp12\6600\6637a.pge GeoSoils, Inc. W.O. 6637-A-SC March 17, 2014 Page 25 I I I I I I I I I I I I I ,, I I 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 55 pounds per cubic foot (pcf) and 65 pct for select and very low expansive native backfill, respectively. The design should include 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 (2H) laterally from the corner. Cantilevered Walls The recommendations presented below are for cantilevered retaining walls up to 10 feet high. Design parameters for walls less than 3 feet in height may be superceded by City of Carlsbad and/or County of San Diego standard design. Active earth pressure may be used for retaining wall design, provided the top of the wall is not restrained from minor deflections. 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. When wall configurations are finalized, the appropriate loading conditions for superimposed loads can be provided upon request. For preliminary planning purposes, the structural consultant should incorporate the surcharge of traffic on the back of retaining walls. The traffic surcharge may be taken as 100 psf/ft in the upper 5 feet of backfill for light truck and cars traffic within "H" feet from the back of the wall, where "H" equals the wall height. This does not include the surcharge of parked vehicles which should be evaluated at a higher surcharge to account for the effects of seismic loading. SURFACE SLOPE OF EQUIVALENT EQUIVALENT RETAINED MATERIAL FLUID WEIGHT P.C.F. FLUID WEIGHT P.C.F. (HORIZONTAL:VERTICAL) (SELECT BACKFILL)(2} (NATIVE BACKFILL)!3l I Leve1<1J I 35 I 45 I 2 to 1 55 65 <1l 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, where H is the height of the wall. <2> SE.:::. 30, P.I. < 15, E.I. < 21, and~ 10% passing No. 200 sieve. <3> E.I. = o to 50, SE> 30, P.1. < 15, E.I. < 21, and< 15% passing No. 200 sieve. Miles-Pacific, LP 1833 Buena Vista Way, Carlsbad File:wp 12\6600\6637a.pge GeoSoils, Inc. W.0. 6637-A-SC March 17, 2014 Page 26 I I I I I I I I I I I I I I I I I I I Seismic Surcharge For engineered retaining walls, GSI recommends that the walls be evaluated for a seismic surcharge (in general accordance with 2013 CBC requirements). The site walls in this category should maintain an overturning Factor-of-Safety (FOS) of approximately 1.25 when the seismic surcharge (increment), is applied. For restrained walls, the seismic surcharge should be applied as a uniform surcharge load from the bottom of the footing (excluding shear keys) to the top of the backfill at the heel of the wall footing. This seismic surcharge pressure (seismic increment) may be taken as 13H where 11H11 for retained walls is the dimension previously noted as the height of the backfill measured from the bottom of the footing to daylight above the heel of the wall footing. The resultant force should be applied at a distance 0.6 H up from the bottom of the footing. For the evaluation of the seismic surcharge, the bearing pressure may exceed the static value by one-third, considering the transient nature of this surcharge. For cantilevered walls the pressure should be an inverted triangular distribution using 13H. Reference for the seismic surcharge for Seismic Design Category "D" is Section 1803.5.12 of the 2013 CBC. Please note this is for local wall stability only. The 12H is derived from a Mononobe-Okabe solution for both restrained cantilever walls. This accounts for the increased lateral pressure due to shakedown or movement of the sand fill soil in the zone of influence from the wall or roughly a 45° -c)>/2 plane away from the back of the wall. The 13H seismic surcharge is derived from the formula: Where: = = Yi H = Seismic increment Probabilistic horizontal site acceleration with a percentage of "g" total unit weight (115 to 125 pcf for site soils @ 90% relative compaction). Height of the wall from the bottom of the footing or point of pile fixity. 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 backdrainage 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 %-inch to 1 %-inch gravel wrapped in approved filter fabric (Mirafi 140 or equivalent). For select 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 up to E.I. = 20, continuous Class 2 permeable drain materials should be used behind the wall. This material should be continuous (i.e., full height) behind the wall, and it should be constructed in accordance Miles-Pacific, LP 1833 Buena Vista Way, Carlsbad File:wp12\6600\6637a.pge GeoSoils, Inc. W.O. 6637-A-SC March 17, 2014 Page 27 I I I I I I I I I 1· I I I I I I I I I (1) Waterproofing membrane·-~ CMU or reinforced-concrete wall ±12 inches Proposed grade t - sloped to drain per precise civil drawings (5) Weep hole Footing and wall design by other.,___.~-i (1) Waterproofing membrane. (2) Gravel= Clean, crushed, % to 1~ inch. Structural footing or settlement-sensitive improvement Provide surface drainage via an engineered V-ditch (see civil plans for details) 2=1 (h=v) slope Native backfill 1=1 (h=v) or flatter backcut to be properly benched (6) Footing (3) Filter fabric= Mirafi 140N or approved equivalent. (4) Pipe: 4-inch-diameter perforated PVC, Schedule 40, or approved alternative with minimum of 1 percent gradient sloped to suitable, approved outlet point (perforations down). (5) Weep hole= Minimum 2-inch diameter placed at 20-foot centers along the wall and placed 3 inches above finished surface. Design civil engineer to provide drainage at toe of wall. No weep holes for below-grade walls. (6) Footing: H bench is created behind the footing greater than the footing width, use level fill or cut natural earth materials. An additional "heel" drain will likely be required by geotechnical consultant. RETAINING WALL DETAIL -ALTERNATIVE A Detail 1 ., .. .// I I I I I I I I I I I I I I I I I I I (1) Waterproofing membrane (optional)-~ CMU or reinforced-concrete wall l 6 inches 1- (5) Weep hole Proposed grade sloped to drain per precise civil drawings /<)~\\'§(\~~'0:3\\0\ Footing and wall design by others-----"'-~ Structural footing or settlement-sensitive improvement Provide surface drainage via engineered V-ditch (see civil plan details) 2=1 (h=v) slope Native backfill 1=1 (h:v) or flatter backcut to be properly benched ---(6) 1 cubic foot of %-inch crushed rock (7) Footing (1) Waterproofing membrane (optional): Liquid boot or approved mastic equivalent. (2) Drain= Miradrain 6000 or J-drain 200 or equivalent for non-waterproofed walls; Miradrain 6200 or J-drain 200 or equivalent for waterproofed walls (all perforations down). (3) Filter fabric: Mirafi 140N or approved equivalent; place fabric flap behind core. (4) Pipe: 4-inch-diameter perforated PVC, Schedule 40, or approved alternative with minimum of 1 percent gradient to proper outlet point (perforations down). (5) Weep hole: Minimum 2-inch diameter placed at 20-foot centers along the wall and placed 3 inches above finished surface. Design civil engineer to provide drainage at toe of wall. No weep holes for below-grade walls. (6) Gravel: Clean, crushed,% to 1~ inch. (7) Footing: If bench is created behind the footing greater than the footing width, use level fill or cut natural earth materials. An additional "heel" drain will likely be required by geotechnical consultant. RETAINING WALL DETAIL -ALTERNATIVE 8 Detail 2 I I I I I I I I I I I I I I I I 1· (1) Waterproofing membrane -- Structural f coting or settlement-sensitive improvement CMU or reinforced-concrete wall ,---.-Provide surface drainage 2=1 (h=v) slope ;'. •' :. :· : '• .· .. . · ... . .. ~ . : . . .... ,• ·:. : .. -=± ±12 inches 1- (5) Weep hole H [Proposed grade sloped to drain per precise civil drawi~~ <0~\\X\~\~ Footing and wall design by others ;:;:;:;:~:;:;:;:;:;:;:;:;:;:;:;:;:;:;:;:;:;: ''.i·~::.::.:·::::·:·.:_:':-;,.:.~ -:-:-:-:-:-:-:-:-:-:-:-:-:-:-:-:-:-:-:-:-:-:-_: .-::.::. :· .. ? (4) Pipe (7) Footing (1) Waterproofing membrane= Liquid boot or approved masticequivalent. (2) Gravel: Clean, crushed, % to 1\ inch. (3) Filter fabric= Mirafi 140N or approved equivalent. (8) Native backfill (6) Clean 1=1 (h=v) or flatter backcut to be properly benched (4) Pipe: 4-inch-diameter perforated PVC, Schedule 40, or approved alternative with minimum of 1 percent gradient to proper outlet point (perforations down). (5) Weep hole= Minimum 2-inch diameter placed at 20-foot centers along the wall and placed 3 inches above finished surface. Design civil engineer to provide drainage at toe of wall. No weep holes for below-grade walls. (6) Clean sand backfill: Must have sand equivalent value (S.E.) of 35 or greater; can be densified by water jetting upon approval by geotechnical engineer. (7) Footing: If bench is created behind the footing greater than the footing width, use level fill or cut natural earth materials. An additional "heel" drain will likely be required by geotechnical consultant. (8) Native backfill= If E.I. {21 and S.E. L35 then all sand requirements also may not be required and will be reviewed by the geotechnical consultant. RETAINING WALL DETAIL -ALTERNATIVE C Detail 3 1. I I I I I I I I I I I I I I I I with the enclosed Detail 1 (Typical Retaining Wall Backfill and Drainage Detail). For limited access and confined areas, (panel) drainage behind the wall may be constructed in accordance with Detail 2 (Retaining Wall Backfill and Subdrain Detail Geotextile Drain). Materials with an expansion index (E.1.) potential of greater than 50 should not be used as backfill for retaining walls. For more onerous expansive situations, backfill and drainage behind the retaining wall should conform with Detail 3 (Retaining Wall And Subdrain Detail Clean Sand Backfill). 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 (E.I. ~ 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 walls 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) b) 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 nottransition conditions exist. Expansion joints should be sealed with a flexible, non-shrink grout. c) 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 11a11 (above) and until such transition is between 45 and 90 degrees to the wall alignment. M iles-Paclflc, LP 1833 Buena Vista Way, Carlsbad File:wp 12\6600\6637a.pge GeoSoils, Inc. W.O. 6637-A-SC March 17, 2014 Page 31 I I I I I I I I I I I I I I I I I I I TOP-OF-SLOPE WALLS/FENCES/IMPROVEMENTS AND EXPANSIVE SOILS Expansive Soils and Slope Creep Some of the soils at the site are likely to be expansive and therefore, become desiccated when allowed to dry. 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, such as swimming pools, concrete flatwork, etc., and in particular top of slope fences/walls. Where removal and recompaction of potentially compressible soils below a 1 :1 (h:v) projection down from the toe of perimeter fill slopes are constrained by property lines, improvements located within about H/3 feet from the tops of fill slopes, where H is the height of the slope, may be adversely affected by creep. 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 all 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 mitigate the tilting of top of slope walls/fences, we recommend that the walls/fences be constructed on a combination of grade beam and caisson foundations. 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: M lies-Pacific, LP 1833 Buena Vista Way, Carlsbad File:wp12\6600\6637a.pge GeoSoils, Inc. W.O. 6637-A-SC March 17, 2014 Page 32 I I I I I I I I I I I I I I I I I I I Creep Zone: Creep Load: Point of Fixity: Passive Resistance: Allowable Axial Capacity: Shaft capacity: Tip capacity: 5-foot vertical zone below the slope face and projected upward parallel to the slope face. 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. Located a distance of 1.5 times the caisson's diameter, below the creep zone. Passive earth pressure of 300 psf per foot of depth per foot of caisson diameter, to a maximum value of 4,500 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. 350 psf applied below the point of fixity over the surface area of the shaft. 4,500 psf. EXPANSIVE SOILS, DRIVEWAY, FLATWORK, AND OTHER IMPROVEMENTS Some of the soil materials on site are likely to 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 all 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: 1. 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. The moisture content of the subgrade should be proof tested within 72 hours prior to pouring concrete. M lies-Pacific, LP 1833 Buena Vista Way, Carlsbad File:wp 12\6600\6637a.pge GeoSoils, Inc. W.O. 6637-A-SC March 17, 2014 Page 33 I I I I I I I I I I I I I I I I I I I 2. 3. 4. 5. 6. 7. 8. 9. Concrete slabs should be cast over a relatively non-yielding surface, consisting of a 4-inch layer of crushed rock, gravel, or clean sand, that should be compacted and level prior to pouring concrete. The layer should wet-down completely prior to pouring concrete, to minimize loss of concrete moisture to the surrounding earth materials. Exterior slabs should be a minimum of 4 inches thick. Driveway 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. 