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HomeMy WebLinkAboutCT 13-03; ROBERTSON RANCH-RANCHO COSTERA; SUPPLEMENT TO THE UPDATED GEOTECHNICAL INVESTIGATION FOR RANCHO COSTERA; 2011-06-06S9 0 Geotechnical 'Geologic' Coastal 'Environmental 5741 Palmer Way • Carlsbad, California 92010 • (760) 438-3155 • FAX (760) 931-0915 June 6, 2011 W.O. 6145-Al-SC Shapeil Homes 8383 Wilshire Boulevard, Suite 700 Beverly Hills, California 90211 Attention: Mr. John Buller Subject: Supplement to the Updated Geotechnical Investigation for Rancho Costera (Formerly Robertson Ranch West Village), Carlsbad, San Diego County, California ear Mr. Buller: In accordance with your request, GeoSoils, Inc. (GSI) has prepared this supplement to the geotechnical investigation (GSI, 2010) for Rancho Costera. The purpose of our supplemental site work is to update the body of work presented in GSI (2010), and to further evaluate geotechnical recommendations. such as shrinkage/bulking, overexcavation, the current version of the proposed grading plan, slope stability, wick drain feasibility in Area PA-1, storm water infiltration rates, erosion in PA-23C, near PA-1 1 in the vicinity of the existing 5:1 (h:v) fill slope, a discussion of earthwork within PA-13, and to update our report with respect to current standards of geotechnical practice, including the 2010 California Building Code ([CBC], California Building Standards Commission [CBSC], 2010, from a geotechnical viewpoint. Unless specifically superceded in the text of this report the conclusions and recommendations presented in GSI (2010) remain valid and applicable. EXECUTIVE SUMMARY Based on our review of the available data (Appendix A), field exploration (Appendix B), and geologic and engineering analysis, the proposed construction appears to be feasible from a geotechnical viewpoint, provided the recommendations presented in the text of this report are properly incorporated into the design and construction of the project. The most significant elements of this study are summarized below: Site exploration was generally completed in order to provide additional information regarding earthwork balance (i.e., shrinkage and bulking), and bedrock structure with respect to slope stability of proposed cut slopes. Earth materials were evaluated with 19 supplemental test pit excavations, exposing existing fill (both agricultural and engineered), colluvium and underlying formational soils. Groundwater was not encountered within test pit excavations completed in preparation of this supplemental investigation. Our review indicates that regional groundwater should not significantly affect site development provided that the recommendations presented in GSI (2010) are implemented. However, deeper utilities in areas of higher groundwater within PA-1 may require dewatering to place the pipes. In general, based on a review of the data obtained to date, groundwater in the general vicinity of Planning area PA-1 may be anticipated to occur at elevations on the order of 42 to 45 feet Mean Sea Level (MSL), or approximately 7 to 10 feet below existing surface grades. In the general vicinity of the "land bridge" between Planning Areas PA-8 and PA-1 0, groundwater may be anticipated to occur at elevations on the order of 36 to 40 feet MSL, or approximately 16 to 20 feet below existing surface grades. Perched groundwater conditions, along zones of contrasting permeabilities, discontinuities, or fill lifts, may not be precluded from occurring in the future due to site irrigation, poor drainage conditions, or damaged utilities. Perched groundwater should be anticipated to occur after development, and may require additional mitigation when it manifests itself. It is our understanding that the controlling authorities are requiring onsite Best Management Practices (BMP's) to clarify and filter onsite storm water run-off within the project to comply with code. Currently, it is unknown what type of BMP will be utilized for the project (i.e., bio-swales, detention/infiltration basins, sand filters, etc.), however; detention/infiltration basin BMP's are generally utilized for residential developments to clarify and filter onsite storm water during rain events. Three (3) infiltration tests were conducted to generally evaluate site soils with respect to anticipated BMP's onsite. One (i) infiltration test was conducted within previously compacted fill materials onsite (depth of approximately ±3 feet) to generally characterize fill soils, and two (2) infiltration tests were conducted within fàrmational soils, to generally characterize "cut" materials. A discussion of the test data are presented in a later section of this report. Our analysis of planned cut slopes, both in-tract, and along El Camino Real, indicates that these slopes are grossly stable (i.e., static and seismic factor-of-safety [FOS] >1.5 and 1. 1, respectively). Graded slopes are generally anticipated to be stable, assuming proper construction, maintenance, and normal climatic conditions. However, owing to the potential for seepage to develop at the face of both plan cut slopes, and fill over cut slopes, stabilization fills are recommended for all such slopes, unless otherwise noted herein. Perched groundwater conditions, not observed in GSl's current and past subsurface studies in these areas (Appendix A) was incorporated into the slope stability evaluation to account for potential for this condition to develop after the residential/commercial buildings are completed. Stabilization fill slope drains and toe drains (cut slopes) are recommended. The Shapell Homes W.O. 6145-Al-SC FiIe:e:\wp9\6100\6145a1.stt Page Two GeoSoils, Inc. approximate location of stabilization fills, drains, and toe drains are shown on Plate 3. Earthwork balance (shrinkage and bulking) was further evaluated in this supplemental investigation. The results of this analysis are presented in a later section of this report. Owing to the potential for non-uniform soil conditions (i.e., sand and clay), inclined bedding, and the potential for perched water, overexcavation of transition lots (i.e., cut/fill lots) and all cut lots is recommended. The depth of the overexcavation is minimally recommended at 3 to 4 feet (sloped to street). The maximum to minimum (ratio) fill thickness within the limits of the proposed buildings is recommended to be 3 to 1. Based on the current, preliminary grading plan prepared by O'Day Consultants ([ODC] 2011 a), a preliminary assessment of subdrain, toe drain, fill slope keyways, and stability fill slopes was provided. The results of this assessment are shown on the "Schematic Grading Exhibit" included in this report as Plate 3. It should be noted that this exhibit does not indicate terrace drains, as required per code. This should be reviewed by the project civil engineer (GSI, 2011 b). In the vicinity of planned residential development within PA-1, existing alluvial soils are anticipated to be on the order of up to 10 feet in thickness (GSI, 2008b). With groundwater likely present at depths as shallow as 3 feet below the surface, up to approximately 7 feet of alluvial soils may be left in place. Given this relatively shallow thickness of potentially left in place alluvium, and planned fill thicknesses on the order of 3 to 5 feet, wick drains are not considered effective, from a geotechnical viewpoint. Graded removals and stabilization of the removal bottom (rock blankets, geotextiles, etc.) is recommended in this area. Re-use of the existing remediated soils is acceptable from a geotechnical standpoint, not withstanding the recommendations herein. PA-1 3 is currently sheet graded, transition (cut/fill) pad (GSI, 2008b). The western portion of the pad consists of engineered fill overlying up to 45 feet of alluvial soil left in place, while the eastern, cut portion exposes Quaternary-age terrace deposits consisting of highly expansive clays. A discussion of alluvial settlement potential, transition mitigation, and expansive soil conditions is presented in a later section of this report. Erosion within the habitat slope located within the eastern portion of PA-1 1 was evaluated to generally be the results of sparse vegetative cover, and the presence of surface obstructions, such as fiber rolls, and/or other surface irregularities, etc., that tend to concentrate surface flow on the slope. A detailed discussion, including mitigative recommendations are presented in a later section of this report and in GSI (2011 c). Shapell Homes W.O. 6145-Al-SC Fi1e:e:\wp9\6100\6145a1.stt Page Three GeoSoils, Inc. ~ -14 Andrew T. Guatelli Geotechnical Engineer, GE 2320 Foundation systems may be designed and constructed in accordance with GSI (2010), and the current edition of the CBC (CBSC, 2010). Please note that GSI (2010) referenced the 2007 Code; however, while some sections numbers have changed from the 2007 Code to the 2010 CBC (CBSC, 2010), the geotechnical design parameters are considered the same from a geotechnical standpoint, unless specifically superceded herein. However, the application of those same parameters may change the resultant design by others, based on the current code. The application of a higher probabilistic horizontal acceleration (PHSA) of 2 percent in 50 years should now be considered in the design of improvements onsite. The revised PHSA has previously been provided (GSI, 2010). Recommendations for conventional, segmental, and top of slope walls/fences are presented in GSI (2010) and are considered valid unless specifically superceded in the text of this report. Recommendations for additional wall/shoring systems are provided in the following sections with respect to site conditions that may be more suited to shoring wall, and/or soil nail wall design, especially in the vicinity of the planned ingress/egress points at Glasgow and Edinburgh Streets, along the north side of the project. The geotechnical design parameters provided herein should be considered during construction by the project structural engineer and/or architect. The opportunity to be of service is greatly appreciated. If you have any questions concerning this report or if we may be of further assistance, please do not hesitate to contact our office. Respectfully submi GeoSoils, Inc. cc No. 1934 ( ( Certified I \ Engineering / ,000e~ Geologist Robert G. crisman\ OF c::oi Engineering Geologist, Paul L. McClay Vice President, RGC/ATG/PMC/Jh /14 0AL o.1117 —I Certified - 1 17ireering Geologist 1- \!OF cP...Z Distribution: (3) Addressee (CD also) Planning Systems, Attention: Paul Klukas O'Day Consultants, Attention: George O'Day (2 wet signed, CD also) Shapell Homes W.O. 6145-Al-SC File:e:\wp9\6100\6145a1.stt Page Four GeoSoils, Inc. TABLE OF CONTENTS SCOPE OF SERVICES ...................................................1 PROPOSED DEVELOPMENT ..............................................2 PREVIOUS WORK .......................................................2 SITE EXPLORATION .....................................................4 SITE EARTH MATERIALS .................................................4 GROUNDWATER ..........................................................5 LABORATORY TESTING ...................................................5 General..........................................................5 Classification ......................................................6 Field Moisture and Density ...........................................6 Laboratory Standard - Maximum Dry Density ............................6 Direct Shear Tests .................................................7 SLOPE STABILITY ANALYSES .............................................7 General..........................................................7 Gross Stability .....................................................7 Surficial Stability ..............................................8 Planned Fill Over Cut Slopes ..9 INFILTRATION TESTING ..................................................9 General..........................................................g Double-Ring Infiltration Test Procedure ...............................10 Conclusions and Recommendations-Infiltration .........................11 PRELIMINARY CONCLUSIONS AND RECOMMENDATIONS ....................12 General.........................................................12 ADDITIONAL RECOMMENDATIONS-EARTHWORK CONSTRUCTION ............13 General..........................................................13 Geotechnical Grading Exhibit .......................................13 Earthwork Balance (Shrinkage/Bulking) ...............................13 Slope Considerations and Slope Design ..............................17 Graded Slopes .............................................17 CutSlopes .................................................17 Planned Fill Over Cut Slopes ..................................17 Stabilization Fill Slopes .......................................18 Subdrains.......................................................18 GeoSoils, Inc. Toe Drains 18 Wick Drains (PA-1) . 18 SUPPLEMENTAL RECOMMENDATIONS REGARDING PA-13 ....................18 As-Built Conditions ................................................19 Proposed Additional Grading .........................................19 Post-Grading Settlement of Alluvium ..................................20 Preliminary Earthwork Recommendations, PA-1 3 ........................20 Preliminary Foundation Design ......................................21 SLOPE EROSION WITH A PORTION OFPA-11 21 Background .....................................................21 Observation Summary .............................................21 Conclusions and Recommendations (PA-1 1) ...........................22 RECOMMENDATIONS - FOUNDATIONS ....................................23 RETAINING WALLS ......................................................23 General..........................................................23 Earthquake Loads (Seismic Surcharge) ...............................23 TEMPORARY/PERMANENT SHORING SYSTEMS ............................24 Lateral Pressure ..................................................27 Tiebacks and Lateral Pier Loads .....................................28 Open Excavations ................................................28 Excavation Observation (All Excavations) ..............................28 Observation......................................................29 Monitoring Existing, Offsite Improvements .............................29 SOIL NAIL WALLS ......................................................29 General.........................................................29 Preliminary Design and Construction .................................30 Anchor (Bonded) Zone, (Qt) Terrace Deposits, or (Tsa) Santiago Formation 30 OTHER DESIGN PROFESSIONALS/CONSULTANTS ..........................30 PLANREVIEW .........................................................31 LIMITATIONS..........................................................31 FIGURES: Figure 1 - Site Location Map .........................................2 Figure 2a - Lateral Earth Pressures for Temporary Shoring Systems ........25 Figure 2b - Lateral Earth Pressures for Permanent Shoring Systems ........26 Shapell Homes - Table of Contents Fi1e:e:\wp9\6100\6145a1.att Page ii ATTACHMENTS: Appendix A - References ...................................Rear of Text Appendix B - Boring Logs ..................................Rear of Text Appendix C - Laboratory Data ...............................Rear of Text Appendix 0 - Slope Stability and Engineering Analysis ...........Rear of Text Appendix E - Infiltration Test Data ............................Rear àf Text Appendix F - General Earthwork and Grading Guidelines .........Rear of Text Plate 1 - Geotechnical Map .........................Rear of Text in Folder Plate 2 - Geologic Cross Sections E-E,' F-F,' H-H,' IT, J-J', K-K............... ..........................................Rear of Text in Folder Plate 3 - Schematic Grading Exhibit ..................Rear of Text in Folder Shapell Homes Table of Contents Fi1e:e:\wp9\6100\6145a1.att Page iii GeoSoils, Inc. SUPPLEMENT TO THE UPDATED GEOTECHNICAL INVESTIGATION FOR RANCHO COSTERA (FORMERLY ROBERTSON RANCH WEST VILLAGE) CARLSBAD, SAN DIEGO COUNTY, CALIFORNIA SCOPE OF SERVICES The scope of our services has included the following: Review of available soils and geologic data (Appendix A), including the findings, conclusions and recommendations presented in previous geotechnical reports for the site and vicinity (GSl; 2011 a, 2011 b, 2011 c, 2010, 2008a, 2008b, 2004a, 2002, 2001 a, and 2001b); Geologic reconnaissance and field mapping. Subsurface exploration consisting of 19 exploratory test pits completed with a rubber tire backhoe was performed for this supplemental evaluation (see Appendix B). Laboratory testing of representative soil samples collected during our supplemental subsurface exploration program, and/or used in our slope stability analysis from the body of existing site work completed by this office (text and Appendix C). Slope stability and engineering analysis (Appendix D). Infiltration testing on representative samples of existing fill and formational soil (Appendix E). Additional evaluation of earthwork shrinkage/bulking, subdrainsjTh keys, undercuts, etc. A review of wick drain feasibility within PA-1. Additional retaining wall design/construction evaluations. A discussion of as-built, and planned construction within Planning Area 13, including settlement, expansive soils, and foundation design.- An evaluation of surficial erosion within an existing, graded portion of PA-1 1. Engineering and geologic analysis of data collected and preparation of this appropriately illustrated geotechnical report. GeoSoits, Inc. PROPOSED DEVELOPMENT Rancho Costera (formerly Robertson Ranch West Village) is a planned residential community consisting of several "Planning Areas" (see Figure 1, Site Location Map). These planning areas are anticipated to consist of single family residential (Planning Areas [PA] PA-3, PA-5, PA-6, PA-9, and PA-1 0), multi-family residential (PA-1, PA-7, and PA-B), and non-residential RV storage (PA-2), park site (PA-4), and open space (PA-23A/23B). PA-il is a planned commercial area and has been partially graded (GSI, 2008a). PA-13 is planned for future residential development and is presently sheet graded, with geotechnical observation and testing services provided by GSI (2008b). The distribution of Planning Areas and preliminary grading (limits, cut/fill, etc.) are shown on Plate 1 (Geotechnical Map), and Plate 3 (Schematic Grading Exhibit). Plates 1 and 3 have been adapted from the 100-scale topographic plan, prepared by O'Day Consultants ([ODC] 2011 a), as a base. Based on a review of the 100-scale "Preliminary Grading Plan" (ODC, 2011a), it appears that proposed earthwork construction will consist of modifying the existing grades to achieve plan grades for single family residential building lots, sheet-graded pads, and associated roadways. The sheet-graded pads will likely be re-graded at a later date to accommodate multi-family residential, commercial, recreational development, and single family residential development within PA-1 3, as well as open space areas. Typical cut and fill grading techniques are anticipated in order to achieve the design grades shown on Plate 1 with maximum planned cut and fill thicknesses on the order of 34 feet (PA-3), and 54 to 56 feet (PA-b, PA-3), respectively. It appears that grade differentials will be accommodated by the construction of engineered cut and fill slopes, with maximum heights on the order of 42 and 52 feet, respectively. Furthermore, along the north side of El Camino Real right-of-way, cut slopes, and fill over cut slopes to approximately 90 feet in height are also planned adjacent to the project. ODC (2011 a, and Plate 1) indicates that the gradients of engineered slopes will be 2:1 (h :v) or flatter, however, the required terrace drains are not shown at this time. GSI anticipates that proposed single- and multi-family residential structures will consist of wood frames with concrete slab-on-grade floors. Specific building loads are currently unknown but are assumed to be typically light for this type of mixed-use development. Sewage disposal is anticipated to be tied into the City of Carlsbad municipal system. The need for import soils is currently unknown. PREVIOUS WORK The findings presented in this report are based on work completed in preparation of this supplemental report and previous work performed by this office for the Robertson Ranch project (GSI; 2010, 201la). The GSI report for the current project (GSI, 2010), summarized and updated several previous reports (GSI; 2004a, 2002,2001 b), regarding the proposed development of the Rancho Costera Project (formerly Robertson Ranch West Village), Shapell Homes W.O. 6145-Al-SC Rancho Costera, Carlsbad June 6, 2011 FiIe:e:\wp9\6100\6145a1.stt Page 2 GeoSoils, Inc. IT E <4 i c", fl 8 "N Iv -.7 Golf 04if 1 ,t 0 lOGO 2000 300C 4000 q. J l!4111.& .y Base Map: TOPO!® c2003 National Geographic, U.S.G.S San Luis Rey Quadrangle, California San Diego Co., 7.5 Minute, dated 1997, current 1999. SITE c4 OV '\ ; , ' I . .. ' 4W47 (AA WO Lou q VIA ..' 4000 Base Map. The Thomas Guide, San Diego Co., Street Guide and Directory. 