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CT 04-01; YAMAMOTO SUBDIVISION; SOILS; 2004-01-01
Geotechnical • Geologic • Environmental 5741 Palmer Way • Carlsbaci, California 92008 • (760)438-3155 • FAX (760) 931-0915 January 26, 2004 W.0.4132-A1-SC Cunningham Consulting, Inc. 6469 Camino del Parque Carlsbad, California 92009 Attention: Subject: References: Mr. Dennis Cunningham Soil Corrosivity Test Results, Yamamota Property, APN 215-040-05, City of Carlsbad, San Diego County California. 1. "Preliminary Geotechnical Evaluation, Yamamota Property, APN 215-040-05, City of Carlsbad, San Diego County California, Work Order 4132-A-SC. dated December 30, 2003, by GeoSoils, Inc. 2. "Uniform Building Code; Wliittier, Califomia," 1997, Intemational Conference of Building Officials,' Dear Mr. Cunningham: GeoSoils, Inc. (GSI) has conducted sampling of site soils at the subject site for corrosivity, as previousfy discussed in GSI, 2003 (see Reference No. 1). Laboratory test results, completed by M.J. Schiff & Associates, Inc. (consulting corrosion engineers), are provided in the attached Figure 1. Unless specifically superseded herein, the conclusions and recommendations contained in the referenced report by GSI (see Reference No. 1), remain pertinent and applicable, and should be appropriately implemented during design and construction. SUMMARY Atypical sample ofthe site material was analyzed by M. J. Schiff and Associates, Inc., for corrosion/addity and sulfate potential. The testing included determination of soluble sulfates, pH, and saturated resistivity. Results indicate that site soils are very strongly acidic (pH=4.8) with respect to acidity and have a saturated resistivity of 1,000 ohm-cm. Thus, the site soils are con'osive to ferrous metals. Corrosive soils are considered to range between 1,000 to 2,000 ohms-cm. Testing indicates that the site soils have a sulfate content of 0.0258 percentage by weight. This corresponds to a negligible sulfate exposure to concrete (UBC range for negligible sulfate exposure is 0.00 to 0.10 percentage by weight soluble [SO4] in soil). Alternative testing methods and additional comments should be obtained from a qualified corrosion engineer. Laboratory test results are presented on the attached Figure 1. We appreciate the opportunity to be of further service. If you should have any questions, please do not hesitate to call our office. Respectfully submltted^^SD /ohn P. Franklin c.4 Engineering GeologistriCe David W. Skelly Civil Engineer, RCE 47857 RB/JPF/DWS/jk Attachment: Figure 1 - Soil Corrosivity Test Results Distribution: (4) Addressee Cunningham Consuiting, Inc. Yamamoto Property, APN 215-040-05 Rle;e;\wp9\4100/4132a1 .set W.0.4132-A1-SC January 26, 2004 Page 2 CrieoSofIs, lne. PRELIMINARY GEOTECHNICAL EVALUATION YAMAMOTA PROPERTY, APN 215-040-05 CARLSBAD, SAN DIEGO COUNTY, CALIFORNIA FOR CUNNINGHAM CONSULTING, INC. 6469 CAMINO DEL PARQUE CARLSBAD, CALIFORNIA 92009 W.O. 4132-A-SC JANUARY 8, 2004 Geotechnical • Geologic • Environmental 5741 Palmer Way • Garlsbad, California 92008 • (760)438-3155 • FAX (760) 931-0915 January 8, 2004 W.O. 4132-A-SC Cunningham Consulting, Inc. 6469 Camino del Parque Carlsbad, California 92009 Attention: Mr. Dennis Cunningham Subject: Preliminary Geotechnical Evaluation, Yamamota Property, APN 215-040-05, Carlsbad, San Diego County Califomia Dear Mr. Cunnignham: in accordance with your request, GeoSoils, Inc. (GSI) has performed a preliminary geotechnical evaluation ofthe subject site. The purpose ofthe study was to evaluate the onsite soils and geologic conditions, and their effects on the proposed site development from a geotechnical viewpoint. ^ - EXECUTIVE SUMMARY Based on-our review ofthe available data (see Appendix A), field exploration, laboratory testing, geologic and^engineering analysis, development of the property appears to be feasible from a geotechnical viewpoint, provided the recommendations presented in the text ofthis report are properly incorporated into the design and construction ofthe project. The most significant elements of this study are summarized below: • Based on the Tentative Map provided by M.L.B. Engineering, Inc., it appears that the proposed development will consist of the preparation of 16 relatively level building pads for the construction of one- or two-story, single-family residences, with associated infrastructure (i.e., underground utilities, streets, etc.). It appears that sewage disposal will be tied into the regional municipal system. The need for import soils is unknown at this time. • All deleterious debris and vegetation should be removed from the site and properly disposed of, should settlement-sensitive improvements be proposed within their influence. Removals of compressible undocumented artificial fill, colluvial soils, and weathered Quaternary-age terrace deposits will be necessary priorto fill placement. Depths of removals are outlined in the "Conclusions and Recommendations" section of this report. In general, removals will be on the order of ± 1 Va to ±5 feet across a majority of the site. However, localized deeper removals cannot be precluded. To provide for a uniform, minimum 3-foot compacted fill blanket, overexcavation of the terrace deposits to a depth of 3 feet below finish pad grade elevation is recommended. If proposed footings or isolated pad footings are deeper than 24 inches below finish pad grade elevation, additional overexcavation will be necessary to provide a minimum 12 inches of compacted fill beneath the footing. Due to the presence of a discontinuous, cemented hardpan exhibited withio-tbe terrace deposits, overexcavation of plan cut fflts tn .-^ fPPt hpinw paH graHo. and stieet rignt-of-ways to 1 foot below lowest utility invert should be considered in order to better facilitate trenching, if relatively lightweight trenching equipment (i.e., rubber tire backhoe) is to be utilized. However, this is not a geotechnical j^uirement. (J\\\s cundiiioii (hard mck poteritial). should be riis?;inRealiQTp~^ jnterested parties, including homeowners.\^ Plan cut lots exhibiting contrasting features and/or heterogenous stratigraphy (i.e., sands juxtaposed to clays) at finish grade should be overexcavated 3 feet below pad grade for mitigation of these conditions. Maximum to minimum fill thickness below the foundation elements ofthe structures should not exceed a ratio of 3:1 (maximum:minimum). Based on site conditions and planned improvements, fill slopes UP to ±21ijegt^in height an^;;;cuLslQPfis iip to ±lil_feet in height are proposed. Based on our evaluation, such slopes are generally anticipated to perform satisfactorily; however, the need for slope stabilization of cut slopes during grading cannot be precluded. The j>;pafistOnp^enti3k)f tested onsite soils rapqefromryeiylow)t6jo\^ . 1^ IndexfE.I.] 0 to So). H^lvever the potential for medium expansive soils exposed at iO* ^ finish grade cannot be precluded. Conventional foundations may hp» i itiiiyed fnr these identified soil conditions: however URC nrltfiria may snpfifefidft the minimf^^, design recommendationsprovided herein, necessitating post-tension design. Post- tensioTi lounaaiions may also be utilized, and may be recommended if pervasive paleoliquefaction features are encountered onsite. • At the present time, laboratory test results concerning the corrosion potential and sulfate exposure of site soils were not available. An addendum report, presenting these laboratory test results, will be issued when the data is made available. • Groundwater was not observed during the field investigation and is not expected to be a major factor in development of the site. However, due to the nature of the site materials, seepage and/or perched groundwater conditions may develop Cunningham Consulting, Inc. . W.O. 4132-A-SC Flle:e:\wp9\4100\4132a.pge Page Two GeoSoils, Inc. throughout the site along boundaries of contrasting permeabilities (i.e., fill/terrace deposit contacts), and should be anticipated. Our evaluation indicates that the site has ^Qgwpotential for liquefaction) Therefore, no recommendations for mitigation are deemed necessary at this time. The seismic acceleration values and design parameters provided herein should be considered during the design ofthe proposed development. Our evaluation indicates that there are no known active faults crossing the site. Adverse geologic features that would predlude project feasibility were not encountered. The recommendations presented in this report should be incorporated into the design and construction phases of the project. The opportunity to be of service is greatly appreciated. If you have any questions concerning this report, or if we may be of further assistance, please do not hesitate to contact any of the undersigned. Respectfully submitted, GeoSoils, Inc. Ryan Boehmer Staff Geologist Reviewed by: John P. Frknklin xJ^^Vx-rr." Engineering Geologist, CEG RB/JPF/DWS/jh/jk Distribution: (6) Addressee Reviewed by: r na\/iH W CiU i,t,J I Kf,T rsr ". .f-7->.-;? \ David W. Skelly Civil Engineer, RCE 478i •'>.0^\/Z Cunningham Consulting, Inc. File:e:\wp9\4100\4132a.pge W.O. 4132-A-SC Page Three OeoSoilSf Ine. TABLE OF CONTENTS SCOPE OF SERVICES 1 SITE CONDITIONS/PROPOSED DEVELOPMENT 1 SITE EXPLORATION 3 REGIONAL GEOLOGY 3 SITE GEOLOGIC UNITS 3 Artificial Fill (Undocumented) - (Map Symbol - afu) 3 Topsoil/Colluvium (Not Mapped) 4 Quaternary-Age Terrace Deposits (Map Symbol - Qt) 4 FAULTING AND REGIONAL SEISMICITY 4 Regional Faults 4 Seismicity 6 Seismic Shaking Parameters 7 Seismic Hazards 8 GROUNDWATER ; 8 LIQUEFACTION POTENTIAL 9 Paleoliquefaction Features 10 SLOPE STABILITY EVALUATION 10 l-ABORATORY TESTING 10 General 10 , Classification . 10 Moisture-Density Relations 11 Laboratory Standard 11 Expansion Potential 11 Direct Shear Test 11 Atterberg Limits 12 Corrosion/Sulfate Testing 12 CONCLUSIONS 12 General 12 EARTHWORK CONSTRUCTION RECOMMENDATIONS 15 General 15 Site Preparation 15 Removals (Unsuitable Surficial Materials) 15 Fill Placement 15 Transitions/Overexcavation 16 GeoSoils, Inc. SUBDRAINS .jg RECOMMENDATIONS - FOUNDATIONS 16 Preliminary Foundation Design 16 Bearing Value 17 Lateral Pressure ^7 Foundation Settlement is Footing Setbacks is Construction .jg Very Low to Low Expansion Potential (E.l. 0 to 50) is Medium Expansion Potential (E.l. 51 to 90) 19 POST-TENSIONED SLAB SYSTEMS 20 Post-Tensioning Institute Method ^ .... ' 21 CORROSION 22 UTILITIES 22 WALL DESIGN PARAMETERS 23 Conventional Retaining Walls ^ ^ " ^ ..... 23 Restrained Walls 23 Cantilevered Walls 23 Retaining Wall Backfill and Drainage 24 Wall/Retaining Wall Footing Transitions 24 TOP-OF-SLOPE WALLS/FENCES/IMPROVEMENTS 28 Slope Creep 28 Top of Slope Walls/Fences 29 DRIVEWAY, FLATWORK, AND OTHER IMPROVEMENTS 30 DEVELOPMENT CRITERIA 32 Slope Deformation 32 Slope Maintenance and Planting ' ^ ^ .." 32 Drainage ' ^ "33 Erosion Control 33 Landscape Maintenance 33 Gutters and Downspouts 34 Subsurface and Surface Water 34 Site Improvements 34 Tile Flooring 35 Additional Grading 35 Footing Trench Excavation ...'.*. 35 Cunningham Consulting, Inc. File:e:\wp9\4100\4132a.pge Table of Contents Page ii GeoSoils, Ine. Trenching 35 Utility Trench Backfill 35 SUMMARY OF RECOMMENDATIONS REGARDING GEOTECHNICAL OBSERVATION AND 36 OTHER DESIGN PROFESSIONALS/CONSULTANTS 37 PLAN REVIEW LIMITATIONS 37 37 FIGURES: Figure 1 - Site Location Map 2 Figure 2 -California Fault Map 5 Detail 1 - Typical Retaining Wall backfill and Drainage Detail .. . . . . . 25 Detail 2 - Retaining Wall Backfill and Subdrain detail Geotextile Drain 26 Detail 3- Retaining Wall and Subdrain Detail Clean Sand Backfill 27 ATTACHMENTS: Appendix A - References Rear of Text Appendix B - Test Pit Logs : . . ".'' Rear of Text Appendix C - EQFAULT, EQSEARCH, and FRISKSP Rear of Text Appendix D - Laboratory Data Rear of Text Appendix E - General Earthwork and Grading Guidelines Rear of Text Plate 1 - Geotechnical Map Rear of Text in Folder Cunningham Consulting, Inc. Table of Contents File:e:\wp9\4100\4132a.pge pggg jjj GeoSoils, Ine. PREUMINARY GEOTECHNICAL EVALUATION YAMAMOTA PROPERTY, APN 215-040-05 CARLSBAD, SAN DIEGO COUNTY, CALIFORNIA SCOPE OF SERVICES The scope of our services has included the following: 1. Review of the available geologic literature for the site (see Appendix A). 2. Geologic site reconnaissance, subsurface exptoration with seven exploratory test pit excavations (see Appendix B), sampling, and mapping. 3. General areal seismicity evaluation (see Appendix C). 4. Appropriate laboratory testing of representative soil samples (see Appendix D). 5. Engineering and geologic analysis of data collected. 6. Preparation of this report. J'. • . .i SITE CONDITIONS/PROPOSED DEVELOPMENT The subject site is a roughly reetangular shaped property located on the southeast corner of the intersection of Black Rail Road and Songbird Avenue in the City of Carlsbad, California (see Figure 1, Site Location Map). The property slopes to the west at an approximate gradient of about 6:1 (horizontal: vertical), or flatter. An approximately 15-foot high (maximum) cut slope is located on the northern margin of the property that was likely constructed for Songbird Avenue. Site drainage is by sheet flow runoff, apparently directed toward the west. Vegetation consists of weeds and one tree. Based on the Tentative Map provided by M.L.B. Engineering, it appears that proposed development will consist of preparing 16 relatively level pads for the construction of one- or two-story, single-family residences, utilizing wood frames and slabs-on-grade, and associated infrastructure (i.e., underground utilities, streets, etc.). Building loads are assumed to be typical for this type of relatively light construction. It appears that cut and fill grading techniques will be utilized to bring the site to design grades. Fill slopes up to ±21 feet in height and cut slopes up to ±10 feet in height are proposed. It is anticipated that sewage disposal will be tied into the regional municipal system. The need for import soils is unknown at this time. GeoSoils, Inc. J-DTopoQuadi Copyright« 1999 D«I.oniie YannouUi, ME 04096 .Sourti Data: USGS Base Map: Encinitas Quadrangle. Californla-San Diego Co., 7.5 Minute Series (Topographic), 1968 (photo revised 1975); by U§GS, 1"=2000' Scale 2000 4000 Feet N W.O. 4084-A-SC SITE LOCATION MAP Figure 1 SITE EXPLORATION Surface observations and subsurface explorations were performed on December 17 2003 by a representative of this office. A survey of line and grade for the subject lot was not conducted by this firm at the time of our site reconnaissance. Near surface soil conditions were explored with seven test pit excavations within the site to evaluate soil and geologic conditions. The approximate locations of each test pit are shown on the attached Geotechnical Map (see Plate 1). Test Pit Logs are presented in Appendix B. REGIONAL GEOLOGY The subject property is located within a prominent natural geomorphic province in southwestem Califomia known as the Peninsular Ranges. It Is characterized by steep elongated mountain ranges and valleys that trend northwesterly. The mountain ranges are underlain by basement rocks consisting of pre-Cretaceous metasedimentary rocks Jurassic metavolcanic rocks, and Cretaceous plutonic rocks of the southem Califomia batholith. In the San Diego County region, deposition occurred during the Cretaceous Period and Cenozoic Era in the continental margin of a forearc basin. Sediments, derived from Cretaceous-age plutonic rocks and Jurassic-age volcanic rocks, were deposited Into the narrow, steep, coastal plain and continental margin ofthe basin. These rocks have been uplifted, eroded, and deeply incised. During early Pleistocene time, a broad coastal plain was developed from