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, slabs should be reinforced at mid-height with a minimum of No. 3 bars placed at 18 inches on center, in each direction. The exterior slabs should be scored or saw cut, 112 to % 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. No traffic should be allowed upon the newly poured 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, sidewalks, and patio slabs adjacent to the house should be separated from the house 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 should not be tied to the house. Overhang structures should be supported on the slabs, or structurally designed with continuous footings tied in at least two directions. Any masonry landscape 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. 10. Utilities should be enclosed within a closed utilidor (vault) or designed with flexible connections to accommodate differential settlement and expansive soil conditions. Miles-Pacific, LP 1833 Buena Vista Way, Carlsbad File:wp12\6600\6637a.pge GeoSoils, Inc. W.O. 6637-A-SC March 17, 2014 Page 34 I I I I I I I I I I I I I I I I I I I 11. Positive site drainage should be maintained at all times. Finish grade on the lots 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 yard drainage gradients are not periodically maintained by the homeowner or homeowners association. 12. Due to expansive soils, air conditioning (A/C) units should be supported by slabs that are incorporated into the building foundation or constructed on a rigid slab with flexible couplings for plumbing and electrical lines. A/C waste water lines should be drained to a suitable non-erosive outlet. 13. 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 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. PRELIMINARY PAVEMENT DESIGN New Pavements New asphaltic concrete pavement sections were analyzed using an assumed A-value and an assumed traffic index (T.1.) value. For preliminary planning purposes, the following AC pavement structural sections are provided in the following table. Final pavement structural sections should be based on A-value testing of soils exposed near the subgrade elevation following grading and underground utility construction. New Asphaltic Concrete (AC) Pavement NEW ASPHALTIC CONCRETE PAVEMENT TRAFFIC SUBGRADE A.C. THICKNESS CLASS 2 AGGREGATE T.1.<1> BASE THICKNEssC2> AREA R-VALUE (Inches) (Inches). I Residential I 5.5 I 30 I 3.0 I 7.5 I Street (1lr1 values have been assumed for planning purposes herein and should be confirmed by the design team during future plan development. (2loenotes standard Caltrans Class 2 aggregate base R > 78, SE > 22). The recommended pavement sections provided above are meant as minimums. If thinner or highly variable pavement sections are constructed, increased maintenance and repair Miles-Pacific, LP 1833 Buena Vista Way, Carlsbad File:wp12\6600\6637a.pge GeoSoils, Inc. W.O. 6637-A-SC March 17, 2014 Page 35 I I I I I I I I I I I I I I I I I I I 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 generally 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 A-value testing and pavement design analysis should be performed upon completion of grading and underground utility trench backfill. 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 generated underground utility construction should be removed or re-compacted as recommended. After the loose soils are removed, the exposed ground should 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 D 1557. Deleterious material, excessively wet or dry pockets, concentrated zones of oversized rock fragments, and any other unsuitable materials encountered during roadway 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 uniformly firm and unyielding surface. All grading and fill placement should be observed by the project soil engineer and/or his representative. Miles-Pacific, LP 1833 Buena Vista Way, Carlsbad File:wp12\6600\6637a.pge GeoSoils, Inc. W.O. 6637-A-SC March 17, 2014 Page 36 I I I I I I I I I I I I I I I I I I I Aggregate Base Compaction tests are required for the recommended aggregate base section. The 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: 1. The asphalt pavement layer is placed within two weeks of completion of base and/or sub base course. 2. Traffic is not routed over completed base before paving. 3. Construction is completed during the dry season of May through October. 4. 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 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 an approved drainage facility. 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. These measures may include, but not limited to, subdrainage devices, thickened curbs, or concrete cut-off walls. Miles-Pacific, LP 1833 Buena Vista Way, Carlsbad File:wp12\6600\6637a.pge GeoSoils, Inc. W.O. 6637-A-SC March 17, 2014 Page 37 I I I I I I I I I I I I I I I I I I I ONSITE INFILTRATION-RUNOFF RETENTION SYSTEMS General Should onsite infiltration-runoff retention systems (OIRRS) be planned for Best Management Practices (BMP's) or Low Impact Development (LID) principles for the project, some guidelines should/must be followed in the planning, design, and construction of such systems. Such facilities, if improperly designed or implemented without consideration of the geotechnical aspects of site conditions, can contribute to flooding, saturation of bearing materials beneath site improvements, slope instability, and possible concentration and contribution of pollutants into the groundwater or storm drain and/or utility trench systems. A key factor in these systems is the infiltration rate ( often referred to as the percolation rate) which can be ascribed to, or determined for, the earth materials within which these systems are installed. Additionally, the infiltration rate of the designed system (which may include gravel, sand, mulch/topsoil, or other amendments, etc.) will need to be considered. The project infiltration testing is very site specific, any changes to the location of the proposed OIRRS and/or estimated size of the OIRRS, may require additional infiltration testing. Locally, relatively impermeable formations include: paralic deposits, claystone, siltstone, cemented sandstone, igneous and metamorphic bedrock, as well as expansive fill soils. Some of the methods which are utilized for onsite infiltration include percolation basins, dry wells, bio-swale/bio-retention, permeable pavers/pavement, infiltration trenches, filter boxes and subsurface infiltration galleries/chambers. Some of these systems are constructed using native and import soils, perforated piping, and filter fabrics while others employ structural components such as stormwater infiltration chambers and filters/separators. Every site will have characteristics which should lend themselves to one or more of these methods; but, not every site is suitable for OIRRS. In practice, OIRRS are usually initially designed by the project design civil engineer. Selection of methods should include (but should not be limited to) review by licensed professionals including the geotechnical engineer, hydrogeologist, engineering geologist, project civil engineer, landscape architect, environmental professional, and industrial hygienist. Applicable governing agency requirements should be reviewed and included in design considerations. The following geotechnical guidelines should be considered when designing onsite infiltration-runoff retention systems: • It is not good engineering practice to allow water to saturate soils, especially near slopes or improvements; however, the controlling agency/authority is now requiring this for OIRRS purposes on many projects. MIies-Pacific, LP 1833 Buena Vista Way, Carlsbad File:wp 12\6600\6637a.pge GeoSoils, Inc. W.O. 6637-A-SC March 17, 2014 Page 38 I I I I I I I I I I I I I I I I I I I • • • • • • • • • If infiltration is planned, infiltration system design should be based on actual infiltration testing results/data, preferably utilizing double-ring infiltrometer testing (ASTM D 3385) to determine the infiltration rate of the earth materials being contemplated for infiltration. Wherever possible, infiltration systems should not be installed within ±50 feet of the tops of slopes steeper than 15 percent or within H/3 from the tops of slopes (where H equals the height of slope). Wherever possible, infiltrations systems should not be placed within a distance of H/2 from the toes of slopes (where H equals the height of slope). The landscape architect should be notified of the location of the proposed OIRRS . If landscaping is proposed within the OIRRS, consideration should be given to the type of vegetation chosen and their potential effect upon subsurface improvements (i.e., some trees/shrubs will have an effect on subsurface improvements with their extensive root systems). Over-watering landscape areas above, or adjacent to, the proposed OIRRS could adversely affect performance of the system. Areas adjacent to, or within, the OIRRS that are subject to inundation should be properly protected against scouring, undermining, and erosion, in accordance with the recommendations of the design engineer. Seismic shaking may result in the formation of a seiche which could potential overtop the banks of an OIRRS and result in down-gradient flooding and scour. If subsurface infiltration galleries/chambers are proposed, the appropriate size, depth interval, and ultimate placement of the detention/infiltration system should be evaluated by the design engineer, and be of sufficient width/depth to achieve optimum performance, based on the infiltration rates provided. In addition, proper debris filter systems will need to be utilized for the infiltration galleries/chambers. Debris filter systems will need to be self cleaning and periodically and regularly maintained on a regular basis. Provisions for the regular and periodic maintenance of any debris filter system is recommended and this condition should be disclosed to all interested/affected parties. Infiltrations systems should not be installed within ±8 feet of building foundations utility trenches, and walls, or a 1 :1 (horizontal to vertical [h:v]) slope (down and away) from the bottom elements of these improvements. Alternatively, deepened foundations and/or pile/pier supported improvements may be used. Infiltrations systems should not be installed adjacent to pavement and/or hard scape improvements. Alternatively, deepened/thickened edges and curbs and/or impermeable liners may be utilized in areas adjoining the OIRRS. Miles-Pacific, LP W.O. 6637-A-SC March 17, 2014 Page 39 1833 Buena Vista Way, Carlsbad File:wp12\6600\6637a.pge GeoSoils, Inc. I I I I I I I I I I I I I I I I I I I • • • • • • • • • • • As with any OIRRS, localized ponding and groundwater seepage should be anticipated. The potential for seepage and/or perched groundwater to occur after site development should be disclosed to all interested/affected parties. Installation of infiltrations systems should avoid expansive soils (Expansion Index [E.1.] ~51) or soils with a relatively high plasticity index (P.I. > 20). Infiltration systems should not be installed where the vertical separation of the groundwater level is less than ± 10 feet from the base of the system. Where permeable pavements are planned as part of the system, the site Traffic Index (T.1.) should be less than 25,000 Average Daily Traffic (ADT), as recommended in Allen, et al. (2011). Infiltration systems should be designed using a suitable factor of safety (FOS) to account for uncertainties in the known infiltration rates (as generally required by the controlling authorities), and reduction in performance over time. As with any OIRRS, proper care will need to provided. Best management practices should be followed at all times, especially during inclement weather. Provisions for the management of any siltation, debris within the OIRRS, and/or overgrown vegetation (including root systems) should be considered. An appropriate inspection schedule will need to adopted and provided to all interested/affected parties. Any designed system will require regular and periodic maintenance, which may include rehabilitation and/or complete replacement of the filter media (e.g., sand, gravel, filter fabrics, topsoils, mulch, etc.) or other components utilized in construction, so that the design life exceeds 15 years. Due to the potential for piping and adverse seepage conditions, a burrowing rodent control program should also be implemented onsite. All or portions of these systems may be considered attractive nuisances. Thus, consideration of the effects of, or potential for, vandalism should be addressed. Newly established vegetation/landscaping (including phreatophytes) may have root systems that will influence the performance