2005 Edition, by Thomas Bros Maps, pages 1106 and 1107. Reproduced with oemiission granted by Thomas Bros. Maps This map is copyrighted by Thomas Bros, Maps it is unlawful to copy or reproduce all or any pan thereof, whether for personal use or rssate without permission. All nghts reserved. w.o. GeosoilS, Iflc. 6145-Al-SC A OTIONCA MAPSITE L NJ Figure 1 while GSI (2011 a) provided an evaluation of improvements along the north side of El Camino Real, adjacent to the southern boundary of Rancho Costera. This supplemental report should be used in conjunction with GSI (2010 and 2011 a) for any subsequent review and/or geotechnical discussion of this project. PA-1 1 is a planned commercial area and has been partially graded (GSI, 2008a). PA-1 2/13 is designated as a community use site (park, school, etc.) and has also been sheet graded, with geotechnical observation and testing services provided by GSI (2008b). The remaining areas of the project are either currently under cultivation, or consist of natural open space. SITE EXPLORATION Surface observations and subsurface explorations were performed by GSI on April 13, 14, and 15, 2011, by a representative of this office. A survey of line and grade for the subject site was not conducted by this firm at the time of our site reconnaissance. Near-surface soil and geologic conditions were explored with 19 exploratory test pits with a rubber tire backhoe. The approximate locations of the exploratory test pits for this study are shown on the attached Geotechnical Map (see Plate 1). Previous GSI test pits and borings are included on Plate 1 for convenience. SITE EARTH MATERIALS Earth materials evaluated for this supplemental investigation are generally consistent with those evaluated and discussed in GSI (2008a, 2008b, and 2010). Earth materials encountered during this supplemental investigation consisted of surficial deposits of agricultural fill (i.e., reprocessed colluvium), engineered fill, colluvium, and underlying deposits of Eocene-age sedimentary bedrock (Santiago Formation). Quaternary-age terrace deposits also occur on the project, but were not encountered during this evaluation, nor were volcanic and/or granitic rocks previously identified in GSI (2010). A detailed discussion of these earth materials are presented in GSI (2008a, 2008b, and 2010). Preliminary recommendations for site preparation and treatment of the earth materials encountered, are presented in GSI (2010, 2011a), and as discussed in the "Earthwork Recommendations" section of this report. The general distribution of earth materials are shown on Plates 1 and 3. Geologic cross sections, showing the spatial relationships of onsite soils/bedrock, are presented herein on Plate 2. Based on a review of GSI (2010), bedding structure observed within the Pleistocene terrace deposits display generally massive to thickly bedded sediments, and poorly developed sub-horizontal orientation. Within the Santiago Formation, bedding varies from thin to thickly bedded, with a general, regional trend of northerly to northeasterly, and westerly to northwesterly with slight inclinations, ranging from near horizontal to about 8 to 9 degrees. Cross bedding within the Santiago Formation was generally thickly bedded, Shapell Homes W.O. 6145-Al-SC Rancho Costera, Carlsbad June 6, 2011 FiIe:e:\wp9\6100\6145a1.stt Page 4 GeoSoils, Inc. and was observed locally, trending northerly to northeasterly, with westerly to northwesterly slight to moderate inclinations, on the order of 10 to 28 degrees, and localized cross beds inclined 2 degrees southeasterly. Jointing within the Santiago Formation was typically highly inclined (65 to 89 degrees), predominately trending north to northwest, and to a lesser extent highly inclined to the northeast. Apparent dips of regional bedding relative to the planned cut slopes were evaluated in this supplemental investigation, and in GSI (2010), and have been considered in our slope stability analysis. Undifferentiated igneous bedrock (Map Symbol - Jsp/Kgr) occurs near the existing ground surface, south of Planning Area 10, within a designated open space area. The type of bedrock generally occurs below approximate elevation of 90 feet MSL, with outcrops generally ascending in elevation offsite to the east, within the adjacent Robertson Ranch East Village. Based on the distribution of earth materials, and an evaluation of topography within Rancho Costera, it is estimated that igneous rock does not occur closer than 60 to 70 feet to planned surface grades within PA 9, and no closer than approximately 20 to 50 feet to planned surface grades in the vicinity of Planning Area 10. An evaluation of rock hardness is presented in GSI (2010) and GSI, 2004a). Supplemental field studies, consisting of seismic refraction surveys, could be used to further constrain this depth. GROUNDWATER Groundwater was not encountered in any of the test pit excavations completed in preparation of this report. However, deeper utilities in areas of higher groundwater within PA-1 may require dewatering to place the pipes. In general, based on a review of the data obtained to date, groundwater in the general vicinity of Planning Area PA-1 may be anticipated to occur at elevations on the order of 42 to 45 feet Mean Sea Level (MSL), or approximately 7 to 10 feet below existing surface grades. In the general vicinity of the "land bridge" between Planning Areas PA-8 and PA-1 0, groundwater may be anticipated to occur at elevations on the order of 36 to 40 feet MSL, or approximately 16 to 20 feet below existing surface grades. Groundwater levels may fluctuate due to seasonal variations in rainfall and temperature. A summary discussion of groundwater occurrence and treatment is presented in GSI (2010). Discussion of groundwater influence on slope stability is included in the slope stability section of this report. LABORATORY TESTING General Laboratory tests were performed on representative samples of the onsite earth materials collected for the present geotechnical investigation, in order to evaluate their physical characteristics and engineering properties with respect to anticipated site development. The test procedures used and subsequent results are presented below. Previous testing Shapell Homes W.O. 6145-Al-SC Rancho Costera, Carlsbad June 6, 2011 F1e:e:\wp9\61006145a1 .stt Page 5 GeoSoils, Inc. performed in preparation of GSI (2008b, 2010, 2011 a) was reviewed and utilized in our supplemental slope stability and settlement analyses. Results used in this supplemental investigation are presented in Appendix C. Classification Soils were classified visually according to the Unified Soils Classification System. The soil classification of onsite soils is provided in the Test Pit Logs in Appendix B. Field Moisture and Density Field moisture content and dry unit weight were determined for relatively "undisturbed" samples of earth materials obtained from GSl's exploratory excavations. The dry unit weight was evaluated in general accordance with ASTM 02937, in pounds per cubic foot (pcf), and the field moisture content was evaluated as a percentage of the dry weight. Water contents were measured in general accordance with ASTM D 2216. Results of these tests are summarized on the Test Pit Logs (see Appendix B), and in the "Earthwork Balance" section of this report. Laboratory Standard - Maximum Dry Density To evaluate the compaction characteristics of representative samples of onsite soil, laboratory testing was performed in accordance with ASTM Test Method D 1557. Test results are presented in the following table: :'• ,LOCATiON OTUMUM MOlSTU- SOI DENJ :A TP-201 @ 0-3' Gray, Silty Sand 118.0 11.5 TP-203 @ 0-3' Gray, Sandy Clay 117.0 13.5 TP-206 @ 0-4' Gray, Clay w/Sand 104.5 23.5 TP-208 @ 0-3' Gray Brown, Silty Sand 125.0 12.0 TP-209 @ 0-3 Light Gray, Silty Sand 116.0 12.5 TP-212 @ 0-2' Gray Brown, Sandy Clay 114.0 15.0 TP-213 © 0-3' Yellowish Brown, Silty Sand 120.0 . 13.0 TP-216 © 0-4' Brown, Silty Clay 107.0 21.0 TP-21 7 © 0-5' Brown, Sandy Silt w/Clay 118.0 13.5 Shapell Homes W.O. 6145-Al-SC Rancho Costera, Carlsbad June 6, 2011 FiIe:e:\wp9\6100\6145a1.stt Page 6 GeoSoils, Inc. Direct Shear Tests Shear testing performed in preparation of GSI (2010, 2011 a) was reviewed and utilized in our supplemental slope stability analysis. Results used in this supplemental investigation are presented in Appendix C. SLOPE STABILITY ANALYSES General GSI performed a slope stability evaluation utilizing the geologic conditions, observed in the subsurface explorations completed in preparation of this study, and in GSI (2010, 2011a), for planned cut slopes within the project. Laboratory test data obtained in preparation of GSI (2010, and 2011 a) was also utilized in our analysis. Analyses have been performed utilizing the two-dimensional slope stability computer program 'GSTABL7 v.2.004" (see Appendix D). The program calculates the factor-of-safety (FOS) for specified surfaces or searches for the block, or irregular slip surface having the minimum FOS using the Janbu (non-circular block) method. Additional information regrading the methodology utilized in this program is included in Appendix D. Shear strength parameters used are provided in Appendix D. Representative cross sections (Sections E-E,' F-F,' H-H,' I-I', J-J') were prepared for analysis (see Plate 2) for this supplemental study. Previous analysis of Cross Sections A-A' through D-D' were provided in GSI (2010). Our analysis utilized data from the current, and previous studies (GSI; 2011a, 2010, 2004a, 2004b, 2002), with respect to the anticipated site grading as shown on Plate 1. The approximate locations of all sections are shown on Plate 1. Gross Stability Slopes reviewed for this study were cut into natural ground. No keyways or benches were included in our evaluation unless the cut was less than the required FOS. Fill over cut slopes will require keyways and mid-slope benches will be included in the final design, which should improve gross stability. Groundwater was evaluated based on anticipated future levels. The development will likely not raise the regional water significantly. Rather, perched groundwater will be on the less permeable layers as depicted in our analyses (Appendix D). Based on the available data, including a review of GSI (2010 and 2011a), it appears that graded fill slopes will be generally stable assuming proper construction and maintenance. Cut slopes, constructed in terrace deposits and earth materials belonging to the Santiago Formation, are anticipated to be generally stable assuming proper construction and maintenance. ShapeD Homes W.O. 6145-Al-SC Rancho Costera, Carlsbad June 6, 2011 FiIe:e:\wp9\6100\6145a1 .stt Page 7 GeoSoils, Inc. In order to assess the long-term gross slope stability of the planned cut slopes, five (5) geologic cross-sections (E-E,' F-F,' H-H', I-I', J-J') were prepared (see Plate 2). Sections E-E', F-F' and H-H' were evaluated in preparation of GSI (2011a), with the remaining Sections I-I' and J-J' evaluated herein. The purpose of the cross-sections was to analyze the relationship of the planned, preliminary graded configurations shown on Plate 1, and the geologic conditions observed at the surface, and at depth. The stability of the planned cut slope and fill over cut slope configurations along the southern edge of the project was evaluated (GSI, 2011a). These slopes vary up to approximately 90 feet in height and achieve maximum slope gradients of 2:1 (h:v). Based on a review of GSI (2011 a), and our current analysis (Appendix D), using the available soil parameters, the slopes appear to be stable, possessing an adequate FOS (greater than 1.5 static and 1.1 seismic). The results of our slope stability analysis performed in preparation of GSI (2011 a) has been included as Appendix D. Two in-tract cut slopes were also evaluated (Sections I-I' and J-J', this study). These slopes vary up to approximately 42 feet in height and achieve maximum slope gradients of 2:1 (h:v). Based on our current analysis (GSI, 2011a; and Appendix 0), using the available soil parameters, the slopes appear to be stable, possessing an adequate FOS (greater than 1.5 static and 1.1 seismic). The results of our slope stability analysis performed in preparation of this report is included as Appendix D. All cut slope construction will require observation during grading in order to evaluate the findings and conclusions presented herein and in subsequent reports. Our analysis assumes that graded slopes are designed and constructed in accordance with guidelines provided by the City, the 2010 CBC (CBSC, 2010), the 2009 "Greenbook," and recommendations provided by this office. These slopes are generally anticipated to be stable, assuming proper construction, maintenance, and normal climatic conditions. Temporary backcuts for construction slopes and keyways, are anticipated to be 1.5:1 (horizontal:vertical [h:v]) or flatter, and are anticipated to have a static FOS of .1.2. Should perched groundwater or other unexpected conditions be exposed during excavation, the project geotechnical consultant should review the conditions and revise recommendations as needed. Fill slopes are also planned up to heights on the order of 50 to 60 feet (in the fill-over-cut slope), at gradients of 2:1 (h:v), or flatter, and are considered grossly stable (i.e., FOS >1.5). Graded fill slopes are generally anticipated to be stable, assuming proper construction, maintenance, and normal climatic conditions. Surficial Stability An analysis of surficial stability was performed for graded slopes constructed of compacted fills and/or formational soil (see Appendix D). Our analysis indicates that proposed slopes Shapell Homes W.O. 6145-Al-SC Rancho Costera, Carlsbad June 6, 2011 FiIe:e:\wp9\6100\6145a1.stt Page 8 GcoSoils, Inc. exhibit an adequate FOS (i.e., >1 .5) against surficial failure, provided that the slopes are properly constructed and maintained, under normal rainfall. Terrace deposits and Santiago Formation bedrock contain granular, sandy soil. If sandy soils with a cohesion of less than 200 psf are used on slope faces derived from these deposits, the slopes may have surficial stability/erosion issues and perhaps a FOS against surficial instability of less than 1.5. Planting and management of surficial drainage is imperative to the surficial performance of slopes. Typically, similar to coastal bluff retreat, a surficial erosion rate (average) of about 11/4 inches/year for natural and unprotected sandy slopes may be assumed. Foot traffic and other activities that exacerbate surficial erosion should not be allowed to occur on slopes. Failure to adhere to these conditions may drastically increase and localize surficial erosion, requiring mitigation, so that headward erosion does not result, and impact roadways, pads, and other improvements. Planned Fill Over Cut Slopes Fill over cut slopes shown on Plates 1 and 3 are generally considered to be grossly stable. However, the cut/fill transition that daylights at the slope face represents a permeability contrast that will accumulate water (i.e., perched groundwater), resulting in seepage at the slope face. Such seepage will saturate near surface soils, resulting in loss of soil strength and an increased potential for surficial slope failure(s). In order to mitigate this condition, as well as the potential for perched groundwater up-gradient, fill over cut slopes should be reconstructed as a stabilization fill slopes. In the case of the larger fill (up to approximately 45 feet) over cut slope above El Camino Real (see Plate 2, Cross Section F-F') the fill key may be provided with a subdrain/backdrain as recommended in Appendix F. As stated previously, the backcut was considered stable for Cross Section F-F' due the anticipated 2:1 inclination (Plate 2). Furthermore, the face cuts and backcuts up to 1.5:1 (h:v) are considered stable (FOS >1.2) INFILTRATION TESTING General It is our understanding that the controlling authorities are requiring onsite Best Management Practices (BMP's) to clarify and filter onsite storm water run-off within the project. Currently, it is unknown what type of BMP will be utilized for the project (i.e., bio-swales, detention/infiltration basins, sand filters, etc.), however; detention/infiltration basin BMP's are generally utilized for residential developments to clarify and filter onsite storm water during rain events. Three (3) infiltration tests were conducted to evaluate site soils with respect to anticipated BMP's onsite. One (1) infiltration test was conducted within previously compacted fill materials onsite (depth of approximately ±3 feet) and two (2) infiltration tests were Shapell Homes W.O. 6145-Al-SC Rancho Costera, Carlsbad June 6, 2011 Fi1e:e:\wp9\6100\6145a1.stt Page 9 GeoSoils, Inc. conducted within the bedrock materials onsite (depth of approximately ±3 feet). Infiltration testing was performed to evaluate potential site conditions with respect to the anticipated detention/infiltration systems and/or other BMP's to retain and filter onsite storm water. Infiltration testing was performed in general conformance with the American Society for Testing and Materials (ASTM) designation D 3385 guidelines, by an engineering geologist from our firm. The field infiltration test data is provided in Appendix E. Procedures for testing are outlined briefly below: Double-Ring Infiltration Test Procedure An approximate area of 4 feet by 4 feet was cleared and excavated to a depth of approximately ±3 feet to evaluate the onsite compacted fill and bedrock materials, and a level surface prepared. The outer (annular) ring of the double-ring infiltrometer test apparatus was driven into the exposed earth materials, approximately ±2 to ±3 inches in depth, utilizing a wooden block and heavy sledge hammer. The inner ring of the double-ring infiltrometer test apparatus was also driven into the exposed earth materials, approximately ±2t0 ±3 inches in depth, utilizing the same block and sledge hammer technique. Both rings were leveled prior to infiltration testing. Measurement depth gages were installed in both the inner and outer ring, and water poured into both rings to same depth within each ring. The graduated mariotte tubes were connected to both the inner and outer rings and filled with clear water for the infiltration testing. After equalization of the inner and outer rings, a periodic flow was started from the graduated mariotte tubes. When the fluid level became constant within the inner and outer rings, measurements from the graduated mariotte tubes, to the nearest millimeter began. Testing: Both ground and water temperatures were recorded during testing. The volume of liquid utilized was measured from the graduated mariotte tubes at intervals of 30 minutes based on the infiltration rate achieved. Due to the relatively low infiltration rates obtained during testing within the artificial fill and bedrock materials, the testing was suspended after 2 hours at each location. Locations: The locations of the infiltrometer tests were chosen to give a general representation of the anticipated infiltration rate of the Shapell Homes W.O. 6145-Al-SC Rancho Costera, Carlsbad June 6, 2011 FiIe:e:\wp9\6100\6145a1.stt Page 10 GeoSoils, Inc. onsite earth materials in relation the anticipated detention/infiltration systems and/or other BMP's selected by design engineer. The approximate locations of the infiltration tests conducted are provided on the enclosed Plate 1. Accuracy: All measurements within the inner and outer ring were read to the nearest 1/16 inch. All test measurements within the graduated mariotte tubes were read to the nearest millimeter. Test Results: The calculated rates from the double-ring infiltration testing performed during this study are 0.18,0.16, and 0.06 inch/hour for Infiltration Test IT-1, 11-2, and IT-3, respectively. The relatively low infiltration rates obtained are likely due to clay content of the artificial fill (IT-1) and the relative density and indurated nature of the bedrock materials (11-2 and 11-3) onsite. As indicated previously, the field test data is provided in Appendix E. Conclusions and Recommendations-Infiltration As indicated above, the calculated infiltration rate of 0.18 inch/hour for the artificial fill and between 0.16 and 0.06 inch/hour for the bedrock materials, obtained at a depth of approximately ±3 feet, may be utilized for design of the proposed detention systems. In addition to the above, an appropriate factor of safety, per the controlling authorities requirements, should also be incorporated into the design calculations. The following comments and/or recommendations should also be considered during design (structural and civil) and implementation of the proposed detention/infiltration and/or other BMP systems onsite: As with any BMP detention/infiltration device, localized ponding and groundwater seepage should be anticipated. Similarly, as with any BMP detention/infiltration device, proper maintenance and care 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/infiltration systems will increase. Provisions for the maintenance of any siltation, debris, and/or overgrown vegetation (i.e., root systems) should be considered. An appropriate inspection and maintenance schedule will need to adopted and provided to all interested/affected parties. Shapell Homes W.O. 6145-Al-SC Rancho Costera, Carlsbad June 6, 2011 FiIe:e:\wp9\6100\6145a1.stt Page 11 GeoSoils, Inc. Any proposed utility backfill materials located within the proposed area of the BMP 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 proposed near the detention/infiltration systems, cut-off walls or other water barriers will likely need to be installed to mitigate the potential for piping and excess water entering the utility backfill materials. Any proposed footings and/or foundations should maintain a minimum of 1:1 horizontal to vertical (h:v) distance from the base of the footing and/or foundation to