the deposition of marine terrace deposits. During mid to late Pleistocene time, this plain was uplifted, eroded, and incised. Alluvial deposits have since filled the lower valleys, and young marine sediments are currently being deposited/eroded within coastal and beach areas. SITE GEOLOGIC UNITC The site geologic units encountered during our subsurface investigation and site reconnaissance included undocumented artificial fill, topsoil/colluvium and Quaternary-age terrace deposits. The earth materials are generally described below from the youngest to the oldest. The distribution of these materials is shown on Plate 1. Artificial Fill (Undocumented) - (Mao Symbol - afu) Undocumented artificial fill was observed to mantle the site within Test Pits TP-3 and TP-5 The encountered undocumented artificial fill consists of brown sands with silt to silty sands that are dry to damp, loose to medium dense, and porous. Varying amounts of deleterious debns were also observed within the fill. These materials are considered potentially compressible in their existing state and will require removal and recompaction if Cunningham Consulting, Inc. ~ ~~ WO 4132 A sr IrTTJ^""^' J-n'^-^y 8."2004 File:e:\wp9\4100\4132a.pge Page 3 GeoSoils, Ine. settlement-sensitive improvements and/or engineered fill are proposed within their influence. Topsoll/Colluvium (Not Mapped) Topsoil/colluvium was observed to directly mantle the site in Test Pits TP-1, TP-2, TP-4, TP-6, and TP-7. These colluvial soils consist of brown to red brown, dry to damp,' loose to medium dense, porous silty sands, and brown, dry to damp, loose, porous sands with silt that are approximately ±1 to ±3 feet thick. These materials are considered potentially compressible in their existing state and will require removal and recompaction if settlement-sensitive improvements and/or engineered fill are proposed within their influence. Quaternarv-Aae Terrace Deposits (Mao Symbol - Qt) Quaternary-age terrace deposits were observed to underlie the undocumented fill and topsoil/colluvium. These deposits are considered suitable bearing strata for the site and consist of very stiff to hard sandy clays, dense to very dense clayey sands, very dense silty sands, and very dense sands with silt. These deposits are generally olive gray to olive brown to yellow brown to orange to dark gray and dry to moist. The upper ±V2 to ±2 feet of these sediments are generally weathered and are considered unsuitable for structural support of settlement-sensitive Improvements and/or engineered fill in its present condition, and should be removed and recompacted or processed in place. Bedding structure was not readily obsen/ed, but regionally is typically flat lying to subhorizontal These sediments are typically massive to weakly bedded. The terrace deposits, encountered, possess a discontinuous, well cemented hardpan. Based on our experience with other projects in the immediate vicinity, this hardpan Is believed to be on the order of ±1 to ±2 feet thick, and most likely will present difficulty during underground utility excavations if relatively light equipment (i.e., rubber-tire backhoe) Is used. However, the hardpan Is generally considered to be rippable with heavy grading equipment (D-9 or equivalent). FAULTING AND REGIONAL SEISMICITY Reaional Faults Our review indicates that there are no known active faults crossing this site within the area proposed for development, and the site Is not within an Earthquake Fault Zone (Hart and Bryant, 1997). However, the site is situated In an area of active as well as potentially active faulting. These include, but are not limited to: the San Andreas fault; the San Jacinto fault; the Elsinore fault; the Coronado Bank fault zone; and the Newport-Inglewood - Rose Canyon fault zone. The location of these, and other major faults relative to the site are indicated on Figure 2 (Califomia Fault Map). The possibility of ground acceleration, or Cunningham Consulting, Inc. ~ WO 4132 A SC Yamamota Property, Carlsbad January 8 2004 File:e:\wp9\4100\4132a.pge Page 4 GeoSoils, Itie. 1100 1000 CALIFORNIA FAULT MAP CUNNINGHAM -400 -300 -200 -100 0 100 200 300 400 500 600 W.O. 4132-A-SC Figure 2 shaking at the site, may be considered as approximately similar to the southern Califomia region as a whole. Major active fault zones that may have a significant affect on the site, should they experience activity, are listed in the following table (modified from Blake 2000a): ABBREVIATED FAULT NAME APPROXIMATE DISTANCE MILES (KM) Rose Canyon 5.5 (8.9) Newport-Inglewood (Offshore) 9.1 (14.6) Coronado Bank 20.9 (33.6) Elsinore-Temecula 24.5 (39.4) Elsinore-Julian 24.5 (39.4) Elsinore-Glen Ivy 37.2 (59.8) Palos Verdes 39.6 (63.8) Earthquake Valley 41.1 (66.2) San Jacinto-Anza 47.3 (76.2) San Jacinto-San Jacinto Valley 48.7 (78.3) Seismicitv The acceleration-attenuation relations of Bozorgnia, Campbell, and NiazI (1999) and Campbell and Bozorgnia (1997) have been incorporated Into EQFAULT (Blake, 2000a). EQFAULT is a computer program developed by Thomas F. Blake (2000a), which performs deterministic seismic hazard analyses using digitized California faults as earthquake sources. The program estimates the closest distance between each fault and a given site. If a fault is found to be within a user-selected radius, the program estimates peak horizontal ground acceleration that may occur at the site from an upper bound ("maximum credible") earthquake on that fault. Site acceleration (g) Is computed by one or more user-selected acceleration-attenuation relations that are contained In EQFAULT. Based on the EQFAULT program, peak horizontal ground accelerations from an upper bound event at the site may be on the order of 0.53g to 0.62g. The computer printouts of portions ofthe EQFAULT program are included within Appendix C. Cunningham Consulting, Inc. Yamamota Property, Carlsbad Flle:e:\wp9\4100\4132a.pge W.O. 4132-A-SC January 8, 2004 Page 6 GeoSoils. Inc. Historical site seismicity was evaluated with the acceleration-attenuation relations of Bozorgnia, Campbell, and Niazi (1999), and the computer program EQSEARCH (Blake, 2000b). This program performs a search of the historical earthquake records for magnitude 5.0 to 9.0 seismic events within a 100-mile radius, between the years 1800 to June, 2003. Based on the selected acceleration-attenuation relationship, a peak horizontal ground acceleration is estimated, which may have effected the site during the specific event listed. Based on the available data and the attenuation relationship used, the estimated maximum (peak) site acceleration during the period 1800 to June, 2003 was 0.41 g. Site specific probability of exceeding various peak horizontal ground accelerations and a seismic recurrence curve are also estimated/generated from the historical data. Computer printouts ofthe EQSEARCH program are presented in Appendix C. A probabilistic seismic hazards analyses was performed using FRISKSP (Blake, 2000c), which models earthquake sources as 3-D planes and evaluates the site specific probabilities of exceedance for given peak acceleration levels or pseudo-relative velocity levels. Based on a review ofthis data, and considering the relative seismic activity ofthe southern California region, a peak horizontal ground acceleration of 0.30g was calculated. This value was chosen as it corresponds to a 10 percent probability of exceedance in 50 years (or a 475-year return period). Computer printouts ofthe FRISKSP program are included in Appendix C. Seismic Shaking Parameters Based on the site conditions. Chapter 16 of the Uniform Building Code ([UBC], International Conference of Building Officials [ICBO], 1997) seismic parameters are provided in the following table: 1997 UBC CHAPTER 16 TABLE NO, SEISMIC PARAMETERS Seismic Zone (per Figure 16-2*) 4 Seismic Zone Factor (per Table 16-1*) 0.40 Soil Profile Type (per Table 16-J*) SD Seismic Coefficient C3 (per Table 16-Q*) 0.44N^ Seismic Coefficient C^(per Table 16-R*) 0.64N^ Near Source Factor N^ (per Table 16-S*) 1.0 Near Source Factor N„ (per Table 16-T*) 1.02 Distance to Seismic Source 5.5 mi (8.9 km) Cunningham Consulting, Inc. Yamamota Property, Carlsbad File:e:\wp9\4100\4132a.pge W.O. 4132-A-SC January 8,2004 Page 7 GeoSoils. Inc. 1997 UBC CHAPTER 16 TABLE NO. SEISMIC PARAMETERS Seismic Source Type (per Table 16-U*) B Upper Bound Earthquake (Rose Canyon fault) M„ 6.9 * Figure and Table references from Chapter 16 of the UBC (ICBO, 1997) Seismic Hazards The following list includes other seismic related hazards that have been considered during our evaluation ofthe site. The hazards listed are considered negligible and/or completely mitigated as a result of site location, soil characteristics, and typical site development procedures: • Dynamic Settlement • Surface Fault Rupture Ground Lurching or Shallow Ground Rupture • Seiche It Is Important to keep in perspective that In the event of a maximum probable or credible earthquake occurring on any of the nearby major faults, strong ground shaking would occur in the subject site's general area. Potential damage to any structure(s) would likely be greatest from the vibrations and Impelling force caused by the inertia of a structure's mass than from those Induced by the hazards considered above. This potential would be no greater than that for other existing structures and improvements in the Immediate vicinity. GROUNDWATER Subsurface water was not encountered within the property during field work performed in preparation of this report. Subsurface water Is not anticipated to adversely affect site development, provided thatthe recommendations contained In this report are Incorporated Into final design and construction. These observations reflect site conditions at the time of our investigation and do not preclude future changes in local groundwater conditions from excessive Irrigation, precipitation, or conditions that were not obvious at the time of our investigation. The regional groundwater table is anticipated to be near Mean Sea Level (MSL). Perched groundwater conditions along fill/terrace deposit contacts, and along zones of contrasting permeabilities, may not be precluded from occurring in the future due to site Irrigation, poor drainage conditions, or damaged utilities and should be anticipated. Cunningham Consulting, Inc. W.O. 4132-A-SC Yamamota Property, Carlsbad January 8, 2004 File:e:\wp9\4100\4132a.pge Page 8 GeoSoils. Inc. Should perched groundwater conditions develop, this office could assess the affected area(s) and provide the appropriate recommendations to mitigate the observed groundwater conditions. LIQUEFACTION POTENTIAL Seismically-induced liquefaction is a phenomenon in which cyclic stresses, produced by earthquake-induced ground motion, create excess pore pressures In soils. The soils may thereby acquire a high degree of mobility, and lead to lateral movement, sliding, sand boils, consolidation and settlement of loose sediments, and other damaging deformations. This phenomenon occurs only below the water table; but after liquefaction has developed. It can propagate upward into overlying, non-saturated soil as excess pore water dissipates. Typically, liquefaction has a relatively low potential at depths greater than 45 feet and is virtually unknown below a depth of 60 feet. Liquefaction susceptibility is related to numerous factors and the following conditions should be concurrently present for liquefaction to occur: 1) sediments must be relatively young in age and not have developed a large amount of cementation; 2) sediments generally consist of medium to fine grained relatively cohesionless sands; 3) the sediments must have low relative density; 4) free groundwater must be present In the sediment; and 5) the site must experience a seismic event of a sufficient duration and magnitude, to Induce straining of soil particles. The condition of liquefaction has two principal effects. One is the consolidation of loose sediments with resultant settlement of the ground surface. The other effect is lateral sliding. Significant permanent lateral movement generally occurs only when there is significant differential loading, such as fill or natural ground slopes within susceptible materials. No such loading conditions were obsen/ed to exist on the site. In the site area, we found there is a potential for seismic activity and a groundwater table deeper than 50 feet below the ground surface. Additionally, the encountered terrace deposits were primarily silty to clayey, fine to medium grained, massively bedded, and become very dense/hard with depth. Since at least two or three of these five required concurrent conditions discussed above do not have the potential to affect the site, and considering the recommended remedial removals, our evaluation indicates that the potential for liquefaction and associated adverse effects within the site is low, even with a future rise in groundwater levels. The site conditions will also be improved by removal and recompaction of low density near-surface soils. Therefore, it is our opinion that the liquefaction potential does not constitute a significant risk to site development. Cunningham Consulting, Inc. \fj Q 4-|32-A-SC Yamamota Property, Carlsbad January 8, 2004 Flle:e:\wp9\4100\4132a.pge Page 9 GeoSoils. Inc. Paleoliquefaction Features Paleoliquefaction features ("sand blows," sand filled fissures and injection dikes, sand vents, etc.) were noted in the area during our field investigation, and were observed by GSI during the grading operations for a nearby site. As stated above, the potential for liquefaction and associated surface manifestation at the site is considered to be low, provided that the recommendations presented in this report are incorporated Into the design and construction phases ofthe project. These features are related to paleoseismic activity and should be mitigated during site grading, provided that every lot contains a minimum 3-foot thick compacted fill blanket across the entire lot. SLOPE STABIUTY EVALUATION Based on laboratory testing and our experience with similar projects, cut and fill slopes constructed using onsite materials, to the proposed heights, should be grossly and surflcially stable provided the recommendations contained herein are implemented during site planning and development. The terrace deposits mapped during pur field investigation were relatively massive to weakly bedded and it has been our experience that the terrace deposits exhibit subhorizontal bedding on a regional scale. Laboratory testing also indicates that these materials possess a high shear strength. These conditions do not suggest a potential for slope Instability. However, geologic structure should be further evaluated during actual site earthwork to assess terrace deposit structure relative to actual slope locations and configurations. Although unlikely, if adverse geologic structures are encountered, supplemental recommendations and earthwork may be warranted. These materials are potentially erosive. Therefore, post-construction slope maintenance measures are recommended. LABORATORY TESTING General Laboratory tests were performed on representative samples of the onsite earth materials In order to evaluate their physical characteristics. The test procedures used and results obtained are presented below. Classification Soils were classified visually according to the Unified Soils Classification System. The soil classifications are shown on the Test Pit Logs In Appendix B. Cunningham Consulting, Inc. W.O. 4132-A-SC Yamamota Property, Carlsbad January 8, 2004 File:e:\wp9\4100\4132a.pge Page 10 GeoSoils. Inc. Moisture-Density Relations The field moisture contents and dry unit weights were determined for selected undisturbed samples in the laboratory. The