of the OIRRS or nearby LID systems. The potential for surface flooding, in the case of system blockage, should be evaluated by the design engineer. Any proposed utility backfill materials (i.e., inlet/outlet p1p1ng and/or other subsurface utilities) located within or near the proposed area of the OIRRS may become saturated. This is due to the potential for piping, water migration, and/or seepage along the utility trench line backfill. If utility trenches cross and/or are Miles-Pacific, LP W.O. 6637-A-SC March 17, 2014 Page 40 1833 Buena Vista Way, Carlsbad File:wp 12\6600\6637a.pge GeoSoils, Inc. I I I I I I I I I I I I I I I I I I I proposed near the OIRRS, cut-off walls or other water barriers will need to be installed to mitigate the potential for piping and excess water entering the utility backfill materials. Planned or existing utilities may also be subject to piping offines into open-graded gravel backfill layers unless separated from overlying or adjoining OIRRS by geotextiles and/or slurry backfill. • The use of OIRRS above existing utilities that might degrade/corrode with the introduction of water/seepage should be avoided. Plan Specific The plans by SHA, Inc. (2012) indicate the construction of stormwater retention basins near the westerly margin of the site (Lots 18 and 19) and near the top of the cut slope descending to Interstate 5. In consideration of the long-term stability of this slope and nearby planned improvements, GSI recommends the following in addition to the above: • The sides and bottoms of these basins and trenches should be lined with an impermeable liner that does not allow for percolated water to weaken the cut slope's soil/rock composition nor result in seepage at the cut slope face. • The foundations for the surrounding retaining walls should be below a 1 :1 (h:v) projection from the bottom of the detention basins(s). • Proper maintenance and care of the basins will need to provided. Best management maintenance practices should be followed at all times, especially during inclement weather. Should regular inspection and/or required maintenance not be performed, the potential for malfunctioning of the detention systems will increase. All inlets, outlets and piping from these temporary drainage features should be properly backfilled and installed per City standards. • Consideration should be given to the sizing of the existing brow ditch on the cut slope descending to Interstate 5. PRELIMINARY OUTDOOR POOL/SPA DESIGN RECOMMENDATIONS The following preliminary recommendations are provided for consideration in pool/spa design and planning. Actual recommendations should be provided by a qualified geotechnical consultant, based on site specific geotechnical conditions, including supplemental subsurface investigation, differential settlement potential, expansive and corrosive soil potential, proximity of the proposed pool/spa to any slopes with regard to slope creep and lateral fill extension, as well as slope setbacks per code, and geometry of the proposed improvements. Recommendations for pools/spas and/or deck flatwork underlain by expansive soils, or for areas with differential settlement greater than 114-inch over 40 feet horizontally, will be more onerous than the preliminary recommendations Miles-Pacific, LP 1833 Buena Vista Way, Carlsbad File:wp12\6600\6637a.pge GeoSoils, Inc. W.O. 6637-A-SC March 17, 2014 Page 41 I I I I I I I 1· I I I I I I I I I I I presented below. The conditions and recommendations presented herein should be disclosed to all homeowners and any interested/affected parties. General 1. The equivalent fluid pressure to be used for the pool/spa design should be 60 pcf for pool/spa walls with level backfill, and 75 pcf for a 2:1 sloped backfill condition. In addition, backdrains should be provided behind pool/spa walls subjacent to slopes. 2. 3. 4. Passive earth pressure may be computed as an equivalent fluid having a density of 150 pcf, to a maximum lateral earth pressure of 1,000 pounds per square foot (psf). An allowable coefficient of friction between soil and concrete of 0.30 may be used with the dead load forces. When combining passive pressure and frictional resistance, the passive pressure component should be reduced by one-third. 5. Where pools/spas are planned near structures, appropriate surcharge loads need to be incorporated into design and construction by the pool/spa designer. This includes, but is not limited to landscape berms, decorative walls, footings, built-in barbeques, utility poles, etc. 6. All pool/spa walls should be designed as "free standing" and be capable of supporting the water in the pool/spa without soil support. The shape of pool/spa in cross section and plan view may affect the performance of the pool, from a geotechnical standpoint. Pools and spas should also be designed in accordance with Section 1808.7.3 of the 2013 CBC (CBSC, 2013). Minimally, the bottoms of the pools/spas, should maintain a distance H/3, where H is the height of the slope (in feet), from the slope face. This distance should not be less than 7 feet, nor need not be greater than 40 feet. 7. The soil beneath the pool/spa bottom should be uniformly moist with the same stiffness throughout. If a fill/paralic deposits transition occurs beneath the pool/spa bottom, the paralic deposits should be overexcavated to a minimum depth of 48 inches, and replaced with compacted fill, such that there is a uniform blanket that is a minimum of 48 inches below the pool/spa shell. If very low expansive soil is used for fill, the fill should be placed at a minimum of 95 percent relative compaction, at optimum moisture conditions. This requirement should be 90 percent relative compaction at over optimum moisture if the pool/spa is constructed within or near expansive soils. The potential for grading and/or re-grading of the pool/spa bottom, and attendant potential for shoring and/or slot excavation, needs to be considered during all aspects of pool/spa planning, design, and construction. Miles-Pacific, LP 1833 Buena Vista Way, Carlsbad File:wp12\6600\6637a.pge GeoSoils, Inc. W.O. 6637-A-SC March 17, 2014 Page 42 I I I I I I I I I I I I I I I I I I I 8. If the pool/spa is founded entirely in compacted fill placed during rough grading, the deepest portion of the pool/spa should correspond with the thickest fill on the lot. 9. Hydrostatic pressure relief valves should be incorporated into the pool and spa designs. A pool/spa under-drain system is also recommended, with an appropriate outlet for discharge. 10. All fittings and pipe joints, particularly fittings in the side of the pool or spa, should be properly sealed to prevent water from leaking into the adjacent soils materials, and be fitted with slip or expandible joints between connections transecting varying soil conditions. 11. An elastic expansion joint (flexible waterproof sealant) should be installed to prevent water from seeping into the soil at all deck joints. 12. A reinforced grade beam should be placed around skimmer inlets to provide support and mitigate cracking around the skimmer face. 13. In order to reduce unsightly cracking, deck slabs should minimally be 4 inches thick, and reinforced with No. 3 reinforcing bars at 18 inches on-center. All slab reinforcement should be supported to ensure proper mid-slab positioning during the placement of concrete. Wire mesh reinforcing is specifically not recommended. Deck slabs should not be tied to the pool/spa structure. Pre-moistening and/or pre-soaking of the slab subgrade is recommended, to a depth of 12 inches (optimum moisture content), or 18 inches (120 percent of the soil's optimum moisture content, or 3 percent over optimum moisture content, whichever is greater), for very low to low, and medium expansive soils, respectively. This moisture content should be maintained in the subgrade soils during concrete placement to promote uniform curing of the concrete and minimize the development of unsightly shrinkage cracks. Slab underlayment should consist of a 1-to 2-inch leveling course of sand (S.E.>30) and a minimum of 4 to 6 inches of Class 2 base compacted to 90 percent. Deck slabs within the H/3 zone, where H is the height of the slope (in feet), will have an increased potential for distress relative to other areas outside of the H/3 zone. If distress is undesirable, improvements, deck slabs or flatwork shou Id not be constructed closer than H/3 or 7 feet (whichever is greater) from the slope face, in order to reduce, but not eliminate, this potential. 14. Pool/spa bottom or deck slabs should be founded entirely on competent paralic deposits or properly compacted fill. Fill should be compacted to achieve a minimum 90 percent relative compaction, as discussed above. Prior to pouring concrete, subgrade soils below the pool/spa decking should be throughly watered to achieve a moisture content that is at least 2 percent above optimum moisture content, to a depth of at least 18 inches below the bottom of slabs. This moisture content should be maintained in the subgrade soils during concrete placement to M lies-Pacific, LP 1833 Buena Vista Way, Carlsbad File:wp12\6600\6637a.pge GeoSoils, Inc. W.O. 6637-A-SC March 17, 2014 Page 43 I I I I I I I I I I I I I I I I I promote uniform curing of the concrete and minimize the development of unsightly shrinkage cracks. 15. In order to reduce unsightly cracking, the outer edges of pool/spa decking to be bordered by landscaping, and the edges immediately adjacent to the pool/spa, should be underlain by an 8-inch wide concrete cutoff shoulder (thickened edge) extending to a depth of at least 12 inches below the bottoms of the slabs to mitigate excessive infiltration of water under the pool/spa deck. These thickened edges should be reinforced with two No. 4 bars, one at the top and one at the bottom. Deck slabs may be minimally reinforced with No. 3 reinforcing bars placed at 18 inches on-center, in both directions. All slab reinforcement should be supported on chairs to ensure proper mid-slab positioning during the placement of concrete. 16. Surface and shrinkage cracking of the finish slab may be reduced if a low slump and water-cement ratio are maintained during concrete placement. Concrete utilized should have a minimum compressive strength of 4,000 psi and a maximum water to cement ratio of 0.50. Excessive water added to concrete prior to placement is likely to cause shrinkage cracking, and should be avoided. Some concrete shrinkage cracking, however, is unavoidable. 17. Joint and sawcut locations for the pool/spa deck should be determined by the design engineer and/or contractor. However, spacings should not exceed 6 feet on-center. 18. Considering the nature of the onsite earth materials, it should be anticipated that caving or sloughing could be a factor in subsurface excavations and trenching. Shoring or excavating the trench walls/backcuts at the angle of repose (typically 25 to 45 degrees), should be anticipated. All excavations should be observed by a representative of the geotechnical consultant, including the project geologist and/or geotechnical engineer, prior to workers entering the excavation or trench, and minimally conform to CAL-OSHA, state, and local safety codes. Should adverse conditions exist, appropriate recommendations should be offered atthattime by the geotechnical consultant. GSI does not consult in the area of safety engineering and the safety of the construction crew is the responsibility of the pool/spa builder. 19. It is imperative that adequate provisions for surface drainage are incorporated by the homeowners into their overall improvement scheme. Ponding water, ground saturation and flow over slope faces, are all situations which must be avoided to enhance long term performance of the pool/spa and associated improvements, and reduce the likelihood of distress. 