any adjacent detention/infiltration system. If a 1:1 (h:v) distance cannot be maintained, a deepened footing and/or foundation will be required. The landscape architect should be notified of the location of the proposed detention/infiltration system(s). If landscaping is proposed over the detention/infiltration system, 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). The potential for surface flooding, in the case of detention/infiltration system blockage, should be evaluated by the design engineer. As the infiltration testing conducted for this study is specific to the anticipated nature of the artificial fill and bedrock materials encountered onsite, any changes to the design of the BMP's and/or estimated size or depth of the system, should be reviewed by this office. Depending upon the nature of any changes, proposed depth of the systems, and the requirements of the reviewing entity, additional infiltration testing may be warranted. Final grading and improvement plans, as well as structural foundation plans, should be submitted to this office for review and comment, as they become available, to minimize any misunderstandings between the preliminary recommendations presented herein. If project designs are found to differ substantially from those stated herein, appropriate recommendations would be offered at that time. PRELIMINARY CONCLUSIONS AND RECOMMENDATIONS General The additional recommendations presented herein consider the additional information and findings obtained during this supplemental evaluation and the conclusions and recommendations presented in GSI (2010). Unless specifically superceded in the test of this report, the conclusions and recommendations presented in GSI (2010) remain valid and applicable. This report should be utilized on conjunction with GSI (2010) when Shapell Homes W.O. 6145-Al-SC Rancho Costera, Carlsbad June 6, 2011 FiIe:e:\wp9\6100\6145a1.stt Page 12 GeoSoils, Inc. reviewing the geotechnical aspects of site development for this project. In the event that any significant changes are made to proposed site development, the conclusions and recommendations contained in this report shall not be considered valid unless the changes are reviewed and the recommendations of this report verified or modified in writing by this office. Foundation design parameters are considered preliminary until the foundation design, layout, and structural loads are provided to this office for review. ADDITIONAL RECOMMENDATIONS-EARTHWORK CONSTRUCTION General All earthwork should conform to the guidelines presented in the 2010 CBC, the 2009 "Green book," the City of Carlsbad, and as recommended herein as Appendix F (this report), except where specifically superceded in the text of this report. When code references or guidance documents are not equivalent, the more stringent code should be followed. During earthwork construction, all site preparation and the general grading procedures of the contractor should be observed and the fill selectively tested by a representative (s) of GSI. If unusual or unexpected conditions are exposed in the field, they should be reviewed by this office and, if warranted, modified and/or additional recommendations will be offered. All applicable requirements of local and national construction and general industry safety orders, the Occupational Safety and Health Act, and the Construction Safety Act should be met. Geotechnical Grading Exhibit A schematic exhibit indicating the approximate location of subdrains, fill slope keyways, limits of removals, and plan cut/fill transitions is presented in this report as Plate 3. Earthwork Balance (Shrinkage/Bulking) The volume change of excavated materials upon compaction as engineered fill is anticipated to vary with material type and location. TIEL P+1 Uscs. OENSI1 C2:. ND 0 . Ag Fill/SC 8.2 103.0 125.0 10.4 ND 1 Ts/SP 15.9 107.6 118.0 0.9 TP-201 ND 2 Ts/SP 13.3 102.6 118.0 5.5 R 3 Ts/SP 7.5 103.4 118.0 4.8 Shapell Homes W.O. 6145-Al-SC Rancho Costera, Carlsbad June 6, 2011 Fi1e:e:\wp9\6100\6145a1.stt Page 13 GeoSoils, Inc. TEST) '-•• .SAMPLE. DEPTHS ±SOIL SOiL' MOiS1URE FIELD.DRY DENSITY.( '1 (PC9 iMAxIMUM. . DRYI `DEN .SHRINlcGi BuLKlNG: TP-2024 ND 0 Ag Fill/SC 8.2 103.8 125.0 9.7 ND 1 Ag Fill/SC 11.2 94.0 118.0 13.4 ND 2 Ag Fill/SC 17.2 108.9 118.0 (0.3) R 1 3 1 Ts/SP 1 12.1 1 108.5 118.0 0.1 TP-203 ND 0 Ag Fill/CL 15.8 102.9 117.0 4.4 ND 1 Ag Fill/CL 19.9 100.3 117.0 6.8 R 2 Qsw/CL 22.1 97.4 117.0 9.5 ND 3 Ts/SP 15.2 1 94.3 1 118.0 13.1 ND 4 Ts/SP 17.0 106.2 118.0 2.2 ND 5 Ts/SP 19.5 111.0 118.0 TP-204t4 ND 0 Ag Fill/SC 9.8 115.6 125.0 (0.5) ND 1 Ts/SP 13.6 109.9 125.0 4.4 R 2 Ts/SP 9.1 105.0 125.0 8.7 ND 3 Ts/SP 14.7 107.2 125.0 6.8 TP-2054 ND 0 Ag Fill/SC 11.4 108.8 125.0 5.4 R 1 Ts/SC 14.6 103.6 116.0 2.9 ND 2 Ts/SC 18.7 106.1 116.0 0.6 ND 1 3 1 Ts/SC 1 18.1 1 110.6 1 116.0 1 (3.6) TP-206 ND 0 Ag Fill/SC 17.9 87.1 125.0 24.3 ND 1 Is/CL 21.2 97.6 117.0 9.3 ND 2 Ts/CL 22.6 87.1 117.0 19.1 ND 3 Ts/CL 1 24.0 93.5 117.0 13.1 R 4 Ts/CL 21.0 96.2 117.0 10.6 TP-207 4 ND 0 Ag Fill/SC 10.4 93.9 125.0 18.3 ND 1 Ts/SP 14.4 115.2 125.0 (0.2) A 2 Ts/SP 19.0 101.7 125.0 11.6 ND 1 3 1 Ts/SP-CL j 18.3 108.7 125.0 1 5.5 TP-208 ND 0 Ag Fill/CL 12.0 103.0 125.0 10.4 ND 1 Ag Fill/CL 20.6 107.6 116.0 (0.8) ND 2 Qsw/SC 22.0 101.0 116.0 5.4 ND 3 Ts/SP 20.0 91.6 116.0 14.2 R 41A Ts/SP 11.6 104.2 116.0 2.4 Shapell Homes W.O. 6145-Al-SC Rancho Costera, Carlsbad June 6, 2011 File:e:\wp9\6100\6145a1.stt Page 14 GeoSo ifs, Inc. BULKINGEVALUATI 771 • :,,T (ft) USCS I1 MOISTURE ' (%) SULKINGPE 9EDoRY. DENSITY (PCFr ç'M DRY DENSIT(2) TP-209 ND 0 Ag Fill/SC 14.8 106.1 125.0 7.7 R 1 Ts/SP 12.8 105.8 116.0 0.9 ND 2 Ts/SP 13.9 105.3 116.0 1.3 ND 3 Ts/SP 1 14.7 1 105.8 1 116.0 1 0.9 TP-21 (4) ND 0 Ag Fill/SC 12.0 108.1 125.0 . 6.0 ND 1 Ts/SP 18.7 110.8 116.0 (3.8) ND 2 Ts/SP 15.5 110.9 116.0 (3.9) R (Dist.) 3 Ts/CL 13.3 0.0 •. 0.0 0.0 TP-2110 ND 0 Ag Fill/SC 14.1 105.5 125.0 8.3 ND 1 Ts/SP 14.0 104.8 118.0 3.5 A 2 Ts/SP 12.6 94.7 118.0 12.8 ND 3 Ts/SP 14.5 106.2 118.0 2.2 TP-212 ND 0 Ag Fill/SM 8.1 109.9 125.0 4.4 ND 1 Ts/SC 24.6 103.8 114.0 1.0 A 2 Ts/SC 12.6 111.7 114.0 (6.5) ND 3 1 Ts/SC 1 26.0 1 102.9 1 114.0 1 1.9 TP-213 ND 0 Ag Fill/SC 14.7 112.0 125.0 2.6 R 1 Ts/SC 15.9 100.4 120.0 9.1 ND 2 Ts/SC 26.3 98.5 120.0 10.8 ND 1 3 1 Ts/SC 1 24.3 1 95.9 1 120.0 1 13.1 TP-214 4 ND 0 Ag Fill/CL 15.4 102.3 117.0 5.0 ND 1 Ts/CL 28.3 . 91.5 104.5 4.8 R 2 Ts/CL 29.9 88.5 104.5 7.9 ND 3 Ts/CL 34.0 85.1 104.5 1 11.5 ND 4 Ts/CL 35.1 85.0 104.5 11.6 TP-21 5(4) ND 0 Ag Fill/SC 13.0 101.6 125.0 11.7 R 1 Ts/SP 16.4 105.2 118.0 3.1 ND 2 Ts/SP 15.8 113.9 118.0 (4.9) ND 1 3 1 Ts/SP 1 18.3 1 107.9 1 118.0 1 0.6 11 Shapell Homes W.O. 6145-Al-SC Rancho Costera, Carlsbad June 6, 2011 FiIe:e:wp9\6100\6145a1.stt Page 15 GeoSoils, Inc. L E/ LKBU ING.EALUATO f L - SoILJ.. MOISTURE 9IPPRY DENSITY 'pcF:DENsITYfr XMU DRY. SHRINKAGE/ BULKING TP-216 ND 0 Ag Fill-Qsw/SC 10.2 88.9 117.0 17.4 ND 1 Ts/SC 17.9 87.0 107.0 11.6 ND 2 Ts/SC 18.2 91.9 107.0 6.6 ND 3 Is/SC 19.0 93.7 107.0 4.8 ND 4 Ts/CL 22.1 95.2 107.0 3.3 ND 5 Ts/CL 22.4 99.8 107.0 (1.4) ND 1 6 1 Ts/CL 1 24.9 1 100.2 1 107.0 1 (1.8) TP-217 ND 0 Qal/SC 12.4 117.8 125.0 (2.4) ND 1 Qal/SC 11.5 105.8 118.0 2.5 ND 2 Qal/SC 12.5 100.4 118.0 7.5 ND 3 Qal/SC 11.1 103.3 118.0 4.8 ND 4 Qal/SC 12.5 101.3 118.0 6.7 ND 5 Qal/SC 15.6 93.3 118.0 14.1 TP-21 8' ND 0 Ag Fill/SC 14.4 110.4 125.0 4.0 ND 1 Ag Fill/SC 18.9 96.5 125.0 16.1 ND 2 Ag Fill/SC 14.2 114.2 125.0 0.7 ND 3 Qsw/SC 13.2 114.2 118.0 (5.2) ND 4 Qsw/SC 18.0 107.4 118.0 1.1 ND 5 Qsw/SC 20.2 106.1 . 118.0 2.3 (') ND = Nuclear Density Gauge, A = Ring Sample. ' Dry density per ASTM D-1557 (see laboratory testing section). Positive number indicates percent shrinkage, Number in paren indicates percent swell, or bulking. (4) Estimated maximum dry density based on soil type comparisons. The overall earthwork shrinkage and bulking may be approximated by using the following parameters: Existing Artificial Fill ................................................nominal Agricultural fill (0-1 foot) ................................20% to 25% shrinkage Agricultural Fill (1-2 foot) ................................15% to 20% shrinkage Agricultural Fill/Colluvium (2-3 foot) ........................5% to 10% shrinkage Colluvium/weathered formation (3-4 foot) .....................3% to 8% shrinkage Colluvium/weathered formation (4-5 foot) ....................1 % to 6% shrinkage Colluvium/weathered formation (5-6 foot) ..............2% to 3% shrinkage or bulk Alluvium .............................................10% to 15% shrinkage Terrace Deposits ..................................2% to 3% shrinkage or bulk Santiago Formation ................................2% to 3% shrinkage or bulk Shapell Homes W.O. 6145-Al-SC Rancho Costera, Carlsbad June 6, 2011 FiIe:e:\wp96100\6145a1 .stt Page 16 GeoSoils, Inc. It should be noted that the above factors are estimates only, based on preliminary data. Alluvium 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. Slope Considerations and Slope Design Graded Slopes All slopes should be designed and constructed in accordance with the minimum requirements of City/County, the 2010 CBC (CBSC, 2010), the 2009 "Greenbook," and the recommendations in Appendix F. Slopes constructed with sand fractions within the terrace deposits or Santiago Formations are anticipated to have erosion and surficial instability issues if left unpianted, and without engineered surface drainage control, and as such, will require periodic and regular maintenance above and beyond what is normally performed for slopes in general. Cut Slopes Cut slopes shown on Plates 1 and 3 are generally considered to be grossly stable. However, the hetrogeneous nature of the formational material (i.e., clay/sand) represents a permeability contrast that will accumulate water (i.e., perched groundwater), resulting in seepage at the slope face. Such seepage will saturate near surface soils, resulting in loss of soil strength and an increased potential for surficial slope failures. In order to mitigate this condition, fill over cut slopes should be reconstructed as a stabilization fill slopes for their entire length. The perimeter cut slope, located along the northern edge of PA-9 does not provide for adequate space to construct a stability fill due to property line restrictions. For this slope, a toe drain is recommended along the toe of slope. Planned Fill Over Cut Slopes Fill over cut slopes shown on Plate 3 are generally considered to be grossly stable. However, the cut/fill transitions that daylight at the slope face represents a permeability contrast that will accumulate water (i.e., perched groundwater), resulting in seepage at the slope face. Such seepage will saturate near surface soils, resulting in loss of soil strength and an increased potential for surficial slope failures. In order to mitigate this condition, fill over cut slopes should be reconstructed as stabilization fill slopes for their entire length (see below). In the case of the larger fill over cut slope above El Camino Real (see Plate 2, Cross Section F-F') the fill key may be provided with a subdrain/backdrain as recommended in Appendix F. Shapell Homes W.O. 6145-Al-SC Rancho Costera, Carlsbad June 6, 2011 FiIe:e:\wp9\6100\6145a1.stt Page 17 GeoSoils, Inc. Stabilization Fill Slopes The construction of stabilization fill slopes will be necessary for fill over cut slopes, and in-tract cut slopes. The construction of stabilization fills will also be necessary for some fill over cut slopes, in order to mitigate the potential for water seepage at the slope face. Such remedial slope construction is indicated schematically on Plate 3 on a preliminary basis. Additional stabilization fills may be recommended based on the configuration of any future plan revisions, and/or conditions exposed in the field during grading. General stabilization fill slope design and construction is presented in Appendix F. Subdrains Subdrains will be recommended at the base of any canyon fill and within the keyway for some perimeter fill slopes. Preliminary subdrain locations are shown on Plate 3. Subdrains will also be recommended within stabilization fill keyways, as shown on Plate 3. If encountered, local seepage along the contact between the bedrock and overburden materials, or along jointing patterns of the bedrock may require a subdrain system. Subdrains are recommended for the fill slope keyway for the fill over cut slope located above El Camino real (see Plate 3). The need for additional subdrain within perimeter fill slope keyways will be evaluated during grading. Typical subdrain design and construction details are presented in Appendix F. Toe Drains In-tract cut slopes should be provided with a "toe drain" as discussed in GSI (2010). Preliminary toe drain locations are shown on Plate 3. Wick Drains (PA-1) In order to accelerate the consolidation and settlement of saturated alluvial soils to be left in place, a vertical wick drain system is typically considered as one of the methods that may be considered. In the vicinity of planned residential development within PA-1, existing alluvial soils are anticipated to be on the order of up to 10 feet in thickness. With groundwater likely present locally, at depths as shallow as 3 feet below the surface, up to approximately 7 feet of alluvial soils may be left in place. Given this relatively shallow thickness of potentially left in place alluvium, and planned fill thicknesses on the order of 3 to 5 feet, wick drains are not considered effective, from a geotechnical viewpoint. Removals and stabilization of the removal bottom (rock blankets, geotextiles, etc.) is recommended in this area. SUPPLEMENTAL RECOMMENDATIONS REGARDING PA-13 Planning Area 13 generally consists of a sheet graded "super pad." Earthwork commenced on, or about, February, 2008, and was generally completed in May, 2008 with Shapell Homes W.O. 6145-Al-SC Rancho Costera, Carlsbad June 6, 2011 Fi1e:e:\wp9\6100\6145a1.stt Page 18 GeoSoils, Inc. observation and testing services provided by GSI. A summary of these observation and testing services is provided in GSI (2008b). A summary of as-built conditions is presented in the following discussion. As-Built Conditions As-built soil conditions to be considered in future earthwork, foundation design and construction are as follows: During mass grading of the site, a designed cut/fill transition was graded without any additional mitigation, such as overexcavation of the cut, since the location of settlement sensitive structures was not known. A fault was encountered during mass grading of PA-1 3 (GSI, 2008b). This fault was evaluated to be pre-Holocene in nature, based on CGS guidelines. Accordingly, recommendations for mitigation of faulting (i.e., structural setbacks), are not warranted. The presence of this pre-Holocene fault in the cut pad, where different soil types may be juxtaposed against each other, creating non-uniformity, will necessitate overexcavation. GSI's review, field work, and 'laboratory testing indicates that onsite soils have a high to very high expansion potential (E.l. greater than 90), and a plasticity index (P.1.) greater. than 42. As-built fill thicknesses range from approximately 181/2 to 30 feet for areas with left in-place saturated alluvium, and approximately 0 to 241/2 feet thick in areas underlain by terrace deposits. Proposed Additional Grading Currently proposed additional grading appears to consist of raising grades up to approximately 3 feet along the top of the existing fill slope, along the west side of PA-1 3, constructing building pads near existing grades along the southern edge of PA-13, and filling up to approximately 10 feet to achieved proposed grades within the interior, and northern edge of PA-13. Based on a review of Plates 1 and 3, proposed fill in areas underlain by existing alluvial soil is anticipated to be on the order of 3 feet, or less, in total thickness. When considering expansive soils in this area, options including, but not limited to: non- selective vs selective grading, and select soil import, may be considered in order to achieve a less onerous foundation design. While foundations can be designed for expansive soils, the construction of typical exterior flatwork and pavement may be problematic on medium to very highly expansive soils. Preliminary recommendations for the treatment of expansive subgrades underlying concrete flatwork, driveways, etc. are presented in GSI (2010). Shapell Homes W.O. 6145-Al-SC Rancho Costera, Carlsbad June 6, 2011 FiIe:e:\wp9\6100\6145a1.stt Page 19 GeoSoils, Inc. Post-Grading Settlement of Alluvium As discussed in GSI (2008b) alluvial materials were left in place, primarily within the western portion of PA-1 3. During mass grading of PA-13 (GSI, 2008b), the areas underlain by alluvial soil, the material were removed to saturated conditions (i.e., ±1 foot above regional ground water level) and recompacted. The approximate thickness of the left in place alluvium varies from near zero, to approximately 50 feet along the toe of the existing, northwest and west facing fill slope shown on Plates 1, 2 (Section K-K'), and 3. Where these materials are left in-place, settlement of the underlying saturated alluvium is anticipated due to the weight of added planned fills. The magnitude of this settlement will vary with the proposed fill heights (i.e., measured from existing grades), and the thickness, texture, and compressibility of the underlying, left-in-place saturated alluvium. Due to the predominantly fine grained texture of the alluvial soils onsite, settlement of the alluvial soil will occur overtime, as evaluated in GSI (2008b). A review of GSI (2008b) indicates that previously calculated total settlements on the order of 3 to 8 inches should be anticipated in these areas. Calculations were performed for total settlements for fill thicknesses of 15, 20, and 30 feet within alluvial areas. Based on our evaluation, calculated total settlements were estimated to be on the order of 4, 5.5, and 7.8 inches, respectively. With an estimated one-quarter of these computed settlements to have occurred during grading, and the remainder constituting the post grading component of the total settlement. Per GSI (2008b), the anticipated post grade differential settlement is expected to be about one-half of the remaining total settlement over a horizontal distance of 40 feet. Waiting periods were estimated to be on the order of at least 18 months, to allow for an adequate amount of settlement to occur prior to construction of settlement-sensitive improvements. A monitoring program was subsequently established in areas were left-in-place alluvium occurred. Given the amount of time passing since the completion of mass grading (at least 36 months), and the proposed placement of not more than approximately 3 feet of additional fill, areas underlain by alluvial soils left-in-place should be designed to withstand an overall total settlement of 2 inches, or less, and a differential settlement of approximately 1 inch over a horizontal distance of 40 feet, under dead plus live loads. Due to the predominantly clayey nature of the underlying wet alluvium, the magnitude of seismic settlement will be less than that due to static loading conditions. The seismic differential settlement for design should be minimally about 1 1/2 inches over a horizontal span of 40 feet. Post-construction settlement monitoring should be incorporated into grading plans for this area to monitor fills for a period of up to 90 days following grading to establish the settlement impact of new fills. Preliminary Earthwork Recommendations, PA-13 Based on the duration of time following rough grading, the removal and recompaction of near surface soils in fill areas is recommended. Based on our review, the upper 2 to 3 feet Shapell Homes W.O. 6145-Al-SC Rancho Costera, Carlsbad June 6, 2011 File:e:\wp9\6100\6145a1.stt Page 20 GeoSoils, Inc. is anticipated to require removal and recompaction. The presence of cut/fill transitions within the sheet graded pad will also require remediation where planned additional fill are less than approximately 4 feet, or the ratio of maximum to minimum fill thickness within a given lots is greater than 3 to 1. Removals/overexcavation should be completed for a minimum lateral distance beyond the improvement, equal to the depth of the removal/overexcavation. Recommendations for the mitigation of transitions, overexcavation, etc. are presented in GSI (2010). Preliminary Foundation Design Our review, field work, and laboratory testing within the general area indicates that onsite soils may have a high to very high expansion potential. The preliminary recommendations for foundation design and construction are presented in GSI (2010) are considered valid and applicable. It should be noted that the importation (or selective grading) of lower expansive soils could potentially make the foundation design in a given area less onerous, relative to existing soil conditions. Final foundation recommendations should be provided at the conclusion of precise grading, and based on laboratory testing of fill materials exposed at finish grade. If low expansive soils are used as capping material in areas underlain with higher expansive soil, the underlying soils will still influence design to some extent. However, this buffer of lower expansive soil will provide for a higher level of performance for flatwork and pavement. SLOPE EROSION WITH A PORTION OF PA-li Background The 5:1 slope was constructed during the mass grading phase of development for a portion of Planning Area 11. Earthwork commenced on, or about, April 