dry unit weight was determined in pounds per cubic foot (pcf), and the field moisture content was determined as a percentage of the dry weight. The results of these tests are shown on the Test Pit Logs in Appendix B. Laboratorv Standard The maximum dry density and optimum moisture content was determined for the major soil type encountered In the test pits. The laboratory standard used was ASTM D-1557. The moisture-density relationship obtained for this soil is shown below: 1 SOIL TYPE LOCATION AND bEPTH (FT) MAXIMUM DRY DENSITY (PCF) OPTIMUM MOISTURE CONTENT (%) 1 SILTY SAND, Dark Brown TP-1 @ 1-3 131.0 8.5 Expansion Potential Expansion testing was performed on a representative samples of site soil in accordance with UBC Standard 18-2. The results of expansion testing are presented In the following table. SAMPLE LOCATION AND DEPTH (FT) EXPANSION INDEX EXPANSION : POTENTIAL TP-1 @ 1-3' <5 Very Low TP-5 @ 3-5 35 Low Direct Shear Test Shear testing was performed on representative, "remolded" and "undisturbed" samples of site soil in general accordance with ASTM Test Method D-3080 In a Direct Shear Machine ofthe strain control type. The shear test results are presented as follows and are provided as Plate D-1 In Appendix D: Cunningham Consulting, Inc. Yamamota Property, Carlsbad Flle:e:\wp9\4100\4132a.pge W.O. 4132-A-SC January 8, 2004 Page 11 GeoSoils. Inc. SAMPLE LOCATION AND DEPTH (FT) PRIMARY RESIDUAL SAMPLE LOCATION AND DEPTH (FT) COHESION (PSF) FRICTION ANGLE (DEGREES) COHESION (PSF) FRICTION ANGLE (DEGREES) TP-1 @ 1-3' (Remolded) 209 29 126 30 TP-6 @ 11/2 (Undisturbed) 194 29 162 29 Atterberg Limits A test was performed on a selected representative fine grained soil sample to evaluate the liquid limit, plastic limit and plasticity index in general accordance with ASTM D4318-64. The test result Is presented in the following table and as Plate D-2 in Appendix D. SAMPLE LOCATION AND DEPTH (FT) LIQUID LIMIT PLASTIC LIMIT PLASTICITY INDEX TP-5 @ 3-5' 36 18 18 Corrosion/Sulfate Testing At the present time, laboratory test results concerning the corrosion potential and sulfate exposure of site soils were not available. An addendum report, presenting these laboratory test results, will be issued when the data is made available. CONCLUSIONS General Based on our field exploration, laboratory testing, and geotechnical engineering analysis, it is our opinion that the site appears suitable for the propesed development from a geotechnical engineering and geologic viewpoint, provided that the recommendations presented In the following sections are Incorporated into the design and construction phases of site development. The primary geotechnical concerns with respect to the proposed development are: Cunningham Consulting, Inc. Yamamota Property, Carlsbad Fiie:e:\wp9\4100\4132a.pge W.O. 4132-A-SC January 8, 2004 Page 12 GeoSoils. Inc. Depth to competent material. Overexcavation of streets and pads. Potential to encounter hard rock, and associated placement difficulties. Potential for perched groundwater after development Expansion and corrosion potential of site soils. Slope stability. Regional seismic activity. The recommendations presented herein consider these as well as other aspects ofthe site. The engineering analyses performed concerning site preparation and the recommendations presented herein have been completed using the information provided and obtained during our field work. In the event that any significant changes are made to proposed site development, the conclusions and recommendations contained in this report shall not be considered valid unless the changes are reviewed and the recommendations of this report 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. 1, Soil engineering, observation, and testing services should be provided during grading to aid the contractor in removing unsuitable soils and In his effort to compact the fill. 2. Geologic observations should be performed during grading to verify and/or further evaluate geologic conditions. Although unlikely. If adverse geologic structures are encountered, supplemental recommendations and earthwork may be warranted. 3. Existing undocumented artificial fill on the order of ±1/2 to ± 1 Va feet thick, colluvial soils to depths ranging from ±iy2 to ±3 feet, and the upper ±1 foot of the weathered terrace deposits are considered unsuitable for the support of settlement-sensitive improvements in their present condition, based on current Industry standards. These materials are potentially compressible in their present condition, and may be subject to differential settlement. Mitigation in the form of removal and recompaction will be necessary. 4. To provide for uniform foundation support, overexcavation of the terrace deposits to a depth of 3 feet below finish pad grade elevation is recommended for transition lots, lots with plan fill less than 3 feet and plan cut lots that exhibit heterogenous stratigraphy (i.e., sands juxtaposed to clays) and/or contrasting features at finish grade. If proposed footings or isolated pad footings are deeper than 24 inches below finish pad grade elevation, additional overexcavation will be necessary to provide a minimum 12 inches of compacted fill beneath the footing. Cunningham Consulting, Inc. W.O. 4132-A-SC Yamamota Property, Carlsbad January 8, 2004 Flle:e:\wp9\4100\4132a.pge Page 13 GeoSoils. Inc. 5. Due to the very dense nature of the hardpan encountered within some of the exploratory test pits, trenching for the placement of underground utilities, within the street areas, may be difficult to non-trenchable at relatively shallow depths with light-weight trenching equipment (i.e., rubber tire backhoe). Overexcavation to 1 foot below the lowest utility invert within the street right-of-way, during grading will better facilitate trenching for street utility improvements. However, this is not a geotechnical requirement. 6. In general and based upon the available data to date, groundwater Is not expected to be a major factor in development of the site assuming shallow excavations. However, perched groundwater conditions along fill/terrace deposit contacts, and along zones of contrasting permeabilities, may not be precluded from occurring in the future due to site Irrigation, poor drainage conditions, or damaged utilities and should be anticipated. Should perched groundwater conditions develop, this office could assess the affected area(s) and provide the appropriate recommendations to mitigate the observed groundwater conditions. In addition, subdrainage systems for the control of localized groundwater seepage should be anticipated. The proposed locations of such drains can be delineated at the grading plan review stage of planning. 7. Due to the non-cohesive nature of some of the onsite materials, some caving and sloughing may be anticipated to be a factor in subsurface excavations and trenching. Therefore, current local and state/federal safety ordinances for subsurface trenching should be enforced. 8. Our laboratory test results and experience on nearby sites related to expansion potential indicate that soils with low to possibly medium expansion Indices (locally) underlie the site. This should be considered during project design. Foundation design and construction recommendations are provided herein for low and medium expansion potential classifications. 9. Based on site conditions, laboratory testing, and our experience with other projects in the vicinity, cut and fill slopes should be grossly and surficlally stable to the proposed heights. Post grading slope maintenance measures are recommended. Additional evaluation during grading is recommended with regard to slope stabilization. 10. The seismlclty-acceleration values provided herein should be considered during the design of the proposed development. 11. General Earthwork and Grading Guidelines are provided at the end ofthis report as Appendix E. Specific recommendations are provided below. Cunningham Consulting, Inc. ~ WO 4132-A-SG Yamamota Property, Carlsbad January 8, 2004 File:e:\wp9\4100\4132a.pge Pagg -^^ GeoSoils, Inc. EARTHWORK CONSTRUCTION RECOMMENDATIONS General All grading should conform to the guidelines presented in Appendix Chapter A33 of the 1997 UBC, the requirements of the City, and the Grading Guidelines presented in Appendix E, except where specifically superceded In the text of this report. Prior to grading, a GSI representative should be present at the preconstruction meeting to provide additional grading guidelines, if needed, and review the earthwork schedule. During earthwork construction, all site preparation and the general grading procedures of the contractor should be observed and the fill selectively tested by a representative(s) of GSI. If unusual or unexpected conditions are exposed In the field, they should be reviewed by this office and, if warranted, modified and/or additional recommendations will be offered. All applicable requirements of local and national construction and general industry safety orders, the Occupational Safety and Health Act (OSHA), and the Construction Safety Act should be met. Site Preparation All deleterious materials should be removed from the site prior to the start of construction. Removals (Unsuitable Surficial Materials) Due to the relatively loose/soft condition of the undocumented artificial fill, topsoil/colluvium, and weathered terrace deposits, these materials should be removed and recompacted in areas proposed for settlement-sensitive improvements or areas to receive compacted fill. At this time, removal depths on the order of ± 1 Va to ±5 feet below existing grade should be anticipated throughout a majority of the site; however, locally deeper removals cannot be precluded and should be anticipated. Removals should be completed below a 1:1 projection down and away from the edge of any settlement-sensitive structure and/or limit of proposed fill. Once removals are completed, the exposed bottom should be scarified in two perpendicular directions to a depth of 8 inches, moisture conditioned to at least optimum moisture content, and recompacted to 90 percent relative compaction. Fill Placement Subsequent to ground preparation, onsite soils may be placed in thin (±6- to 8-inch) lifts, cleaned of vegetation and debris, brought to at least optimum moisture content, and compacted to achieve a minimum relative compaction of 90 percent. Fill materials greater than 12 inches In diameter should not be placed within 10 feet from finish grade, per the 1997 UBC. If fill soil importation is planned, a sample of the soil Import should be evaluated by this office prior to Importing, In order to assure compatibility with the onsite soils and the recommendations presented in this report. At least three business days of Cunningham Consulting, Inc. VV.O. 4132-A-SC Yamamota Property, Carlsbad January 8, 2004 File:e:\wp9\4100\4132a.pge Pagg -15 GeoSoils, Inc. lead time should be allowed by builders or contractors for proposed import submittals. This lead time will allow for particle size analysis, specific gravity, relative compaction, expansion testing, and blended import/native characteristics as deemed necessary. Import soils for a fill cap should be very low to low expansive (Expansion Index [E.I.] less than or equal to 50). The use of subdrains at the bottom ofthe fill cap or in drainage swales may be necessary, and subsequently recommended based on the nature and thickness of planned fill, flowline gradients, etc. Transitions/Overexcavation In order to provide forthe uniform support ofthe proposed structures, a minimum 3-foot thick fill blanket is recommended for lots containing earth material transitions (i.e., fill juxtaposed to terrace deposits). Any cut portion of a transition lot or lots with planned fills less than 3 feet should be overexcavated a minimum 3 feet below finish pad grade in order to provide for a minimum 3-foot compacted fill blanket. Additionally plan cut lots exhibiting heterogenous stratigraphy (i.e., sands juxtaposed to clays) and/or contrasting features at finish grade should also be overexcavated 3 feet below finish grade. If proposed footings or isolated pad footings are deeper than 24 inches below finish pad grade elevation, additional overexcavation will be necessary to provide a minimum 12 Inches of compacted fill beneath the footing. Maximum to minimum fill thickness below the foundation elements ofthe structures should not exceed a ratio of 3:1 (maximum:minimum). Consideration for overexcavation of the street right of ways to 1 foot below the lowest utility Invert Is recommended to better facilitate trenching for underground utilities If relatively lightweight trenching equipment (i.e., rubber tire backhoe) is to be utilized. However, this is not a geotechnical requirement. Once overexcavation is complete the exposed subgrade should be scarified in two perpendicular directions to a depth of 8 inches, moisture conditioned to the soil's optimum moisture content, and be recompacted to 90 percent relative compaction prior to the placement of engineered fill. SUBDRAINS Subdrainage systems for the control of localized perched water seepage should be anticipated. The proposed locations of such drains will be evaluated during grading. RECOMMENDATIONS - FOUNDATIONS Preliminarv Foundation Design In the event that the Information concerning the proposed development plans Is not correct, or any changes in the design, location, or loading conditions of the proposed structures are made, the conclusions and recommendations contained in this report are Cunningham Consulting, inc. VV.O. 4132-A-SC Yamamota Property, Carlsbad January 8,2004 Flle:e:\wp9\4100\4132a.pge Page 16 GeoSoils. Inc. forthe subject site only, and shall not be considered valid unless the changes are reviewed and conclusions of this report are modified or approved in writing by this office. The information and recommendations presented in this section are considered minimums and are not meant to supercede design (s) by the project structural engineer or civil engineer specializing in structural design, or codes. They are considered preliminary recommendations for proposed construction, in consideration of our field investigation, laboratory testing, and engineering analysis. Upon request, GSI could provide additional consultation regarding soil parameters, as related to foundation design. Our review, field work, and recent laboratory testing Indicates that onsite soils have a very low to low expansion potential (E.l. = 0 to 50). However the possibility of medium expansive soils (E.l. = 51 to 90) to be exposed at finish grade cannot be precluded. Preliminary recommendations for foundation design and construction are presented below. Final foundation recommendations should be provided at the conclusion of grading, based on laboratory testing of fill materials exposed at finish grade. Bearing Value 1. The foundation systems should be designed and constructed in accordance with guidelines presented in the latest edition of the UBC. 2. An allowable bearing value of 1,500 pounds per square foot (psf) may be used for design of continuous footings 12 inches wide and 12 Inches deep, and for design of Isolated pad footings 24 inches square and 18 inches deep (excluding the upper 6-inch landscape zone), founded entirely into compacted fill and connected by grade beam or tie beam In at least one direction. Isolated pad footings are not recommended for medium expansive soils. This value may be increased by 20 percent for each additional 12 inches In depth to a maximum value of 2,500 psf. The above values may be increased by one-third when considering short duration seismic or wind loads. No increase in bearing for footing width is recommended. Lateral Pressure 1. For lateral sliding