20. Regardless of the methods employed, once the pool/spa is filled with water, should it be emptied, there exists some potential that if emptied, significant distress may occur. Accordingly, once filled, the pool/spa should not be emptied unless evaluated by the geotechnical consultant and the pool/spa builder. Miles-Pacific, LP 1833 Buena Vista Way, Carlsbad File:wp12\6600\6637a.pge GeoSoils, Inc. W.O. 6637-A-SC March 17, 2014 Page 44 I I I I I I I I I I I I I I I I I 21. For pools/spas built within (all or part) of the 2013 CBC setback and/or geotechnical setback, as indicated in the site geotechnical documents, special foundations are recommended to mitigate the affects of creep, lateral fill extension, expansive soils and settlement on the proposed pool/spa. Most municipalities or County reviewers do not consider these effects in pool/spa plan approvals. As such, where pools/spas are proposed on 20 feet or more of fill, medium or highly expansive soils, or rock fill with limited "cap soils" and built within 2013 CBC setbacks, or within the influence of the creep zone, or lateral fill extension, the following should be considered during design and construction: OPTION A: Shallow foundations with or without overexcavation of the pool/spa "shell," such that the pool/spa is surrounded by 5 feet of very low to low expansive soils (without irreducible particles greater that 6 inches), and the pool/spa walls closer to the slope(s) are designed to be free standing. GSI recommends a pool/spa under-drain or blanket system (see Typical Pool/Spa Detail [Appendix F]). The pool/spa builders and owner in this optional construction technique should be generally satisfied with pool/spa performance under this scenario; however, some settlement, tilting, cracking, and leakage of the pool/spa is likely over the life of the project. OPTION B: Pier supported pool/spa foundations with or without overexcavation of the pool/spa shell such that the pool/spa is surrounded by 5 feet of very low to low expansive soils (without irreducible particles greater than 6 inches), and the pool/spa walls closer to the slope(s) are designed to be free standing. The need for a pool/spa under-drain system may be installed for leak detection purposes. Piers that support the pool/spa should be a minimum of 12 inches in diameter and at a spacing to provide vertical and lateral support of the pool/spa, in accordance with the pool/spa designers recommendations, local code, and the 2013 CBC. The pool/spa builder and owner in this second scenario construction technique should be more satisfied with pool/spa performance. This construction will reduce settlement and creep effects on the pool/spa; however, it will not eliminate these potentials, nor make the pool/spa "leak-free." 22. The temperature of the water lines for spas and pools may affect the corrosion properties of site soils, thus, a corrosion specialist should be retained to review all spa and pool plans, and provide mitigative recommendations, as warranted. Concrete mix design should be reviewed by a qualified corrosion consultant and materials engineer. 23. All pool/spa utility trenches should be compacted to 90 percent of the laboratory standard, under the full-time observation and testing of a qualified geotechnical consultant. Utility trench bottoms should be sloped away from the primary structure on the property (typically the residence). Miles-Pacific, LP 1833 Buena Vista Way, Carlsbad File:wp12\6600\6637a.pge GeoSoils, Inc. W.O. 6637-A-SC March 17, 2014 Page 45 I I I I I I I I I I I I I I I I I I I 24. Pool and spa utility lines should not cross the primary structure's utility lines (i.e., not stacked, or sharing of trenches, etc.). 25. The pool/spa or associated utilities should not intercept, interrupt, or otherwise adversely impact any area drain, roof drain, or other drainage conveyances. If it is necessary to modify, move, or disrupt existing area drains, subdrains, ortightlines, then the design civil engineer should be consulted, and mitigative measures provided. Such measures should be further reviewed and approved by the geotechnical consultant, prior to proceeding with any further construction. 26. The geotechnical consultant should review and approve all aspects of pool/spa and flatwork design prior to construction. A design civil engineer should review all aspects of such design, including drainage and setback conditions. Prior to acceptance of the pool/spa construction, the project builder, geotechnical consultant and civil designer should evaluate the performance of the area drains and other site drainage pipes, following pool/spa construction. 27. All aspects of construction should be reviewed and approved by the geotechnical consultant, including during excavation, prior to the placement of any additional fill, prior to the placement of any reinforcement or pouring of any concrete. 28. Any changes in design or location of the pool/spa should be reviewed and approved by the geotechnical and design civil engineer prior to construction. Field adjustments should not be allowed until written approval of the proposed field changes are obtained from the geotechnical and design civil engineer. 29. Disclosure should be made to homeowners and builders, contractors,, and any interested/affected parties, that pools/spas built within about 15 feet of the top of a slope, and/or H/3, where His the height of the slope (in feet), will experience some movement or tilting. While the pool/spa shell or coping may not necessarily crack, the levelness of the pool/spa will likely tilt toward the slope, and may not be esthetically pleasing. The same is true with decking, flatwork and other improvements in this zone. 30. Failure to adhere to the above recommendations will significantly increase the potential for distress to the pool/spa, flatwork, etc. 31. Local seismicity and/or the design earthquake will cause some distress to the pool/spa and decking or flatwork, possibly including total functional and economic loss. 32. The information and recommendations discussed above should be provided to any contractors and/or subcontractors, or homeowners, interested/affected parties, etc., that may perform or may be affected by such work. M lies-Pacific, LP 1833 Buena Vista Way, Carlsbad File:wp12\6600\6637a.pge GeoSoils, Inc. W.O. 6637-A-SC March 17, 2014 Page 46 I I I I I I I I I I I I I I I I I I I DEVELOPMENT CRITERIA Slope Deformation 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 (LFE). 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 (e.g., separations and/or cracking), placed near the top-of-slope, up to a maximum distance of approximately 15 feet from the top-of-slope, depending on the slope height. This movement generally results in rotation and differential settlement of improvements located within the creep zone. LFE occurs due to deep wetting from irrigation and rainfall on slopes comprised of expansive materials. 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. 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 2013 CBC), positive structural separations (i.e., joints) between improvements, and stiffening and deepening of foundations. Expansion joints in walls should be placed no greater than 20 feet on-center, and in accordance with the structural engineer's recommendations. All of these measures are recommended for design of structures and improvements. The ramifications of the above conditions, and recommendations for mitigation, should be provided to all interested/affected parties. 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 adversely affects site improvements, and causes 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 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 Miles-Pacific, LP 1833 Buena Vista Way, Carlsbad File:wp12\6600\6637a.pge GeoSoils, Inc. W.O. 6637-A-SC March 17, 2014 Page 47 I I I I I I I I I I I I I I I I I I I develop. A rodent control program to prevent burrowing should be implemented. Irrigation of natural (ungraded) slope areas is generally not recommended. These recommendations regarding plant type, irrigation practices, and rodent control should be provided to all interested/affected parties. Over-steepening of slopes should be avoided during building construction activities and landscaping. Drainage Adequate 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 the property, and especially near structures and tops of slopes. 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 the property 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 tops of slopes, and not allowed to pond and/or seep into the ground. In general, site drainage should conform to Section 1804.3 of the 2013 CBC. Consideration should be given to avoiding construction of planters adjacent to structures (buildings, pools, spas, etc.). Building 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 5 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 surficial 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 would recommend that any proposed open-bottom planters adjacent to proposed structures be eliminated for a minimum distance of 1 O feet. As an alternative, closed-bottom type planters could be utilized. An outlet placed in the bottom of the planter, could be installed to direct drainage away from structures or any exterior concrete flatwork. If planters are constructed adjacent to structures, the sides and bottom of the planter should be provided with a moisture barrier to prevent penetration of irrigation water M lies-Pacific, LP 1833 Buena Vista Way, Carlsbad File:wp12\6600\6637a.pge GeoSoils, Inc. W.O. 6637-A-SC March 17, 2014 Page 48 I I I I I I I I I I I I I I I I I I I 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 flatwork with their extensive root systems). From a geotechnical 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. Gutters and Downspouts As previously discussed in the drainage section, the installation of gutters and downspouts should be considered to collect roof water that may otherwise infiltrate the soils adjacent to the structures. If utilized, the downspouts should be drained into PVC collector pipes or other non-erosive devices (e.g., paved swales or ditches; below grade, solid tight-lined PVC pipes; etc.), that will carry the water away from the house, to an appropriate outlet, in accordance with the recommendations of the design civil engineer. Downspouts and gutters are not a requirement; however, from a geotechnical viewpoint, provided that positive drainage is incorporated into project design (as discussed previously). Subsurface and Surface Water Subsurface and surface water are not anticipated to affect site development, provided that 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 (e.g., pools, spas, etc.) are planned for the site, recommendations concerning the geological or geotechnical aspects of design and construction of said improvements could be provided upon request. Pools and/or spas should not be constructed without specific design and construction recommendations from GSI, and this construction recommendation should be provided to all interested/affected parties. 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 backfills, flatwork, etc. Miles-Pacific, LP 1833 Buena Vista Way, Carlsbad File:wp12\6600\6637a.pge GeoSoils, Inc. W.O. 6637-A-SC March 17, 2014 Page 49 I I I I I I I I I I I I I I I I I I I Tile Flooring Tile flooring can crack, reflecting cracks in the concrete slab below the tile, although small cracks in a conventional slab may not be significant. Therefore, the designer should consider additional steel reinforcement for concrete slabs-on-grade where tile will be placed. The tile installer should consider installation methods that reduce possible cracking of the tile such as slipsheets. Slipsheets or a vinyl crack isolation membrane (approved by the Tile Council of America/Ceramic Tile Institute) are recommended between tile and concrete slabs on grade. Additional Grading This office should be notified in advance of any fill placement, supplemental regrading of the site, or trench backfilling after rough grading has been completed. This includes completion of grading in the street, driveway approaches, driveways, parking areas, and utility trench and retaining wall backfills. 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 have been 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. Trenching/Temporary Construction Backcuts Considering the nature of the onsite earth materials, it should be anticipated that caving or sloughing could be a factor in subsurface excavations and trenching. Shoring or excavating the trench walls/backcuts at the angle of repose (typically 25 to 45 degrees [except as specifically superceded within the text of this report]), should be anticipated. All excavations should be observed by an engineering geologist or soil engineer from GSI, prior to workers entering the excavation or trench, and minimally conform to CAL-OSHA, state, and local safety codes. Should adverse conditions exist, appropriate recommendations would be offered at that time. The above recommendations should be provided to any contractors and/or subcontractors, or homeowners, etc., that may perform such work. Miles-Pacific, LP 1833 Buena Vista Way, Carlsbad File:wp12\6600\6637a.pge GeoSoils, Inc. W.O. 6637-A-SC March 17, 2014 Page 50 I I I I I I I I I I I I I I I I I I I Utility Trench Backfill 1. 2. 3. 