7, 2008, and was generally completed on June 9, 2008. Mass grading was generally performed in accordance with the approved plans, prepared by ODC (2006). A summary of observation and testing services provided by this office during the placement of these materials is presented in GSI (2008). Observation Summary Based on our recent field review (this study) and a review of GSI (2008), surficial soils generally consist of engineered artificial fill, consisting of a light brown to dark brown, clayey sand and sandy clay/clay. Erosion of the slope face appears to consist primarily of rills and small gullies developed within the lower reaches of the slope. Where observed, the largest gullies were up to 1 to 2 feet in depth (please note that engineered fills in the area are on the order of 7 to 15 feet thick). Detrital soils washed out of the ril led and gull ied areas was also noted to be deposited along the base of the slope. An existing irrigation system was observed across the slope face, and does not appear to be active, with several Shapell Homes W.O. 6145-Al-SC Rancho Costera, Carlsbad June 6, 2011 Fi1e:e:\wp9\6100\6145a1 .stt Page 21 GeoSoils, Inc. broken, and/or missing sprinkler heads noted. Vegetation across the slope appeared relatively sparse, consisting of scattered grasses, weeds, and small shrubs. The percent of vegetative ground cover is estimated at approximately 50 percent. Fiber rolls were also noted across the slope face locally. The two main erosive agents affecting a landscape are wind and water (Toy, et al., 2002; Morgan, 2005). The process of erosion is typically a function of the amount and rate of rainfall, or wind speed, the slope gradient, plant cover, and soil type. Of these two erosive agents, the activity of water (rainfall) is considered to be significantly more erosive. Observations of the slope area indicate the presence of erosional features such as rills and gullies, predominantly developed with the lower reaches of the slope. A combination of raindrop impact on the slope face, and overland flow (sheet flow) would be the predominant erosional mechanisms affecting the slope face, especially in the case of prolonged rainfall, once the infiltration capacity of the soil is exceeded. Overland flow is typically characterized as a mass of anastomosing water courses with no pronounced channels (Morgan, 2005). The flow is locally broken up by irregularities on the slope surface such as pebbles, stones, vegetation cover, and man made "drainage control" such as fiber rolls. Fiber rolls are significant in that they tend to pond and/or channelize water on the upslope side of the roll to a point where water breaches, and/or undermines the obstacle (fiber roll) causing more erosion down slope. As overland flow is concentrated, rills and gullies tend to develop, resulting in the observed erosion. Conclusions and Recommendations (PA-1 11 Based on our observations, the lower reaches of the slope appear to have eroded locally due to sparse vegetative cover, and the presence of surface obstructions, such as fiber rolls, and/or other surface irregularities, etc., that tend to concentrate surface flow on the slope. Portions of the slope with little or no vegetative cover can be expected to continue to erode, absent mitigation. The use of slope protection fabrics, or erosion control blankets/products, such as jute, etc. may be considered as a short-term method of reducing erosion until a suitable vegetative cover is established. Hydraulically applied, stabilized fiber matrix, spray on polymer, etc. may also be utilized. These surficiat "cover" products are not intended for long-term erosion control. Existing gullies should be filled with engineered-compacted earth materials, and re- vegetated. To reduce disturbance of the surrounding area, repair work using hand equipment may perform better than heavy equipment. The existing irrigation system should also be repaired in order to facilitate vigorous plant growth. Pressure testing of the system should also be performed, so as to eliminate the potential for leaks to exacerbate erosion, and sprinkler heads adjusted per the landscape architect. The irrigation system should also be properly adjusted to provide only the amount of water necessary to sustain ShapeD Homes W.O. 6145-Al-SC Rancho Costera, Carlsbad June 6, 2011 FiIe:e:\wp9\6100\6145a1.stt Page 22 GeoSoils, Inc. plant growth. All planting and irrigation should be reviewed by the project landscape architect for comment and design modifications, as needed. RECOMMENDATIONS -FOUNDATIONS The proposed foundation systems should be designed and constructed in accordance with current standards of practice, the guidelines contained within the 2010 CBC, the 2009 "Greenbook," the ACI (2008), and the design parameters presented in GSI (2010). Please note that GSI (2010) referenced the 2007 Code; however, while some sections numbers have changed from the 2007 Code to the 2010 CBC (CBSC, (2010), the geotechnical foundation design parameters (post-tension design, etc.) are the same. RETAINING WALLS General Recommendations for conventional, segmental, and top of slope walls/fences are presented in GSI (2010) and are considered valid unless specifically superceded in the text of this report. Recommendations for additional wall/shoring systems are provided in the following sections with respect to site conditions that may be more suited to shoring wall, and/or soil nail wall design, especially in the vicinity of the planned ingress/egress points at Glasgow and Edinburgh Streets, along the north side of the project. Where 2010 CBC values of equivalent fluid pressure (EFP) exceed those herein, those values should be used in preliminary design until onsite graded conditions are complete. Earthquake Loads (Seismic Surcharge) In accordance with 2010 CBC, and given the granular nature of the site soils and the anticipated level of potential earthquake shaking evaluated herein, GSI recommends that for walls that retain more than, or equal to, 6 feet of retained soil and are 6 feet or less from structures, or may inhibit ingress/egress for the site roads or lots, or critical access pathways (i.e., collector streets, fire access roads, etc.), a seismic surcharge (increment) of 14H should be used where H is the height of the wall and the surcharge is applied as a uniform pressure for restrained walls. For cantilever walls, this distribution may be taken as an inverted triangular distribution. This complies with a Probabilistic Horizontal Site Acceleration (PHSA), as previously noted in this report. The resulting wall design should be safe from seismic induced overturning with a minimum FOS of 1.1 to 1.3 should be considered and is dependant on the backfill conditions and the potential consequences of seismic induced deformations/failure. Basement walls or utility vaults, if proposed, will need to be evaluated as retaining walls, as well as part of the wall design from a seismic standpoint per the 2010 CBC. Shapell Homes W.O. 6145-Al-SC Rancho Costera, Carlsbad June 6, 2011 FiIe:e:\wp9\6100\6145a1 .stt Page 23 GeoSo ifs, Inc. TEMPORARY/PERMANENT SHORING SYSTEMS A permanent shoring wall may be considered as an alternative to the construction of a typical, cantilevered retaining wall. The following recommendations are for the shoring of excavations up to approximately 20 feet, or less, in height. We recommend that permanent slopes may be retained by a cantilever shoring system deriving passive support from cast-in-place soldier piles lagged with either pre-cast concrete or wood lagging (H-pile and lagging-shoring system). Based on our experience with similar projects in the San Diego area, if lateral movement of the shoring system on the order of 1 inch (permanent shoring) and 2 inches (temporary shoring) cannot be designed for or tolerated, we recommend the utilization of an internal bracing/raked shoring system, or a stiffer shoring system to limit deflection to less than 1 inch. Terzaghi and Peck (1967) suggested that shoring for excavations up to 20 feet in depth should consider settlement on the order of 0.65 percent in the backfill, or retained material, as backfill settlement. This would imply less than 1 inch of backfill or retained material settlement for a shored system retaining up to 20 feet. This is likely a conservative estimate given the depth of the formation below the surface. Locally, 0.2 percent is used for soils which would indicate approximately 1/2 inch of settlement. However, settlement on the order of 1/2 to 1½ inches should be evaluated for improvements near the rear of the wall. Anticipated deflection of the soldier beams should be evaluated by the structural consultant. GSI should review the anticipated deflection from the structural consultant and revisit the settlement behind the shored excavation. Shoring of excavations of this size is typically performed by specialty contractors with knowledge of the San Diego County area soil conditions. We recommend that shoring contractors provide the excavation shoring design. However, for the shoring design parameters, we provide the lateral earth pressures in Figures 2a and 2b, for both temporary and permanent shoring conditions. The use of soil anchors (tie-backs) may not be feasible on this site due to the location of adjacent residential property, or other easements. If desired, additional anchor recommendations will be provided. Since design of retaining systems is sensitive to surcharge pressures behind the excavation, we recommend that this office be consulted if unusual load conditions are anticipated. Care should be exercised when excavating into the on-site soils since caving or sloughing of these materials is possible. Observation of soldier pile excavations should be performed during construction. As an alternative to a tieback wall, a cantilever H-pile and lagging may be used. If the same system is used without tiebacks, the wall may be cost prohibitive for cantilever walls over 15 feet. Therefore, walls up to 15 feet in height may be used with a sloping backfill up to 5 feet in height, in order to achieve the same elevation of backfill. This sloping backfill should not exceed 1:1 (h:v). Earth pressures for inclined backfill up to 1:1 (h:v) are provided herein for import soils. Shoring of the excavation is the responsibility of the contractor. Extreme caution should be used to reduce offsite damage to existing pavement and utilities caused by settlement or reduction of lateral support Accordingly, we recommend that adjacent improvements be surveyed prior to and during construction to evaluate the effects of shoring on these structures. Photodocumentation of pre-construction conditions is also advised. Shapell Homes W.O. 6145-Al-SC Rancho Costera, Carlsbad June 6, 2011 File:e:\wp96100\6145a1.stt Page 24 GeoSoils, Inc. 02 H (ft.) - Reaiatance - behind this One \\\ H (feet) 0.2(ft) lie Back = ®Bond Strew _____ _ - 7 depth -7!7 for supporting ID Minimum H I Piero I'. 0.35P(paf) 400D(paf)®+27H(pefI® R—I— - - Y Cantilever Shoring System - - Surcharge Pressure P (pat) - - Line Load I H (feet) D (feet) 35H(paf)' I- •1 0.35 P (pat) I 400D(paf) I - - Surcharge Preasure P (pat) Tie-Back Shoring System I- - - Line Load P / 0.1 0.6H Y (feet) 0.3 0.6H 0.5 0.56H 0.7 0.48H X. R (0.4 0.55 OL )0.4 CX-7+1") NOTES Include groundwater effects below groundwater level. Include water effects below groundwater level. Grouted length greater than 7 feet; field teat anchor strength. ® Neglect passive pressure below base of excavation to a depth of one pier diameter. Cantilever Shoring System - Surcharge Pressure P (pet) - - Line Load I. _ R ---- -- H(feet) .. 0.1 0.6H 0.3 0.6H Y(feet) 0.5 0.56H 0.7 0.48H 45 H (pet) I - I (0.4 0.55 0L 0.35 P (pat) - )0.4 /0.64 °L' I 300D(pef) - Surcharge Pressure P (pet) Tie-Back Shoring System P (Dat) - - Line Load 0L0d8) - - Resistance behind this Or R-1— - - T' I D (feet) 02 I1 (ft.) 300 D (pat) Tie Back I I 1000.paf I I Bond Stress - - - Minimum 7 depth for supporting H piers 35I® 0.35P(pet) H(DBt) 94 NOTES Include groundwater effects below groundwater level. lnckde water effects below groundwater level. Grouted length greater than 7 feet: field teat anchor strength. ® Neglect passive pressure below base of excavation to a depth of one pier diameter. Lateral Pressure The active pressure to be utilized for trench wall shoring design may be computed by the rectangular active pressure (psf) as shown in GSI (2010). Passive pressure may be computed as an equivalent fluid having a given density shown in Figures 2a and 2b. The passive pressure near the bottom of the shored excavation to a depth equal to 1- to 1 1/2-pile diameters, should be reduced or ignored due to potential disturbance if the soldier beams are not embedded into formation. The lateral pressures indicated in Figures 2a and 2b assume that hydrostatic pressure is not allowed to build up behind excavation walls. If water is allowed to accumulate behind walls, an additional hydrostatic pressure surcharge should be added. These recommendations are for excavation of temporary/permanent shoring walls up to approximately 20 feet high. Active earth pressure may be used for trench wall design, provided the wall is not restrained from minor deflections. An empirical equivalent fluid pressure approach may be used to compute the horizontal pressure against the wall. Appropriate fluid unit weights are provided for specific slope gradients of the retained material: these do not include other superimposed loading conditions such as traffic, structures, seismic events, expansive soils or adverse geologic conditions. For excavation shoring walls that are to be present for more than 8 months and greater than 6 feet in height, a seismic increment of 14H (uniform pressure) may be considered for level excavation. For walls, these seismic loads should be applied at 0.61-1 up from the bottom of the wall to the height of retained earth materials. Due to the effects of soil movements on nearby improvements, including underground utilities, shoring lagging should be designed using a I( value of 0.5 and a maximum value of 300 pounds per lineal foot. The annulus between soil and lagging should be filled with either 1/2 to 3/4 inch gravel, or 1-to 2-sack slurry, due to the potential for sloughing surficial soils on this project, gravel, if used, will need to be separated from soil with a geotextile filter fabric to reduce the potential for piping, or migration of fines. B. If wood lagging is used, the permanent shoring wall will likely require an additional layer of steel reinforcement with panel drains using a shotcrete facing. Shapell Homes W.O. 6145-Al-SC Rancho Costera, Carlsbad June 6, 2011 FiIe:e:\wp9\6100\6145a1.stt Page 27 GeoSoils, Inc. 9. Permanent shoring walls using tiebacks should use corrosion protection for all tendons, anchors, and anchor hardware. Refer to the structural engineer and corrosion consultant for corrosion protection recommendations. Tiebacks and Lateral Pier Loads The piers will gain their lateral support primarily from the underlying terrace deposits. The lateral pier deflection under static soil and structural loads is estimated at 1-inch, or less. To reduce the potential for distress on the improvements above the wall, tiebacks may be added to the piers. The tiebacks will reduce the deflection of the foundation piers to less than 1/4 inch. Tiebacks should have a bonded length embedded into the formation (Santiago or terrace deposits) a minimum of 25 feet. For this project location, tie-backs should have a minimum batter of 20 degrees from the horizontal (2.75:1 [h:v]). It is anticipated that the tiebacks will be mounted through the monolithically placed concrete piers and/or grade beams. The depth below the top of pier for this tieback connection is anticipated to be 1- to 3-pier diameters. Tieback spacing is not anticipated to be more than 10 feet laterally. Given the assumed tieback loads of 60 to 180 kips, tieback diameters are anticipated to vary based on the load but should be considered as 4 to 8 inches. Tieback static loads are assumed to be 60 to 180 kips, and the allowance for 25 percent increase for transient seismic or wind loads should be included in the seismic design of the tiebacks. Select tiebacks should be tested to a minimum of 80 percent of the design ultimate strength. Creep of the selected tiebacks should be monitored for at least 24 hours. All production tiebacks should be proof tested. All tiebacks will consist of DYWIDAG system international (DSI) anchors with Type C double-corrosion protection. Open Excavations Construction materials and/or stockpiled soil should not be stored within "H" feet of the top of any temporary slope or trench wall (where "H" equals the slope or wall height). Temporary/permanent provisions should be made to direct any potential runoff away from the top of temporary excavations. It is the responsibility of the general contractor and his subcontractor to provide a safe working environment and to protect site improvements as well as adjacent existing improvements during construction. Excavation Observation (All Excavations) Monitoring should include the measurement of any horizontal and vertical movements of both the existing structures and the shoring and/or bracing. Locations and type of the monitoring devices should be selected as soon as the total shoring system is designed and approved. The program of monitoring should be agreed upon between the project team, the site surveyor and the Geotechnical Engineer of Record, prior to excavation. ShapeD Homes W.O. 6145-Al-SC Rancho Costera, Carlsbad June 6, 2011 File:e:\wp9\6100\6145a1.stt Page 28 GeoSoils, Inc. Reference points on the existing structures should be placed as low as possible on the exterior walls of buildings adjacent to the excavation. Exact locations may be dictated by critical points within the structure, such as bearing walls or columns for buildings; and surface points on roadways and sidewalks near the top of the excavation. The points on the shoring should be placed under or very near the points on the structures. For a survey monitoring system, an accuracy of a least 0.01 foot should be required. Reference points should be installed and read initially prior to excavation. The readings should continue until all construction below ground has been completed and the backfill has been brought up to final grade. The frequency of readings will depend upon the results of previous readings and the rate of construction. Weekly readings could be assumed throughout the duration of construction with daily readings during rapid excavation near the bottom and at critical times during the installation of shoring or support. The reading should be plotted by the Surveyor and then reviewed by the Geotechnical Engineer. In addition to the monitoring system, it would be prudent for the Geotechnical Engineer and the Contractor to make a complete inspection of the existing structures both before and after construction. The inspection should be directed toward detecting any signs of damage, particularly those caused by settlement. Notes should be made and pictures should be taken where necessary. Observation It is recommended that all excavations be observed by the Geologist or Geotechnical Engineer. Any fill which is placed should be approved, tested, and evaluated if utilized for engineered purposes. Temporary trench excavations should be observed by the Geologist or Geotechnical Engineer. Should the observation reveal any unforseen hazard, the Geologist or Geotechnical Engineer will recommend treatment. Please inform us at least 24 hours prior to any required site observation. Monitoring Existing, Offsite Improvements It is recommended that existing, offsite improvement be inspected prior to the start of earthwork and be monitored during and at the conclusion of grading to evaluate if earthwork, or shoring at the site has influenced these improvements. SOIL NAIL WALLS General Soil nails are a passive reinforcement, usually in the form of a bar or rod of solid or hollow cross section, installed into the ground, usually at a sub horizontal angle (15 to ShapeH Homes W.O. 6145-Al-SC Rancho Costera, Carlsbad June 6, 2011 File: e:\wp9\6100\6145a1 .stt Page 29 GeoSoils, Inc. 25 degrees) to enhance the stability of the reinforced ground mass primarily by mobilizing the axial tensile strength of the soil nail. As an alternative to a typical cantilevered retaining wall, a soil nail wall may be constructed. Soil nailing may be performed by the process of drilling and grouting, where the nail is inserted into a pre-drilled hole and then grouted into position. A bearing plate is then connected to the head of the soil nail to transfer a component of load directly to the ground surface. Each bearing plate would then be tied together with a structural concrete facing (soil nail wall). Preliminary Design and Construction The following soil parameters may be used in soil nail reinforcement design. Anchor (Bonded) Zone, (Qt) Terrace Deposits, or (isa) Santiago Formation Angle of Internal Friction: 28 degrees Soil Unit Weight: 120 pcf Cohesion: 200 psf Bond Stress 1,000 psf Soil nails may be installed at a maximum spacing of 5 feet on center, both vertically and laterally across the affected area of the slope, and embedded at least 30 feet into the slope. This assumes an unbonded length of approximately 10 feet for walls up to 20 feet in exposed height. The angle of soil nail installation shall be 20 degrees from horizontal. The tendon diameter shall be at least 1 inch, with a grouted nail diameter of at least 6 inches. All soil