resistance, a 0.35 coefficient of friction may be utilized for a concrete to soil contact when multiplied by the dead load. 2. Passive earth pressure may be computed as an equivalent fluid having a density of 250 pcf with a maximum earth pressure of 2,500 psf. 3. When combining passive pressure and frictional resistance, the passive pressure component should be reduced by one-third. Cunningham Consulting, Inc. VV.O. 4132-A-SC Yamamota Property, Carlsbad January 8,2004 File:e:\wp9\4100\4132a.pge Page 17 GeoSoils. Inc. Foundation Settlement Foundation systems should be designed to accommodate a differential settlement of at least %-inch In a 40-foot span. Footing Setbacks All footings should maintain a minimum 7-foot horizontal setback from the base of the footing to any descending slope. This distance Is measured from the footing face at the bearing elevation. Footings should maintain a minimum horizontal setback of H/3 (H = slope height) from the base ofthe footing to the descending slope face and no less than 7 feet, nor need be greater than 40 feet. Footings adjacent to unlined drainage swales should be deepened to a minimum of 6 inches below the invert of the adjacent unlined swale. Footings for structures adjacent to retaining walls should be deepened so as to extend below a 1:1 projection from the heel fo the wall. Alternatively, walls may be designed to accommodate structural loads from buildings or appurtenances as described in the "Retaining Wall" section of this report. Alternatively, walls may be designed to accommodate structural loads from buildings or appurtenances as described in the "Retaining Wall" section of this report. Construction The following foundation construction recommendations are presented as a minimum criteriafrom a soils engineering standpoint. The onsite soil expansion potential Is generally very lowto low (E.l. 0 to 50) to possibly medium (E.l. 51 to 90). Recommendations for very low to low and medium expansive soil conditions are presented herein. Recommendations by the project's design-structural engineer or architect, which may exceed the soils engineer's recommendations, should take precedence over the following minimum requirements. Final foundation design will be provided based on the expansion potential of the near surface soils encountered during grading. Very Low to Low Expansion Potential (E.l. 0 to 50) 1. Exterior and interior footings should be founded at a minimum depth of 12 inches for one-story floor loads, and 18 inches for two-story floor loads, into compacted fill. Isolated column and panel pads, or wall footings, should be founded at a minimum depth of 18 Inches into compacted fill (excluding the upper 6-Inch landscape zone). All footings should be reinforced with two No. 4 reinforcing bars, once placed near the top and one placed near the bottom ofthe footing. Footing widths should be as indicated in UBC (ICBO, 1997). 2. A grade beam, reinforced as above, and at least 12 Inches square, should be provided across large (e.g., doonways) entrances. The base of the grade beam Cunningham Consulting, Inc. ~~ WO 4132-A-SC Yamamota Property, Carlsbad January 8, 2004 File:e:\wp9\4100\4132a.pge Pagg -^Q GeoSoils, Inc. should be at the same elevation as the bottom of adjoining footings. Isolated, exterior square footings should be tied within the main foundation in at least one direction with a grade beam. 3. Concrete slabs, including garage slabs, should be underlain with a vapor barrier consisting ofa minimum of 10-mil polyvinyl chloride, or equivalent membrane, with all laps sealed. This membrane should be covered above and below with a minimum of 2 inches of sand (total of 4 inches) to aid in uniform curing of the concrete, and to protect the membrane from puncture. 4. Concrete slabs should be a minimum of 4 inches thick and should be reinforced with No. 3 reinforcing bar at 18 inches on center In both directions. All slab reinforcement should be supported to ensure placement near the vertical midpoint of the concrete. "Hooking" of reinforcement is not considered an acceptable method of positioning the reinforcement. 5. Garage slabs should be reinforced as above and poured separately from the structural footings and quartered with expansion joints or saw cuts. A positive separation from the footings should be maintained with expansion joint material to permit relative movement. 6. Presaturation is not required for these soil conditions. The moisture content of the subgrade soils should be equal to, or greater than, optimum moisture content In the slab areas, prior to concrete placement. Medium Expansion Potential (E.l. 51 to 90) 1. Conventional continuous footings should be founded at a minimum depth of 18 inches below the lowest adjacent ground surface for one- or two-story floor loads Into compacted fill. Interior footings may be founded at a depth of 12 Inches below the lowest adjacent ground surface. Footings for one-story floor loads should have a minimum width of 12 inches, and footings for two-story floor loads should have a minimum width of 15 inches. All footings should be reinforced with a minimum of two No. 4 reinforcing bars at the top and two No. 4 reinforcing bars at the bottom. Isolated interior and/or exterior piers and columns are not recommended. 2. A grade beam, reinforced as above, and at least 12 Inches square, should be provided across the garage entrances. The base of the reinforced grade beam should be at the same elevation as the adjoining footings. 3. Concrete slabs in residential and garage areas should be underlain by a vapor barrier consisting of a minimum of 10-mil, polyvinyl-chloride membrane with all laps Cunningham Consulting, Inc. VV.O. 4132-A-SC Yamamota Property, Carlsbad January 8,2004 Flle:e:\wp9\4100\4132a.pge Pagg 19 GeoSoils. Inc. sealed, placed mid-depth within 4 inches of washed sand in order to facilitate uniform curing of the concrete and mitigate puncturing of the vapor barrier. Concrete slabs, including garage areas, should be a minimum of 4 Inches thick, and reinforced with No. 4 reinforcement bars placed on 18-inch centers, in'two horizontally perpendicular directions (i.e., long axis and short axis). All slab reinforcement should be supported to ensure proper mid-slab height positioning during placement of the concrete. "Hooking" of reinforcement is not an acceptable method of positioning. Garage slabs should be poured separately from the residence footings and be quartered with expansion joints or saw cuts. A positive separation from the footings should be maintained with expansion joint material to permit relative movement. Presaturation of slab areas is recommended for these soil conditions. The moisture content of each slab area should be 120 percent, or greater, above optimum and verified by the soil engineer to a depth of 18 Inches below adjacent ground grade In the slab areas, within 72 hours of the vapor barrier placement. As an alternative, an engineered post-tension foundation system may be used. Post-tension foundation recommendations can be provided upon request. Soils generated from footing excavations to be used onsite should be compacted to a minimum relative compaction 90 percent ofthe laboratory standard, whether It is to be placed Inside the foundation perimeter or in the yard/right-of-way areas. This material must not alter positive drainage patterns that direct drainage away from the structural areas and toward the street. Foundations near the top of slope should be deepened to conform to the latest edition of the UBC (ICBO, 1997) and provide a minimum of 7 feet horizontal distance from the slope face. Rigid block wall designs located along the top of slope should be reviewed by a soils engineer. POST-TENSIONED SLAB SYSTEMS The recommendations presented below should be followed in addition to those contained in the previous sections, as appropriate, should post-tension foundations be utilized. The information and recommendations presented below In this section are not meant to supercede design by a registered structural engineer or civil engineer familiar with post-tensioned slab design. Post-tensioned slabs should be designed using sound engineering practice and be in accordance with local and/or national code requirements. Upon request, GSI can provide additional data/consultation regarding soil parameters as related to post-tensioned slab design. Cunningham Consulting, Inc. VV.O. 4132-A-SC Yamamota Property, Carlsbad January 8, 2004 File:e:\wp9\4100\4132a.pge Page 20 GeoSoils. Inc. From a soil expansion/shrinkage standpoint, a common contributing factor to distress of structures using post-tensioned slabs is fluctuation of moisture in soils underlying the penmeter ofthe slab, compared to the center, causing a "dishing" or "arching" ofthe slabs. To mitigate this possibility, a combination of soil presaturation and construction of a perimeter cut-off wall should be employed. Perimeter cut-off walls should be a minimum of 12 or 18 inches deep for very low to low and medium expansive soils, respectively. The cut-off walls may be integrated into the slab design or Independent of the slab. The concrete slab should be a minimum of 6 inches thick. Slab underlayment should consist of 4 inches of washed sand with a vapor barrier consisting of 10-mil polyvinyl chloride or equivalent placed mid-depth within the sand. Specific soil presaturation is required if medium expansive soils are exposed at finish grade. The moisture content ofthe slab subgrade soils should be equal to, or greater than, 120 percent of the soil's optimum moisture content to a depth of 18 inches below grade' for medium expansive soils. Post-Tensioning Institute Method Post-tensioned slabs should have sufficient stiffness to resist excessive bending due to non-uniform swell and shrinkage of subgrade soils. The differential movement can occur at the corner, edge, or center of the slab. The potential for differential uplift can be evaluated using the 1997 UBC, Section 1816, based on design specifications of the Post-Tensioning Institute. The following table presents suggested minimum coefficients to be used in the Post-Tensioning Institute design method. Thornthwaite IVIoisture Index -20 inches/year Correction Factor for Irrigation 20 inches/year Depth to Constant Soil Suction 7 feet Constant soil Suction (pf) 3.6 Modulus of Subgrade Reaction (pei) 75 Moisture Velocity 0.7 inches/month The coefficients are considered minimums and may not be adequate to represent worst case conditions such as adverse drainage and/or Improper landscaping and maintenance. The above parameters are applicable provided structures have positive drainage that Is maintained away from structures. Therefore, it is important that Information regarding Cunningham Consulting, Inc. Yamamota Property, Carlsbad Flle:e:\wp9\4100\4132a.pge W.O. 4132-A-SC January 8.2004 Page 21 GeoSoils. Inc. drainage, site maintenance, settlements, and effects of expansive soils be passed on to future owners. Based on the above parameters, the following values were obtained from figures or tables ofthe 1997 UBC Section, 1816. The values may not be appropriate to account for possible differential settlement of the slab due to other factors. If a stiffer slab is desired, higher values of ym may be warranted. EXPANSION INDEX OF 1 SOIL SUBGRADE VERY LOW EXPANSION {E.i: = 0-20) LOW EXPANSION (E.I. = 21-50) MEDIUM EXPANSION (E.l. = 51-90) 1 Gn, center lift 5.0 feet 5.0 feet 5.5 feet 1 e„, edge lift 2.5 feet 3.5 feet 4.0 feet 1 yn, center lift 1.0 inch 1.7 inches 2.7 inches 1 y,n edge lift 0.3 inch 0.75 inch 0.75 inch Deepened footings/edges around the slab perimeter must be used to minimize non- uniform surface moisture migration (from an outside source) beneath the slab. An edge depth of 12 Inches should be considered a minimum. The bottom of the deepened footing/edge should be designed to resist tension, using cable or reinforcement per the structural engineer. Other applicable recommendations presented under conventional foundation and the California Foundation Slab Method should be adhered to during the design and construction phase of the project. CORROSION Upon completion of grading, additional testing of soils (including Import materials) for corrosion to concrete and metals should be performed prior to the construction of utilities and foundations. UTILITIES Utilities should be enclosed within a closed utilldor (vault) or designed with flexible connections to accommodate differential settlement and expansive soil conditions. Due to the potential for differential settlement, air conditioning (A/C) units should be supported by slabs that are Incorporated into the building foundation or constructed on a rigid slab with flexible couplings for plumbing and electrical lines. A/C waste wateriines should be drained to a suitable outlet. Cunningham Consulting, Inc. Yamamota Property, Carlsbad File:e:\wp9\4100\4132a.pge W.O. 4132-A-SC January 8, 2004 Page 22 GeoSoils, Inc. WALL DESIGN PARAMETERS Conventional Retaining Walls The design parameters provided below assume that either non expansive soils (Class 2 permeable filter material or Class 3 aggregate base) or native materials (up to and including medium expansion potential) are used to backfill any retaining walls. The type of backfill (i.e., select or native), should be specified by the wall designer, and clearly shown on the plans. Building walls, below grade, should be water-proofed or damp- proofed, depending on the degree of moisture protection desired. The foundation system for the proposed retaining walls should be designed In accordance with the recommendations presented in this and preceding sections ofthis report, as appropriate. Footings should be embedded a minimum of 18 inches below adjacent grade (excluding landscape layer, 6 Inches) and should be 24 Inches in width. There should be no increase in bearing for footing width. Recommendations for specialty walls (i.e., crib, earthstone, geogrid, etc.) can be provided upon request, and would be based on site specific conditions. Restrained Walls Any retaining walls that will be restrained priorto placing and compacting backfill material or that have re-entrant or male corners, should be designed for an at-rest equivalent fluid pressure (EFP) of 65 pounds per cubic foot (pcf), plus any applicable surcharge loading. For areas of male or re-entrant corners, the restrained wall design should extend a minimum distance of twice the height of the wall (2H) laterally from the corner. Cantilevered Walls The recommendations presented below are for cantilevered retaining walls up to 10 feet high. Design parameters for walls less than 3 feet in height may be superseded by City and/or County standard design. Active earth pressure may be used for retaining wall design, provided the top ofthe wall is not restrained from minor deflections. An equivalent fluid pressure approach may be used to compute the horizontal pressure against the wall. Appropriate fluid unit weights are given below for specific slope gradients of the retained material. These do not Include other superimposed loading conditions due to traffic, structures, seismic events or adverse geologic conditions. When wall configurations are finalized, the appropriate loading conditions for superimposed loads can be provided upon request. Cunningham Consulting, Inc. VV.O. 4132-A-SC Yamamota Property, Carlsbad January 8, 2004 File:e:\wp9\4100\4132a.pge Page 23 GeoSoils, Inc. SURFACE SLOPE OF RETAINED MATERIAL (H:V) SELECT BACKFILL EQUIVALENT FLUID WEIGHT (PCF) NATIVE BACKFILL EQUIVALENT FLUID WEIGHT (PCF) Level* 2 to 1 38 55 45 60 * Level backfill behind a retaining wall is defined as compacted earth materials, properly drained, without a slope for a distance of 2H behind the