4. All interior utility trench backfill should be brought to at least 2 percent above optimum moisture content and then compacted to obtain a minimum relative compaction of 90 percent of the laboratory standard. As an alternative for shallow (12-inch to 18-inch) under-slab trenches, sand having a sand equivalent value of 30 or greater may be utilized and jetted or flooded into place. Observation, probing and testing should be provided to evaluate the desired results. Exterior trenches adjacent to, and within areas extending below a 1 :1 plane projected from the outside bottom edge of the footing, and all trenches beneath hardscape features and in slopes, should be compacted to at least 90 percent of the laboratory standard. Sand backfill, unless excavated from the trench, should not be used in these backfill areas. Compaction testing and observations, along with probing, should be accomplished to evaluate the desired results. All trench excavations should conform to CAL-OSHA, state, and local safety codes. Utilities crossing grade beams, perimeter beams, or footings should either pass below the footing or grade beam utilizing a hardened collar or foam spacer, or pass through the footing or grade beam in accordance with the recommendations of the structural engineer. 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/recertification. • • • During excavation . During placement of subdrains or other subdrainage devices, prior to placing fill and/or backfill. After excavation of building footings, 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 presoaking/presaturation of building pads and other flatwork subgrade, before the placement of concrete, reinforcing steel, capillary break (i.e., sand, pea-gravel, etc.), or vapor retarders (i.e., visqueen, etc.). Miles-Pacific, LP 1833 Buena Vista Way, Carlsbad File:wp12\6600\6637a.pge GeoSoils, Inc. W.O. 6637-A-SC March 17, 2014 Page 51 I I I I I I I I I I I I I I I I I I I • • • • • • During retaining wall subdrain installation, prior to backfill placement. During placement of backfill for area drain, interior plumbing, utility line trenches, and 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. When any developer or homeowner improvements, such as flatwork, spas, pools, walls, etc., are constructed, prior to construction. A report of geotechnical observation and testing should be provided at the conclusion of each of the above stages, in order to provide concise and clear documentation of site work, and/or to comply with code requirements. OTHER DESIGN PROFESSIONALS/CONSULTANTS The design civil engineer, structural engineer, post-tension designer, 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 slabs, foundations and other elements possibly applicable to the project. These criteria should not be considered as substitutes for actual designs by the structural engineer/designer. Please note that the recommendations contained herein are not intended to preclude the transmission of water or vapor through the slab or foundation. The structural engineer/foundation and/or slab designer should provide recommendations to not allow water or vapor to enter into the structure so as to cause damage to another building component, or so as to limit the installation of the type of flooring materials typically used for the particular application. 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 slab, 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. M lies-Pacific, LP 1833 Buena Vista Way, Carlsbad Flle:wp12\6600\6637a.pge GeoSoils, Inc. W.O. 6637-A-SC March 17, 2014 Page 52 I I I I I I I I I I I I I I I I I I I 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. In order to mitigate potential distress, the foundation and/or improvement's designer should confirm to GSI and the governing agency, in writing, that the proposed foundations and/or improvements can tolerate the amount of differential settlement and/or expansion characteristics and other design criteria specified herein. PLAN REVIEW Final project plans (grading, precise grading, foundation, retaining wall, landscaping, etc.), should be reviewed by this office prior to construction, so that construction is in accordance with the conclusions and recommendations of this report. Based on our review, supplemental recommendations and/or further geotechnical studies may be warranted. Improvement plans should also be reviewed for subdrainage and piping (washing of fines) conditions, in light of the proposed sewer's close proximity to the cut slope descending to Interstate 5. 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, either express or implied, is given. Standards of practice are subject to 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 portion of the project. All samples will be disposed of after 30 days, unless specifically requested by the client, in writing. M lies-Pacific, LP 1833 Buena Vista Way, Carlsbad File:wp 12\6600\6637a.pge GeoSoils, Inc. W.O. 6637-A-SC March 17, 2014 Page 53 I I I I I I I APPENDIX A I REFERENCES I I. I I I I I I I I GeoSoils, Inc. I I I I I I I I I I I I I I I I I I I I APPENDIX A REFERENCES ACI Committee 318, 2008, Building code requirements for structural concrete (ACl318-08) and commentary, dated January. ACI Committee 302, 2004, Guide for concrete floor and slab construction, ACI 302.1 R-04, dated June. Allen, V., Connerton, A., and Carlson, C., 2011, Introduction to Infiltration Best Management Practices (BMP), Contech Construction Products, Inc., Professional Development Series, dated December. American Society for Testing and Materials (ASTM), 2003, Standard test method for infiltration rate of soils in field using double-ring infiltrometer, Designation D 3385-03, dated August. __ , 1998, Standard practice for installation of water vapor retarder used in contact with earth or granular fill under concrete slabs, Designation: E 1643-98 (Reapproved 2005). __ , 1997, Standard specification for plastic water vapor retarders used in contact with soil or granular fill under concrete slabs, Designation: E 1745-97 (Reapproved 2004). American Society of Civil Engineers, 2006, Minimum design loads for buildings and other structures, ASCE Standard ASCE/SEI 7-05. BHA, Inc., 2012, Tentative map and coastal development plan CT 12-01/CDP 12-15 for: Miles-Pacific Subdivision, Carlsbad, CA, Sheets1, 2, and 3 of 5, 30-scale, plot dated August 29. 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 December 2009, 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 SMIP99 seminar on utilization of strong-motion data, September 15, Oakland, pp. 23-49. GeoSoils, Inc. I I I I I I I I I I I I I I I I I I I 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. California Building Standards Commission, 2013, California Building Code, California Code of Regulations, Title 24, Part 2, Volume 2 of 2, Based on the 2012 International Building Code, 2013 California Historical Building Code, Title 24, Part 8; 2013 California Existing Building Code, Title 24, Part 1 o. California Department of Water Resources, 1993, Division of Safety of Dams, Guidelines for the design and construction of small embankments dams, reprinted January. California Stormwater Quality Association (CASQA), 2003, Stormwater best management practice handbook, new development and redevelopment, dated January. County of San Diego, Department of Planning and Land Use, 2007, Low impact development (LID) handbook, stormwater management strategies, dated December 31. GeoSoils, Inc., 2008, Update preliminary geotechnical evaluation, APNs 155-140-37, and -38, Jefferson Street, City of Carlsbad, San Diego County, California, W.O. 5701-A-SC, dated June 17. __ , 2003, Preliminary geotechnical evaluation, APNs 155-140-37, and -38, Jefferson Street, City of Carlsbad, San Diego County, California, W.O. 3213-A-SC, dated September 18. Hydrologic Solutions, StormChamber™ installation brochure, pgs. 1 through 8, undated. International Conference of Building Officials, 2001, California building code, California code of regulations title 24, part 2, volume 1 and 2. __ , 1998, Maps of known active fault near-source zones in California and adjacent portions of Nevada. Jennings, C.W., 1994, Fault activity map of California and adjacent areas: California Division of Mines and Geology, Map Sheet No. 6, scale 1 :750,000. Kanare, H.M., 2005, Concrete floors and moisture, Engineering Bulletin 119, Portland Cement Association. Kennedy, M.P, and Tan, S.S, 2005, Geologic map of the Oceanside 301 x 60' quadrangle, California, United States Geological Survey. Romanoff, M., 1957, Underground corrosion, originally issued April 1. M lies-Pacific, LP File:wp 12\6600\6637a.pge GeoSoils, Inc. Appendix A Page 2 I I I I I I I I I I I I I I I I I I I Seed, 2005, Evaluation and mitigation of soil liquefaction hazard "evaluation of field data and procedures for evaluating the risk of triggering (or inception) of liquefaction", in Geotechnical earthquake engineering; short course, San Diego, California, April 8-9. Sowers and Sowers, 1979, Unified soil classification system (After U. S. Waterways Experiment Station and ASTM 02487-667) in Introductory Soil Mechanics, New York. State of California, 2014, Civil Code, Sections 895 et seq. State of California Department of Transportation, Division of Engineering Services, Materials Engineering, and Testing Services, Corrosion Technology Branch, 2003, Corrosion Guidelines, Version 1.0, dated September. Tan, S.S., and Giffen, D.G., 1995, Landslide hazards in the northern part of the San Diego Metropolitan area, San Diego County, California, Landslide hazard identification map no. 35, Plate 35A, Department of Conservation, Division of Mines and Geology, DMG Open File Report 95-04. Tan, S.S., and Kennedy, M.P., 1996, Geologic maps of the northwestern part of San Diego County, California: California Division of Mines and Geology, Open File Report 96-02. United States Geological Survey, 2011, Seismic hazard curves and uniform hazard response spectra -v5.1.0, dated February 2 __ , 1999, San Luis Rey quadrangle, San Diego County, California, 7.5 minute series, 1 :24,000 scale. Miles-Pacific, LP File:wp12\6600\6637a.pge GeoSoils, Inc. Appendix A Page 3 I I I I I I I APPENDIX B I EXPLORATION LOGS I I I I I I I I I I GeoSoils, Inc. I I I I I I I I I I I I I I I I I I I I UNIFIED SOIL CLASSIFICATION SYSTEM ~ 'iii 0 (J) ~ 15 . Cf)~ -g gi C: Ul -~ ~ CJ 0. ch ~ .E o u.. E 0 'cf. 0 LO Major Divisions Highly Organic Soils C: Ul "' "'C a, C: -"' (.) Cf) Unified Soil Classification Cobbles 3" Group Symbols GW GP GM GC SW SP SM SC ML CL OL MH CH OH PT coarse Typical Names Well-graded gravels and gravel- sand mixtures, little or no fines Poorly graded gravels and gravel-sand mixtures, little or no fines Silty gravels gravel-sand-silt mixtures Clayey gravels, gravel-sand-clay mixtures Well-graded sands and gravelly sands, little or no fines Poorly graded sands and gravelly sands, little or no fines Silty sands, sand-silt mixtures Clayey sands, sand-clay mixtures Inorganic silts, very fine sands, rock flour, silty or clayey fine sands Inorganic clays of low to medium plasticity, gravelly clays, sandy clays, silty clays, lean clays Organic silts and organic silty clays of low plasticity Inorganic silts, micaceous or diatomaceous fine sands or silts, elastic silts Inorganic clays of high plasticity, fat clays Organic clays of medium to high plasticity Peat, mucic, and other highly organic soils 3/4" #4 Gravel I fine coarse CONSISTENCY OR RELATIVE DENSITY CRITERIA Standard Penetration Test Penetration Resistance N Relative (blows/ft) Density 0-4 Very loose 4 -10 Loose 10 • 30 Medium 30 · 50 Dense > 50 Very dense Standard Penetration Test Penetration Resistance N (blows/ft) <2 2-4 4-8 8 -15 15 • 30 >30 #10 Sand I medium Consistency Very Soft Soft Medium Stiff Very Stiff Hard #40 I fine Unconfined Compressive Strength (tons/ft2) <0.25 0.25 • .050 0.50 -1.00 1.00 • 2.00 2.00 • 4.00 >4.00 #200 U.S. Standard Sieve Silt or Clay MOISTURE CONDITIONS MATERIAL QUANTITY OTHER SYMBOLS Dry Slightly Moist Moist Very Moist Wet Absence of moisture: dusty, dry to the touch Below optimum moisture content for compaction Near optimum moisture content Above optimum moisture content Visible free water; below water table BASIC LOG FORMAT: trace few little some 0-5 % 5-10% 10 -25 % 25-45% C Core Sample S SPTSample B Bulk Sample ~ • Groundwater Qp Pocket Penetrometer 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;\SoilClassif.wpd PLATE 8-1 I I I I I I I I HAND AUGER ELEV. DEPTH NO. (ft.) (ft.) HA-1 ±194 0-V. I 'h -3 3-5 I I HA-2 ± 193% 0-3 3-4 I I I I I I I I W.O. 6637-A-SC Client Name: Miles Pacific Project Location: 1833 Buena Vista Way Logged By: TG December 16, 2013 LOG OF EXPLORATORY HAND AUGER BORINGS SAMPLE FIELD GROUP DEPTH MOISTURE DRY DESCRIPTION SYMBOL (ft.) (%) DENSITY (pcf) .. SP QUATERNARYCOLLUVIUM:SAND,darkbrownishgray, moist, loose. SM WEATHERED OLD PARALIC DEPOSITS: SILTY SAND, reddish yellow, moist, loose becoming medium dense with depth. SC Sm. Bag QUATERNARY OLD PARALIC DEPOSITS: CLAYEY SAND, reddish @4 yellow, moist, dense. Total Depth = 5' No Groundwater/Caving Encountered Backfilled on 12-16-2013 SM ND@1' 6.3 98.8 WEATHERED OLD PARALIC DEPOSITS: SILTY SAND, light reddish yellow, dry, dense. SM QUATERNARY OLD PARALIC DEPOSITS: SILTY SAND, reddish yellow, damp, dense. ND = Nuclear Densometer Total Depth = 4' No Groundwater/Caving Encountered Backfilled 12-16-2013 PLATE B-2 I I I I I I I I HAND AUGER ELEV. DEPTH GROUP NO. (ft.) (ft.) SYMBOL HA-3 ±194% 0-3% SM I 3V, • 5 SM I HA-4 ± 188% 0-3% SM I 3% • 4 SM I I I I I I I I W.O. 6637-A-SC Client Name: Miles Pacific Project Location: 1833 Buena Vista Way Logged By: TG December 16, 2013 LOG OF EXPLORATORY HAND AUGER BORINGS SAMPLE FIELD DEPTH MOISTURE DRY DESCRIPTION (ft.) (%) DENSITY (pcl) . Bulk@ 0 • 5 WEATHERED OLD PARALIC DEPOSITS: SILTY SAND, reddish (Composite) yellow, damp, medium dense; trace rootlets in upper V. foot. QUATERNARY OLD PARALIC DEPOSITS: SILTY SAND, reddish yellow, damp, medium dense. Total Depth = 5' No Groundwater/Caving Encountered Backfilled on 12-16-2013 Ring@ Y, 5.3 102.9 WEATHERED OLD PARALIC DEPOSITS: SILTY SAND, reddish yellow, moist, loose, becoming medium dense with depth; porous, abundant roots. QUATERNARY OLD PARALIC DEPOSITS: SILTY SAND, reddish yellow, damp, medium dense. Total Depth = 4' No Groundwater/Caving Encountered Backfilled on 12-16-2013 PLATE B-3 I I BORING LOG I GeoSoils, Inc. w.o. 6637-A-SC PROJECT: MILES-PACIFIC, LLP BORING B-1 SHEET_1_ OF-3_ I 1833 Buena Vista Way, Carlsbad DATE EXCAVATED 1-10-14 Sample SAMPLE METHOD: Modified Cal Sampler, 140 lbs@ 30" Drop I Approx. Elevation: ±188%' MSL 13 m Standard Penetration Test 0 .e ~ 'Si.