nails will consist of DYWIDAG system international (DSI) anchors. If deemed necessary by the structural consultant, corrosion engineer, or reviewer, Type C double-corrosion protection should be provided for the DYWIDAG bar(s). Additional parameters regarding seismic design are presented in a previous section. These recommendations are meant as minimums. Soil nail design should be reviewed by the soil nail designer and modified as necessary. Final soil nail construction plans should be reviewed by this office for compliance with the intent of this report. The construction and installation of soil nails should also be observed by this office. Soil nail walls should be completed using a panel drain(s) and a shotcrete facing to improve long-term performance. OTHER DESIGN PROFESSIONALS/CONSULTANTS The design civil engineer, structural engineer, architect, landscape architect, wall designer, etc., should review the recommendations provided herein, incorporate those recommendations into all their respective plans, and by explicit reference, make this report part of their project plans. This report presents minimum design criteria for the design of foundations and other elements possibly applicable to the project. These criteria should Shapell Homes W.O. 6145-Al-SC Rancho Costera, Carlsbad June 6, 2011 Fule:e:\wp9\6100\6145a1 .sfl Page 30 GeoSoils, Inc. not be considered as substitutes for actual designs by the structural engineer/designer. The structural engineer/designer should analyze actual soil-structure interaction and consider, as needed, bearing, expansive soil influence, and strength, stiffness and deflections in the various foundation, and other elements in order to develop appropriate, design-specific details. As conditions dictate, it is possible that other influences will also have to be considered. The structural engineer/designer should consider all applicable codes and authoritative sources where needed. If analyses by the structural engineer/designer result in less critical details than are provided herein as minimums, the minimums presented herein should be adopted. It is considered likely that some, more restrictive details will be required. If the structural engineer/designer has any questions or requires further assistance, they should not hesitate to call or otherwise transmit their requests to GSI. PLAN REVIEW Any additional project plans generated for this project should be reviewed by this office, prior to construction, so that construction is in accordance with the conclusions and recommendations of this report. Should grading plans change, additional review and/or investigation may be necessary. LIMITATIONS The materials encountered on the project site and utilized for our analysis are believed representative of the area; however, soil and bedrock materials vary in character between excavations and natural outcrops or conditions exposed during mass grading. Site conditions may vary due to seasonal changes or other factors. Inasmuch as our study is based upon our review and engineering analyses and laboratory data, the conclusions and recommendations are professional opinions. These opinions have been derived in accordance with current standards of practice, and no warranty is expressed or implied. Standards of practice are 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 project. Shapell Homes W.O. 6145-Al-SC Rancho Costera, Carlsbad June 6, 2011 FiIe:e:\wp96100\6145a1 .stt Page 31 GeoSoils, Inc. APPENDIX A REFERENCES APPENDIX A REFERENCES California Stormwater Quality Association, 2003, New development and redevelopment handbook, infiltration basin design considerations, No. IC-i 1, dated January. California Building Standards Commission, 2010, California Building Code, California Code of Regulations, Title 24, Part 2, Volume 2 of 2, Based on the 2009 International Building Code, 2010 California Historical Building Code, Title 24, Part 8; 2010 California Existing Building Code, Title 24, Part 10. California Code Of Regulations, 1996, CAL-OSHA State of California Construction and Safety Orders, dated July 1. California Department of Conservation, California Geological Survey, 2008, Guidelines for evaluating and mitigating seismic hazards in California: California Geological Survey Special Publication ii 7A (revised 2008), 102 p. Carlsbad, City of, 1993, Standards for design and construction of public works improvements in the City of Carlsbad. GeoSoils, Inc., 2011 a, Geotechnical investigation for the planned improvement of El Camino Real, between Cannon Road and Tamarack Avenue, Rancho Costera (Formerly Robertson Ranch West Village), Carlsbad, San Diego County, California, W.O. 6145-E-SC, dated May 11. 2011 b, Slopes, drainage, retaining walls, remedial removals, and pavement conditions, Rancho Costera and El Camino Real, Carlsbad, San Diego County, California, W.O. 6145-A3-SC, dated April 28. 2011 c, Soil texture and groundwater evaluation, Planning Area 23C (Wetland/Habitat Area), Rancho Costera, Carlsbad, San Diego County, California., W.O. 6145-A2-SC, dated April 22. 2011d, Geotechnical review of surilcial erosion, portion of Planning Area 11, Rancho Costera (Robertson Ranch West Village), City of Carlsbad, San Diego County, California, W.O. 6145-Al-SC, dated April 21. 2010, Updated geotechnical investigation for Robertson Ranch West Village, Carlsbad, San Diego County, California, W.O. 6145-A-SC, dated October 10. 2008a, Report of mass grading, Planning Area 11, Robertson Ranch habitat corridor and widening of El Camino Real at Cannon Road, Robertson Ranch West, Carlsbad, San Diego County, California 92010, City of Carlsbad Planning Department Application No. SUP 06-1 2/HDP 06-04, W.O. 5247-132-SC, dated July 16. GeoSoils, Inc. 2008b, Report of mass grading, Planning Area 12 (13.44 Acres), and Planning Area 13 (6.92 Acres), Robertson Ranch West, Carlsbad, San Diego County, California 92010, City of Carlsbad Planning• Department Application No. SUP 06-12/HOP 06-04, W.O. 5247-B1-SC, dated June 5. 2007, Preliminary geotechnical evaluation, Planning Area 12 (13.44 Acres), and Planning Area 13 (6.92 Acres), Robertson Ranch West, Carlsbad, San Diego County, California 92010, City of Carlsbad Planning Department Application No. SUP 06-12/HOP 06-04, W.O. 5247-A-SC, dated January 31. 2004a, Updated geotechnical evaluation of the Robertson Ranch property, Carlsbad, San Diego County, California, W.O. 3098-A2-SC, dated September 20. 2004b, Unpublished large diameter bucket auger boring logs (including laboratory testing), Robertson Ranch, West Village, W.O. 3098-A2-SC. 2002, Geotechnical evaluation of the Robertson Ranch Property, City of Carlsbad, San Diego County, California, W.O. 3098-Al-SC, dated January 29. 2001a, Preliminary findings of the geotechnical evaluation, Robertson Ranch Property, City of Carlsbad, California, W.O. 3098-A-SC, dated July 31. 2001 b, Preliminary geotechnical evaluation, Calavera Hills II, College Boulevard and Cannon Road Thoroughfare, District No. 4 (B&TD), City of Carlsbad, California, W.O. 2863-A-SC, dated January 24. Gregory, G.H., 2003, GSTABL7 with STEDwin, slope stability analysis system; Version 2.004. Krinitzsky, E.L., Gould, J.P., and Edinger, P.H., 1993, Fundamentals of earthquake resistant construction: John H. Wiley & Sons, Inc., 299 p. Morgan, R.P.C., 2005, Soil Erosion and Conservation, Third Edition, Blackwell Publishing Naval Facilities Engineering Command, 1986a, Soil mechanics design manual 7.01, Change 1 September: U.S. Navy. 1986b, Foundations and earth structures, design manual 7.02, Change 1 September: U.S. Navy. O'Day Consultants, 2011a, Composite grading plan, 100-scale, 1 sheet, Job No. 1007, dated May 11. 2011b, Grading and storm drain plan for: EL Camino Real, Rancho Costera, Sheets 7 through 15, 40-scale, dated January. Shapell Homes Appendix A FiIe:e:\wp9\6100\6145a1.stt Page 2 GeoSoils, Inc. 2008, Settlement points for Planning areas 12 and 13, J.N. 061172-4, dated August 14. 2006, Grading plans for Robertson Ranch Future PA 12 and PA 13, Sheet 1 through 6, Job no. 01 -1014, dated October. Public Works Standards, Inc., 2009, "Greenbook" standard specifications for public works construction, 2009 edition (and any supplements). Sowers and Sowers, 1970, Unified soil classification system (After U. S. Waterways Experiment Station and ASTM 02487-667) in Introductory Soil Mechanics, New York. Taniguchi, E., and Sasaki, Y., 1986, Back analysis of landslide due to Nagánoken Seibu Earthquake of September 14, 1984; Proceedings, XI ISSMFE Conference, Session 713, San Francisco, California. Rolla, MO: University of Missouri. Terzaghi, K., and Peck, R.B., 1967, Soil mechanics in engineering practice: John Wiley and Sons, New York, Second Edition. Toy, T.J., Foster, G.R., and Renard, K.G., 2002, Soil Erosion, processes, prediction, measurement, and control, John Wiley & Sons, pub. Shapell Homes Appendix A Fi1e:e:\wp9\6100\6145a1 .stt Page 3 GeoSoils, Inc. APPENDIX B BORING LOGS (This Study; GSI; 2010,2007, and 2004b) o > o c- > 'c • — C, .! ti 6 o o E .9 Z __ C" .- ( 0 H LO 9 0-0 CD U) 00 — 0 C0 .r cis 0.U) Oco 0 C20 0Z in' !!U) E • Cl) LL 0 U) >•.. U) 0.! .ij 0 o ca .° in •o Ln 50 55 0,z U) CIS 13 CL d,o .9 o - to Is, U)27 U) 0) Highly Organic Soils II UNIFIED SOIL CLASSIFICATION SYSTEM CONSISTENCY OR RELATIVE DENSITY Group Typical Names CRITERIA I Ii Major Divisions Symbols Well-graded gravels and gravel- GW sand mixtures, little or no fines Standard Penetration Test Poorly graded gravels and Penetration GP gravel-sand mixtures, little or no Resistance N Relative fines (blows/It) Density Silty gravels gravel-sand-silt 0-4 mixtures 4-10 Clayey gravels, gravel-sand-day mixtures 10-30 Well-graded sands and gravelly 35 sands, little or no fines >50 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, Kick flour, silty or clayey fine sands Penetration Inorganic clays of low to medium plasticity, gravelly clays, Resistance N sandy clays, silty clays, lean (blowsm) clays <2 Organic silts and organic silty clays of low plasticity 2-4 Inorganic silts, micaceous or diatomaceous fine sands or silts, 4-8 elastic silts 8-15 Inorganic clays of high plasticity, fat clays 15-30 >30 Organic clays of medium to high plasticity Peat, mucic, and other highly organic soils 3/4" #4 #10 GM GC SW SP SM SC ML CL 01 MH CH OH PT 3" Very loose Loose Medium Dense Very dense #200 U.S. Standard Sieve Standard Penetration Test Unconfined Compressive Strength Very Soft <0.25 Soft 0.25-.050 Medium 0.50-1.00 Stiff 1.00-2.00 Very Stiff 2.00-4.00 Hard >4.00 #40 Soil 1 1 Gravel I Sand Silt or Clay I Unified Cobbles coarse I fine coarse I medium fine Classification MOISTURE CONDITIONS MATERIAL QUANTITY OTHER SYMBOLS Dry Absence of moisture: dusty, dry to the touch trace 0-5% C Core Sample Slightly Moist Below optimum moisture content for compaction few 5-10% S SPT Sample Moist Near optimum moisture content little 10-25% B Bulk Sample Very Moist Above optimum moisture content some 25-45% V Groundwater Wet Visible free water; below water table Op Pocket Penetrometer BASIC LOG FORMAT: Group name, Group symbol, (grain size), color, moisture, consistency or relative density. Additional comments: odor, presence of roots, mica, gypsum, coarse grained particles, etc. EXAMPLE: Sand (SP), fine to medium grained, brown, moist, loose, trace silt, little fine gravel, few cobbles up to 4" in size, some hair roots and rootlets. File:Mgr: c;\SoilClassif.wpd • PLATE Bi cj. W.O. 6145-Al-SC Shapell Homes Rancho Costera Logged By: SHW April 13, 2011 LOG OF EXPLORATORY TEST PITS FIELD --,DRY-. t 'DtPTH- -(pcf)_ - TP-201 88 0-1/2 SC Bag @ 8.2 103.0 AGRICULTURAL FILL: CLAYEY SAND, fine grained, light olive gray, 0-3 moist, loose. 1/2 1 SP 15.9 107.6 SANTIAGO FORMATION: SANDSTONE, fine grained, light gray, moist, soft; poorly cemented to friable, moderately weathered and fractured, massive. 1-2 13.3 102.6 Becomes medium dense. 231/2 Ring @ 3 7.5 103.4 With iron oxide staining. Total Depth = 31/2' No Groundwater/Caving Encountered Backfilled 4-13-2011 TP-202 156 0-21/2 SC Bag @ 8.2 103.8 AGRICULTURAL FILL: CLAYEY SAND, fine grained, olive gray, moist, 0-3 11.2 94.0 loose. 17.2 108.9 21/2 31/2 SP Ring @ 3 12.1 108.5 SANTIAGO FORMATION: SANDSTONE, fine grained, light gray, very moist, loose; friable, moderately weathered and fractured, massive. Total Depth = 31/2' No Groundwater/Caving Encountered Backtilled 4-13-2011 PLATE B-2 /2 W.O. 6145-Al-SC Shapell Homes Rancho Costera Logged By: SHW April 13, 2011 LOG OF EXPLORATORY TEST PITS .;FiELDpRY :5 'DEPTH,.- .,,MOIST* URE...--..!. DE "DIE PTI 1 :SYB.; TrD rTH:: TP-203 174 0-1/2 CL Bag @ 15.8 102.9 AGRICULTURAL FILL: SANDY CLAY, fine grained, grayish brown, 0-3 slightly moist to moist, soft. ½-1 ½ 19.9 100.3 moist to very moist 11/2-3 CL Ring @ 2 22.1 97.4 COLLUVIUM: SANDY CLAY, fine grained, grayish brown, slightly moist to moist, soft. 3-5 SP 15.2 94.3 SANTIAGO FORMATION: SANDSTONE, fine to medium grained, light 17.0 106.2 gray, moist, medium dense; moderately cemented, slightly weathered and 19.5 111.0 fractured, massive. Total Depth = 5' • No Groundwater/Caving Encountered Backfilled 4-13-2011 TP-204 163 0-1/4 SC Bag @ 9.8 115.6 AGRICULTURAL FILL: CLAYEY SAND, fine grained, grayish brown, 0-3 moist, loose. 1/4.3 SP 13.6 109.9 SANTIAGO FORMATION: SANDSTONE, fine grained, light brownish • 9.1 105.0 gray, moist, loose to medium dense; poorly cemented to friable, Ring @ 2 14.7 107.2 moderately weathered and fractured, 'massive to weakly sub-horizontal bedding, N170W, 30SW. Total Depth = 3' No Groundwater/Caving Encountered Backfilled 4-13-2011 PLATE B-3 W.O. 6145-Al-SC Shapell Homes Rancho Costera Logged By: SHW April 13, 2011 LOG OF EXPLORATORY TEST PITS PLE TEST ELEV DEPTH SYMBOL SAM DEPTH , %DESCPit 'DENSY - RI TP-205 198 0-1 SC Bag @0 11.4 108.1 AGRICULTURAL FILL: CLAYEY SAND, fine grained, brownish gray, Ring @ 1 moist, loose. 1-3 SC 14.6 103.6 SANTIAGO FORMATION: CLAYEY SANDSTONE, fine grained, light gray, 18.7 106.1 moist, soft; poorly cemented to friable, weathered and fractured, massive. 18.1 110.6 Total Depth = 3' No Groundwater/Caving Encountered Backfilled 4-13-2011 TP-206 175 0 1/2 SC Bag @ 17.9 87.1 AGRICULTURAL FILL: CLAYEY SAND, fine grained, brownish gray, 0-4 moist, loose. 1/2-2 CL 21.2 97.6 SANTIAGO FORMATION: SANDY CLAYSTONE, fine grained, light gray to light olive, moist, soft; poorly cemented, slightly weathered, massive to poorly bedded. 241/2 CL 22.6 87.1 CLAYSTONE, mottled light gray and dark olive, moist, medium stiff; 24.0 93.5 moderately cemented, poorly bedded. Bedding: N30E, 140NW. Ring @ 4 21.0 96.2 • Total Depth = 41/2' No Groundwater/Caving Encountered Backfilled 4-13-2011 PLATE B-4 God1n c. c1 W.O. 6145-Al-SC Shapell Homes Rancho Costera Logged By: SHW April 13, 2011 LOG OF EXPLORATORY TEST PITS SAMPLE DRY .TEST,;..: .ELEV.. DEPTH GROUP . DEPTH MOIST1JRE DENSITY . • SYMBOL - (%) - . - - ',.•: :-. ;-•--:, -._ : .:: , TP-207 220 0-1/2 . SC Bag @ 10.4 93.9 AGRICULTURAL FILL: CLAYEY SAND, fine grained, light gray, moist, 0-3 very loose. 1,/2..2 SP Ring @ 2 14.9 115.2 SANTIAGO FORMATION: SANDSTONE, fine to medium grained, light 19.0 101.7 olive gray, moist, medium dense; moderately cemented, slightly weathered, moderately fractured with red and olive mottled CLAYSTONE in east half of pit. 2-3 SP/CL 18.3 108.7 SANDSTONE/CLAYSTONE thinly bedded to massive. Bedding: N16°E, 11°SE. Total Depth= 3' No Groundwater/Caving Encountered Backfilled 4-13-2011 PLATE B-5 W.O. 6145-Al-SC Shapell Homes Rancho Costera Logged By: SHW April 13, 2011 LOG OF EXPLORATORY TEST PITS TEST ELEV. DEPTH GROUP SAMPLE DEPTH IN MOIRE FIELD DRY (Pc f) DEN SITY .. DESCRIPTION . TP-208 152 0-1 CL Bag @ 12.0 103.0 AGRICULTURAL FILL: SANDYCLAY, fine grained, brownish gray, moist, 0-4 soft. 121/2 CL 20.6 107.6 very moist, with plastic debris. 21/2-4 SC 22.0 101.0 COLLUVIUM: CLAYEY SAND, fine grained, brownish gray, very moist, loose; bore holes. 4-5 SP Ring @ 20.0 91.6 SANTIAGO FORMATION: SANDSTONE, light gray, moist, loose to 41/2 . 11.6 104.2 medium dense; poorly cemented to friable, moderately weathered, massive. Total Depth = 5' No Groundwater/Caving Encountered Backfilled 4-13-2011 TP-209 173 0-1/2 SC Bag @ 14.8 106.1 AGRICULTURAL FILL: CLAYEY SAND, fine grained, brownish gray, 0-3 moist, loose. 1/3 SP Ring @ 1 12.8 105.8 SANTIAGO FORMATION: SANDSTONE, fine grained, light gray, moist, 13.9 105.3 loose to medium dense; friable, weathered, moderately fractured, massive 14.7 105.8 to poorly bedded. Bedding: N820E, 10°SE. Total Depth = 3' No Groundwater/Caving Encountered Backfilled 4-13-2011 PLATE B-6 W.O. 6145-Al-SC Shapell Homes Rancho Costera Logged By: SHW April 13, 2011 LOG OF EXPLORATORY TEST PITS zDEPTW.!,. DENSITY DE TP-210 182 0-'/2 SC Bag @ 12.0 108.1 AGRICULTURAL FILL: CLAYEY SAND, fine grained, grayish brown, 0-3 moist, loose. 1/2-3 SP 18.7 110.8 SANTIAGO FORMATION: SANDSTONE, fine grained, olive gray, moist, 15.5 110.9 soft; friable, massive to poorly bedded, weathered, fractured. 3-31/2 CL Ring @ 3 13.3 -- CLAYSTONE, mottled reddish brown and olive, moist, medium dense; moderately to well cemented, fractured, slightly weathered, thickly bedded. Bedding: N70°W, 7°SW. Total Depth = 31/2' No Groundwater/Caving Encountered Backfilled 4-13-2011 TP-21 1 211 0-½ SC Bag @ 14.1 105.5 AGRICULTURAL FILL: CLAYEY SAND, fine grained, brown, moist, loose 0-3 SP 14.0 104.8 SANTIAGO FORMATION: SANDSTONE, white to pale yellowish gray, moist, medium dense; poorly cemented, massive to poorly bedded, slightly weathered, slightly fractured, oxide staining. 11/2-3 SP Ring @ 2 12.6 94.7 Dense; moderately cemented, sub-horizontal bedding. Bedding: N35°E, 14.5 106.2 4°SE. • Total Depth = 3' No Groundwater/Caving Encountered Backfilled 4-13-2011 PLATE B-7 t .. J2 W.O. 6145-Al-SC Shapell Homes Rancho Costera Logged By: SHW April 13, 2011 LOG OF EXPLORATORY TEST PITS . WOISTURO TP-212 154 0-1/2 SM Bag @ 8.1 109.9 AGRICULTURAL FILL: SILTY SAND, fine to medium grained, grayish 0-3 brown, slightly moist, loose. 1/2-11/2 SC 24.6 103.8 SANTIAGO FORMATION: CLAYEY SANDSTONE, fine grained, light gray, moist, loose; poorly cemented, slightly weathered, fractured, weakly bedded to massive, sub-horizontal bedding. 11/1- 3 SC Ring @ 2 12.6 111.7 Becomes olive gray. 26.0 102.9 Total Depth = 3' No Groundwater/Caving Encountered Backfilled 4-13-2011 TP-213 138 0-1/2 SC Bag @ 14.7 112.0 AGRICULTURAL FILL: CLAYEY SAND, fine grained, grayish brown, 0-3 moist, loose. 1/2..3 SC Ring @ 1 15.9 100.4 SANTIAGO FORMATION: CLAYEY SANDSTONE, fine grained, mottled 26.3 98.5 gray and olive brown, very moist, loose; poorly cemented, moderately 24.3 95.9 weathered and fractured, poorly bedded to massive. Bedding: N500W, 6°SW. Total Depth = 3' No Groundwater/Caving Encountered Backfilled 4-13-2011 . - PLATE B-8 ;••' ,. c Ce W.O. 6145-Al-SC Shapell Homes Rancho Costera Logged By: SHW April 13,2011 LOG OF EXPLORATORY TEST PITS TEST -SAMPLE FIELD DRY ELEV DEPTH DEPTH MOISTURE , DESCRIPTION -1 TP-21 4 116 0-1 CL Bag @ 15.4 102.3 AGRICULTURAL FILL: SANDY CLAY, fine grained, olive brown, moist, 0-4 soft. - 1-4 CL Ring @ 2 28.3 91.5 SANTIAGO FORMATION: CLAYSTONE, olive gray, very moist, soft; 29.9 88.5 moderately cemented, highly weathered and fractured, thickly bedded, 34.0 85.1 heavy oxide staining, trace gypsum. 35.1 - 85.0 Total Depth = 4' - No Groundwater/Caving Encountered Backfilled 4-13-2011 TP-215 210 0 1/2 SC Bag @ 13.0 101.6 AGRICULTURAL FILL: CLAYEY SAND, fine grained, brownish gray, 0-3 slightly moist, loose. ½-3 SP Ring @ 1 16.4 105.2 SANTIAGO FORMATION: SANDSTONE, fine grained, light gray, moist, 15.8 113.9 loose to medium dense; poorly cemented, massive to poorly bedded, 18.3 107.9 moderately weathered and fractured. Bedding: N66°W, 6°SW. Total Depth = 3' No Groundwater/Caving Encountered - - Backfilled 4-13-2011 PLATE B-9 r -- - -: - ----•--------- -- - W.O. 6145-Al-SC Shapell Homes Rancho Costera Logged By: SHW April 13, 2011 LOG OF EXPLORATORY TEST PITS fEL . : DH ::tj'j t. • TP-216 124 0-1 SC Bag @ 10.2 88.9 AGRICULTURAL FILL/COLLUVIUM: CLAYEY SAND, fine grained, 0-4 brownish gray, moist, loose. 1-4 Sc 17.9 87.0 SANTIAGO FORMATION: CLAYEY SANDSTONE, fine grained, light gray, 18.2 91.9 moist, loose; poorly cemented, highly weathered and fractured. 19.0 . 93.7 CL 22.1 95.2 CLAYSTONE, light gray to olive gray, moist, hard; moderately cemented, :4:-6 22.4 99.8 poorly bedded, sub-horizontal. 24.9 100.2 Total Depth = 6' No Groundwater/Caving Encountered Backfilled 4-13-2011 TP-217 76 0-1 SC Bag @ 12.4 117.8 ALLUVIUM: CLAYEY SAND, fine grained, dark grayish brown, moist, • 0-5 loose to medium dense. 1-2 SC 11.5 105.8 Becomes brown. 2-5 SC 12.5 100.4 Becomes grayish brown, slightly moist, loose to medium dense. • 11.1 103.3 • 12.5 101.3 15.6 93.3 • Total Depth = 5' No Groundwater'/Caving Encountered - Backfilled 4-13-2011 PLATE B-b W.O. 6145-Al-SC Shapell Homes Rancho Costera Logged By: SHW April 13, 2011 LOG OF EXPLORATORY TEST PITS TEST PIT NO. ELEV. (ft.) DEPTH (ft.) GROUP. SYMBOL SAMPLE DEPTH (ft.) . MOISTURE . (%) . •. FIELD DRY DENSITY :. (pc . . . . . DESCRIPTION.• :. . TP-218 118 0-1 Sc Bag @ 14.4 110.4 AGRICULTURAL FILL: CLAYEY SAND, fine grained, brownish gray, 0-5 moist, loose. 1-2 Sc 18.9 96.5 Becomes very moist. 2-3 Sc 19.2 114.2 Plastic debris. 3-6 SC Ring @ 3 13.2 114.2 SLOPEWASH: CLAYEY SAND, brown, very moist, medium dense; oxide 18.0 107.4 stringers, and porous. 20.2 106.1 671/2 sc SANTIAGO FORMATION: CLAYEY SANDSTONE, olive brown, very moist, soft; poorly cemented, weathered, massive, fine grained. Total Depth = 7½' L ___________ No Groundwater/Caving Encountered Backfilled 4-13-2011 TP-219 96 0-1 SC/CL ARTIFICIAL FILL: CLAYEY SAND, gray brown, slightly moist, medium dense to loose. 