wall, where H is the height of the wall. Retaining Wall Backfill and Drainage Positive drainage must be provided behind all retaining walls In the form of gravel wrapped In geofabric and outlets. A backdrain system Is considered necessary for retaining walls that are 2 feet or greater In height. Details 1, 2, and 3, present the back drainage options discussed below. Backdrains should consist of a 4-inch diameter perforated PVC or ABS pipe encased In either Class 2 permeable filter material or Va-inch to y4-lnch gravel wrapped In approved filter fabric (Mirafi 140 or equivalent). For low expansive backfill, the filter material should extend a minimum of 1 horizontal foot behind the base of the walls and upward at least 1 foot. For native backfill that has up to medium expansion potential, continuous Class 2 permeable drain materials should be used behind the wall. This material should be continuous (i.e., full height) behind the wall, and it should be constructed in accordance with the enclosed Detail 1 (Typical Retaining Wall Backfill and Drainage Detail). For limited access and confined areas (panel) drainage behind the wall may be constructed in accordance with Detail 2 (Retaining Wall Backfill and Subdrain Detail Geotextile Drain). Materials with an E.l. potential of greater than 90 should not be used as backfill for retaining walls. For more onerous expansive situations, backfill and drainage behind the retaining wall should conform with Detail 3 (Retaining Wall And Subdrain Detail Clean Sand Backfill). Outlets should consist of a 4-inch diameter solid PVC or ABS pipe spaced no greater than ±100 feet apart, with a minimum of two outlets, one on each end. The use of weep holes in walls higher than 2 feet should not be considered. The surface ofthe backfill should be sealed by pavement or the top 18 Inches compacted with native soil (E.l. <.90). Proper surface drainage should also be provided. For additional mitigation, consideration should be given to applying a water-proof membrane to the back of all retaining structures. The use of a waterstop should be considered for all concrete and masonry joints. Wall/Retaining Wall Footing Transitions Site walls are anticipated to be founded on footings designed In accordance with the recommendations in this report. Should wall footings transition from cut to fill, the civil designer may specify either: Cunningham Consulting, Inc. Yamamota Property, Carlsbad File:e:\wp9\4100\4132a.pge W.O. 4132-A-SC January 8, 2004 Page 24 GeoSoils, Inc. DETAIL Provide surface drainage (T) Voter proofing nenbrane (optional) (5) V/eephole Finished surface /4 or flatter ® WATER PROOFING MEMBRANE (optional). Liquid boot or approved equivalent, ® RDCKi 3/4 to 1-1/2' (Inches) roci<. (3) FILTER FABRIC. Mirafi HON or approved equivalent place fabric flap behind core. ® PIPE" 4' (inches) dianeter perforated PVC. schedule 40 or approved alternative with ninlnun of IX gradient to proper outlet point, (5) VEEPHDLEi MInlnun 2' (Inches) dianeter placed at 20' (feet) on centers along the wall, and 3' (Inches) above finished surface. TYPICAL RETAINING WALL BACKFILL AND DRAINAGE DETAIL DETAIL 1 Geotechnical • Geologic • Environmental DETAIL Provide surface drainage i (T) Water proofing nenbrane (optional)) (5) Weephole Finished surface (J) WATER PRDDFING MEMBRANE (optional). Liquid boot or approved equivalent, (2) DRAIN. Miradrain 6000 or J-draIn 200 or equivalent for non-waterproofed walls. Miradrain 6200 or J-draln 200 or equivalent for water proofed walls. (D FILTER FABRIC Mirafi MON or approved equivalent place fabric flap behind core. ® PIPE. 4' (Inches) dianeter perforated PVC. schedule 40 or approved alternative with ninlnun of 1'/. gradient to proper outlet point. © WEEPHDLEi MInlnun 2' (Inches) dianeter placed at 20' (feet) on centers along the wall, and 3' (Inches) above finished surface. RETAINING WALL BACKFILL AND SUBDRAIN DETAIL GEOTEXTILE DRAIN DETAIL 2 Geotechnical • Geologic • Environmental DETAIL Provide surface drainage Native Backfill H/2 nin. ±12'—I r)Water proving' nenbrane • (optional) H (^6) Weephole Finished surface Slope or Level /4 or flater Clean sand backfill Heel width (T) WATER PROOFING MEMBRANE (optional). Liquid boot or approved equivalent. ® CLEAN SAND BACKFILL. Must have sand equivalent value of 30 or greaterj can be densified by water Jetting. ® ® ROCK. FILTER FABRIC Mirafi HON or approved equivalent, (5) PIPE. 1 cubic foot per linear feet of pipe of 3/4 to 1-1/2' (Inches) rock 4' (Inches) dianeter perforated PVC. schedule 40 or approved alternative with ninlnun of V/. gradient to proper outlet point. © WEEPHDLEi MInlnun 2' (Inches) dianeter placed at 20' (feet) on centers along the wall, and 3' (Inches) above finished surface. RETAINING WALL AND SUBDRAIN DETAIL CLEAN SAND BACKFILL DETAIL 3 Geotechnical • Geologic • Environmental a) A minimum of a 2-foot overexcavation and recompaction of cut materials for a distance of 2H, from the point of transition. b) Increase of the amount of reinforcing steel and wall detailing (i.e., expansion joints or crack control joints) such that a angular distortion of 1/360 for a distance of 2H on either side ofthe transition may be accommodated. Expansion joints should be sealed with a flexible, non-shrink grout. c) Embed the footings entirely into native formational material (i.e., deepened footings). If transitions from cut to fill transect the wall footing alignment at an angle of less than 45 degrees (plan view), then the designer should follow recommendation "a" (above) and until such transition is between 45 and 90 degrees to the wall alignment. TOP-OF-SLOPE WALLS/FENCES/IMPROVEMENTS Slope Creep Soils at the site may be expansive and therefore, may become desiccated when allowed to drv. Such soils are susceptible to surficial slope creep, especially with seasonal changes In moisture content. Typically In southern California, during the hot and dry summer period, these soils become desiccated and shrink, thereby developing surface cracks. The extent and depth of these shrinkage cracks depend on many factors such as the nature and expansivity of the soils, temperature and humidity, and extraction of moisture from surface soils by plants and roots. When seasonal rains occur, water percolates Into the cracks and fissures, causing slope surfaces to expand, with a corresponding loss In soil density and shear strength near the slope surface. With the passage of time and several moisture cycles, the outer 3 to 5 feet of slope materials experience a very slow, but progressive, outward and downward movement, known as slope creep. For slope heights greater than 10 feet, this creep related soil movement will typically impact all rear yard flatwork and other secondary Improvements that are located within about 15 feet from the top of slopes, such as swimming pools, concrete flatwork, etc., and in particular top of slope fences/walls. This Influence Is normally in the form of detrimental settlement, and tilting ofthe proposed Improvements. The desslcatlon/swelling and creep discussed above continues over the life of the Improvements, and generally becomes progressively worse. Accordingly, the developer should provide this Information to any homeowners and homeowners association. Cunningham Consulting, Inc. W.O. 4132-A-SC Yamamota Property, Carlsbad January 8, 2004 File:e:\wp9\4100\4132a.pge Page 28 GeoSoils. Inc. Top of Slope Walls/Fences Due to the potential for slope creep for slopes higher than about 10 feet, some settlement and tilting ofthe walls/fence with the corresponding distresses, should be expected. To mitigate the tilting of top of slope walls/fences, we recommend that the walls/fences be constructed on deepened foundations, or a combination of grade beam and caisson foundations. The grade beam should be at a minimum of 12 Inches by 12 inches in cross section, supported by drilled caissons, 12 inches minimum in diameter, placed at a maximum spacing of 6 feet on center, and with a minimum embedment length of 7 feet below the bottom ofthe grade beam. The strength ofthe concrete and grout should be evaluated by the structural engineer of record. The proper ASTM tests for the concrete and mortar should be provided along with the slump quantities. The concrete used should be appropriate to mitigate sulfate corrosion, as warranted. The design ofthe grade beam and caissons should be In accordance with the recommendations ofthe project structural engineer, and Include the utilization ofthe following geotechnical parameters: Creep Zone: 5-foot vertical zone belowthe slope face and projected upward parallel to the slope face. Creep Load: The creep load projected on the area of the grade beam should be taken as an equivalent fluid approach, having a density of 60 pcf. For the caisson. It should be taken as a uniform 900 pounds per linear foot of caisson's depth, located above the creep zone. Point of Fixity: Located a distance of 1.5 times the caisson's diameter, below the creep zone. Passive Resistance: Passive earth pressure of 300 psf per foot of depth per foot of caisson diameter, to a maximum value of 4,500 psf may be used to determine caisson depth and spacing, provided that they meet or exceed the minimum requirements stated above. To determine the total lateral resistance, the contribution ofthe creep prone zone above the point of fixity, to passive resistance, should be disregarded. Allowable Axial Capacity: Shaft capacity: 350 psf applied below the point of fixity over the surface area of the shaft. Tip capacity: 4,500 psf. Cunningham Consulting, Inc. W.O. 4132-A-SC Yamamota Property, Carlsbad January 8, 2004 File:e:\wp9\4100\4132a.pge Page 29 GeoSoils, Inc. DRIVEWAY. FLATWORK. AND OTHER IMPROVEMENTS The soil materials on site may be expansive. The effects of expansive soils are cumulative, and typically occur over the lifetime of any improvements. On relatively level areas, when the soils are allowed to dry, the dessication and swelling process tends to cause heaving and distress to flatwork and other improvements. The resulting potential for distress to Improvements may be reduced, but not totally eliminated. To that end, it is recommended that the developer should notify any homeowners or homeowners association of this long-term potential for distress. To reduce the likelihood of distress, the following recommendations are presented for all exterior flatwork on expansive soils: 1. Slab subgrade (i.e., existing fill materials) should be compacted to a minimum 90 percent relative compaction and moisture conditioned to the soil's optimum moisture content (120 percent of soil's optimum moisture content if medium expansive soils are present) to a minimum depth of 12 Inches. This should be verified by this office at least 72 hours priorto pouring concrete. The use of Class 2, Class 3, or decomposed granite (i.e., DG) as a base for the concrete slab In non-vehicle traffic areas is not required. 2. Concrete slabs should be cast over a relatively non-yielding surface, consisting of a 4-inch layer of crushed rock, gravel, or clean sand, that should be compacted and level prior to pouring concrete. The layer should wet-down completely prior to pouring concrete, to minimize loss of concrete moisture to the surrounding earth materials. 3. Exterior slabs should be a minimum of 4 inches thick. Driveway slabs and approaches should additionally have a thickened edge (12 Inches) adjacent to all landscape areas, to help Impede infiltration of landscape water under the slab. 4. The use of transverse and longitudinal control joints are recommended to help control slab cracking due to concrete shrinkage or expansion. Two ways to mitigate such cracking are: a) add a sufficient amount of reinforcing steel, increasing tensile strength of the slab; and, b) provide an adequate amount of control and/or expansion joints to accommodate anticipated concrete shrinkage and expansion. In order to reduce the potential for unsightly cracks, slabs should be reinforced at mid-height with a minimum of No. 3 bars placed at 18 inches on center, in each direction. The exterior slabs should be scored or saw cut, Vz to % inches deep, often enough so that no section is greater than 10 feet by 10 feet. For sidewalks or narrow slabs, control joints should be provided at intervals of every 6 feet. The slabs should be separated from the foundations and sidewalks with expansion joint filler material. Cunningham Consulting, Inc. W.O. 4132-A-SC Yamamota Property, Carlsbad January 8, 2004 File:e:\wp9\4100\4132a.pge Page 30 GeoSoils, Inc. 5. No traffic should be allowed upon the newly poured concrete slabs until they have been properly cured to within 75 percent of design strength. Concrete compression strength should be a minimum of 2,500 psi. 6. Driveways, sidewalks, and patio slabs adjacent to the house should be separated from the house with thick expansion joint filler material. In areas directly adjacent to a continuous source of moisture (i.e.. Irrigation, planters, etc.), all joints should be additionally sealed with flexible mastic. 7. Planters and walls should not be tied to the house. 8. Overhang structures should be supported on the slabs, or structurally designed with continuous footings tied in at least two directions. 9. Any masonry landscape walls that are to be constructed throughout the property should be grouted and articulated in segments no more than 20 feet long. These segments should be keyed or doweled together. 10. Utilities should be enclosed within a closed utilldor (vault) or designed with flexible connections to accommodate differential settlement and expansive soil conditions. 11. Positive site drainage should be maintained at all times. Finish grade on the lots should provide a minimum of 1 to 2 percent fall to the street, as indicated herein. It should be kept in mind that drainage reversals could occur, including post-construction settlement, if relatively flat yard drainage gradients are not periodically maintained by the homeowner or homeowners association. 12. Air conditioning (A/C) units should be supported by slabs that are incorporated into the building foundation or constructed on a rigid slab with flexible couplings for plumbing and electrical lines. A/C waste water lines should be drained to a suitable non-erosive outlet. 