-Groundwater ,R "O .c C 0 Q) E ~ C: ~ Undisturbed, Ring Sample ~ Seepage $ -e i >, ~ 0 I ,=;i Cl) ·2: "" .c Cl) ::, ~ a. -"' '5 u :::, iii ::, Q) "3 C: Cl) i':' ·5 m Description of Material Cl co :::, ai :::, Cl ~ (/) SM WEATHERED OLD PARALIC DEPOSITS: I -~ @ O' SILTY SAND, dark yellowish brown, dry becoming damp -/' with depth, loose becoming medium dense with depth; porous. ..r-..,.._. I SM QUATERNARY OLD PARALIC DEPOSITS: @ 3%' SIL TY SAND, dark yellowish brown, damp, dense. 69 SP 116.8 6.9 43.7 @ 5' SAND with trace SILT, dark yellowish brown, damp, dense; I fine grained. I 30/ SM 120.8 8.4 60.4 ...,... @ 10' SIL TY SAND with trace CLAY, reddish yellow, moist, very I 50-6" dense; fine grained. -./' I v"' 33/ SC 124.1 8.4 67.0 @ 15' CLAYEY SAND, grayish brown, moist, very dense; fine to 50-5" medium grained. I 17 18 I 19 20 67 SP 109.4 3.6 18.5 @ 20' SAND, brownish gray, dry, dense; fine grained. 21 I 22 23 I 24 25 421 105.9 3.0 14.1 @ 25' SAND, gray, dry, very dense; fine grained. 26 I 27 28 I 29 GeoSolls, Inc. 1833 Buena Vista Way, Carlsbad PLATE 8-4 I I I I I I I I I I I I I I I I I I I I BORING LOG GeoSoils, Inc. W. 0. 6637-A-SC PROJECT: MILES-PACIFIC, LLP BORING B-1 SHEET _3_ OF _3_ $ .s::: ii QJ Cl 31- 32- 33- 34- 35- 36- 37- 38- 39- 40- 41- 42- 43- "" :i co 1833 Buena Vista Way, Carlsbad Sample "C QJ -e i ::, "' '6 C ::, iii ~ 36/ 50-5" ~ 26/ ~ 50-5%" 0 .0 E >, (/) (/) (.) (/) ::, SP 'ti' .e, ;; ·2 ::, ~ i 0 C ~ 0 ::, ~ "' ::, ~ Cl ·o 1ii ~ (/) 110.5 2.1 11.3 104.1 3.8 17.0 DATE EXCAVATED 1-10-14 SAMPLE METHOD: Modified Cal Sampler, 140 lbs@ 30" Drop m ~ Standard Penetration Test Undisturbed, Ring Sample Approx. Elevation: ±188%' MSL 'Sl-Groundwater ~ Seepage Description of Material @ 30' SAND, dark yellowish brown and gray, dry, very dense; fine grained. @ 35' SAND, dark yellowish brown and gray, dry, very dense; fine grained. @ 36%' Cobbles encountered, difficult drilling. @ 40' Attempted sampling; however, cobbles impeded the advancement of the sampler. ~ 421 99.8 4.3 17.4 @ 42%' SAND, dark yellowish brown and gray, dry, very dense; ~ ::;: ... SP fine to coarse qrained/ 44-TERTIARY SANTIAGO FORMATION: r 45 @43%' SANDSTONE, light brownish gray, moist, very dense; ~ 50-6" SM 113.6 12.4 72.2 ~-L...:v:..C,eC!..1-rv-'"-fin:...:,e,c._..:,:_:Ora::,:;in:.:ce::c:d::i...:,,m=i;,::cc::::.ac~e:c..:o=-=u=s:,:,.·----~-,------=----~/ 46-~ ""' @ 45' SIL TY SANDSTONE, light gray, moist, dense; fine 1---¥-UL+---!----1-----+----f--+---+-\'---'a~r~a~in~e~d~-~--=c,...,.,...----------------~1 47-Total Depth= 46%' 48- 49- 50- 51- 52- 53- 54- 55- 56- 57- 58- 59- 1833 Buena Vista Way, Carlsbad No Groundwater/Caving Encountered Backfilled 1-20-2014 GeoSoils, Inc. PLATE 8-5 I I I I I I I I I I I I I I I I I I I GeoSoils, Inc. PROJECT: MILES-PACIFIC, LLP 1833 Buena Vista Way, Carlsbad Sample 13 0 s '1:J .0 ~ C Q) E ~ -e i!'. >, -~ Cl) .c ~ <n Cl) ·c ~ 0. °"' 'o i (.) ::i Q) :i C: Cl) c!' ·a 0 ID ::i ai ::i 0 ::i: SM 1- 2-SM 3 SM 4- 5-~ 61 121.8 6.3 6- 7- 8- 9- 10-~ 33/ 117.0 8.5 11-50-5" 12- 13- 14- 15 ~ 33/ SC 118.9 7.7 16-50-5%" 17- 18- 19- 20 SP 21- 22- 23-~ 40/ 107.1 2.1 50-5" 24- 25- 26- 27- 28- 29- 1833 Buena Vista Way, Carlsbad BORING LOG w.o. 6637-A-SC BORING 8-2 SHEET_1_ OF~ DATE EXCAVATED 1-10-14 SAMPLE METHOD: Modified Cal Sampler, 140 lbs @ 30" Drop Approx. Elevation: ±193' MSL m Standard Penetration Test ~ ¥ Groundwater 0 C: ~ Undisturbed, Ring Sample ~ Seepage ,g ~ ::, oi Description of Material Cl) ...,... ARTIFICIAL FILL -UNDOCUMENTED: I ...,... ® O' ASPHAL TIC CONCRETE. . ...,... @ 1/6' SILTY SAND, dark grayish brown, moist, medium dense; ...,... ! ...,... trace aravel. ...,... QUATERNARY COLLUVIUM: ...,... I ...,... 7rfi 1 %' SIL TY SAND dark aravish brown damo loose. ...,... . QUATERNARY OLD PARALIC DEPOSITS: ...,... @ 3' SILTY SAND, dark yellowish brown, damp, dense. ...,... 46.8 ...,... @ 5' SIL TY SAND, dark yellowish brown, damp, dense; fine ...,... grained . ...,... J- ·...;,,:-...,... .-./' ...,... ...,... ...,... ...,... 54.4 ...,... @ 1 O' SIL TY SAND with trace CLAY, reddish yellow and dark ...,... .-..,-.. gray, moist, very dense; fine grained, moderately cemented. ...,... ...,... -./' ...,... ...,... -..r '-"' -..,c- 52.1 ~ @ 15' CLAYEY SAND, grayish brown, moist, very dense; fine to ~ medium grained. ~ ~ « @ 20' SAND, brownish gray, dry, very dense; fine grained. 10.1 @22%' As per 20'. GeoSoils, Inc. PLATE B-6 I I I I I I I I I I I I I I I I I I I GeoSoils, Inc. PROJECT: MILES-PACIFIC, LLP 1833 Buena Vista Way, Carlsbad Sample 13 0 .e, " .c ~ ,R. Q) E 0 !E. -e it >, en -!!? ~ ·c: % 1 en ::, ~ ~ 'o (.) Q) :i C: en i::' ·o 0 al ::, ai ::, 0 ~ ~ 30/ SP 118.5 5.1 31-50-5%" 32- 33- 34- 35- 36- 37- ~ 37/ SW 111.2 3.7 38-50-5%" 39- 40- 41- 42- 43- 44- 45 ~ 28/ SP 90.2 8.1 46-50-6" 47- 48- 49- 50 ~ 44/ SM 116.1 11.4 51-50-3" 52- 53- 54- 55- 56- 57- 58- 59- 1833 Buena Vista Way, Carlsbad BORING LOG w.o. 6637-A-SC BORING B-2 SHEET_..3_ OF_..3_ DATE EXCAVATED 1-10-14 SAMPLE METHOD: Modified Cal Sampler, 140 lbs @ 30" Drop Approx. Elevation: ±193' MSL m Standard Penetration Test ,R. 'Sl Groundwater 0 C: ~ Undisturbed, Ring Sample 0 f\a Seepage :;:; e! :::, iii Description of Material en 33.8 @ 30' SAND with trace SILT, grayish brown, damp, very dense; fine grained. 20.3 .. @ 37%' SAND, light brownish gray, dry, very dense; fine to .. .. . . coarse grained . .. .. .. . . . . . . . . .. . . . . .. . . .. . . . . .. . . . . . . . . .. . . . . . . .. . . . . . . . . 25.6 TERTIARY SANTIAGO FORMATION: @ 45' SANDSTONE with trace SILT, grayish brown, dry, very dense; very fine grained, micaceous. 71.4 "° @ 50' SIL TY SANDSTONE, light gray, moist, very dense; fine to ..,,.. ..,,.. coarse grained. Total Depth= 51Yz' No Groundwater/Caving Encountered Backfilled 1-10-2014 GeoSoils, Inc. PLATE B-7 I I I I I I I I I I I I I I I I I I I GeoSoils, Inc. PROJECT: MILES-PACIFIC, LLP 1833 Buena Vista Way, Carlsbad Sample 'fi' 0 e ~ "C ..c ~ ~ Q) E 0 C: !!:!. -e u:: >-{I:' 0 :::, (/) 'E :;::, li 1n cil (/) :::, ~ e! .>< '5 i (.) :::, Q) :i C: (/) ~ ·5 1ii Cl co :::, ai :::, Cl ~ (/) SP SP SC 78 118.1 10.6 69.9 50-6" 112.9 9.4 53.5 12 13 14 15 24/ SC/CL 16 50-6" 17 18 19 20 21 22 23 24 25 26 27 28 29 1833 Buena Vista Way, Carlsbad BORING LOG W 0. 6637-A-SC BORING B-3 SHEET_1_ OF_1_ DATE EXCAVATED 12-16-13 SAMPLE METHOD: Modified Cal Sampler, 140 lbs@ 30" Drop Approx. Elevation: ±186' MSL Standard Penetration Test Undisturbed, Ring Sample "Sl Groundwater f\t Seepage Description of Material QUATERNARY COLLUVIUM: @ O' SAND with trace SILT, grayish brown, damp, loose; trace organics, fine grained. WEATHERED OLD PARALIC DEPOSITS: @2' SAND with trace SILT, dark yellowish brown, damp, medium dense· fine rained. QUATERNARY OLD PARALIC DEPOSITS: @ 3' CLAYEY SAND, reddish yellow, moist, very dense; moderately cemented. @ 5' CLAVEY SAND, reddish yellow, moist, very dense; manganese oxide staining, moderately cemented. @ 10' CLAYEY SAND, reddish yellow, moist, dense; moderately cemented. @ 15' CLAYEY SAND/SANDY CLAY, reddish yellow and reddish brown, moist, dense/hard. Practical Refusal @ 18%' No Groundwater/Caving Encountered Backfilled 12-16-2013 GeoSoils, Inc. PLATE B-8 I I I I I I I APPENDIX C I SLOPE STABILITY ANALYSES I I· I I I I I I I I GeoSoils, Inc. I I I I I I I I I I I I I I I I I I I I 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 surface 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: a. Phreatic and piezometric surfaces b. Pore pressure grid c. R factor d. 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: 1. 2. 3. 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 O 900488 573, 1981. Landslides: Analysis and Control, by R.L. Schuster and R.J. Krizek (editors), Special Report 176, Transportation Research Board, National Academy of Sciences, 234 pages, ISBN O 309 02804 3, 1978. GeoSoils, Inc. I I I I I I I I I I I I I I I I I GSTABL7 v.2 Features The present version of GSTABL7 v.2 contains the following features: 1. 2. 3. 4. 5. 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: 1. Unit weight, residual cohesion, residual friction angle, peak cohesion, and peak friction angle of earth mateials and bedding planes. Residual cohesion and friction angle is used for static stability analysis. Where as, peak cohesion and friction angle is for dynamic stability analysis. 2. Slope geometry and surcharge boundary loads. 3. Apparent dip of bedding plane can be modeled in an anisotropic angular range (i.e., from Oto 90 degrees. With the exception of the Tertiary Santiago Formation, isotropic values were used for all earth materials. For the Tertiary Santiago Formation, GSI used an anisotropic angular range of 1 degree in an out-of-slope direction and 4 degrees in an into slope direction. GSI also incorporated cross bed and parallel bed strengths for the Santiago Formation. Parallel bed strengths were reduced by approximately 16 to 17 percent from the cross bed strengths. 4. 5. Pseudo-static earthquake loading (an earthquake loading of 0.151) was used in the analyses. 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. 6. Soil parameters used in the slope stability analyses are provided in the following table: Miles-Pacific, LP File:wp12\6600\6637a.pge GeoSoils, Inc. Appendix C Page 2 I I I I I I I I I I I I I I I TABLE C-1 -SOIL STRENGTH PARAMETERS SOIL UNIT STATIC SHEAR SEISMIC SHEAR WEIGHT (pcf) STRENGTH PARAMETERS STRENGTH PARAMETERS SOIL MATERIALS C (psf) <I> {degrees) C (psf) <I> {degrees) Moist Saturated Bedding Bedding Cross Parallel Cross Parallel Cross Parallel Cross Parallel Tertiary Santiago Formation 115 125 300 250 33 28 360 300 37.9 32.5 (Tsa). Quaternary Old Paralic Deposits -Silty Sand 124 135 150 29 180 33.6 Member (Qop-SM) Quaternary Old Paralic Deposits -Sand Member 124 135 150 29 180 33.6 (Qop-SP) Artificial Fill- Undocumented 110 130 250 17 300 20.1 (Afu) Quaternary Colluvium 110 130 250 17 300 20.1 (Qcol) 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 inertia force 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 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 0.15g. Miles-Pacific, LP File:wp12\6600\6637a.pge GeoSoils, Inc. Appendix C Page 3 I I I I I I I I I I I I I I I I I I I 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 0.15i 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 0.15i was used in our analysis for a M7.1 event on the offshore segment of the Newport-Inglewood fault. GSI also incorporated a peak ground acceleration (PGA) of 0.45g into the seismic analysis as this represents Ssf2.5. Output Information Output information includes: 1 . All input data. 2. FOS for the 1 o most critical surfaces for static and pseudo-static stability situation. 3. High quality plots can be generated. The plots include the slope geometry, the critical surfaces and the FOS. 4. Note, that in the analysis, 100 to 1,000 trial surfaces were analyzed for each section for either static or pseudo-static analyses. Results of Slope Stability Calculations The following table provides a summary of the results of our stability analyses for the easterly-facing slope descending from the site to Monroe Street shown on Geologic Cross Section X-X' (see Plate 2). Computer printouts from the GSTABL7 program are also included herein. TABLE C-2-SUMMARY OF SLOPE STABILITY ANALYSES FACTOR OF SAFETY (FOS) LOCATION EXISTING SLOPE CONDITION METHOD STATIC SEISMIC Section X-X' 1.5 1.1 Jan bu (See Plate C-1) (See Plate C-2) Miles-Pacific, LP File:wp12\6600\6637a.pge GeoSoils, Inc. COMMENTS Requires setback from slope Appendix C Page 4 ------------------- ~ 9 "tJ a, s;:~ -I -...J m:x> C) I I (f) ...... C) 6637-A-SC Miles Pacific section X-X' FOS 1.5 using Janbu w/ Ru deep h2o c:\program files\g72sw\6637-a-sc miles pacific sextion x-x' fos 1.5 janbu1 .pl2 Run By: GeoSoils Inc. 3/14/2014 04:58PM 380 r;:=====~==+=========i==========i:=========+=========+======:::;-;::==r:::=========i:===:::;-~~,-~-~~-r-----~·~- # FS a 1.502 b 1.502 C 1.502 d 1.502 340 e 1.502 --f-i .502 g 1.502 h 1.502 i 1.502 j 1.502 300 260 220 180 140 t•l 100 0 GSTABL7 .. Soil Soil Total Saturated Cohesion Friction Pore Pressure Piez. Desc. Type Unit Wt. Unit Wt. Intercept Angle Pressure Constant Surface No. (P.cf) (pcf) ' (psf) (deg) Param. (psf) No. Tsa 1 115.0 125.0 : Anisa Anisa 0.00 o.o W1 Qop-sp 2 124.0 135.0 ' 150.0 29.0 0.00 0.0 W1 _QQP.:-~llJ--~ __ -1MQ __ J~g.Q __ :_ 1~0.,Q __ _?