1-3 SC/CL Becomes moist, medium dense. Total Depth = 3' No Groundwater/Caving Encountered Backfilled 4-13-2011 PLATE B-il BORING LOG GeoSoils, Inc. WO. 5247-A PROJECT: ROBERTSON RANCH WEST BORING B-I SHEET OF PA-13 DATEEXCAVATED 1-3-07 LOGGED BY:______ - Sample - SAMPLE METHOD- 140 Lb. Hammer @ 3(r Drop - - ApproL Elevation: • MSL Standard Penefrabbn Test - £ V Groundwater Undisturbed, Ring Sample a u Ad CL - C.) Cl) .5 . Description of Material M/M ALLUVIUM: 1- ©. 0' SILTY SAND/SANDY SILT, brown, damp, loose/soft. - 85 CL 109.2 16.0 82.5 @ 2W SANDY CLAY, dark gray, wet, hard. 40 18.8 @ 5' As per 2W, dark brown. 6- 7- IVA 8- 37 107.8 20.3 100.4 @7W As per 5', stiff. 9- 10 T 40 19.6 @ 10' As per 71N, hard. 11- @ 10' Groundwater encountered. 12- 13- 14- 15- 55 132.4 17.9 100.3 © 15' As per 10'. 16- 17- 18- 19- 20-33 226 @ 20' As per 15', hard; scattered gravel, sandy. 21- 22- . @ 22' Scattered rocks. 23- 24- 25 — 38 CL 113.0 780 102.6 @ 25' SANDY CLAY, brown, saturated, very stiff. 26' 27 28 29 GeoSoils, Inc. Plate B-12 BORING LOG GeoSoils, Inc. WO. 5247-A PROJECT: ROBERTSON RANCH WEST BORING B-i SHEET OF PA-13 DATE EXCAVATED 1-3-07 LOGGED BY:______ Sample SAMPLE METHOD: 140 Lb. Hammer @30" Drop - - - Approx. Elevation: • MSL Standard Penefrabbn Test .5 V Groundwater w E I Undisturbed, Ring Sample Description of Material Q. .5 0 c ° 0 ' 0 0 03 U) - 30 Sc 245 . ALLUVIUM (continued): 31- I @ 30' CLAYEY SAND, brown, saturated, medium dense. 28 I CL I 100.6 I 24.4 1100.4 very 37 46 I SC I 1 22.2 @ 40' CLAYEY SAND, gray-red brown, saturated, dense; scattered 41 gravel. 43 106.2 21.3 101.0 @45' As per 40', medium dense. 47- 48- 49- 50-- -- __ _ 43 SM 20.9 SANTIAGO FORMATION: •: @ 50' SILTY SANDSTONE, light gray, wet, dense. - Total Depth =51W Groundwater Encountered @ 10' Backfihled wlBentonite 1-3-2007 59 I GeoSoils, Inc. Plate B-13 BORING LOG Geosoils, Inc. WO. 6145-A PROJECT: SHAPELL HOMES BORING BA-101 SHEET OF Robertson Ranch West DATE EXCA VA TED 6-10-10 LOGGED BY:RBB - Sample - SAWLE METHOD: Modified Cal Sampler, 140 tis @ Xr Drop — — Approx. Elevation: j' MSL Standard Penetration Test .B - .(. Groundwater Undistutheo Ring Sample Description of Material — — CL — TOPSOIL: 1 0' SANDY CLAY, dark grayish brown, moist, stiff. WEAThERED SANTIAGO FORMATION: SM 3. @2' Interbedded SILTY fine SANDSTONE and SANDY CLAYSTONE, yellowish brown to brownish gray, moist, medium dense/stiff; highly fractured (infilled). 5. .-•: TERTIARY SANTIAGO FORMATION: 5-9" 121.6 13.3 97.7 : @2W SILTY SANDSTONE, yellowish brown to buff, moist, dense; fine 6- grained. - 7 ''• @ 3W Bedding: N30"W/5"SW. Fracture: N420W/84"NE :: @ 5' As per 2W, saturated; trace infilled fractures. ::: @ 7' Bedding: N19"W/120SW. :' I @ 121/2' Low angle cross-bedding. @ 13' Bedding: N400E/2°NW. 14- 15- : @ 14W SILTY SANDSTONE, light gray; fine- to coarse-grained. 7-10" 122.7 10.2 77.4 @ 15' SILTY SANDSTONE, light gray to light brown, wet, medium 16 : dense; fine-grained. 17- . : @ 151/2' Bedding: N330E15°NW. © 161/2' Caliche infilled fracture: N40"W161"SW. Sub-horizontal bedding. SILTY SANDSTONE, light gray; fine grained. :•. © 20' Cross bedding (low angle). : @21' SILTY SANDSTONE, gray, moist, dense. 22- 23- @ 23' Bedding: N70"W/7"SW. :-':• -4-12 SM/SC 116.4 11.5 72.5 : @25' SILTY SANDSTONE, light gray, moist, medium dense; fine —5. :j grained to CLAYEY SANDSTONE, grayish brown, moist, medium dense. 26'CLAYEY SANDSTONE, grayish brown, moist, dense. -SM : \ @ 26W SILTSTONE, gray to reddish yellow; slick ped surfaces. Bedding: N76"E113"NW. .:: @27' SILTY SANDSTONE, light gray; fine grained. t28' As per 26W. Bedding: N42"E/7"NW. GeoSoils, Inc. Robertson Ranch West . . Plate B-14 BORING LOG GeoSoils, Inc. WO. 6145-A pp.ojEcr SHAPELL HOMES BORING BA-101 SHEET2 OF Robertson Ranch West DATEEXCAVATED 6-10-10 LOGGED BY:RBB Sample - SAMPLE METHOD: Modified Cal Sampr, 140 lbs © 30" Drop - - Approx. Elevation: j' MSL Standaid Penetration Test L Groundwater Undisturbea Ring Sample C) - - g2 75 Description of Material SM :: @ 30' As per 26W. 31 : @31' SILTY SANDSTONE, yellowish brown to light gray. 32- Fault: N6"WNert. Bedding: N12"W/13°NE. 33- @ 33' Concretion 16-13" 122.0 11.9 88.8 @ 35' SILTY SANDSTONE, light gray, wet, medium dense; fine .4 grained, near vertical fracture. @ 38' Bedding: N30"W/4"SW. @ 39' Fault: NI"ENert. 40- 41- 42- @ Fault: N15"W168"SW offsets SILTY fine SANDSTONE and 43- -": SILTY fine- to coarse-grained SANDSTONE. 16-14" 123.5 7.5 58.8 . @ 45' SILTY SANDSTONE, light gray, moist, dense; fine grained, trace 46- -.:• coarse grains. 47- 48- 49- 50- 51- 52- 53- 54- 55- 16-111, 118.7 9.0 60.5 . @ 55' SILTY SANDSTONE, buff, moist, dense; fine grained. 58- Bedding: N7"E14"NW. Bedding: N30"E/15"NW. GeoSoils Inc. Robertson Ranch West Plate B-i 5 BORING LOG GeoSoils, Inc. w.o. 6145-A PROJECT SHAPELL HOMES BORING BA-101 SHEET OF Robertson Ranch West DATE EXCA VATED 6-10-10 LOGGED BY RBB - Sample SAMPLE METHOD: Modified Cal Sampler, 140 bs @ 30" Drop - - Approx. Elevation: 14' MSL Standard Penet,bbn Test - - Groundwater Undisturbed Ring Sample .2 Lo - — 0 Description of Material SM 61- 62- 63- 64- 65- 24-12" 108.5 8.2 41.4 . @65 SILTY SANDSTONE, buff to yellowish brown, damp, dense; fine :-: grained. ::• Bedding: NI0°W/10°NE. 67 .. @ 66' Cross bedding: N20°W/10°SW. 68- 69- 70- 71- '72- 73- @ 73' Bedding: N51°E/10°NW. 26-11" 115.3 7.9 48.4 . SILTY SANDSTONE, buff to yellowish brown, damp, dense; fine 76 -?-'• to medium grained. ±: Bedding: NI00E/10"NW. 77- 78- 79- 80- 81- 82- 83- 84- 85 - 24-12" SW 118.3 11.6 77.3 @ 85' SILTY SANDSTONE, light gray, wet, dense; fine to coarse - — _______ - ...q,ined. Total Depth = 86' No Groundwater/Caving Encountered Backfllled 6-10-2010 0-35'- 3 Kelly Weights; 35-65'- 2 Kelly Weights (Inner); 65-86'- 1 Kelly - - - Weight (Innermost) F ' GeoSoils, Inc. Robertson Ranch West . Plate B-16 BORING LOG GeoSoils, Inc. WO. 3098-A2 PROJECT: CALAVERA HILLS II, LLC BORING BA-1 si-tEEn 1 OF Robertson Ranch, Carlsbad DATE EXCAVATED 9-14-04 LOGGED BY:____ Sample SAMPLE METHOD: 0-27' 3,500 Ibs; 27-55'Z400 s; 55-85' 1,500 lbs — — Approx. Elevation: j' MSL Standard Penetration Test Q. 2 Groundwater >E , Undisturbed, Ring Sample 0. to — C .9 t' :)I Co U) Description of Material — — SC COLLLM(JM: iTh fl' (I Avi=v czAmn rIrfr nruich hmwn +a'. ,.r,,ek kn.rn,n ,1n, 2------- — ____ — fj'. __fewroots. t.= fl I •JU VV• S# U 7ICII 11 JflI I, fly. SC . SANTIAGO FORMATiON: 7 © 2' CLAYEY SANDSTONE, brown, dry, loose to medium dense; 4. :/ randomly fractured, caliche common along fractures (N70E, 85NW; 5 ,.. N40E, BOSE; N32W, 76SW), fine grained. 6 114.0 14.6 85.9 @ 5'Caliche less common. 7------ SM : @ 7' SILTY SANDSTONE, yellowish brown, dry, dense; massive, 8- -: caliche generally absent. 10- 8 125.8 10.6 88.8 @ 12' Becomes moist. . 15- 6 119.9 11.7 81.8 ... 16- 17- 20 5 1062 195 69.1 @ 20 Bedding attitude N30E 2NW 21 22 23 25- 5 SC 106.4 19.1 91.0 7' @25' CLAYEY SANDSTONE, brown to olive brown, slightly moist, /. dense; fractured (N76W, 18NE; N20E, 44SE; N40W, 60SW; N5W, " : 22NE). 29----- *4 SM . @ 29, SILTY SANDSTONE, yellowish brown, slightly moist, dense; — ' 8 SC 109 3 17.2 888 77 \_massive,fine grained. @ 30' CLAYEY SANDSTONE, olive brown, moist, dense. 3/ GeoSoils, Inc. Robertson Ranch, Carlsbad Plate B-17 BORING LOG GeoSoils, Inc. WO. 3098-A2 PROJECT CALAVERA HILLS II, LLC BORING BA-1 SHEET OF Robertson Ranch, Carlsbad DATEEXCAVATED 9-1404 LOGGED BY:______ - Sample - SAMPLE METHOD. 0-27 3,500 Ibs; 27-55' 2,400 s: 55-85' 1,500 lbs - - Approx. Elevation: j.' MSL Standard Penetration Test — . - -- Groundwater CD E Undistuited Ring Sample CL Ae 0 Iwo Description of Material - 10 SC 116.3 14.3 89-4 - SM .. @ 36' SILTY SANDSTONE, olive brown to gray brown, moist, dense; 37 indurated, massive. - - . contact: NIOE,4NW. _39'Basal SP 40 © 39' SANDSTONE, grayish brown, moist, dense; massive, fine to 38 * 42i 17 1274 88 783 medium grained. 41 13 120.4 8.8 62.0 46- 47- 48- 49- 50- 20 122.9 8.3 63.2 51- 52 - : @ 52' SILTY SANDSTONE, gray brown, moist, dense; cross-bedded 53. (N40W, I2SW; NBW, BSW), fine grained. 12 119.3 12.8 87.7 -. 56 A 57. - SC CLAYEY SANDSTONE, olive brown, moist, dense; bedding: 58 N 1 QE, 8NW, fine grained. - - - Sm ______ - SILTY SANDSTONE, olive brown, moist, dense; massive. 59. : 30 116.6 12.9 78.2 -'• ®60'As per 58'. 62 - - sc - .7 @ 62' CLAYEY SANDSTONE, olive brown, moist, dense; bedding: 63 - - - N12E,iiNW. 64 '_@_63'1"CLAYSTONEinterbed,N5W,7SW. © 63' 1" CLAYSTONE interbed, N5W, 7SW. .• 65 30 117.7 9.6 62.7 : © 63' SILTY SANDSTONE, olive brown, slight moist, dense; bedding: :• N30E,6NW. 67 68- 69 GeoSoils, Inc. Robertson Ranch, Carlsbad Plate B-18 BORING LOG Geosoils, Inc. WO. 3098-A2 PROJECT: CALAVERA HILLS II, LLC BORING BA-1 SHEET OF Robertson Ranch, Carlsbad DATEEXCAVATED 9-14-04 LOGGED BY:______ Sample - - SAMPLE METHOD: 0-27 3,500 Ibs; 27-552,40D Pas; 55-85' 1,500 bs - Approx. Elevation: j' MSL Standard I'enefration Test .5 - -- Groundwater . Undisturbed Ring Sample Description of Material - NO 30 SM 1159 81 505 @ 70 As per 63 30 114.8 8.0 48.3 '.'- @ 75' As per 70', cross-bedding in SANDSTONE: N5E, 4NW, basal 76 M : contact: N40E, 5SE. I 77 - @ 77' CLAYEY SANDSTONE, grayish brown, moist, dense. 4 SM .. @ 79 SILTY SANDSTONE, light brown to grayish brown, moist, dense; 30 116.3 12.6 78.9 bedding: N2OE, 5NW 8-i- A @ 80' As per 79'. 85 30 118.7 12.8 861 - @85' As per 80'. - - - ________ ______________________________________________________________ Total Depth = 86' No Groundwater Encountered Backfilled 9-142004 With Bentonite Chips 91 92 93 94 95 96 97 98 99 100 101 102 103 104 GeoSoils, Inc. Robertson Ranch, Carlsbad Plate B-19 BORING LOG GeoSoils, Inc. PROJECT. CALAVERA HILLS II, LLC McMillin, Robertson Ranch Sample O Co w .0 c D ' 2 In 0 .0 E >. U) U) U) : SM 2- 3- 4- 5 7. WO. 3098-Al BORING HB-5 SHEET OF DATE EXCAVATED 10-3-01 LOGGED BY. SAMPLE METHOD: 1301.8 HAMMER @40" DROP Approx. Elevation:' MSL Standard Penetration Test V Groundwater Undisturbed, Ring Sample Description of Material - COLLLMUMTOPSOIL @ 0' SILTY SAND, brown, dry to moist, loose. 'I- -I- ALLUViUM SANDY CLAY, brown, moist, very stiff. GROUNDWATER. 10 27 @ 10' SANDY CLAY, brown, wet, very stiff. 11 12 13 15- 29 @ 15' SANDY CLAY, greenish brown to brown, wet, very stiff. 16- 17- 18- 19- 20-@ 20' SANDY CLAY, light brown, saturated, medium stiff. 21- 22- 23- 24- 25- 6 @ 25' SANDY CLAY w/SILT, light brown, saturated, stiff. I 27 GeoSoils, Inc. . . McMillin, Robertson Ranch Plate B-20 . BORING LOG GeoSoils, Inc. PROJECT. CALAVERA HILLS II, LLC McMillin, Robertson Ranch Sample 4 . .5 0. 2 0 to a o 15 SM 31- 32- 33- 34- 351 14 WO. 3098-Al BORING 1-113-5 SHEET OF DATE EXCAVATED 10-3-01 LOGGED BY:______ - SAMPLE METHOD: I3OLB HAMMER @40" DROP EM Approx. Elevation: • MSL Standard Penetration Test Groundwater Undisturbed, Ring Sample co Description of Material - •: @ 30' SILTY SAND, olive brown, saturated, medium dense: orange : iron oxide. r. 4-. @ 35' SILTY SAND, light brown, saturated, medium dense; orange iron .-:• oxide. © 40' SILTY SANDSTONE, olive brown, saturated, medium dense; orange iron oxide. 47 50- -56 ML - SANTIAGO FORMATION 51- @ 50' CLAYEY SILTSTONE, olive, dry to damp, hard. 52- - Total Depth = 51.5' Groundwater @ 6 53. Backf,lled on 10/03101 57 59 GeoSoils, Inc. McMillin, Robertson Ranch Plate B-21 BORING LOG GeoSoils, Inc. WO. 6145-E PROJECT: SHAPELL HOMES BORING B-201 SHEET OF Rancho Costera, El Camino Real DATE EXCAVATED 3-28-11 LOGGED BY: RGC Sample SAMPLE METHOD: Ho&.v Stem Auger - - Approx. Elevation: 114' MSL Standard Penetration Test 2: .0 Groundwater E > Undisturbed, Ring Sample U) 0. • .5 .9 C,' M Co U) ° Description of Material - - CL r4 COLLUV1UM: 1- @ 0' SANDY CLAY, dark olive brown, wet, soft. - SC . TERRACE DEPOSITS (Qt): 4 @ 3' SILTY SAND wICLAY, brown, moist, loose. 50 SM 110.1 10.7 56.5 ••: @ 5' Becomes SILTY SAND, brown, moist, dense; weakly developed, 6 ::: sub-horizontal bedding. 7- 8- 9- 1 - 47 3WSC 98.0 233 91.3 f:•• @10'Asper5',CLAYEYSANDinterbeds. 15 50+ 106.7 17.6 84.8 @ 15' As per 10' SILTY SAND w/CLAYEY SANDinterbeds, mottled 16 A olive brown and brown, moist, dense; sub-horizontal bedding. 17- 18- 19- 20 50+ 107.8 16.8 83.1 @ 20' As per 15'. 21 22 23 24 25 50+ ;cisc 108.7 11.3 57.2 @ 25' Interbedded CLAYEY SAND and fine to medium grained SAND, 26 ::: olive brown to brown, slightly moist to moist, dense. 27 28 29 Rancho Costera, El Camino Real GeoSoils, Inc. Plate B-22 BORING LOG GeoSoils, Inc. WO. 6145-E PROJECT: SHAPELL HOMES BORING B-201 SHEET OF Rancho Costera, El Camino Real DATE S(CAVATED 3-28-11 LOGGED BY: RGC - Sample - SAMPLE METHOD: .140110N Stem Auger - - ApproL Elevation: 114' MSL Standard Penetration Test - - Groundwater UndsturW. Ring Sample U) Description of Material - 451' SP 94.7 62 220 @ 30' SAND wICLAY, moist, dense; medium grained, poorly sorted. 31 50-4" 109.8 10.3 53.9 32- 33- 34 - 50-6-1 SC o Recove, - . @ 35' CLAYEY SAND, brown to olive brown, moist, dense. 96.6 I 6.1 I 22.5 1*::n © 40' SAND and CLAYEY SAND interbeds, sub-horizontal 50-4" :• © 45' As per 40'. Total Depth = 46' No Groundwater Encountered Backfilled 3-28-2011 51 53 57 58 GeoSoils Rancho Costera, El Camino Real , Inc. Plate B-23 41 47 48 APPENDIX C LABORATORY DATA (This Study; GSI, 2010 and 2004b) APPENDIX D SLOPE STABILITY AND ENGINEERING ANALYSIS APPENDIX D SLOPE STABILITY ANALYSIS INTRODUCTION OF GSTABL7 v.2 COMPUTER PROGRAM Introduction GSTABL7 v.2 is a fully integrated slope stability analysis program. It permits the engineer to develop the slope geometry interactively and perform slope analysis from within a single program. The slope analysis portion of GSTABL7 v.2 uses a modified version of the popular STABL program, originally developed at Purdue University. GSTABL7 v.2 performs a two dimensional limit equilibrium analysis to compute the factor of safety (FOS) for a layered slope using the simplified Bishop or Janbu methods. This program can be used to search for the most critical 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: Phreatic and piezometric surfaces Pore pressure grid Rfactor Constant pore water pressure 6. Pseudo-static earthquake loading 7. Surcharge boundary loads 8. Automatic generation and analysis of an unlimited number of circular, noncircular and block-shaped failure surfaces 9. Analysis of right-facing slopes 10. Both SI and Imperial units General Information If the reviewer wishes to obtain more information concerning slope stability analysis, the following publications may be consulted initially: The Stability of Slopes, by E.N. Bromhead, Surrey University Press, Chapman and Hall, N.Y., 411 pages, ISBN 412 01061 5, 1992. Rock Slope Engineering, by E. Hoek and J.W. Bray, Inst. of Mining and Metallurgy, London, England, Third Edition, 358 pages, ISNB 0 900488 573, 1981. Landslides: Analysis and Control, byR.L. Schusterand R.J. Krizek (editors), Special Report 176, Transportation Research Board, National Academy of Sciences, 234 pages, ISBN 0 309 02804 3, 1978. GeoSoils, Inc. GSTABL7 v.2 Features The present version of GSTABL7 v.2 contains the following features: Allows user to calculate FOS for static stability and seismic stability evaluations. Allows user to analyze stability situations with different failure modes. Allows user to edit input for slope geometry and calculate corresponding FOS. Allows user to readily review on-screen the input slope geometry. Allows user to automatically generate and analyze defined numbers of circular, non-circular and block-shaped failure surfaces (i.e., bedding plane, slide plane, etc.). Input Data Input data includes the following Items: Unit weight, residual cohesion, residual friction angle, peak cohesion, and peak friction angle of fill material, bedding plane, and bedrock, respectively. Residual cohesion and friction angle is used for static stability analysis, where as peak cohesion and friction angle is for dynamic stability analysis. Slope geometry and surcharge boundary loads. Apparent dip of bedding plane can be modeled in an anisotropic angular range (i.e., from 0 to 90 degrees. Pseudo-static earthquake loading (an earthquake loading of 0.15 iwas used in the analysis). A 20 percent (20%) increase in soil strengths to model transient seismic loading of the slope, as is customary in geotechnical practice, was used in these analyses. Seismic Discussion Seismic stability analyses were approximated using a pseudo-static approach. The major difficulty in the pseudo-static approach arises from the appropriate selection of the seismic coefficient used in the analysis. The use of a static inertia force equal to this acceleration during an earthquake (rigid-body response) would be extremely conservative for several reasons including: (1) only low height, stiff/dense embankments or embankments in confined areas may respond essentially as rigid structures; (2) an earthquake's inertia force is enacted on a mass for a short time period. Therefore, replacing a transient force by a Shapell Homes Appendix D FiIe:e:\wp9\61O06145a1.stt Page 2 GeoSoils, Inc. 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 0.051 to 0.251. For example, past regulatory guidelines within the city and county of Los Angeles indicated that the slope stability pseudostatic coefficient = 0.1i to 0.151. The method developed by Krinitzsky, Gould, and Edinger (1993) which was in turn based on Taniguchi and Sasaki (1986), was referenced. This method is based on empirical data and the performance of existing earth embankments during seismic loading. Our review of "Guidelines for Evaluating and Mitigating Seismic Hazards in California" (California Department of Conservation, California Geological Survey, 2008) indicates the State of California recommends using pseudo-static coefficient of 0.15 for design earthquakes of M 8.25 or greater and using 0.1 for earthquake parameter M 6.5. Therefore, for reasonable conservatism, a seismic coefficient of 0.15i was used in our analysis for an M6.9 event. Output Information Output information includes: All input data. FOS for the 10 most critical surfaces for static and pseudo-static stability situation. High quality plots can be generated. The plots include the slope geometry, the critical surfaces and the FOS. Note, that in the analyses, 100 to 1,000 trial surfaces were analyzed for each section for either static or pseudo-static analyses. Results of Slope Stability Calculation Attached are the soil parameters and computer print out sheets from our analyses of the existing bluff slope stability for Sections E-E', F-F', H-H', I-I', and J-J' at the site. Both static and psuedo static analysis were used to evaluate the stability of the existing slopes. The results in all cases reviewed indicated a minimum FOS of >1.5 for static and >1.1 for psuedo static (seismic) conditions. Shapell Homes Appendix D FiIe:e:\wp9\6100\6145a1.stt Page 3 GeoSoils, Inc. TABLE Dl - SOIL PARAMETERS USED 6IUNIT- STAT I::tSElSMiC SHEAR :: J ( WElGHT(pcf) \ STRENGTh PARAMErERS J 4STRENGTh PARAMEERS Paraill, 7 ParalIE tçSOiL4 MATERIALS r ' "Bedding T Bedding Bedding ' j Bedding Moist; SatUrated .. ... .... , ,, .,•. ,.- -.. (degrees) (dCgrees) jpsf) :(degrees): tjp (degrees) Section H-H' 110 125 100 22 25Afu - - 120 - - Section H-H' tSP/SM/0t2 105 125 100 33 - - 120 37 - - Section H-H' Qt SWSC/Qt, 120 135 1,000 18 500 18 1,200 21 600 21 Section H-H' 105 125 100 30 - - - 120 34 - - Section H-H' Qt SC 120 135 300 33 - - 360 37 - - Section E-E'/F-F' l-l'/H-H' 125 135 100 34 100 28 120 38 120 32 isa SM3 Section E-E'/F-F'/J-J' isa SMdSM 125 135 300 34 200 28 360 38 240 32 Section E-E'/J-J' isa SM/SC 125 135 500 30 200 28 600 34 240 32 Section E-E'/I-I' TsaCL 125 135 1,0D0 21 200 18 1,200 24 240 21 Section F-F Afe 115 125 100 31 - - 120 35 - - Section H IL Tsa SM I 125 135 300 I 32 _ 200 28 360 36 240 32 TABLE D-2 :FACTOR. OSAFP(FOs)f . LOcA1ON ' DESthIIPTION WITH PLANNED SLOPE CONDITION METHOD t. .... - '. :-' STAT1Cf'.. .z. SEISMIC 2 Block, Perched H20 1.9 1.5 Janbu Section E-E' 3 Block, Perched H20 1.8 1.3 Janbu 2 Block, Perched H20 2.1 1.6 Janbu 3 Block, Perched H20 1.8 1.4 Janbu 2 Block, Perched H20 Section F-F' in Fill 2.2 1.6 Janbu 3 Block Perched H20 2 Below _Keyway 2.1 1.6 Janbu Shapell Homes Appendix D Fi1e:e:\wp9\6100\6145a1.stt Page 4 GeoSoils, Inc. LOCAT(ON , SCRIP11ON c' .. METHOD 1j Section H-H' 2 Block, Perched H20 2.1 1.8 Janbu 3 Block, Perched H20 2.0 1.7 Janbu Section H'2 Block, Perched H20 3.1 2.4 Janbu 3 Block, Perched H20 2.1 1.6 . Janbu Section J-J' 2 Block, Perched H20 2.1 1.8 Janbu 3 Block, Perched H20 1.7 1.3 Janbu TABLE D-3 - INS FACOR 9AFFOS)) STRENGTh PARAMETERS Artificial Fill (Qt/Qal) 1.6 31 180 Santiago Fm. (Tsa, SM) 2.6. 