13. Shrinkage cracks could become excessive If proper finishing and curing practices are not followed. Finishing and curing practices should be performed per the Portland Cement Association Guidelines. Mix design should incorporate rate of curing for climate and time of year, sulfate content of soils, corrosion potential of soils, and fertilizers used on site. Cunningham Consulting, Inc. W.O. 4132-A-SC Yamamota Property, Carlsbad January 8, 2004 File:e:\wp9\4100\4132a.pge Page 31 GeoSoils, Inc. DEVELOPMENT CRITERIA Slope Deformation Compacted fill slopes designed using customary factors of safety for gross or surficial stability and constructed in general accordance with the design specifications should be expected to undergo some differential vertical heave or settlement In combination with differential lateral movement in the out-of-slope direction, after grading. This post-construcfion movement occurs in two forms: slope creep, and lateral fill extension (LFE). Slope creep Is caused by alternate wetting and drying ofthe fill soils which results in slow downslope movement. This type of movement is expected to occur throughout the life of the slope, and is anficipated to potenfially affect improvements or structures (i.e., separations and/or cracking), placed near the top-of-slope, up to a maximum distance of approximately 15 feet from the top-of-slope, depending on the slope height. This movement generally results in rotation and differenfial settlement of improvements located within the creep zone. LFE occurs due to deep wetting from irrigafion and rainfall on slopes comprised of expansive materials. Although some movement should be expected, long-term movement from this source may be minimized, but not eliminated, by placing the fill throughout the slope region, wet ofthe fill's opfimum moisture content It is generally not pracfical to attempt to eliminate the effects of either slope creep or LFE. Suitable mifigafive measures to reduce the potential of lateral deformafion typically include: setback of improvements from the slope faces (per the UBC and/or California Building Code), positive structural separations (i.e., joints) between improvements, and stiffening and deepening of foundations. All of these measures are recommended for design of structures and improvements. The ramificafions of the above conditions, and recommendafions for mitigation, should be provided to each homeowner and/or any homeowners associafion. Slope Maintenance and Planting Water has been shown to weaken the inherent strength of all earth materials. Slope stability is significantly reduced by overly wet conditions. Positive surface drainage away from slopes should be maintained and only the amount of Irrigafion necessary to sustain plant life should be provided for planted slopes. Over-watering should be avoided as It can adversely affect site improvements, and cause perched groundwater conditions. Graded slopes constructed utilizing onsite materials would be erosive. Eroded debris may be minimized and surficial slope stability enhanced by establishing and maintaining a suitable vegetafion cover soon after construction. Compacfion to the face of fill slopes would tend to minimize short-term erosion unfil vegetafion is established. Plants selected for landscaping should be light weight, deep rooted types that require little water and are capable of surviving the prevailing climate. Jute-type matting or other fibrous covers may aid in allowing the establishment of a sparse plant cover. Ufilizing plants other than those recommended above will Increase the potenfial for perched water, staining, mold, etc., to Cunningham Consulting, Inc. W.O. 4132-A-SC Yamamota Property, Carlsbad January 8, 2004 File:e:\wp9\4100\4132a.pge Page 32 GeoSoils. Inc. develop. A rodent control program to prevent burrowing should be implemented. Irrigafion of natural (ungraded) slope areas is generally not recommended. These recommendafions regarding plant type, irrigafion pracfices, and rodent control should be provided to each homeowner. Over-steepening of slopes should be avoided during building construcfion activifies and landscaping. Drainage Adequate lot surface drainage is a very important factor in reducing the likelihood of adverse performance of foundafions, hardscape, and slopes. Surface drainage should be sufficient to prevent ponding of water anywhere on a lot, and especially near structures and tops of slopes. Lot surface drainage should be carefully taken Into considerafion during fine grading, landscaping, and building construcfion. Therefore, care should be taken that future landscaping or construction acfivities do not create adverse drainage condifions. Posifive site drainage within lots and common areas should be provided and maintained at all times. Drainage should not flow uncontrolled down any descending slope. Water should be directed away from foundafions and not allowed to pond and/or seep Into the ground. In general, the area within 5 feet around a structure should slope away from the structure. We recommend that unpaved lawn and landscape areas have a minimum gradient of one percent sloping away from structures, and whenever possible, should be above adjacent paved areas. Consideration should be given to avoiding construcfion of planters adjacent to structures (buildings, pools, spas, etc.). Pad drainage should be directed toward the street or other approved area(s). Although not a geotechnical requirement, roof gutters, down spouts, or other appropriate means may be utilized to control roof drainage. Down spouts, or drainage devices should outlet a minimum of 5 feet from structures or into a subsurface drainage system. Areas of seepage may develop due to irrigafion or heavy rainfall, and should be anficipated. Minimizing Irrigafion will lessen this potential, ff areas of seepage develop, recommendafions for minimizing this effect could be provided upon request. Erosion Control Cut and fill slopes will be subject to surficial erosion during and after grading. Onsite earth materials have a moderate to high erosion potenfial. Considerafion should be given to providing hay bales and silt fences for the temporary control of surface water, from a geotechnical viewpoint. Landscape Maintenance Only the amount of irrigafion necessary to sustain plant life should be provided. Over-watering the landscape areas will adversely affect proposed site improvements. We would recommend that any proposed open-bottom planters adjacent to proposed structures be eliminated for a minimum distance of 10 feet. As an alternative, closed- bottom type planters could be utilized. An outlet placed In the bottom ofthe planter, could Cunningham Consulting, Inc. W.O. 4132-A-SC Yamamota Property, Carlsbad January 8, 2004 File:e:\wp9\4100\4132a.pge page 33 GeoSoils, Inc. be installed to direct drainage away from structures or any exterior concrete flatwork. \1 planters are constructed adjacent to structures, the sides and bottom ofthe planter should be provided with a moisture barrier to prevent penetration of irrigation water into the subgrade. Provisions should be made to drain the excess irrigation water from the planters without saturating the subgrade below or adjacent to the planters. Graded slope areas should be planted with drought resistant vegetafion. Consideration should be given to the type of vegetation chosen and their potenfial effect upon surface improvements (i.e., some trees will have an effect on concrete flatwork with their extensive root systems). From a geotechnical standpoint leaching is not recommended for establishing landscaping. If the surface soils are processed for the purpose of adding amendments, they should be recompacted to 90 percent minimum relafive compaction. Gutters and Downspouts As previously discussed In the drainage section, the installation of gutters and downspouts should be considered to collect roof water that may othenA/ise infiltrate the soils adjacent to the structures. If ufilized, the downspouts should be drained Into PVC collector pipes or non-erosive devices that will carry the water away from the house. Downspouts and gutters are not a requirement; however, from a geotechnical viewpoint, provided that positive drainage Is incorporated Into project design (as discussed previously). Subsurface and Surface Water Subsurface and surface water are not anficipated to affect site development, provided that the recommendations contained in this report are incorporated into final design and construction and that prudent surface and subsurface drainage pracfices are Incorporated into the construcfion plans. Perched groundwater conditions along zones of contrasting permeabilifies may not be precluded from occurring in the future due to site Irrigafion, poor drainage condifions, or damaged ufilifies, and should be anficipated. Should perched groundwater condifions develop, this oflice could assess the affected area(s) and provide the appropriate recommendafions to mifigate the observed groundwater condifions. Groundwater conditions may change with the introduction of irrigafion, rainfall, or other factors. Site Improvements Recommendafions for exterior concrete flatwork design and construcfion can be provided upon request. If In the future, any additional improvements (e.g., pools, spas, etc.) are planned forthe site, recommendafions concerning the geological or geotechnical aspects of design ahd construction of said improvements could be provided upon request. This office should be notified in advance of any fill placement, grading of the site, or trench backfilling after rough grading has been completed. This Includes any grading, utility trench, and retaining wall backfills. Cunningham Consulting, Inc. W.O. 4132-A-SC Yamamota Property, Carlsbad January 8, 2004 File:e:\wp9\4100\4132a.pge Page 34 GeoSoils, Inc. Tile Flooring Tile flooring can crack, reflecting cracks in the concrete slab below the file, although small cracks in a convenfional slab may not be significant. Therefore, the designer should consider additional steel reinforcement for concrete slabs-on-grade where tile will be placed. The file installer should consider Installafion methods that reduce possible cracking of the file such as slipsheets. Slipsheets or a vinyl crack isolafion membrane (approved by the Tile Council of America/Ceramic Tile Institute) are recommended between tile and concrete slabs on grade. Additional Grading This office should be notified In advance of any fill placement, supplemental regrading of the site, or trench backfilling after rough grading has been completed. This includes complefion of grading in the street and parking areas and utility trench and retaining wall backfills. Footing Trench Excavation All foofing excavafions should be observed by a representative of this firm subsequent to trenching and prior to concrete form and reinforcement placement. The purpose of the observafions Is to verify that the excavafions are made into the recommended bearing material and to the minimum widths and depths recommended for construction. If loose or compressible materials are exposed within the foofing excavafion, a deeper footing or removal and recompacfion ofthe subgrade materials would be recommended at that fime. Footing trench spoil and any excess soils generated from ufility trench excavafions should be compacted to a minimum relative compacfion of 90 percent. If not removed from the site. Trenching Considering the nature ofthe onsite soils, it should be anficipated that caving or sloughing could be a factor in subsurface excavafions and trenching. Shoring or excavating the trench walls at the angle of repose (typically 25 to 45 degrees) may be necessary and should be anticipated. All excavafions should be observed by one of our representatives and minimally conform to CAL-OSHA and local safety codes. Utility Trench Backfill 1. All interior ufility trench backfill should be brought to at least 2 percent above opfimum moisture content and then compacted to obtain a minimum relative compacfion of 90 percent ofthe laboratory standard. As an alternafive for shallow (12-inch to 18-Inch) under-slab trenches, sand having a sand equivalent value of Cunningham Consulting, Inc. W.O. 4132-A-SC Yamamota Property, Carlsbad January 8, 2004 Flle:e:\wp9\4100\4132a.pge Page 35 GeoSoils, Inc. 30 or greater may be ufilized and jetted or flooded into place. Observafion, probing and tesfing should be provided to verify the desired results. Exterior trenches adjacent to, and within areas extending below a 1:1 plane projected from the outside bottom edge of the foofing, and all trenches beneath hardscape features and in slopes, should be compacted to at least 90 percent of the laboratory standard. Sand backfill, unless excavated from the trench, should not be used in these backfill areas. Compacfion tesfing and obsen/ations, along with probing, should be accomplished to verify the desired results. All trench excavafions should conform to CAL-OSHA and local safety codes. Ufilities crossing grade beams, perimeter beams, or footings should either pass belowthe foofing or grade beam ufilizing a hardened collar or foam spacer, or pass through the foofing or grade beam in accordance with the recommendafions ofthe structural engineer. SUMMARY OF RECOMMENDATIONS REGARDING GEOTECHNICAL OBSERVATION AND TESTING We recommend that observation and/or tesfing be performed by GSI at each of the following construcfion stages: During grading/recertlficafion. After excavation of building foofings, retaining wall footings, and free standing walls foofings, prior to the placement of reinforcing steel or concrete. Prior to pouring any slabs or flatwork, after presoaking/presaturafion of building pads and other flatwork subgrade, before the placement of concrete, reinforcing steel, capillary break (i.e., sand, pea-gravel, etc.), or vapor barriers (i.e., visqueen, etc.). During retaining wall subdrain installation, prior to backfill placement. During placement of backfill for area drain, interior plumbing, utility line trenches, and retaining wall backfill. During slope construcfion/repair. When any unusual soil condifions are encountered during any construcfion operations, subsequent to the issuance of this report. Cunningham Consulting, Inc. W.O. 4132-A-SC Yamamota Property, Carlsbad January 8, 2004 File:e:\wp9\4100\4132a.pge Page 36 GeoSoils. Inc. When any developer or homeowner improvements, such as flatwork, spas, pools, walls, etc., are constructed. A report of geotechnical observafion and testing should be provided at the conclusion of each of the above stages. In order to provide concise and clear documentation of site work, and/or to comply with code requirements. OTHER DESIGN PROFESSIONALS/CONSULTANTS The design civil engineer, structural engineer, post-tension designer, architect, landscape architect, wall designer, etc., should review the recommendations provided herein, incorporate those recommendafions into all their respective plans, and by explicit reference, make this report part of their project plans. PLAN REVIEW Final project plans should be reviewed by this office prior to construcfion, so that construcfion is in accordance with the conclusions and recommendafions of this report. Based on our review, supplemental recommendations and/or further geotechnical studies may be warranted. LIMITATIONS The materials encountered on the project site and ufilized for our analysis are believed representative ofthe area; however, soil and bedrock materials vary In character between excavafions and natural outcrops or condifions exposed during mass grading. Site condifions 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 recommendafions are professional opinions. These opinions have been derived in accordance with current standards of pracfice, and no warranty is expressed or Implied. Standards of pracfice are subject to change with time. GSI assumes no responsibility or liability for work or tesfing performed by others, or their inacfion; or work performed when GSI is not requested to be onsite, to evaluate ff our recommendafions have been properly implemented. Use of this report constitutes an agreement and consent by the user to all the limitafions oufiined above, notwithstanding any other agreements that may be in place. In addition, this report may be subject to review by the controlling authorifies. Cunningham Consulting, Inc. W.O. 4132-A-SC Yamamota Property, Carlsbad January 8, 2004 Flle:e:\wp9\4100\4132a.pge Page 37 GeoSoils, Inc. APPENDIX A REFERENCES APPENDIXA REFERENCES Blake, Thomas F., 2000a, EQFAULT, A computer program for the esfimafion of peak horizontal acceleration from 3-D fault sources; Windows 95/98 version. . 2000b, EQSEARCH, A computer program for the estimafion of peak horizontal acceleration from California historical earthquake catalogs; Updated to December, 2002, Windows 95/98 version. . 