~.!) ___ Q.jg_ _Q_.Q ___ -"'!1 _ Qcol 4 110.0 130.0 : 250.0 17.0 0.15 0.0 W1 Afu 5 110.0 130.0 , 250.0 17.0 0.00 O.Q W1 40 80 120 160 200 •Load I LI L2 240 GST ABL7 v.2 FSmin:1.502 Value 100 psf 1500 psf 280 Safety Factors Are Calculated By The Simplified Janbu Method 320 360 400 -- - -- - - - - - - - - - -- -- - 6637-A-SC Miles Pacific section X-X' using Janbu w/ Ru deep h2o Seismic 1.1 c:\program files\g72sw\6637-a-sc miles pacific sextion x-x' janbu1 seismic1 .1.pl2 Run By: GeoSoils Inc. 3/14/2014 04:55PM 380 r;=====::::::;;==F=========F=========F=========i==========i======:::::;;:==i==========i:====;-~~--r---~~~~ # FS a 1.156 b 1.156 C 1.156 d 1.156 340 e 1.156 -f-1.156 g 1.156 h 1.156 1.156 1.156 300 260 220 180 I 140 1 11 ~ 0 "O 0) 100 ;~ 0 -I -...J m:.b, (') I I C/) I\.) (') GSTABL7 .. Soil Soil Total Saturated Cohesion Friction Pore Pressure Piez. Desc. Type Unit Wt. Unit Wt. Intercept Angle Pressure Constant Surface No. (P.cf) (pcf) ' (psf} (deg) Param. (psf) No. Tsa 1 115.0 125.0 : Anisa Anisa 0.00 0.0 W1 Qop-sp 2 1~4.0 135.0 : 180.0 33.6 o.oo o.~ W1 _QQP:~llJ-_q __ 1~4.Q _. Jgg.Q_. ,.1eo.,Q .. ~~-P-.. Q.Jg _ _O.Q _ _ _\/'!1 .. Qcol 4 110.0 130.0 : 300.0 20.1 0.15 0.0 W1 Afu 5 1 io.o 130.0 , 300.0 20.1 o.oo o.6 w1 a 'Load : LI ' L2 Peak(A) i<,h Coef. Value 100 psf 1500 pst 0.450(g) 0.150(g)< ' L2 I./ " / 'i If fu:::e::~'~;/~====~====~1~31?~3=========1::=:==========Q:=:======~4=====:::-'-':3f-O-:Q:::=~-i=--===o-=~ ' 2./ 40 80 120 160 200 240 280 320 360 GSTABL7v.2 FSmin:1.156 Safety Factors Are Calculated By The Simplified Janbu Method 400 I I I I I I I APPENDIX D I EQFAULT AND EQSEARCH I I I I I I I I I I GeoSoils, Inc. I I I I I I I I I I I I *********************** * * * E Q F A U L T * * * * version 3.00 * * * *********************** DETERMINISTIC ESTIMATION OF PEAK ACCELERATION FROM DIGITIZED FAULTS JOB NUMBER: 6637-A-SC JOB NAME: MILES PACIFIC, LP CALCULATION NAME: 6637 DATE: 01-31-2014 FAULT-DATA-FILE NAME: c:\Program Files\EQFAULTl\CGSFLTE.DAT SITE COORDINATES: SITE LATITUDE: 33.1693 SITE LONGITUDE: 117.3349 SEARCH RADIUS: 62.2 mi ATTENUATION RELATION: 11) Bozorgnia Campbell Niazi (1999) Hor.-Pleist. Soil-cor. UNCERTAINTY (M=Median, S=Sigma): s Number of sigmas: 1.0 DISTANCE MEASURE: cdist SCOND: 1 Basement Depth: .00 km Campbell SSR: 0 Campbell SHR: 0 COMPUTE PEAK HORIZONTAL ACCELERATION FAULT-DATA FILE USED: c:\Program Files\EQFAULTl\CGSFLTE.DAT I MINIMUM DEPTH VALUE (km): 3.0 I I I I I I I Page 1 W.O. 6637-A-SC PLATE D-1 I I I I I I I I I I I I I I I I I I I Page 1 EQFAULT SUMMARY DETERMINISTIC SITE PARAMETERS !ESTIMATED MAX. EARTHQUAKE EVENT APPROXIMATE !------------------------------- ABBREVIATED DISTANCE I MAXIMUM I PEAK !EST. SITE FAULT NAME mi (km) !EARTHQUAKE! SITE !INTENSITY I I MAG.(Mw) I ACCEL. g IMOD.MERC. ================================l==============l==========l==========I========= NEWPORT-INGLEWOOD (Offshore) I 5.8( 9.4)1 7.1 I 0.566 I X ROSE CANYON I 6.3( 10.2)1 7.2 I 0.561 I x CORONADO BANK I 21.9( 35.3)1 7.6 I 0.263 I IX ELSINORE (TEMECULA) I 23.3( 37.5)1 6.8 I 0.145 I VIII ELSINORE (JULIAN) I 23.5( 37.9)1 7.1 I 0.176 I VIII ELSINORE (GLEN IVY) I 32.8( 52.8)1 6.8 I 0.102 I VII SAN JOAQUIN HILLS I 34.9( 56.1)1 6.6 I 0.119 I VII PALOS VERDES I 35.9( 57.8)1 7.3 I 0.131 I VIII EARTHQUAKE VALLEY I 43.6( 70.2)1 6.5 I 0.062 I VI NEWPORT-INGLEWOOD (L.A.Basin) I 45.6( 73.4)1 7.1 I 0.089 I VII SAN JACINTO-ANZA I 45.9( 73.8)1 7.2 I 0.095 I VII SAN JACINTO-SAN JACINTO VALLEY I 46.3( 74.5)1 6.9 I 0.076 I VII CHINO-CENTRAL AVE. (Elsinore) I 47.0( 75.6)1 6.7 I 0.092 I VII WHITTIER I 50.8( 81.8)1 6.8 I 0.064 I VI SAN JACINTO-COYOTE CREEK I 51.8( 83.4)1 6.6 I 0.055 I VI ELSINORE (COYOTE MOUNTAIN) I 58.0( 93.4)1 6.8 I 0.056 I VI SAN JACINTO-SAN BERNARDINO I 58.8( 94.7)1 6.7 I 0.052 I VI PUENTE HILLS BLIND THRUST I 60.8( 97.9)1 7.1 I 0.093 I VII ******************************************************************************* -END OF SEARCH-18 FAULTS FOUND WITHIN THE SPECIFIED SEARCH RADIUS. THE NEWPORT-INGLEWOOD (Offshore) FAULT IS CLOSEST TO THE SITE. IT IS ABOUT 5.8 MILES (9.4 km) AWAY. LARGEST MAXIMUM-EARTHQUAKE SITE ACCELERATION: 0.5658 g Page 2 W.O. 6637-A-SC PLATE D-2 I I I I I I I I I I I I I I I I I I I 1000 900 800 700 600 500 400 300 200 100 0 CALIFORNIA FAULT MAP MILES PACIFIC, LP -400 -300 -200 -100 0 100 200 300 400 500 600 W.O. 6637-A-SC PLATE D-3 I I I I I I 1 I I I -C) -.1 C I 0 .:: ca ... Cl) -Cl) I (J (J <( I .01 I I I .001 I I I I .1 MAXIMUM EARTHQUAKES MILES PACIFIC, LP 1 I'll ~ • • 10 Distance (mi) ~ ,~ ... '"' ... ~ I 100 W.O. 6637-A-SC PLATE D-4 I I I I I I I I I I I I I I I I I I I JOB NUMBER: 6637-A-SC ************************* * * * * * E Q S E A R C H Version 3.00 * * * * * ************************* ESTIMATION OF PEAK ACCELERATION FROM CALIFORNIA EARTHQUAKE CATALOGS DATE: 01-31-2014 JOB NAME: MILES PACIFIC, LP EARTHQUAKE-CATALOG-FILE NAME: ALLQUAKE.DAT SITE COORDINATES: SITE LATITUDE: 33.1693 SITE LONGITUDE: 117.3349 SEARCH DATES: START DATE: 1800 END DATE: 2012 SEARCH RADIUS: 62.2 mi 100.1 km ATTENUATION RELATION: 11) Bozorgnia Campbell Niazi (1999) Hor.-Pleist. soil-car. UNCERTAINTY (M=Median, S=Sigma): s Number of Sigmas: 1.0 ASSUMED SOURCE TYPE: ss [SS=Strike-slip, DS=Reverse-slip, BT=Blind-thrust] SCOND: 1 Depth source: A Basement Depth: .00 km Campbell SSR: 0 Campbell SHR: 0 COMPUTE PEAK HORIZONTAL ACCELERATION MINIMUM DEPTH VALUE (km): 3.0 Page 1 W.O. 6637-A-SC PLATE D-5 I I I I I I I I I I I I I I I I I I I EARTHQUAKE SEARCH RESULTS Page 1 -------------------------------------------------------------------------------I I TIME I I I SITE !SITE! APPROX. FILE! LAT, I LONG. I DATE I (UTC) IDEPTHIQUAKEI ACC. I MM I DISTANCE CODE! NORTH I WEST I I HM Seel (km)I MAG. I g !INT.I mi [km] ----+-------+--------+----------+--------+-----+-----+-------+----+------------DMG l33.0000l117.3000lll/22/1800l2130 0.01 0.01 6.501 0.232 I IX I 11.9( 19.1) MG! l33.0000l117.0000I09/21/1856I 730 0.01 0.01 5.001 0.048 I VI I 22.6( 36.4) MG! l32.8000l117.1000I05/25/1803I O O 0.01 0.01 5.001 0.038 I VI 28.9( 46.5) DMG l32.7000l117.2000I05/27/1862l20 0 0.01 0.01 5.901 0.056 I VI I 33.3( 53.6) PAS l32.9710l117.8700I07/13/1986l1347 8.21 6.01 5.301 0.038 I VI 33.8( 54.5) T-A l32.6700l117.1700l12/00/1856I O O 0.01 0.01 5.001 0.030 I VI 35.8( 57.6) T-A l32.6700l117.1700l10/21/1862I O O 0.01 0.01 5.001 0.030 I VI 35.8( 57.6) T-A l32.6700l117.1700I05/24/1865I O O 0.01 0.01 5.001 0.030 I VI 35.8( 57.6) DMG l33.2000l116.7000I01/0l/1920I 235 0.01 0.01 5.001 0.029 I VI 36.7( 59.1) DMG l33.7000l117.4000I05/13/1910I 620 0.01 0.01 5.001 0.029 I v I 36.8( 59.3) DMG l33.7000l117.4000I05/15/1910l1547 0.01 0.01 6.001 0.053 I VI I 36.8( 59.3) DMG l33.7000l117.4000I04/ll/1910I 757 0.01 0.01 5.001 0.029 I VI 36.8( 59.3) DMG l33.6990l117.5110I05/31/1938I 83455.41 10.01 5.501 0.038 I v I 38.0( 61.1) DMG l32.8000l116.8000l10/23/1894l23 3 0.01 0.01 5.701 0.040 I VI 40.1( 64.6) MG! l33.2000l116.6000ll0/12/1920l1748 0.01 0.01 5.301 0.030 I v I 42.5( 68.4) DMG l33.7100l116.9250I09/23/1963l144152.6I 16.51 5.001 0.024 I VI 44.2( 71.1) DMG l33.7500l117.0000I04/21/1918l223225.0I 0.01 6.801 0.074 I VIII 44.5( 71.6) DMG l33.7500l117.0000I06/06/1918l2232 0.01 0.01 5.001 0.024 I v I 44.5( 71.6) MG! l33.8000l117.6000I04/22/1918l2115 0.01 0.01 5.001 0.023 I IV I 46.1( 74.3) DMG l33.5750l117.9830I03/ll/1933I 518 4.01 0.01 5.201 0.026 I v I 46.7( 75.2) DMG 133.80001117.0000112;25/189911225 o·.01 0.01 6.401 o.053 I vr I 47.6( 76.6) DMG l33.6170l117.9670I03/ll/1933I 154 7.81 0.01 6.301 0.049 I VI I 47.8( 76.9) DMG l33.6170l118.0170I03/14/1933l19 150.0I 0.01 5.101 0.023 I IV I 50.0( 80.5) GSP l33.5290l116.5720l06/12/2005l154146.5I 14.0I 5.201 0.024 I IV I 50.5( 81.3) DMG l33.9000l117.2000ll2/19/1880I O O 0.01 0.01 6.001 0.038 I VI 51.0( 82.1) GSG 33.4200l116.4890I07/07/2010l235333.5I 14.01 5.501 0.027 I VI 51.8( 83.3) PAS 33.50101116.5130I02/25/1980l104738.5I 13.61 5.501 0.027 I VI 52.6( 84.7) GSP 33.5080l116.5140l10/31/200ll075616.6I 15.0I 5.101 0.021 I IV I 52.8( 85.0) DMG 33.5000l116.5000I09/30/1916I 211 0.01 0.01 5.001 0.020 I IV I 53.3( 85.8) DMG 33.0000l116.4330I06/04/1940l1035 8.31 0.01 5.101 0.021 I IV I 53.5( 86.0) DMG 33.6830l118.0500l03/ll/1933I 658 3.01 0.01 5.501 0.026 I v I 54.4( 87.5) DMG 33.70001118.0670103/ll/19331 51022.0I 0.01 5.101 0.020 I IV I 55.9( 89.9) DMG 33.70001118.0670103/ll/19331 85457.0I 0.01 5.101 0.020 I IV I 55.9( 89.9) DMG 34.00001117.2500107/23/19231 73026.0I 0.01 6.251 0.039 I v I 57.6( 92.6) MGI 34.0000l117.5000l12/16/1858l10 0 0.01 0.01 7.001 0.064 I VI I 58.1( 93.6) DMG 33.3430l116.3460I04/28/1969l232042.9I 20.01 5.801 0.029 I VI 58.3( 93.9) DMG 33.7500ll18.0830l03/ll/1933I 230 0.01 0.01 5.101 0.019 I IV I 58.9( 94.7) DMG 33.7500ll18.0830I03/11/1933I 323 0.01 0.01 5.001 0.018 I IV I 58.9( 94.7) DMG 33.7500l118.0830I03/11/1933I 910 0.01 0.01 5.101 0.019 I IV I 58.9( 94.7) DMG 33.7500ll18.0830l03/13/1933l131828.0I 0.01 5.301 0.021 I IV I 58.9( 94.7) DMG l33.7500l118.0830I03/ll/1933I 2 9 0.01 0.01 5.001 0.018 I IV I 58.9( 94.7) GSG l33.9530l117.7610I07/29/2008l184215.71 14.01 5.301 0.021 I IV I 59.4( 95.6) DMG l33.9500l116.8500I09/28/1946I 719 9.01 0.01 5.001 0.017 I IV I 60.7( 97.7) DMG l33.4000l116.3000I02/09/1890l12 6 0.01 0.01 6.301 0.037 I VI 61.8( 99.5) ******************************************************************************* Page 2 W.O. 6637-A-SC PLATE D-6 I I I I I I I I I I I I I I I I I I I -END OF SEARCH-44 EARTHQUAKES FOUND WITHIN THE SPECIFIED SEARCH AREA. TIME PERIOD OF SEARCH: 1800 TO 2012 LENGTH OF SEARCH TIME: 213 years THE EARTHQUAKE CLOSEST TO THE SITE IS ABOUT 11.9 MILES (19.1 km) AWAY. LARGEST EARTHQUAKE MAGNITUDE FOUND IN THE SEARCH RADIUS: 7.0 LARGEST EARTHQUAKE SITE ACCELERATION FROM THIS SEARCH: 0.232 g COEFFICIENTS FOR GUTENBERG & RICHTER RECURRENCE RELATION: a-value= 0.907 b-value= 0.364 beta-value= 0.837 TABLE OF MAGNITUDES AND EXCEEDANCES: Earthquake I Number of Times I cumulative Magnitude I Exceeded I No. I Year -----------+-----------------+------------4.0 I 44 I 0.20755 4.5 I 44 I 0.20755 5.o I 44 I 0.20755 5.5 I 16 I o.07547 6.0 I 9 I o.04245 6. s I 3 I o. 01415 7.0 I 1 I o.00472 Page 3 W.O. 6637-A-SC PLATE D-7 I I I I I I I I I I I I I I I I I I I 1000 900 800 700 600 500 400 300 200 100 0 EARTHQUAKE EPICENTER MAP MILES PACIFIC, LP LEGEND x M =4 0 M=5 D M=6 6 M=7 OM=S -400 -300 -200 -100 0 100 200 300 400 500 600 W.O. 6637-A-SC PLATE D-8 I I I I I I I ... C\1 ~ I --z -U) ... I C CD > w -I 0 ... CD .Cl E I :::, z CD > ~ I C\1 -:::, E E I :::, 0 I I I I I I 100 10 1 .1 .01 .001 ..... EARTHQUAKE RECURRENCE CURVE MILES PACIFIC, LP -.......... .~ •• ~ I'... --~ ' . .__ ~-"""'-it .......... ... I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 8.5 9.0 Magnitude (M) W.O. 6637-A-SC PLATE D-9 I I I I I I I APPENDIX E I LABORATORY DATA I I I I I I I I I I GeoSoils, Inc. I I I I I I I I I I I I I I I I I I I I en :::, a'. (!) i w N cii z :;;: 0:: (!) en ::, U.S. SIEVE OPENING IN INCHES I U.S. SIEVE NUMBERS I HYDROMETER 6 4 3 2 1.5 1 3/4 1/23/8 3 4 6 810 1416 20 30 40 50 60 100140200 100 I II I I II I I I I I I I I : \ 95 \ : : 90 ~ 85 80 : : \ : 75 \ 70 I-65 :c (!) : w6o \ s: fu 55 , c::: W50 : \ : z ~45 z : ~40 \ c::: ~ ~35 : : ""~ 30 "" 25 : 20 : : : 15 : 10 5 0 100 10 1 0.1 0.01 0.001 GRAIN SIZE IN MILLIMETERS I GRAVEL SAND I SILT OR CLAY I COBBLES I coarse J I coarse fine medium fine Sample Depth Range Visual Classification/USCS CLASSIFICATION LL PL Pl Cc Cu • B-3 5.0 Clayey Sand Sample Depth D100 D60 D30 D10 o/oGravel %Sand %Silt I %Clay • B-3 5.0 2 0.278 0.077 0.0 70.3 29.7 GeoSoils, Inc. GRAIN SIZE DISTRIBUTION ~Si 57 41 Palmer Way Project: MILES PACIFIC Carlsbad, CA 92008 Number: 6637-A-SC Telephone: (760) 438-3155 Fax: (760) 931-0915 Date: March 2014 Plate: E -1 I I I I I I I I I I I I I I I I I I I AP Engineering & Testing, Inc. DIRECT SHEAR TEST RESULTS ASTM D 3080 Project Name: Miles Pacific Initial Dry Density: Boring No.: B-3 Moisture Content (before): Sample No_: Moisture Content (after): Depth {ft}: 15 Sample Type: Mod. Cal. Soil Description: _C_la ..... y_e._y _S_an_d ____ _ Test Condition: Inundated C 115.8 pcf 7.2 % ---16.6 % ! 2_0 +-------h..»