34 300 Santiago Fm. (Tsa, SM/SC) 2.6 32 300 Terrace Deposits (Qt) 1.7 30 200 I,- j. Shapell Homes Appendix 0 ..1...e:\wp961006145a1.stt Page 5 GeoSoils, Inc. SURFICIAL SLOPE STABILITY ANALYSIS Seepage l to slope Tract/Project: Shapell Homes Material Type: Fill _Artificial (Qt/Qal) Fs = Static Safety Factor = (4)) + C z (YYw) Cos2(I) Tan z (y,) Sin (i) Cos (I) d3(QO3 i.j W.O. 6145-Al -SC SURFICIAL SLOPE STABILITY 2: 1 SLOPE Plate D-25 Depth of Saturation (z) 4 feet Slope Angle (i) (for 2:1 slopes) 76 degrees Unit Weight of Water (ye) 62.4 lb/ft3 Saturated Unit Weight of Soil () 125 lb/ft3 Apparent Angle of Internal Friction (4)) 31 degrees Apparent Cohesion (C) 180 lb/ft2 DEPTH OF SATURATION SLOPE FACTOR OF SAFETY 4 FEET 2:1 1.61 SURFICIAL SLOPE STABILITY ANALYSIS Seepage parallel to slope Tract/Project: Shapell Homes Material Type: Formation _Santiago (TsaISM) Fe = Static Safety Factor = (4)) z (y -'y,) Cos2(i) Tan + C i4f.. W.O. 6145-Al -SC SURFICIAL SLOPE STABILITY 2: 1 SLOPE Plate D-26 Depth of Saturation (z) 4 feet Slope Angle (i) (for 2:1 slopes) 76 degrees Unit Weight of Water (7w) 62.4 lb/ft3 Saturated Unit Weight of Soil (y) 125 lb/ft3 Apparent Angle of Internal Friction (4)) 34 degrees Apparent Cohesion (C) 300 lb/ft2 DEPTH OF SATURATION SLOPE FACTOR OF SAFETY 4 FEET 2:1 z (yJ Sin (I) Cos (11) (Ocj 2.64 SURFICIAL SLOPE STABILITY ANALYSIS Tract/Project: Shapell Homes Material Type: L Santiago Formation (Tsa/SM and SC) Depth of Saturation (z) 4 feet Slope Angle (I) (for 2:1 slopes) 76 degrees Unit Weight of Water () 62.4 lb/f 3 Saturated Unit Weight of Soil (y) 125 lb/f 3 Apparent Angle of Internal Friction (4 32 degrees Apparent Cohesion (C) 1 300 11b1fe Fs = Static Safety Factor = z (y d-y,) Cos2(i) Tan (4) + C z (y.J Sin (i) Cos (i) DEPTH OF SATURATION SLOPE FACTOR OF SAFETY 4 FEET 2:1 2.63 SURFICIAL SLOPE STABILITY ANALYSIS Seepage parallel to slope Tract/Project Stiapell Homes Material Type: TerraceDeposits (Qt) Fs = Static Safety Factor = z(t'yw)Cos2(I)Tan(4))+C Z (Ysat) Sin (I) COS (i) OROM,Iifb. W.O. 6145-Al-SC SURFICIAL SLOPE STABILITY 2: 1 SLOPE Plate 0-28 Depth of Saturation (z) 4 feet Slope Angle (i) (for 2:1 slopes ) 76 degrees Unit Weight of Water () 62.4 1b/ft3 Saturated Unit Weight of Soil (y) 125 lb/ft3 Apparent Angle of Internal Friction (4)) 30 degrees Apparent Cohesion (C) 200 lb/ft2 DEPTH OF SATURATION SLOPE FACTOR OF SAFETY 4 FEET 2:1 1.78 APPENDIX E INFILTRATION TEST DATA APPENDIX F EARTHWORK AND GRADING GUIDELINES GENERAL EARTHWORK, GRADING GUIDELINES, AND PRELIMINARY CRITERIA General These guidelines present general procedures and requirements for earthwork and grading as shown on the approved grading plans, including preparation of areas to be filled, placement of fill, installation of subdrains, excavations, and appurtenant structures or flatwork. The recommendations contained in the geotechnical report are part of these earthwork and grading guidelines and would supercede the provisions contained hereafter in the case of conflict. Evaluations performed by the consultant during the course of grading may result in new or revised recommendations which could supercede these guidelines or the recommendations contained in the geotechnical report. Generalized details follow this text. The contractor is responsible for the satisfactory completion of all earthwork in accordance with provisions of the project plans and specifications and latest adopted code. In the case of conflict, the most onerous provisions shall prevail. The project geotechnical engineer and engineering geologist (geotechnical consultant), and/or their representatives, should provide observation and testing services, and geotechnical consultation during the duration of the project. EARTHWORK OBSERVATIONS AND TESTING Geotechnical Consultant Prior to the commencement of grading, a qualified geotechnical consultant (soil engineer and engineering geologist) should be employed for the purpose of observing earthwork procedures and testing the fills for general conformance with the recommendations of the geotechnical report(s), the approved grading plans, and applicable grading codes and ordinances. The geotechnical consultant should provide testing and observation so that an evaluation may be made that the work is being accomplished as specified. It is the responsibility of the contractor to assist the consultants and keep them apprised of anticipated work schedules and changes, so that they may schedule their personnel accordingly. All remedial removals, clean-outs, prepared ground to receive fill, key excavations, and subdrain installation should be observed and documented by the geotechnical consultant prior to placing any fill. It is the contractor's responsibility to notify the geotechnical consultant when such areas are ready for observation. Laboratory and Field Tests Maximum dry density tests to determine the degree of compaction should be performed in accordance with American Standard Testing Materials test method ASTM designation D 1557. Random or representative field compaction tests should be performed in accordance with test methods ASTM designation D 1556, D 2937 or D 2922, and D 3017, GeoSoils, Inc. at intervals of approximately ±2 feet of fill height or approximately every 1,000 cubic yards placed. These criteria would vary depending on the soil conditions and the size of the project. The location and frequency of testing would be at the discretion of the geotechnical consultant. Contractors Responsibility All clearing, site preparation, and earthwork performed on the project should be conducted by the contractor, with observation by a geotechnical consultant, and staged approval by the governing agencies, as applicable. It is the contractor's responsibility to prepare the ground surface to receive the 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 may be reused as compacted fills. Any materials incorporated as part of the compacted fills should be approved by the geotechnical consultant. Any underground structures such as cesspools, cisterns, mining shafts, tunnels, septic tanks, wells, pipelines, or other structures not located prior to grading, are to be removed or treated in a manner recommended by the geotechnical consultant. Soft, dry, spongy, Shapell Homes Appendix F FiIe:e:\wp9\6100\6145a1.stt Page 2 GeoSoils, Inc. highly fractured, or otherwise unsuitable ground, extending to such a depth that surface processing cannot adequately improve the condition, should be overexcavated down to firm ground and approved by the geotechnical consultant before compaction and filling operations continue. Overexcavated and processed soils, which have been properly mixed and moisture conditioned, should be re-compacted to the minimum relative compaction as specified in these guidelines. Existing ground, which is determined to be satisfactory for support of the fills, should be scarified (ripped) to a minimum depth of 6 to 8 inches, or as directed by the geotechnical consultant. After the scarified ground is brought to optimum moisture content, or greater and mixed, the materials should be compacted as specified herein. If the scarified zone is greater than 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 1/2 the height of the slope. Standard benching is generally 4 feet (minimum) vertically, exposing firm, acceptable material. Benching may be used to remove unsuitable materials, although it is understood that the vertical height of the bench may exceed 4 feet. Pre-stripping may be considered for unsuitable materials in excess of 4 feet in thickness. All areas to receive fill, including processed areas, removal areas, and the toes of fill benches, should be observed and approved by the geotechnical consultant prior to placement of fill. Fills may then be properly placed and compacted until design grades (elevations) are attained. COMPACTED FILLS Any earth materials imported or excavated on the property may be utilized in the fill provided that each material has been evaluated to be suitable by the geotechnical consultant. These materials should be free of roots, tree branches, other organic matter, ShapeD Homes Appendix F Fi1e:e:\wp9\6100\6145a1.stt Page 3 GeoSoils, Inc. or other deleterious materials. All unsuitable materials should be removed from the fill as directed by the geotechnical consultant. Soils of poor gradation, undesirable expansion potential, or substandard strength characteristics may be designated by the consultant as unsuitable and may require blending with other soils to serve as a satisfactory fill material. Fill materials derived from benching operations should be dispersed throughout the fill area and blended with other approved material. Benching operations should not result in the benched material being placed only within a single equipment width away from the fill/bedrock contact. Oversized materials defined as rock, or other irreducible materials, with a maximum dimension greater than 12 inches, should not be buried or placed in fills unless the location of materials and disposal methods are specifically approved by the geotechnical consultant. Oversized material should be taken offsite, or placed in accordance with recommendations of the geotechnical consultant in areas designated as suitable for rock disposal. 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 10 feet, unless specified differently in the text of this report. The governing agency may require that these materials need to be deeper, crushed, or reduced to less than 12 inches in maximum dimension, at their discretion. To facilitate future trenching, rock (or oversized material), should not be placed within the hold-down depth feet from 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 previously tested is encountered during grading, an appropriate analysis of this material should be conducted by the geotechnical consultant as soon as possible. Approved fill material should be placed in areas prepared to receive fill in near horizontal layers, that when compacted, should not exceed about 6 to 8 inches in thickness. The Shapell Homes Appendix F Fi1e:e:\wp9\6100\6145a1.stt Page 4 GeoSoils, Inc. geotechnical consultant may approve thick lifts if testing indicates the grading procedures are such that adequate compaction is being achieved with lifts of greater thickness. Each layer should be spread evenly and blended to attain uniformity of material and moisture suitable for compaction. Fill layers at a moisture content less than optimum should be watered and mixed, and wet fill layers should be aerated by scarification, or should be blended with drier material. Moisture conditioning, blending, and mixing of the fill layer should continue until the fill materials have a uniform moisture content at, or above, optimum moisture. After each layer has been evenly spread, moisture conditioned, and mixed, it should be uniformly compacted to a minimum of 90 percent of the maximum density as evaluated by ASTM test designation D 1557, or as otherwise recommended by the geotechnical consultant. Compaction equipment should be adequately sized and should be specifically designed for soil compaction, or of proven reliability to efficiently achieve the specified degree of compaction. Where tests indicate that the density of any layer of fill, or portion thereof, is below the required relative compaction, or improper moisture is in evidence, the particular layer or portion shall be re-worked until the required density and/or moisture content has been attained. No additional fill shall be placed in an area until the last placed lift of fill has been tested and found to meet the density and moisture requirements, and is approved by the geotechnical consultant. In general, per the 1997 UBC and/or latest adopted version of the California Building Code (CBC), fill slopes should be designed and constructed at a gradient of 2:1 (h:v), or flatter. Compaction of slopes should be accomplished by over-building a minimum of 3 feet horizontally, and subsequently trimming back to the design slope configuration. Testing shall be performed as the fill is elevated to evaluate compaction as the fill core is being developed. Special efforts may be necessary to attain the specified compaction in the fill slope zone. Final slope shaping should be performed by trimming and removing loose materials with appropriate equipment. A final evaluation of fill slope compaction should be based on observation and/or testing of the finished slope face. Where compacted fill slopes are designed steeper than 2:1 (h:v), prior approval from the governing agency, specific material types, a higher minimum relative compaction, special reinforcement, and special grading procedures will be recommended. If an alternative to over-building and cutting back the compacted fill slopes is selected, then special effort should be made to achieve the required compaction in the outer 10 feet of each lift of fill by undertaking the following: An extra piece of equipment consisting of a heavy, short-shanked sheepsfoot should be used to roll (horizontal) parallel to the slopes continuously as fill is placed. The sheepsfoot roller should also be used to roll perpendicular to the slopes, and extend out over the slope to provide adequate compaction to the face of the slope. Shapell Homes Appendix F File:e:\wp9\6100\6145a1.stt Page 5 GeoSoils, Inc. Loose fill should not be spilled out over the face of the slope as each lift is compacted. Any loose fill spilled over a previously completed slope face should be trimmed off or be subject to re-rolling. Field compaction tests will be made in the outer (horizontal) ±2 to ±8 feet of the slope at appropriate vertical intervals, subsequent to compaction operations. After completion of the slope, the slope face should be shaped with a small tractor and then re-rolled with asheepsfoot 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 lip, water, mix, and recompaôt the slope material as necessary to achieve compaction. Additional testing should be performed to evaluate compaction. SUBDRAIN INSTALLATION Subdrains should be installed in approved ground in accordance with the approximate alignment and details indicated by the geotechnical consultant. Subdrain locations or materials should not be changed or modified without approval of the geotechnical consultant. The geotechnical consultant may recommend and direct changes in subdrain line, grade, and drain material in the field, pending exposed conditions. The location of constructed subdrains, especially the outlets, should be recorded/surveyed by the project civil engineer. Drainage at the subdrain outlets should be provided by the project civil engineer. EXCAVATIONS Excavations and cut slopes should be examined during grading by the geotechnical consultant. If directed by the geotechnical consultant, further excavations or overexcavation and refilling of cut areas should be performed, and/or remedial grading of cut slopes should be performed. When fill-over-cut slopes are to be graded, unless otherwise approved, the cut portion of the slope should be observed by the geotechnical consultant prior to placement of materials for construction of the fill portion of the slope. The geotechnical consultant should observe all cut slopes, and should be notified by the contractor when excavation of cut slopes commence. If, during the course of grading, unforeseen adverse or potentially adverse geologic conditions are encountered, the geotechnical consultant should investigate, evaluate, and make appropriate recommendations for mitigation of these conditions. The need for cut ShapeH Homes Appendix F FiIe:e:wp9\6100\6145a1.stt Page 6 GeoSoils, Inc. 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 orfilling 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 GSl, getting the job done safely is of primary concern. The following is the company's safety considerations for use by all employees on multi-employer construction sites. On-ground personnel are at highest risk of injury, and possible fatality, on grading and construction projects. GSI recognizes that construction activities will vary on each site, and that site safety is the prime responsibility of the contractor; however, everyone must be safety conscious and responsible at all times. To achieve our goal of avoiding accidents, cooperation between the client, the contractor, and GSI personnel must be maintained. In an effort to minimize risks associated with geotechnical testing and observation, the following precautions are to be implemented for the safety of field personnel on grading and construction projects: Shapell Homes Appendix F FiIe:e:\wp9\6100\6145a1 .stt Page 7 GeoSoils, Inc. Safety Meetings: GSI field personnel are directed to attend contractor's regularly scheduled and documented safety meetings. Safety Vests: Safety vests are provided for, and are to be worn by GSI personnel, at all times, when they are working in the field. Safety Flags: Two safety flags are provided to GSI field technicians; one is to be affixed to the vehicle when on site, the other is to be placed atop the spoil pile on all test pits. Flashing Lights: All vehicles stationary in the grading area shall use rotating or flashing amber beacons, or strobe lights, on the vehicle 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 slope. The contractor's representative should effectively keep all equipment at a safe operational distance (e.g., 50 feet) away from the slope during this testing. The technician is directed to withdraw from the active portion of the fill as soon as possible following testing. The technician's vehicle should be parked at the perimeter of the fill in Shapell Homes Appendix F FiIe:e:wp9\61OD6145a1.stt Page 8 GeoSoils, Inc. a highly visible location, well away from the equipment traffic pattern. The contractor should inform our personnel of all changes to haul roads, cut and fill areas or other factors that may affect site access and site safety. In the event that the technician's safety is jeopardized or compromised as a result of the contractor's failure to comply with any of the above, the technician is required, by company policy, to immediately withdraw and notify his/her supervisor. The grading contractor's representative will be contacted in an effort to affect a solution. However, in the interim, no further testing will be performed until the situation is rectified. Any fill placed can be considered unacceptable and subject to reprocessing, recompaction, or removal. In the event that the soil technician does not comply with the above or other established safety guidelines, we request that the contractor bring this to the technician's attention and notify this office. Effective communication and coordination between the contractor's representative and the soil technician is strongly encouraged in order to implement the above safety plan. Trench and Vertical Excavation It is the contractors responsibility to provide safe access into trenches where compaction testing is needed. Our personnel are directed not to enter any excavation or vertical cut which: 1) is 5 feet or deeper unless shored or laid back; 2) displays any evidence of instability, has any loose rock or other debris which could fall into the trench; or 3) displays any other evidence of any unsafe conditions regardless of depth. All trench excavations or vertical cuts in excess of 5 feet deep, which any person enters, should be shored or laid back. Trench access should be provided in accordance with Cal/OSHA and/or state and local standards. Our personnel are directed not to enter any trench by being lowered or "riding down" on the equipment. If the contractor fails to provide safe access to trenches for compaction testing, our company policy requires that the soil technician withdraw and notify his/her supervisor. The contractor's representative will be contacted in an effort to affect a solution. All backfill not tested due to safety concerns or other reasons could be subject to reprocessing and/or removal. If GSI personnel become aware of anyone working beneath an unsafe trench wall or vertical excavation, we have a legal obligation to put the contractor and owner/developer on notice to immediately correct the situation. If corrective steps are not taken, GSI then has an obligation to notify Cal/OSHA and/or the proper controlling authorities. I Shapell Homes Appendix F FiIe:e:wp9\6100\6145a1.stt Page 9 1 GeoSoils, Inc. ---------- \--Na tur& grade \_ :Prop ed grade -- Colluvium and alluvium (remove) : . Typical benching Bedrock or approved native material See Alternate Details TYPE B Natural grade Proposed grade Colluvium and alluvium (remove Typical benching Bedrock or approved native material See Alternate Details Selection of alternate subdrain details, location, and extent of subdrains should be evaluated by the geotechnical consultant during grading. IG4 1c.I CANYON SUBDRAIN DETAIL Plate F—i 6-Inch minimum rA A-i 6-Inch 1-12-inch minimum I La- 6-inch minimum 6-in minimum mini - : : •1•I• ccc N........ _t 6-incmnum B-i Filter material: Minimum volume of 9 cubic feet per FILTER MATERIAL lineal foot of pipe. Sieve Size Percent Passing Perforated pipe: 6-inch-diameter ABS or PVC pipe or 1 inch 100 approved substitute with minimum 8 perforations 3% inch 90-100 (Y4-inch diameter) per lineal foot in 3/ inch 40-100 bottom half of pipe (ASTM D-2751, SDR-35, or No. 4 25-40 ASTM D-1527, Schd. 40). No. 8 18-33 No. 30 5-15 For continuous run in excess of 500 feet. use No. 50 0-7 8-inch-diameter pipe (ASTM D-3034, SDR-35, or No. 200 0-3 ASTM D-1785, Schd. 40). ALTERNATE 1: PERFORATED PIPE AND ALTER MATERIAL \- 6-inch minimum \ / 6-inch minimum _-a--- r-6-inch minimum 6 inch minimum Fitter fabric 6-inch minimum —' 6-inch minimtvii B-2 Gravel Material: 9 cubic feet per lineal foot. Perforated Pipe: See Alternate 1 Gravel: Clean 3%-inch rock or approved substitute. Filter Fabric: Mirafi 140 or approved substitute. ALTERNATE .2: PERFORATED PIPE, GRAVEL AND ALTER FABRIC CANYON SUBDRAIN ALTERNATE DETAILS Plate F-2 Toe of slope as shown on grading plan Original ground surface to be restored with compacted fill -ad 2D - I -.