2000c, FRISKSP, A computer program for the probabilisfic esfimation of peak acceleration and uniform hazard spectra using 3-D faults as earthquake sources; Windows 95/98 version. Bozorgnia, Y., Campbell K.W., and Niazi, M., 1999, Vertical ground mofion: Characteristics, relafionship with horizontal component, and building-code implications; Proceedings of the SMIP99 seminar on ufilizafion of strong-motion data, September 15, Oakland, pp. 23-49. Buccola Engineering, Inc., 2001 (revised 2002) CUP Development Plan, Casa Montessori School, 20 scale, sheet 1 of 1, Job Number 100-121, dated June 25 (revised August 13, 2002). Campbell, K.W. and Bozorgnia, Y., 1997, Attenuation relafions for soft rock conditions; in EQFAULT, A computer program for the estimafion of peak horizontal accelerafion from 3-D fault sources; Windows 95/98 version, Blake, 2000a. Campbell, K.W., 1997, Empirical near-source attenuation relafionships for horizontal and vertical components of peak ground acceleration, peak ground velocity, and pseudo-absolute accelerafion response spectra, Seismological Research Letters, vol. 68, No. 1, pp. 154-179. Hart, E.W. and Bryant, W.A., 1997, Fault-rupture hazard zones in California, Alquist-Priolo earthquake fault zoning act with index to earthquake fault zones maps; California Division of Mines and Geology Special Publication 42, with Supplements 1 and 2,1999. Internafional Conference of Building Officials, 1997, Uniform building code: Whittier, California, vol. 1, 2, and 3. Jennings, C.W., 1994, Fault acfivity map of California and adjacent areas: California Division of Mines and Geology, Map sheet no. 6, Scale 1:750,000. GeoSoils, Inc. Joyner, W.B, and Boore, D.M., 1982a, Esfimation of response-spectral values as funcfions of magnitude, distance and site condifions, m eds., Johnson, J.A., Campbell, K.W., and Blake, T.F.: AEG Short Course, Seismic Hazard Analysis, June 18, 1994. , 1982b, Predicfion of earthquake response spectra, U.S. Geological Sun/ey Open- File Report 82-977, 16p. Kennedy, M.P. and Tan S.S., 1996, Geologic maps of the northwest part of San Diego County, California., Division of Mines and Geology, Plate 2, scale 1:24,000. MLB Engineering, Inc., Undated, Yamamoto tentafive map, 40-scale, No job number, No drawing number. Sadigh, K., Egan, J., and Youngs, R., 1987, Predictive ground mofion equafions,in Joyner, W.B. and Boore, D.M., 1988, measurement, characterlzafion, and prediction of strong ground mofion, jn Von Thun, J.L., ed.. Earthquake engineering and soil dynamics II, recent advances in ground motion evaluation, American Society of Civil Engineers Geotechnical Special Publicafion No. 20, pp. 43-102. Sowers and Sowers, 1970, Unified soil classification system (After U. S. Watenways Experiment Stafion and ASTM 02487-667) m Introductory Soil Mechanics, New York. Cunningham Consulting, Inc. W.O. 4132-A-SC Flle:e:\wp9\4100\4132a.pge Page 2 GeoSoils, Inc. APPENDIX B TEST PIT LOGS 4132-A-SC Cunningham Consulting, Inc.A'amamoto Property December 17, 2003 LOG OF EXPLORATORY TEST PITS TEST PIT NO. DEPTH (ft.) GROUP SYMBOL SAMPLE DEPTH (ft.) MOISTURE (%) FIELDDRY DENSITY (pcf) DESCRIPTION TP-1 0-3 SM Undisturbed @ 2 Bulk® 1-3 3.7 112.1 TOPSOIL/COLLUVIUM: SILTY SAND, brown tn r^d hrnwn dry to damp, loose to medium dense; porous, organics near the surface. TP-1 3-5 CLysc Bulk @ 3-5 WEATHERED TERRACE DEPOSITS: SANDY CA AY/ CUVYEY SAND, olive gray to orange, damp to moist, medium stiff to stiff/medium dense; slightly porous. TP-1 5-6 SC/CL QUATERNARY TERRACE DEPOSITS: CLAYEY SAND/ SANDY CI_AY, olive gray to orange, damp; dense/hard. TP-1 Practical Refusal @ 6' No Groundwater/Caving Encountered Backfilled 12-17-2003 PLATE B-1 4132-A-SC Cunningham Consulting, Inc./Yamamoto Property December 17, 2003 LOG OF EXPLORATORY TEST PITS TEST PIT NO. DEPTH (ft.) GROUP SYMBOL SAMPLE DEPTH (ft.) MOISTURE (%) FIELD DRY DENSITY (pcf) DESCRIPTION TP-2 0-1 SP TOPSOIL/COLLUVIUM: SAND w/RII T hrr^wn Hry tn damp, loose; porous, organics near the surface. TP-2 1-272 SM WEATHERED TERRACE DEPOSITS: Sll TY SAND ypllnw brown, damp, medium dense to dense; slightly porous. TP-2 21/2-3 SM QUATERNARY TERRACE DEPOSITS: SIITY .9AMn w/CU\Y, yellow brown to orange, damp to moist, very dense; Paleoliquefaction features (sand dikes). TP-2 Practical Refusal @ 3' No Groundwater/Caving Encountered Backfilled 12-17-2003 PLATE B-2 4132-A-SC Cunningham Consulting, Inc./Yamamoto Property December 17, 2003 LOG OF EXPLORATORY TEST PITS TEST PIT NO. DEPTH (ft.) GROUP SYMBOL SAMPLE DEPTH •^^•V-::-(ft^),::r-:^ MOISTURE FIELDDRY DENSITY (pcf) DESCRIPTION TP-3 0-3 SP ARTIFICIAL FILL (UNDOCUMENTED): SAND w/SILT. brown, dry, loose; porous. TP-3 3-31/2 SP QUATERNARY TERRACE DEPOSITS: SAND w/SILT. dark gray to orange, dry, very dense (cemented). TP-3 Practical Refusal @ 31/2' No Groundwater/Caving Encountered Backfilled 12-17-2003 PLATE B-3 4132-A-SC Cunningham Consulting, Inc./Yamamoto Property December 17, 2003 LOG OF EXPLORATORY TEST PITS TEST PIT NO. DEPTH (ft.) GROUP SYMBOL SAMPLE DEPTH (ft.) MOISTURE (%) FIELD DRY DENSITY (pcf) DESCRIPTION TP-4 0-1 SM TOPSOIL/COLLUVIUM: Sll TY .SAND hrr^wn r^ry Inneo- porous. TP-4 1-3 SC Undisturbed @ 1 3.0 118.8 WEATHERED TERRACE DEPOSITS: HI AYFY .9ANn brown to orange, damp, medium dense; porous. TP-4 3-4 CL/SC QUATERNARY TERRACE DEPOSITS: SANDY f^l AY tr. CLAYEY SAND, olive gray to yellow brown, damp to moist, hard to very dense; Paleoliquefaction features (sand dikes) TP-4 Practical Refusal @ 4' No Groundwater/Caving Encountered Backfilled 12-17-2003 PLATE B-4 4132-A-SC Cunningham Consulting, Inc./Vamamoto Property December 17, 2003 LOG OF EXPLORATORY TEST PITS TEST PIT NO. DEPTH (ft.) GROUP SYMBOL SAMPLE DEPTH (ft.) MOISTURE (%) FIELDDRY DENSITY ipcf) DESCRIPTION TP-5 0-11/2 SM ARTIFICIAL FILL (UNDOCUMENTED): SILTY SAND brown, damp, loose to medium dense; porous, organics near the surface, plastic tarpaulin. TP-5 11/2-3 SM WEATHERED TERRACE DEPOSITS: SIITY .qAND w/CLAY, yellow brown to orange, damp, medium dense; slightly porous, Paleoliquefaction features (sand dikes). TP-5 3-4 CUSM Bulk @ 3-4 QUATERNARY TERRACE DEPOSITS: SANDY Cl AY tn SILTY SAND, olive gray to orange, damp to moist; very stiff to very dense (cemented); massive. TP-5 Practical Refusal @ 4' No Groundwater/Caving Encountered Backfilled 12-17-2003 PLATE B-5 4132-A-SC Cunningham Consulting, Inc./Yamamoto Property December 17, 2003 LOG OF EXPLORATORY TEST PITS TEST PIT NO. DEPTH (ft.) GROUP SYMBOL SAMPLE DEPTH (ft.) MOISTURE (%) FIELDDRY DENSITY (pcf) DESCRIPTION TP-6 0-1 SM TOPSOIL/COLLUVIUM: Sll TY .SAND hrnwn Hry Innco- porous, abundant organics near the surface. TP-6 1-11/2 SM WEATHERED TERRACE DEPOSITS: SILTY SAND ypllnw brown, dry, medium dense; slightly porous. TP-6 11/2-4 SC/CL Undisturbed @ 11/2 6.3 118.9 QUATERNARY TERRACE DEPOSITS: Cl AYFY SAND/ SANDY CLAY, olive brown, damp, very dense/hard. TP-6 Practical Refusal @ 4' No Groundwater/Caving Encountered Backfilled 12-17-2003 PLATE B-6 4132-A-SC Cunningham Consulting, Inc./Yamamoto Property December 17, 2003 LOG OF EXPLORATORY TEST PITS TEST PIT NO. DEPTH (ft,) GROUP SYMBOL SAMPLE DEPTH m MOISTURE (%) FIELD DRY DENSITY (pcf) DESCRIPTION TP-7 0-1 SP TOPSOIL/COLLUVIUM: SAND w/SILT. hrnwn dry, lnn.<?P- porous, abundant organics near the surface. TP-7 1-21/2 SP WEATHERED TERRACE DEPOSITS: SAND w/SlI T yellow brown, dry, medium dense; slightly porous, iron stone concretions. TP-7 21/2-31/2 CL QUATERNARYTERRACE DEPOSITS: SANDY Cl AY nliw gray to orange, damp, very stiff to hard. TP-7 Practical Refusal @ 31/2' No Groundwater/Caving Encountered Backfilled 12-17-2003 PLATE B-7 APPENDIX C EQFAULT, EQSEARCH, AND FRISKSP s c .9 CD i_ 0 0 O o < MAXIMUM EARTHQUAKES CUNNINGHAM 1 .1 .01 .001 .1 X X X X X x^ ;x X I Mil 11 11 1 10 Distance (mi) 100 W.O. 4132-A-SC Plate C-1 (0 >- tn •*-> c 0) > 0 E u z 0 > '.*-> ro E E =3 o 100 EARTHQUAKE RECURRENCE CURVE CUNNINGHAM .001 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 Magnitude (M) 7.5 8.0 8.5 9.0 W.O. 4132-A-SC Plate 0-2 1100 1000 -- 900 EARTHQUAKE EPICENTER MAP CUNNINGHAM -400 -300 -200 -100 100 200 300 400 500 600 W.O. 4132-A-SC Plate C-3 PROBABILITY OF EXCEEDANCE BOZ. ET AL.(1999)HOR SR UNC 1 100 n cc n o CL 0 O c CO u 0 0 o X LU 25 yrs 75 yrs 50 yrs 100 yrs 0.00 0.25 0.50 0.75 1.00 1.25 1.50 Acceleration (g) W.O. 4132-A-SC Plate C-4 b ro CO o CO o • •••• 0 CL c +-» 0 2 S* t-h O cn RETURN PERIOD VS. ACCELERATION BOZ. ET AL.(1999)HOR SR UNC 1 100000 10000 1000 100 0.00 0.25 0.50 0.75 1.00 Acceleration (g) 1.25 1.50 APPENDIX D LABORATORY DATA 3,000 2,500 2,000 1,500 1,000 500 500 1.000 1,500 2,000 NORMAL PRESSURE, psf 2,500 3,000 §1 ^1 ul Sample Depth/El. Primary/Residual Shear Sample Type \ MCV. c <i> • TP-1 1.0 Primary Shear Remolded 117.9 8.5 209 T 29 • TP-1 1.0 Residual Shear Remolded 117.9 8.5 126 30 L Note: Sample Innundated prior to testing GeoSoils, Inc. DIRECT SHEAR TEST f&«'- 5741 Palmer Way %,l|lc. Carlsbad, CA 92008 Project: CUNNINGHAM 1 Telephone: (760)438-3155 Number: 4132-A-SC 1 1 Fax: (760)931-0915 Date: December 2003 Plate D-1 1 1 I Fax: (760)931-0915 Date: December 2003 Plate D-1 1 60 50 L5 40 Q Z o I-w a. 20 10 CL •CH / / / / / / / / / / / / • / ML MH y ML MH ML MH Sample LIQUID LIMIT Depth/El. LL PL Pl Fines Classification TP-5 3.0 36 18 18 j0m gm.m GeoSoils, Inc. 5741 Palmer Way Carlsbad, CA 92008 Telephone: (760)438-3155 Fax: (760)931-0915 ATTERBERG LIMITS' RESULTS Project: CUNNINGHAM Number: 4132-A-SC Date: December 2003 Plate D-3 APPENDIX E GENERAL EARTHWORK AND GRADING GUIDELINES GENERAL EARTHWORK AND GRADING GUIDELINES General These guidelines present general procedures and requirements for earthwork and grading as shown on the approved grading plans, Including preparation of areas to filled, placement of fill, installation of subdrains and excavations. The recommendations contained in the geotechnical report are part ofthe 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 recommendations which could supersede these guidelines or the recommendations contained in the geotechnical report. The contractor is responsible for the satisfactory completion of all earthwork in accordance with provisions of the project plans and specifications. The project soil engineer and engineering geologist (geotechnical consultant) or their representatives should provide observation and testing services, and geotechnical consultation during the duration ofthe 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 conformance with the recommendations of the geotechnical report, the approved grading plans, and applicable grading codes and ordinances. The geotechnical consultant should provide testing and obsen/atlon so that determination 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 clean-outs, prepared ground to receive fill, key excavations, and subdrains should be observed and documented by the project engineering geologist and/or soil engineer prior to placing and fill. It is the contractors's responsibility to notify the engineering geologist and soil engineer when such areas are ready for obsen/ation. Laboratorv 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-1557-78. Random field compaction tests should be performed in accordance with test method ASTM designation D-1556-82, D-2937 or D-2922 and D-3017, at intervals of approximately 2 feet of fill height or every 100 cubic yards of fill placed. These criteria would vary depending on the soil conditions and the size ofthe project. The location and frequency of testing would be at the discretion of the geotechnical consultant. CeoSoilSf Inc. Contractor's Responsibility All clearing, site preparation, and earthwork performed on the project should be conducted by the contractor, with observation by geotechnical consultants and staged approval by the governing agencies, as applicable. It isthe contractor's responsibility to prepare the ground surface to receive the fill, to the satisfaction of the soil engineer, and to place, spread, moisture condition, mix and compact the fill in accordance with the recommendations of the soil engineer. The contractor should also remove all major non-earth material considered unsatisfactory by the soil engineer. It Is the sole responsibility ofthe contractor to provide adequate equipment and methods to accomplish the earthwork In accordance with applicable grading guidelines, codes or agency ordinances, and approved grading plans. Sufficient watering apparatus and compaction equipment should be provided by the contractor with due consideration forthe fill material, rate of placement, and climatic conditions. If, In the opinion ofthe 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. Existing fill, soil, alluvium, colluvium, or rock materials determined by the soil engineer or engineering geologist as being unsuitable In-place should be removed prior to 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 soil engineer. 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 soil engineer. Soft, dry, spongy, highly fractured, or othenwise 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 soil engineer before compaction and filling operations continue. Overexcavated and processed soils which have been properly mixed and moisture Cunningham Consulting, Inc. Appendix E Flle:e:\wp9\4100\4132a.pge Page 2 GeoSoils, Inc. 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 to a minimum depth of 6 inches or as directed by the soil engineer. 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 grater that 6 inches in depth, it may be necessary to remove the excess and place the material in lifts restricted to about 6 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 soils engineer and/or engineering geologist. Scarification, disc harrowing, or other acceptable fomi 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, hollow, hummocks, 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), 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 soil engineer and/or engineering geologist In fill over cut slope conditions, the recommended minimum width ofthe 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 Soil Engineer, the minimum width of fill keys should be approximately equal to Vz the height ofthe 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 ofthe 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 toe of fill benches should be observed and approved by the soil engineer and/or engineering geologist priorto 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 determined to be suitable by the soil engineer. These materials should be free of roots, tree branches, other organic matter or other deleterious materials. All unsuitable materials should be removed from the fill as directed by the soil engineer. Soils of poor gradation, undesirable expansion potential, or substandard strength Cunningham Consulting, Inc. ~ ~~ Appendix E File:e:\wp9\4100\4132a.pge Page 3 GeoSoils, Inc. 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 throughoutthe fill area and blended with other bedrock derived material. Benching operations should not result 1^.?®^^^'^ 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 matenals and disposal methods are specifically approved by the soil engineer Oversized material shou Id be taken off-site or placed in accordance with recommendations ofthe soil engineer in areas designated as suitable for rock disposal. Oversized material should not be placed within 10 feet vertically of finish grade (elevation) or within 20 feet horizontally of slope faces. To facilitate future trenching, rock should not be placed within the range of foundation excavations, future utilities, or underground construction unless specifically approved bv the soil engineer and/or the developers representative. If Import material is required for grading, representative samples ofthe materials to be utilized as compacted fill should be analyzed in the laboratory by the soil engineer to determine its physical properties. If any material other than that previously tested is encountered dunng grading, an appropriate analysis ofthis material should be conducted by the soil engineer 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 6 inches in thickness. The soil engineer 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. F'ill layers at a moisture content less than optimum should be watered and mixed and wet fl I layers should be aerated by scarification or should be blended with drier material Moisture condition, 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 maximum density as determined by ASTM test designation, D-1557-78, or as otherwise recommended by the soil engineer Compaction equipment should be adequately sized and should be specifically designed for soil compaction or of proven reliability to efficiently achieve the specified deqree of compaction. Cunningham Consulting, Inc. ~ Apnendix F File:e:\wp9\4100\4132a.pge Page 4 GeoSoils, Ine. 1 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 soil engineer. 