-----f-----+----i-----t------,f-----+------i j Q_Q ____ _._ ___ +----------------------;----------~ 0 4 3 I _, 0 ~- r'~ 0 0 1 Strength Parameters Cohesion (psf): Friction Angle: 0.1 0.2 Shear Deformation (inches) ,.,) V ~~ ... ,,,J. , ... ,,,,,. /v,.... ,.... L .. ~ r--~ 2 3 4 5 Peak 200 32 ° Nonnal Stress (ksf) Ultimate 150 29 ° 0.3 0.4 I• Peak O Ultimate I 6 7 a PLATE E-2 I I I I I I I I I I I I I I I I I I I 6,000 5,000 4,000 ~~ V 'lii 1~ a. :r: I-(.!) z w 3,000 0:: ~ V I-(/) 0:: <( w :r: (/), ~ 2,000 ~ # 1,000 ~ / 0 0 1,000 2,000 3,000 4,000 5,000 6,000 NORMAL PRESSURE, psf Sample Depth/El. Range Classification Primary/Residual Sample Type 'Yct MC% C cl> • B-1 42.5 Sand wt Silt Primary Shear Undisturbed 96.6 4.3 345 34 D B-1 42.5 Residual Shear Undisturbed 96.6 4.3 98 35 Reshear Shear Undisturbed Reshear Shear Undisturbed Note: Sample lnnundated Prior To Test GeoSoils, Inc. DIRECT SHEAR TEST ~~& 57 41 Palmer Way Project: MILES PACIFIC Carlsbad, CA 92008 ~~L\. Telephone: (760) 438-3155 Number: 6637-A-SC Fax: (760) 931-0915 Date: March 2014 Plate: E - 3 I I I I I I I I I I I I I I I I I I I 6,000 5,000 4,000 -rn C. ::c I-Cl z w 3,000 c:: I-(/) c:: i'.5 :c (/) 2,000 1,000 / V /" 0 0 1,000 2,000 Sample Depth/El. Range Classification • 8-2 45.0 Sand w/ Silt D 8-2 45.0 Note: Sample lnnundated Prior To Test GeoSoils, Inc. ~· 57 41 Palmer Way Carlsbad, CA 92008 Telephone: (760) 438-3155 Fax: (760) 931-0915 ..-11 / / V V / 3,000 4,000 5,000 6,000 NORMAL PRESSURE, psf Primary/Residual Sample Type yd MC% C cl> Primary Shear Undisturbed 90.1 8.1 320 32 Residual Shear Undisturbed 90.1 8.1 247 33 Reshear Shear Undisturbed Reshear Shear Undisturbed DIRECT SHEAR TEST Project: MILES PACIFIC Number: 6637-A-SC Date: March 2014 Plate: E -4 I I I I I I I I I I I I I I I I I I I 1Cal Land Engineering, Inc. dba Quartech Consultant Geotechnical, Environmental, and Civil Engineering SUMMARY OF LABORATORY TEST DATA GeoSolls, Inc. 5741 Palmer Way, Suite D Carlsbad, CA 92010 Client Miles Pacific W.O. 6637-A-SC Sample ID B-3 Sample Depth 0-5' QCI Project No.: 14-029-01 F Date: January 31, 2014 Summarized by: KA Corrosivity Test Results pH Chloride Sulfate Resistivity CT-417 CT-532 CT-422 %By CT -532 (643) (643) (ppm) Weight (ohm-cm) 7.04 103 0.0130 1,800 PLATE E-5 576 East Lambert Road, Brea, California 92821; Tel: 714-671-1050; Fax: 714-671-1090 -I I I I I I I I I I I I I I I I I I I I APPENDIX F GENERAL EARTHWORK AND GRADING GUIDELINES GeoSoils, Inc. I I I I I I I I I I I I I I I I I I I GENERAL EARTHWORK AND GRADING GUIDELINES 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. GeoSoits, Inc. I I I I I I I I I I I I I I I I I I I 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, 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. Contractor's 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 fill, 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 Miles-Pacific, LP File:wp12\6600\6637a.pge GeoSoils, Inc. Appendix F Page 2 I I I I I I I I I I I I I I I I I I I 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, 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 6 to 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 % 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. M lies-Pacific, LP File:wp12\6600\6637a.pge GeoSoils, Inc. Appendix F Page 3 I I I I I I I I I I I I I I I I I I I 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, 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. GSI 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 1 O 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 for use onsite. Such testing should be performed three (3) days prior to importation. If any material other than that Miles-Pacific, LP File:wp12\6600\6637a.pge GeoSoils, Inc. Appendix F Page 4 I I I I I I I I I I I I I I I I I I I 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 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 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 1 o feet of each lift of fill by undertaking the following: M iles-Paclflc, LP File:wp12\6600\6637a.pge GeoSoils, Inc. Appendix F Page 5 I I I I I I I I I I I I I I I I I I I 1. 2. 3. 4. 5. 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. 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. M lies-Pacific, LP File:wp12\6600\6637a.pge GeoSoils, Inc. Appendix F Page 6 I I I I I I I I I I I I I I I I I I I 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 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 geotechnical 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. Miles-Pacific, LP File:wp12\6600\6637a.pge GeoSoils, Inc. Appendix F Page 7 I I I I I I I I I I I I I I I I I I I 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: 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 during all 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 Miles-Pacific, LP File:wp12\6600\6637a.pge GeoSoils, Inc. Appendix F Page 8 I I I I I I I I I I I I I I I I I I I 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 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 nottested 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, GSI then has an obligation to notify Cal/OSHA and/or the proper controlling authorities. M iles-Paclflc, LP File:wp12\6600\6637a.pge GeoSoils, Inc. Appendix F Page 9 ------------------- Toe of slope as shown on grading plan Proposed grade \ / / .,,,-- / Natural slope to be restored with compacted fill Compacted fill Backcut varies NOTES: -----r Subdrain as recommended by geotechnical consultant ·.. ': •, ... 1. Where the natural slope approaches or exceeds the design slope ratio, special recommendations would be provided by the geotechnical consultant. 2. The need for and disposition of drains should be evaluated by the geotechnical consultant, based upon exposed conditions. .:·. ·,·,. . .. . ,, . ....... FILL OVER NATURAL (SIDEHILL FILL) DETAIL Plate F-7 ------------------- H • height of elope Cut/fill contact as shown on grading plan Cut/fill contact as shown on as-built plan __ Original (existing) grade Proposed grade 4-foot minimum Subdrain as recommended by geotechnical consultant NOTE= The cut portion of the slope should be excavated and evaluated by the geotechnical consultant prior to construction of the fill portion. ~~11...c. ~~· --------- FILL OVER CUT DETAIL Plate F-8 ------------------- H • height of slope : .:· ;.· ·.·. ·;" ... ·\ ·. ··.·<.·, .. ·:: .:::.·:·.~ ·.·; .... · key depth Proposed finish grade ----... Natural grade Typical benching (4-foot minimum) Subdrain as recommended by geotechnical consultant NOTES= 1. 15-foot minimum to be maintained from proposed finish slope face to backcut. minimum 2. The need and disposition of drains will be evaluated by the geotechnical consultant based on field conditions. 3. Pad overexcavation and recompaction should be performed if evaluated to be necessary by the geotechnical consultant. SKIN FILL OF NATURAL GROUND DETAIL Plate F-10 ------------------- Reconstruct compacted fill slope at 2=1 or flatter (may increase or decrease pad area) Overexcavate and recompact replacement fill Back-cut varies Avoid and/ or clean up spillage of materials on the natural slope Natural grade Subdrain as recommended by geotechnical consultant NOTES= Subdrain and key width requirements will be evaluated based on exposed subsurface conditions and thickness of overburden. 2. Pad overexcavation and recompaction should be performed if evaluated necessary by the geotechnical consultant. DAYLIGHT CUT LOT DETAIL Plate F-11 I I I I I I I I I I I I I I I I I I I Natural grade __ J_ u-~--Y>-\ ~0.~~~y\\\'«\~Y/\ ,,,\\\~~v:-\'\;((0~,,y;,.\ ~0.0'\v\\Y ~ 3-to 7-foot minimum- -(' overexcavate and recompact -\ ..... A"-~~\ Bedrock or per text o1 report A\ :::.,{\ approved native material Typical benching CUT LOT OR MATERIAL -TYPE TRANSmON Natural grade ... :··. ·' . .-., · . .-.• ..... ··.··-::: .. :,: J_ •., ... :.-~ .. . ·----- ---- --... ·: ,._ . TRANSITION LOT DETAILS Plate F-12 I I I I I I I I I I I I I I I MAP VIEW NOTTO SCALE Concrete cut-off wall SEENOTEl~-S~~~~~~~~~ 2-inch-thick sand layer Bl Gravity-flow, nonperforated subdrain I=== pipe <transverse] Toe of slope 4 4-inch perforated subdrain pipe (longitudinal) A I I Coping A' -1 1 s1eet Pool )> ... 4-inch perforated subdrain pipe (transverse) Pool Direction of drainage B' CROSS SECTION VIEW Coping NOTTO SCALE SEE NOTES Pool encapsulated in 5-foot thickness of sand ----. 6-inch-thick gravel layer 4-inch perforated subdrain pipe B r H NOTES: Q"avity-flow nonperforated subdrain pipe Vapor retarder Perforated subdrain pipe 1. 6-inch-thick, clean gravel {% to ~ inch) sub-base encapsulated in Mirafi 140N or equivalent, underlain by a 15-mil vapor retarder, with 4-inch-diameter perforated pipe longitudinal connected to 4-inch-diameter perforated pipe transverse. Connect transverse pipe to 4-inch-diameter nonperforated pipe at low point and outlet or to sump pump area 2. Pools on fills thicker than 20 feet should be constructed on deep foundations; otherwise, distress {tilting, cracking, etc.) should be expected. 3. Design does not apply to infinity-edge pools/spas. TYPICAL POOL/SPA DETAIL Plate F-17 I I I I I I I I I I I I I. I I I I I I Flag .. , .. . .... SIDE VIEW Test pit TOP VIEW Spoil pile Flag Light Vehicle -----50 feet 50 feet·----- -------------'IOOfee,1------------- TEST PIT SAFETY DIAGRAM Plate F-20 .• i --------------------------------------------------------------------------------___ ... ~ _____ ----------- -----~--~-----------------GS/ LEGEND ------------ ---~----~------~=---------~--------~--------~----~-~----~-~--~---~= ---·---:·---~~ :::========== ---_____ ::::~-----~~::::::::=::::_::-------==::==~-=----·:::_:---==-~~:::: __ -_:_-~~=:2::::::_ ---==~~ -=---~---. ~~~:~~-==-==~:::::>---:::-..--. --------------~~~~~~~~~~~~~~~~~~3 ----::_:::::: ---=-------------~---------------------------=----------- Afu Qop ARnFJCIAL FILL -UNDOCUMENTED --------------------------~----- .__"' .... -.... -----__ ... j~_,. --------------------------------=::::-fr,; _., ~: .:·,.·,· .. .' j ·?:'..: ···.· ..::1 > ·. ·.-••... · ~. V1 . . . , • '-<-.-; ~··.········1·· ¥--.... .. .. . . . . .• . . ------,, I I 11 ;1 20'R ---- --~---, _,_ , • • r7 1~ I if?,86' " ~ 9,532 SF 108,00' (193) 9, 558 SF_,.,'Y ' ,"' 108,00 1 Qop Ts ., .,. --3··. --. 0 72,001 .,. ~ -- 4 .. .... ~ 9,504 ,SF ---.----r- 5 13,63~ .. SF -......._.:._ ~ (11, 655--SQ ------+---- • C) C) (iJ / ...;--- "' I'-" ,"' 72.00' 0 -7 ~n, 9,504 SF ' ., ' .,. .. -... ' , - .,. ~ .. .... ---~ ~~- . C) -C) 0 C) lD -~C'\J-+-~ r,,'P (Y) .-l ..._q -~ 0, :..·----.._o, " ,... "' -.·: ,: ,_ ',. ·::"'·'?.; - -. . . . ':~.. "'"· . -~-··-~ ... :Afu lo -~:·: .. '' .. : ;_ ' ; .. -.··· .. ,-: ,7.: "-- i (1 5 1 9, 9 4 ' 0 C) 10 ('\J .-< ---------~------------------·------------------------------------------·~-, QUA TERNARY OLD PARALIC DEPOSITS, CIRCLED WHERE BURIED 1,,, ! I "' <?" ... g :.( ...... ' .I!> ' 12,249 SF ~ I !: "'v f ~HA-2~ i 'cf , .. HA-1 ~-,.,, I / I 1 I I I ,. I .. L I \. ' < J II 1 I I ,_ ! I ' I [ ___ ~ l .. - •. ·:.:·--·~--. ·, ·.· Tsa -B-3 ... , .. TERnARY SANnAGO FORMA noN, CIRCLED WHERE BURIED APPROX/MA TE LOCA noN OF GEOLOGIC CONTACT TD=51 ?lz' .. APPROX/MA TE LOCATION OF HOLLOW STEM AUGER BORING WITH TOTAL DEPTH IN FEET X , I I"--. " c._) HA-4 'cf , .. TD=5' APPROX/MA TE LOCATION OF HAND~AUGER BORING WITH TOTAL DEPTH IN FEET . X'·. I APPROX/MA TE LOCA T/ON · OF GEOLOGIC CROSS SECTION • 3.1.J AC GROSS • R-1 (9,500} • MINIMUM LO.T SIZE; 9,500 sf • 60' MINIMUM LOT WIDTH -' . ' • SETBACKS; • FRONT: 20' • SID[: 10% OF W/0 TH • REAR: 2x SID£ YARD SEIBACK • PUBLIC ROAD: J4' GRAPHIC SCALE 2C O 10 20 40 80 ~liiiiiiiiiiiiill ~~I •••• l~~~~~~I I" = 20' • This document or efile is not a parl of the Construction Documents and should not be relied upon as being an accurate depiction of design. GEOTECHNICAL MAP Plate 1 w.o. 6637-A-SC DATE: 03/14 SCALE: 1" = 20' , ' I Proposed Street X B-3 (Projected N201' SE) 160 Static Factor-of-Safety = 1.5' Qco/ -·-Qop 150 (SM/SC) -;:, ~ ~ TD=IBY,, • • • § 140 Qop ~ • • • "' (SP/SW) GJ • • 1JO Region~ ~in~T . -40 Tsa 120 0 10 20 JO 40 50 . • 60 Proposed Lot 8 Proposed Lot 10 -·- -·- • • • • • • - . - . -40 70 80 90 100 110 120 DISTANCE: (FEET) Nso·E ' GS/ LEGEND Afu ARTIFlctALRLL -uNDocuMENTED Qco/ QUATERNARY COLLU\IIUM Qop -QUATERNARY OLD PARALIC DEPOSITS (SILTY SAND/ CLAYEY SAND MEMBER) (SM/SC) Qop -QUATERNARY OLD PARAL/C DEPOSITS (SAND MEMBER) (SP/SW). Tsa TERTIARY SANTIAGO FORMATION --APPROX/MA TE LOCATION OF GEOLOGIC CONTACT -·-·-4' BEDDING A IB1UDE, 1'117H APPARENT DIP IN DEGREES Proposed Lot 11 B-2 (Projected NJO' SE) Afu X' Qcol If. 160 Qcol -Qop -·- _. _ (SM/SC) 150 -;:, • • • ! Qop • • • 140 is (SP/SW) • • • "' ~ ~ - . - . -40 TD=51 Y,, 1JO Tsa 120 130 140 150 160 170 180 370.5 GRAPHIC SCALE 20 0 10 20 40 80 I -~~I I l~~~~~~I /" = 20' ALLLOCATIONSAREAPPROXIMATE This document or efi/e Is not a parl of the Construction Documents and should not be relied upon as being an accurate depiction of design. GEOLOGIC CROSS SECTION X-X' Plate2 · w.o. 6637-A-SC DATE: 03/14 SCALE: 1" = 20'