- ...... / •. •.. •.: •.. I Compâcted.Pill A . . .. . / el Anticipated rem Original ground surface unaullable material (depth per gootechnical enneer) "- Provide a 1:1 (H:V) minimum projection from toe of Back-cut varies. For deep removals, slope as shown on grading plan to the recommended backcut should be made no steeper removal depth. Slope height, site conditions, and/or than 1:1 (H:V), or flatter as necessary local conditions could dictate flatter projections. for safety considerations. J G"' FILL SLOPE TOEING OUT ON FLAT ALLUVIATED CANYON DETAIL Plate F-3 Previously placed, temporary Proposed grade compacted fill for drainage only Proposed additional compacted fill p - iinsu,table material (to be removed) Existing compacted fill ç' Bedrock or approved native material To be removed before placing additional compacted fill IOP REMOVAL ADJACENT TO EXISTING FILL ADJOINING CANYON FILL DETAIL Plate F-4 Drainage per design civil engineer Blanket fill (if recommended by the geotechnical consultant) Design finish slope 15 foot j=rn Buttress or stabilization fill foot f' 2-Percent Gradient 2-foot minimum ____ Heel key depth I 2-Percent Gradient_-- t I 15-foot minimum - -. - - __________________ - or H/2 where H Is the I slope height I Typical benching 4-inch-diameter non-perforated outlet pipe and backdrain (see detail Plate F-6). Outlets to be spaced at 100-foot maximum intervals and shall extend 2 feet beyond the face of slope at time of rough grading completion. At the completion of rough grading. the design civil engineer should provide recommendations to convey any outlet's discharge to a suitable conveyance, utilizing a non-erosive device. 15-foot typical 1 t 2_ drain spacing Typical benching (4-foot minimum) '- Bedrock or approved native material Subdrain as recommended by geotechnical consultant TYPICAL STABILIZATION / BUTTRESS FILL DETAIL Plate F-5 I 2-foot 2-foot I'minvnumH minimum 2-foot nmwnm I _ - 4-inch r" 3 foot Filter Material: Minimum of 5 cubic feet per lineal foot of pipe or 4 cubic feet per lineal feet of pipe when placed in square cut trench. Alternative in Lieu of Filter Material: Gravel may be encased in approved filter fabric. Filter fabric shall be Mirafi 140 or equivalent. Filter fabric shall be lapped a minimum of 12 inches in all joints. Minimum 4-Inch-Diameter Pipe: ABS-ASTM D-2751, SDR 35; or ASTM D-1527 Schedule 40, PVC-ASTM D-3034, SDR 35; or ASTM D-1785 Schedule 40 with a crushing strength of 1,000 pounds minimum, and a minimum of 8 uniformly-spaced perforations per foot of pipe. Must be installed with perforations down at bottom of pipe. Provide cap at upstream end of pipe. Slope at 2 percent to outlet pipe. Outlet pipe to be connected to subdrain pipe with tee or elbow. Notes: 1. Trench for outlet pipes to be backfilled and compacted with onsite soil. 2. Backdrains and lateral drains shall be located at elevation of every bench drain. First drain located at elevation just above lower lot grade. Additional drains may be required at the discretion of the geotechnical consultant. Filter Material shall be of the following Gravel shall be of the following specification or an approved equivalent, specification or an approved equivalent. Sieve Size Percent Passing Sieve Size Percent Passing 1 inch 100 iY2 inch 100 3/4 inch 90-100 No. 4 50 /8 inch 40-100 No. 200 8 No. 4 25-40 No. 8 18-33 No. 30 5-15 No. 50 0-7 No. 200 0-3 I TYPICAL BUTTRESS SUBDRAIN DETAIL Plate F—S 2-foot minimum In bedrock or :• flapproved - earth material Proposed grade Toe of slope as shown on grading plan Natural slope to be restored with compacted fill Backcut varies Compacted fill I :•.• e ecet09°' -sulk \U%j 4-foot minimum r Bench width—, \oot mmurn if Bedrock or \ '__\ \ \_•% '- -'- •' ' I "approved - ------------ native material 2-Percent Gradient - ' \\ '(\ - 15-foot minimumi 'N 1-1/2 where H is Subdrain as recommended by the elope height geotechnical consultant NOTES: Where the natural slope approaches or exceeds the design slope ratio, special recommendations would be provided by the geotechnical consultant. The need for and disposition of drains should be evaluated by the geotechnical consultant, based upon exposed conditions. FILL OVER NATURAL (SIDEH ILL FILL) DETAIL Plate F-7 Cut slope• Proposed grade Maintain h1r1Um150ot Compacted fill backcut to face - ... I Cut/fill contact as shown on grading plan Cut/fill contact as shown on as-built plan H height of elope Original (existing) grade e entgrajent F"0i-.- may very-- (4-toot minimum) inimumit I I Subdrain as recommended by 15-toot minimum or key depth L.._ H/2 where H Is I the elope height 1 geotechnical consultant Bedrock or approved native material NOTE: The cut portion of the slope should be excavated and evaluated by the geotechnical consultant prior to construction of the fill portion. G4" C, FILL OVER CUT DETAIL Plate F-8 Natural slope Proposed finish grade .' Rirnove:uneuilablo Material. _= Typical benching (4-foot minimum) H ....- — - A Compacted stablization fill 1-loot rthimum tilt back Bedrock or other approved native material If recommended by the geotechnical \ consultant, the remaining cut portion of Y t 2 Percent Gradient ____ the slope may require removal and '-- \ -:--< replacement with compacted fill. I w Subdrain as recommended by geotechnical consultant NOTES: 1. Subdrains may be required as specified by the geotechnical consultant. 2 W shall be equipment width (15 feet) for slope heights less than 25 feet. For slopes greater than 25 feet, W shall be evaluated by the geotechnical consultant. At no time, shall W be less than H/2, where H is the height of the slope. jG4"jve- I STABLIZATION FILL FOR UNSTABLE MATERIAL EXPOSED IN CUT SLOPE DETAIL Plate F-9 Proposed finish grade Natural grade ------------------ H - height of slope TM :'•>' NO Bedrock or approved native material Typical benching (4-foot minimum) 2-Percent Qr .4 Ien—.--.... 2-toot minimum 15-foot Subdrain as recommended by key depth I or H/2 if H)30 feet geotechnical consultant I NOTES: 1. 15-foot minimum to be maintained from proposed finish slope face to backcut. 2. The need and disposition of drains will be evaluated by. the geotechnical consultant based on field conditions. Pad overexcavation and recompaction should be performed if evaluated to be necessary by the geotechnical consultant. J G4" &Mli C', 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 Natural grade Rernavib Back-cut varies . I grade . j. 3-loot minimum fill blanket Avoid and/or clean up ........ /. '1 . spillage of materials on . ••. ••. . *\--\ - the natural slope 2-foot minimum : -. . :. •.: , Bedrock or approved JkeY width • .. ..• \ • 7 \\- - native material - L Typical benching T •i . T• -percent gradient (4-foot minimum) I . : Subdrain as recommended by geotechnical consultant NOTES: 1. 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. I G ,c. DAYLIGHT CUT LOT DETAIL . Plate F-i 1 Natural grade T1TTT I Proposed pad grade Natural grade Proposed pad grade S 10 an 'Wei at 2 toward street _ _ I 3- to 7-foot m*numo overexcavate and recompact L Bedrock or per text of report approved native Typical benching material CUT LOT OR MATERIAL-TYPE TRANSITION Subgrade at 2 percent gradient, drain~p toward street Me per text of report *Deeper overexcavation may be Bedrock or recommended by the geotechnical consultant in steep cut-fm transition approved native areas, such that the underlying Typical benching material topography is no steeper than 3:1 (H-.V) (4-foot minimum) CUT-FILL LOT (DAYLIGHT TRANSITION) TRANSITION LOT DETAILS Plate F-12 VIEW NORMAL TO SLOPE FACE Proposed finish grade CE) Hold-down depth co co ,0 CXD0 i i CO - co I (A) _____ CD) d3-------15-foot - dD minimum native material VIEW PARALLEL TO SLOPE FACE Proposed finish grade (B) (E) Hold-down depth I I maximum I (D) 15-100t minimum 3-foot minimum T25-foot minimum yon w -J- (C) 5-foot J \ % Bedrock or approved minimum native material NOTES: One equipment width or a minimum of 15 feet between rows (or windrows). Height and width may vary depending on rock size and type of equipment. Length of windrow shall be no greater than 100 feet. If approved by the geotechnical consultant, windrows may be placed direclty on competent material or bedrock, provided adequate space is available for compaction. Orientation of windrows may vary but should be as recommended by the geotechnical engineer and/or engineering geologist. Staggering of windrows is not necessary unless recommended. Clear area for utility trenches, foundations, and swimming pools; Hold-down depth as specified in text of report, subject to governing agency approval. All fill over and around rock windrow shall be compacted to at least 90 percent relative compaction or as recommended. After fill between windrows is placed and compacted, with the lift of fill covering windrow, windrow should be proof rolled with a D-9 dozer or equivalent. VIEWS ARE DIAGRAMMATIC ONLY AND MAY BE SUPERSEDED BY REPORT RECOMMENDATIONS OR CODE ROCK SHOULD NOT TOUCH AND VOIDS SHOULD BE COMPLETELY FILLED I OVERSIZE ROCK DISPOSAL DETAIL Plate F-13 ROCK DISPOSAL PITS Fill lifts compacted over rock after embedment 7 r - - - Granular material L_..__.... Large Rock --------1 I I Size of excavation to I Compacted Fill be commensurate I with rock size ROCK DISPOSAL LAYERS Granular soil to fill voids, densified by flooding r Compacted fill Layer one rock high Proposed finish grade Hold-down depth PRORLE ALONG LAYER Oversize layer • Hold-down depth AL Ap I Compacted fill - 3-loot mnum Fill Slope * clear zone TOP VIEW -r Layer one rock high Hold-down depth or below lowest utility as specified in text of report, subject to governing agency approval. . Clear zone for utility trenches, foundations, and swimming pools, as specified in text of report. VIEWS-ARE DIAGRAMMATIC ONLY AND MAY BE SUPERSEDED BY REPORT RECOMMENDATiONS OR CODE ROCK SHOULD NOT TOUCH AND VOIDS SHOULD BE COMPLETELY FILLED IN ROCK DISPOSAL DETAIL Plate F-14 Existing grade Existing grade 5-foot-high impact/debris wall ____ _/ Pad grade 5-foot-high impact/debris wall METHOD 1 METHOD 2 -..-...- Pad grade e catchment area -foot-high npact/debris wall Pad grade METHOD 3 Existing grade 2:1 NO slope Fence 2:1 (h:v) slope METHOD 4 Pad grade NOT TO SCALE IG'Ic.j DEBRIS DEVICE CONTROL METHODS DETAIL J Plate F—iS Rock-filled gabion basket Existing grade -- 5-foot nun or as recommended by geotechnical conauttant Proposed grade Filter fabric Drain rock Compacted fill Gabion impact or diversion wall should be constructed at the base of the ascending slope subject to rock fall. Walls need to be constructed with high segments that sustain impact and mitigate potential for overtopping, and low segment that provides channelization of sediments and debris to desired depositional area for subsequent clean-out. Additional subdrain may be recommended by geotechnical consultant. From GSA. 1987 I I ROCK FALL MITIGATION DETAIL Plate F-16 y- Proposed finish grade -im----- I - -'-'- 5feet 5feet 5 feet - - - - - I I 2 feet 100, __ .... .. . __ __ / Bottom of cleanout 1 foot - 4 Provide a minimum 1-foot .......................... bedding of compacted sand NOTES: Locations of settlement plates should be clearly marked and readily visible (red flagged) to equipment operators. Contractor should maintain clearance of a 5-foot radius of plate base and withiin 5 feet (vertical) for heavy equipment. Fill within clearance area should be hand compacted to project specifications or compacted by alternative approved method by the geotechnical consultant (in writing, prior to construction). After 5 feet (vertical) of fill is in place, contractor should maintain a 5-foot radius equipment clearance from riser. Place and mechanically hand compact initial 2 feet of fill prior to establishing the initial reading. In the event of damage to the settlement plate or extension resulting from equipment operating within the specified clearance area, contractor should immediately notify the geotechnical consultant and should be responsible for restoring the settlement plates to working order. An alternate design and method of installation may be provided at the discretion of the geotechnical consultant. SETTLEMENT PLATE AND RISER DETAIL Plate F-18 2-foot x 2-foot x Y4-inch steel plate 3tandard 3%-inch pipe nipple welded to top of plate 1-inch x 5-foot galvanized pipe, andard pipe threads top and bottom; ctensions threaded on both ends and Jded in 5-foot increments 3-inch schedule 40 PVC pipe sleeve, add n 5-foot increments with glue joints Finish grade %-inch-diameter X 6-inch-long carriage bolt or equivalent I • • • 6-inch diameter X 3 to 6 feet S 3Y-inch-long hole • d6 • - Concrete backfill TYPICAL SURFACE SETTLEMENT MONUMENT Plate F-19 SIDE VIEW Spoil pile 2V Test pit TOP MEW Flag Flag Spoil pile Test pit Light Vehicle 50 feet rn 50 feet 100 feet TEST PIT SAFETY DIAGRAM Plate F-20 I I I I I I I "'.." I I : ~ I _____ I ! GS! LEGEND . I I I I ~ I I 1 I - I I ~ / kfil/1,71- I I - I I I I ~ . _~ , i 01 ''I ~ I/I. I ~ I I, 11 Irial/ " - I I / .. ,, fl-,~1, all'; ~II / ":::: '__1 I_---_~:: --- ~ _ __ - - __ I I : Roadway fill I I i A fr - I I I- I ,~ , / . I I . i I I /~~ I /p IAN " jjs""'il"I'll -JU, -) ~ ,a I I . : III . , ---_z I C 'im I ~ I—, .1/~W,q?r,u1_3_, 1-11 11%W / I . I '', , ~-1---l...- I , \,~./,~' X11 ~ 'Iitl~ 1i --,-, I .- - _-, - __ - i i ,,-' I , . , - __ __71 11 - ~~ , . Y". :,\ X~~ / / , . . ~ / , , ~ 1 V; It 11 '11 i - " I I ~ - -is ~ I / 11 ,, , , 111,1,:~";~,,% I ~~;~ -_ `- t \ ~ I A fn - Non structured fill, GS1 (2008c) ~")/ ~L / ~ Afc -Artificial fill - placed under the purveiw of GSI (2008a) /,i` I/////, , / / I " - A 1,11h, 11, . L~~__ . . \ - '/ I i I I - 71~xj~ Il ^ . ", !R_ x 1, / ~ - Quaternary alluvium (circled where buried) I /, w , , \//,,L,', __j- , - ~ ~ Qal I , I., ). .-- l -J~- I I I I ~-, , / 1) , , I . I //' ~ I I - Z;~ ,or- " I 1_~~ -,~I/l Qt ... ~_ ". Iya - -~_:== -_ - ~ _/ / I je'-If ~ A' )_,~__ I'. ~- - Quaternary terrace deposits (circled where buried)1. ) // , I I I / I 11, 1 1 I I 6JI/ , ~*6~ , , /,W--Br 1 =;:~4__M , I -1 __ / I . I 1-1.11 _~~ I I - ,, I I I . 1 L I . ~A K A_ 10 --- ~--,77______",:~1_1 ,,,, --:~,,-__,~__~~ ~~__ "~__ / ) ) 1 1 1 1 1 1 / ; 1 / V I / I I I ( 'I • Tsa - Tertiary Santiago Formation (circled where buried) 1 ' ///II ,/, _ 4' / T gi ]ll isplKgr - Jurassic Santiago Peak Volcanics and Cretaceous granitics I I I / / 1 / / - / - Approximate location of ___ 8 - i I \ \ i k J 11 115 - Approximate location of geologic contact (queried -where uncertain) - " ", A/ " 'I ~, R", I ~ i F20~ - Approximate depth of removal (feet) I I . ,,, , //, / , , /.// I/ K I i/ , , /, ~",' Y - ~?g) ~)1,71;~,, , I ~-, i 'l I t, 1, \ - - \11 8 / -1 / . I I . I /// ; Ifil, ,,~, - ~, //, , _~-,~ ;~ ~;,,,,,/ ~ ~ /I ,f ,,, I I , ~ ", ,I V\1 1XV , - 'I ~ ~ ~ ~- - - --> - Approximate location of SubdrainlToe Drain I I / / -1 j, // I I I I 1, III till" f", I I ~ \ . ~~11'1",\\Iv~ "-,, C,V/ - /I I ~, -1 \~, ~ , , , , , # , '' )F I li\ J~ . 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I I 1 117 ~N)\ li~! - ~ I I , ,/??,1'x /,,~, I ~,,,,11" /-,,~ / ( , / - - 1;7~ - ) 11__/ / )` 11 0- , \ 10, n_(_~ " ~", __~t_ ,---/ / RIVERSIDE CO. I . L I I ,..11 GÔSÔI1 iic ORANGE Co. IL SANDIEGOCO. REWSED5M1/2O11 . I I r H I . I . SCHEMATIC I ' L HAPH/C SCALE GRADING EXHIBIT I I 100 0 12O 200 - Plate 3 = 100' wO. 6145-A 1-SC DATE: 6/11 f SCALE: 1" 100' p62' 1T 63 @75' 4j,/5 GSI LEGEND / B-201 I b-_. Afr — Roadway fill 0 - Approximate location and total depth of hollow—stem explaratory boring " Y A fn - Non structured fill, CS! (2008a) (Cs!, 2011a) Afc - Artificial fill - placed under the purveiw of CS! (2008a) 0 Approximate location and total depth of hollow stem explaratory boring ,. / - ' -. I /7 11 ; ,lI'/ /ih' TD=41 1/2' (csi, 2010) '' ' ' ':j/j/I. "; 'J' '' / / "Iji A; Qal - Quaternary alluvium (circled where buried) BA-lol / / / / / : -jj . Q t - Quaternary terrace deposits (circled where buried) TD6' - Approximate location and total depth of large diameter exploratory boring ', /0 / I' ' , , / / I / I -_ / L sa - Tertiary Santiago Formation (circled where buried) B-I / / / r NTO7'EXIST 14 [/ I ' / ii,,, / / ,. ... 6 / WAfrERLINE _ft1 J sp/Kgr - Jurassic Santiago Peak Volcanics and retaceous granitics TD=51 - Approximate location and total depth of hollow—stem exploratory boring / 1 , - DqG191-7j (circled where buried) 2 J - / / / / / /r/ A B644 I @ 1' 6\.'(10%d" '81,' t74 I /,' ': / I ifi - P/ann in g Area - Approximate location and total depth of large diameter exploratory boring BA2 \ \ ' ' I ! fl':: 1' ,t / /' , / ' , ' " ',, '181 69 '' "z' ", í'!. ' 9 - Approximate location of pre—Holocen e fault, queried where uncertain TD 100 (CS!, 2004b) / @ 19 2 5 "i/ / / 1 / (I / / / 7, /i / \ HB-6 @ 6' 16i / ,,o' / , / ,// , / / I / ' / / / , , - Approximate location of geologic contact (queried where un certain) - Approximate location and total depth of hollow—stem exploratory boring @ 29 ,"4 ''/ / / ' ' " 1 -- " BA-4 / 'I " ('(I; / \ \\ - Approximate location of concealed geologic contact TD51 5' (Gsl, 2oo2 @ 9' 171 @44' 3\ '2' / '- 'L' / <TD=100' / O1)P1 )I (queried where uncertain) K' . . @18' 6 ///S yi ; - 'T'sa - 56tç/ _____________ - Approximate location of geologic cross section 45' 2 - / / ,/ / / ,/ _) / ': - '> " i / i / I i / ,, V \\ 55 \\ \ / - Fault attitude with dip (in degrees) -' 'a-- /-' ' _' 'J',' /',,' / - I / ,, I /j I ' 80 1201 - Approximate depth of removal (feet) @ 19 10 / ,g, '- I/I! / - Bedding attitude with dip (in degrees) 82 27 ' -; / - ,i9 10 I I : :- • \' '\ ,\ 152 161 - Approximate elevation (feet MSL) of removal bottom @ 26' 10j 65 7 / / / // / / ,., , ; - 7' ," ; / L 9T 'i - Approximate location of horizontal bedding ______________________________________________________________________________________ I ' - ,'" -- / . /0 / / 44 ./aJ"4/ 1\ ( / , r'/J:/I5/vpi46E. 90 - Fault attitude with dip (in degrees) 91,_c'O,IO 12/ 161 7'4\8 @44' -' / ,/ V " ,, ' ' ;/ / 2 '189 5 ' 15 " - -' - / ' / / -" //5/ / / / ,I I I TP-218 @57' - -/ / -T1 (\ / — / / / I /\/'S - Approximate location of exploratory test pit @19' 121 ,'—_- -- )/ , ' i--, 4 55 / 1 5' - Approximate location of exploratory test pit i @7' /4 5 -. %-,,'t i°' -'' 5'" / / 1675 1665 T'406 (GS! 2010) @47' 4 .\ ' '/ "'' ""-''' ' --.' - - - - - -'"' ''" TP-43 - -5, / , ,- /'_/ - - - - — - , TIE TO 'EXIST - - - 168 ' 166 ' '' (CS!, 2002) / 'y ' . C" ,g,/;/' /// / I, ._ j"/. r) / 9 , - \\\ 5 I I @55' 241 )' -5 :.9 - 2F / . -'5 / / .- •. . Tsa // /\/, / 1 - - - - - 7' , ' " ' 5, / / 4/ / / 196 / / / 7 / - / / l61 5 / / _______________________________________________ - " - -, - - ----', ' ," 'I,,- 7,,,; ',' ' y" / 11 ,/ Z1'96 / / / / / / / - / 7 / / / 7 \ \ \ / / / ;-'5 ( / / / / / / / / - L / i)i.,_Ic-< / Ø i,., \J (II •. -"' '_ < (, - / 'I_'_ '' / ';-- - -5,, -.5 5'pI. - / / ,, /L::" / / / TP-208/ _\\"\\ \ - .tTP-204 ' >c ." / ,5,S'6 —vJc-55I '5<r--L 'I\fl '1 1 U • / //_,\_ <-''jrp.'1 ,----,, / '~/,,-- '.// I—& / '5< J'/ / \, 5-. .,' . - z -\ 9 '\I I I - . .. /. I 'S V I /"'1"' -5' 5' -S -. •" . / ' '\- . •' S I I , ft(2 / I "— : ) " _~i L 1) I / / ' '-1 , 173 5" "5"- 16 / / / ,/SI j / / I I / N, "\ 55 / / / '/ I- / /14 H bl-1 \\ / 4\UNDARY / jø ,..-.-/ '/ A-2 'V5' / 1 I r'/i 'I' / / - 2 5" 5' 1/ I / _______________________________________________________________________________ //IPER/'MASTERPLAN-..''/'1.'/f!,' 140 _- .-- , '-- - --- . 5, ,,,'7 -'- ,\///I /4/. 5/ //5 /t / _______ / v-/f,"\ - 5, /Y//- " ,/ s ''rp 104 -' -'5 --.5-- - - I - I / - - - / , I\ - -/ / / /<'/ ' /y / / I I -- ____ ___ I I I / /1 / - T- ____ - - '- " " ;_; - '' - -- - /1 / /1 N 182 -' 182- 83'- -184 "-, I / / \ / , 73 / 1 '/\ - - "5 /\//\/\ 55 - "5- / / / / N,, '. 18" 184 182 180 178 I / 1755 - I / ---" / 9a*m,,SS)\\\//\\ 55'--' ."" _." 1/f/I / - \ ' / - Tsa1..... --. ' / ' ,1' '-'5 :- I -. // -.5-- .55'- - 55 -'-_,5 '5 - / / /_ 1 4; 2- c J \'5..'5_'.. :S5'5 / I / / / 55 TP-3- I - 4 / '5 -'5 -' \ \ -----.5 - / \ 4, -'c------ /S,"5'S5'•"b \ \ \ / -' I --,, <"N ., - - \ '5"C,_____ ,N ( - / \ I-"'-4 '5- N, I N 5' "'-- / - - 55, ,, - - -'--N'--'-,, ' '4 \ / I / /,' " '--.5' '- '-._,,,,, N, -, 5'. TP-6 - - 59 / / \'\ \\ '-T- ''k, / 166 67-5 169 11695 16 / 1695 168 166 164 162 \ \\\\\\\\\\\\\\\ -J 7' \/5' _— — -- 4 / $QIS ' f 'Ill /7 /44 / - / N 5' - / - - - TP- I - 458 /\ / i / / 1 I / / / / 1 / I / 'x // / / / / \ N.,, ', '" .' - $ / '_\ \ ___ / - '- - i " f I / 1 1 I / / / / / '\\ &:, " '-.5/-- - b" / / / •- 6 1 69" 169 5 1 Cl 69 1 67 1 65 5 1 61 5 r60 ,i ' ' / / / 'i' /,/ / I / / / / 4 -/ -, - -' -- \ iY'/ / T I IL /// II (Figure No "11-8 )"_- II, - — -/ / / -' — 7 /// I''N" / / I / / I I I I / ECEIVED 3//2Oi 1- ' ' ;' \ \. " N] ,, -. \ '_' /i 3 0'\ TP-102 7':-. ' I / / / "R. ,, ,, --<,, 5' 143 1435 1435 r 142 - /'\ (// / ' / /I 6 1 TP-212 - ,7/ - - 55 / I '-' I ,/'/ - //j - / / I --'_ \PI i / / / I i, / - /\ \/ 1/ \ ç" I\ I I t_, _\ '5' 5' -. - -e------ ••— ___?_:-------S. - I " _" , 4/ / ,/ / 1/ ,/ / / 1 )1 / / A 5' A 1 3'5'- _____ — — — — - - : k-'- ".t 71_i I a 1 / / "k / / I 't \ -_ )/./'t \/ 55 — 55, / I oa 0 ' /_/ ' I / '/1 / / / // / /, / /i I ' / \' \ ' \\ C.. / / "'-._, , ,,/ ' 7/ / // / i-., / \// ' 140 I - - / 6 / , //JI ///I II / 1 1 I I I 7J ' <b'-'N]" - I - / !_---_ ,,, / V ,\ - - - / :- // 4 / / * N - N N / ___J / I / / i / / I - '5 QaI ' 3 5 L.J ,_-" "/// / /Z_ ui/ / ,', j __ ' -I /' -'5' 4 (fi25/ ')1 / /\\ 5555 / / 1 / / / I 5' ',/// ) 1/,' II i/)/i/ ,j / 'u1"//y / '''::' \ \ \ h, I 5'__/ /4 --,_-- / / 1 5' I / , 4 .5-_S / / / / jll ,, / / \BAI - 14 1515 / / 1' ' / 138 / / / - —' I vI /1 TP22 Afc \\\\\ .\f 5' ( // 38 0 Afcj - 0__ - / •N I / TD-86"5 TP26 '--i_:----_: 132 - - -v--i /i'J \ 0T,7 ' -•. / area, please refer to GS!(2008a) / '//'/ 7'' / / . ,hh///,//•1 " M1fl I'--- /1_._ "\ i "jI/I e.4i , S / 4z2 26 - - a - - r - '5 ii 27 /124 - "'- \f //\\I\ \' ' area,pleaserefertoGS!(2008b) / ' @66' @39 _______________________________________________ @ 73' 10 1 @ 52' 8J 12\ - . ', . . - -. RIVERSIDE Co. 11 GeoSoiLc, hic ORANGE co. 57' 8 1 -...,' -, . -. SAN DIEGO CO.