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. Afinal determination 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 (horizontal to vertical), specific material types, a higher minimum relative compaction, and special grading procedures, may he 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 perpendicularto the slopes, and extend out over the slope to provide adequate compaction to the face ofthe slope. Loose fill should not be spilled out over the face of the slope as each lift is compacted. Any loose fill spilled over a previously completed slope face should be trimmed off or be subject to re-rolling. Field compaction tests will be made in the outer (horizontal) 2 to 8 feet ofthe slope at appropriate vertical intervals, subsequent to compaction operations. After completion of the slope, the slope face should be shaped with a small tractor and then re-rolled with a sheepsfoot to achieve compaction to near the slope face. Subsequent to testing to verify compaction, the slopes should be grid-rolled to achieve compaction to the slope face. Final testing should be used to confirm compaction after grid rolling. Where testing Indicates less than adequate compaction, the contractor will be responsible to rip, water, mix and re-compact the slope material as necessary to achieve compaction. Additional testing should be performed to verify compaction. Cunningham Consulting, Inc. ~ ~ Appendix E Flle:e:\wp9\4100\4132a.pge p^gg g GeoSoils, Inc. 6. Erosion control and drainage devices should be designed by the project civil engineer in connpiiance with ordinances ofthe controlling govemmental agencies geologist^''''°^ ^"""^ "^'^^^ recommendation of the soil engineer or engineering SUBDRAIN INSTAI I ATir>M Subdrains should be installed in approved ground in accordance with the approximate alignment and details indicated by the geotechnical consultant. Subdrain locations or matenals should not be changed or modified without approval of the geotechnical consultant. The soil engineer and/or engineering geologist may recommend and direct char^ges in subdrain line, grade and drain material in the field, pending exposed conditions The location of constructed subdrains should be recorded by the project civil engineer." EXCAVATIONS Excavations and cut slopes should be examined during grading by the enaineerina geologist. If directed by the engineering geologist, further excavations or overe^^^^^^^^^ and re-filling 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 othenwise approved the cut portion of the slope should be observed by the engineering geologist prior to placement of materials for construction of the fill portion of the slope. The engineering geologist should obsen/e all cut slopes and should be notified by the contractorwhen cut slopes are started. If. during the course of grading, unforeseen adverse or potential adverse geologic conditions are encountered, the engineering geologist and soil engineer should investigate, evaluate and make recommendations to treat these problems. The need for cut slope buttressing or stabilizing should be based on in-gradinq evaluation by the engineering geologist, whether anticipated or not. Unless othenwise specified in soil and geological reports, no cut slopes should be excavated higher or steeper than that allowed by the ordinances of controllinq govemmental agencies. Additionally, short-term stability of temporary cut slopes is the contractors responsibility. ^ ch°f iTK''°''*''°'f ""^ "^^^''^^^ ^^^'9"^^ by the project civil engineer and should be constructed in compliance with the ordinances ofthe controlling govemmental agencies and/or in accordance with the recommendations of the soil engineer or engineering geologist amcci ui Cunningham Consulting. Inc. " —7 -Tr-= Flle:e:\wp9\4100\4132a.pge Appendix E Page 6 GeoSoils, Ine. COMPLETION Obsen/ation, testing and consultation by the geotechnical consultant should be conducted during the grading operations in order to state an opinion that all cut and filled areas are graded in accordance with the approved project specifications. After completion of grading and after the soil engineer and engineering geologist have finished their observations ofthe work, final reports should be submitted subjectto review by the controlling govemmental agencies. No further excavation or filling should be undertaken without prior notification of the soil engineer and/or engineering geologist. 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 GeoSoils, Inc. (GSI) getting the job done safely is of primary concem. The followinq 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 firime 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 obsen/ation the following precautions are to be implemented forthe safety of field personnel on gradinq'and construction projects: ^ Safety Meetings: GSI field personnel are directed to attend contractors regularly scheduled and documented safety meetings. Safety Vests: Safety vests are provided for and are to be wom 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. Cunningham Consulting, Inc. ' ' r File:e:\wp9\4100\4132a.pge Appendix E Page 7 GeoSoils, Ine. Flashing Lights: All vehicles stationary in the grading area shall use rotating or flashing amber beacon, 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 thatthe 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 techniclans's safety. Efforts will be made to coordinate locations with the grading contractors authorized representative, and to select locations following or behind the established traffic pattern, preferably outside of current traffic. The contractors authorized representative (dump man, operator, supen/isor. grade checker, etc.) should direct excavation ofthe pit and safety during the test period. Of paramount concern should be the soil technicians safety and obtaining enough tests to represent the fill. Test pits should be excavated so that the spoil pile is placed away form 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 ofthe test holes, particulariy 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 decreased test results. When taking slope tests the technician should park the vehicle directly above or belowthe 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 operation distance (e.g.. 50 feet) away from the slope during this testing. The technician is directed to withdraw from the active portion ofthe fill as soon as possible following testing. The technician's vehicle should be parked at the perimeter ofthe fill in a highly visible location, well away from the equipment traffic pattern. The contractor should inform our personnel of all changes to haul roads, cut and fill areas or other factors that may affect site access and site safety. In the event that the technicians safety is jeopardized or compromised as a result ofthe contractors failure to comply with any ofthe above, the technician is required, by company policy, to immediately withdraw and notify his/her supen/isor. The grading contractors Cunningham Consulting. Inc. ~ ~ Apnendix F File:e:\wp9\4100\4132a.pge '^^ p^gg g GeoSoils, Inc. representative will eventually be contacted in an effort to effect a solution. However, in the interim, no further testing will be performed until the situation is rectified. Any fill place 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 brings this to his/her attention and notify this office. Effective communication and coordination between the contractors representative and the soils technician is strongly encouraged in order to implement the above safety plan. Trench and Vertical Excavation It Is the contractor's responsibility to provide safe access into trenches where compaction testing is needed. Our personnel are directed not to enter any excavation or vertical cut which: 1) is 5 feet or deeper unless shored or laid back; 2) displays any evidence of Instability, has any loose rock or other debris which could fall into the trench; or3) displays any other evidence ofany unsafe conditions regardless of depth. All trench excavafions 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 supen/isor. The contractors representative will eventually be contacted in an effort to effect a solufion. 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 obligafion to put the contractor and owner/developer on nofice to immediately correct the situation. If corrective steps are not taken. GSI then has an obligafion to notify CAL-OSHA and/or the proper authorities. Cunningham Consulting, Inc. Appendix E File:e:\wp9\4100\4132a.pge Page 9 GeoSoils, Ine. CANYON SUBDRAIN DETAIL TYPE A PROPOSED COMPACTED FILL NATURAL GROUND COLLUVIUM AND ALLUVIUM (REMOVE) TYPICAL BENCHING '^r^:^ V^W^I BEDROCK V/ SEE ALTERNATIVES TYPE B PROPOSED COMPACTED RLL NATURAL GROUND COLLUVIUM AND ALLUVIUM IREMOVE) \///^\\ TYPICAL BENCHING Jr SEE ALTERNATIVES NOTE: ALTERNATIVES. LOCATION AND EXTENT OF SUBDRAINS SHOULD BE DETERMINED BY THE SOILS ENGINEER ANO/OR ENGINEERING GEOLOGIST DURING GRADING. Dl ATH rn—1 CANYON SUBDRAIN ALTERNATE DETAILS ALTERNATE 1: PERFORATED PIPE AND FILTER MATERIAL MINIMUM A~1 FILTER MATERIAL MINIMUM VOLUME OF 9 FT.» .- -.^^. .^ /LINEAR FT. 6- i ABS OR PVC PIPE OR APPROVED ^'•.Viv.*'^ c;ilRSTITUTF WITH MINIVItlU » M/Z-rflDlTDCc ^'.•.•^li^ ^ SUBSTITUTE WITH MINIMUM 8 l1/A"SnPERFS. LINEAR FT. IN BOTTOM HALF OF PIPE. ASTM D2751. SDR 35 OR ASTM D1527. SCHD. .40 ASTM D3034. SDR 35 OR ASTM D1785, SCHD. 40 FOR CONTINUOUS RUN IN EXCESS OF56o FT. USE B-JBf PIPE MINIMUM 1 6" MINIMUM B-1 FILTER MATERIAL. SIEVE SIZE PERCENT PASSING 1INCH ,10b 3/4 INCH .90-100 3/8 INCH 40-100 NO. k 25-AO. NO. 8 18-33 .NO. 30 -.S-IS 'NO. 50 .0-7 NO. 200 0-3 ALTERNATE 2: PERFORATED PIPE. GRAVEL AND.FILTER FABRIC ^^^'"I-MTNIMUM OVERLAP 6" MINIMUM OVERLAP ^6" MINIMUM COVER =4' MINIMUM BEDDING A-2 4- MINIMUM BEDDINGZZ^ GRAVEL MATERIAL 9 FP/LINEAR FT. B-2 PERFORATED PIPE SEE ALTERNATE 1 GRAVEL CLEAN 3/4 INCH ROCK OR APPROVED SUBSTITUTE FILTER FABRIC: MIRAFI UO OR APPROVED SUBSTITUTE PLATE EG-2 DETAIL FOR FILL SLOPE TOEING OUT ON FLAT ALLUVIATED CANYON TOE OF SLOPE AS SHOWN ON GRADING PLAM ORIGINAL GROUND SURFACE TO BE RESTORED WITH COMPACTED FILL BACKCUTS-VARIES. FOR DEEP REMOVALS./.^ BACKCUT ^VKSHOULD BE MADE NO STEEPER THAIKJ:! OR AS NECESSARY FOR SAFETY v.^^ONSIDERATIONS.y COMPACTED RLL ORIGINAL GROUND SURFACE r ANTICIPATED ALLUVIAL REMOVAL _r:":~ MINIMUM PROJECTION FROM TOE OF SLOPE AS SHOWN DN GRADING PLAN TO THE RECOMMENDED REMOVAL DEPTH. SLOPE HEIGHT. SITE CONDITIONS AMD/OR LOCAL CONDITIONS COULD DICTATE FLATTER PROJECTIONS REMOVAL ADJACENT TO EXISTING FILL ADJOINING CANYON FILL COMPACTED RLL LIMITS LINE Oaf IEXISTING..COMPACTED FILL) '<?^N x^TEMPORARY COMPACTED RLL ^,^POR DRAINAGE ONLY ^ • >>. , • Qal ITO BE REMOVED) Qaf \^ ' i Tn DC DITLJftX/crn Bf-r-nni-TO BE REMOVED BEFORE PLACING ADDITIONAL COMPACTED RLL LEGEND Qaf ARTIFICIAL FILL Qal ALLUVIUM PLATE EG~3 TYPICAL STABILIZATION / BUTTRESS FILL DETAIL 15" TYPICAL 1-2' CLEA A > H m m o I 4^ TOE OUTLETS TO BE SPACED AT 100'MAXIMUM INTERVALS. AND SHALL EXTEND 12- BEYOND THE FACE OF SLOPE AT TIME OF.ROUGH GRADING COMPLETION. DESIGN RNISH SLOPE 15'MINIMUM 1 BLANKET FILL IF RECOMMENDED BY THE SOIL ENGINEER .2% GRADIENT 10'MINIMUM 25" MAXIMUM, L TYPICAL BENCHING BUTTRESS OR SIDEHILL RuJ \> \- DIAMETER NON-PERFORATED OUTLET PIPE b AND BACKDRAIN (SEE ALTERNATIVES) BEDROCK ^ WslS'MINIMUM OR H/2 ' HEEL 3* MINIMUM KEY DEPTH > -H m m CD I Ol TYPICAL STABIUZATION / BUTTRESS SUBDRAIN DETAIL U- MINIMUM PIPE 2' MINIMUM MINIMUM PIPE 2- MINIMUM FILTER MATERIAL MINIMUM OF FIVE FI'/LINEAR Fl OF PIPF OR FOUR FP/LINEAR Fl OF PIPE WHEN PLACED IN SQUARE CUT TRENCH. ALTERNATIVE IN LIEU OF RLTER MATERIAL: GRAVEL MAY BE EMCASED IN APPROVED FILTER FABRIC. FILTER FABRIC SHALL BE MIRAFI 140 OR EQUIVALENT. FILTER FABRIC SHALL BE LAPPED A MINIMUM OF 12" ON ALL JOINTS. MINIMUM 4- DIAMETER PIPE: ABS-ASTM D-2751. SDR 35 OR ASTM D-1527 SCHEDULE 40 PVC-ASTM 0-3034. SpR 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 INSTALLED WITH PERFORATIONS OF BOTTOM OF PIPE. PROVIDE CAP AT UPSTREAM END OF PIPE. SLOPE AT 2% TO OUTLET PIPE. OUTLET PIPE TO BE CONNECTED TO SUBDRAIN PIPE WITH TEE OR ELBOW. NOTE: 1. TRENCH FOR OUTLET PIPES TO BE BACKFILLED t WITH ON-SITE 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 SOILS " ENGINEER AND/OR ENGINEERING GEOLOGIST. FILTER MATERIAL SHALL BE OF THE FOLLOWING SPECIFICATION OR AN APPROVED EQUIVALENT: SIEVE SIZE PERCENT PASSING 1 INCH 100 3/4 INCH 90-100 3/8 INCH 40-100 NO. 4 25-40 NO. 8 18-33 NO. 30 5-15 NO. 50 0 — 7 NO. 200 0-3 GRAVEL SHALL BE OF THE FOLLOWING SPECIFICATION OR AN APPROVED EQUIVALENT: SIEVE SIZE PERCENT PASSING 1 1/2 INCH- NO. 4 NO. 200 100 50 8 SAND EQUIVALENT: MINIMUM OF 51 FILL OVER NATURAL DETAIL SIDEHILL FILL PROPOSED GRADE COMPACTED FILL 'MAINTAIN MINIMUM 15" WIDTH TOE OF SLOPE AS SHOWN ON GRADING PLAN PROVIDE A 1:1 MINIMUM PROJECTION FROM DESIGN TOE OF SLOPE TO TOE OF KEY AS SHOWN ON AS BUILT > m m CD I cn NATURAL SLOPE TO BE RESTORED WITH COMPACTED FILL BACKCUT VARIES ^|?77TOrr. MINIMUM BENCH WIDTH MAY VARY 15* MINIMUM KEY WIDTH 2'X 3'MINIMUM KEY DEPTH 2'MINIMUM IN BEDROCK OR APPROVED MATERIAL I "^'.MINIMUM PTE: 1. WHERE THE NATURAL SLOPE APPROACHES OR EXCEEDS THE DESIGN SLOPE RATIO. SPECIAL RECOMMENDATIONS WOULD BE PROVIDED BY THE SOILS ENGINEER. 2. THE NEED FOR AND DISPOSITION OF DRAINS WOULD BE DETERMINED BY THE SOILS ENGINEER BASED UPON EXPOSED CONDITIONS. FILL OVER CUT DETAIL CUT/RLL CQNTACT 1. AS SHOWN ON GRADING PLAN 2. AS SHOWN ON AS BUILT MAINTAIN MINIMUM 15'FILL SECTION FROM BACKCUT TO FACE OF FINISH SLOPE BENCH WIDTH MAY VARY ^^^y^ BEDROCK OR APPROVED MATERIAL LOWEST BENCH WIDTH 15'MINIMUM OR H/2 > m m o I NOTE: THE CUT PORTION OF THE SLOPE SHOULD BE EXCAVATED AND EVALUATED BY THE SOILS ENGINEER AND/OR ENGINEERING GEOLOGIST PRIOR TO CONSTRUCTING THE FILL PORTION. STABILIZATION FILL FOR UNSTABLE MATERIAL EXPOSED IN PORTION OF CUT SLOPE TI ^^-^^^J^ UNWEATHERED BEDROCK OR APPROVED MATERIAL COMPACTED STABILIZATION FILL V MINIMUM TILTED BACK > m m o I CQ IF RECOMMENDED BY THE SOILS ENGINEER AND/OR ENGINEERING GEOLOGIST, THE REMAINING CUT PORTION OF THE SLOPE MAY REQUIRE REMOVAL AND REPLACEMENT WITH COMPACTED RLL NOTE: 1. SUBDRAINS ARE NOT REQUIRED UNLESS SPECIFIED BY SOILS ENGINEER AND/OR ENGINEERING GEOLOGIST, 2. 'Wf SHALL BE EQUIPMENT WIDTH IIB') FOR SLOPE HEIGHTS LESS THAN 25 FEET. FOR SLOPES GREATER' THAN 25 FEET "W SHALL BE DETERMINED BY THE PROJECT SOILS ENGINEER AND /OR ENGINEERING GEOLOGIST. AT NO TIME SHALL 'W BE LESS THAN H/2. SKIN FILL OF NATURAL GROUND ORIGINAL SLOPE 15'MINIMUM TO BE MAINTAINED FROM PROPOSED RNISH SLOPE FACE TO BACKCUT PROPOSED RNISH SLOPE INISH ORADb 1^3'MINIMUM 2'MINIMUMI^ KEY DEPTH fA ^ BEDROCK OR APPROVED MATERIAL IB^MINIMI NIMUM KEY WIDTH MINIMUM KEY DEPTH m m CD I NOTE: 1. THE NEED AND DISPOSITION OF DRAINS WILL BE DETERMINED! BY THE SOILS ENGINEER AND/OR ENGINEERING GEOLOGIST BASED ON FIELD CONDITiONS. 2. PAD OVEREXCAVATION AND RECOMPACTION SHOULD BE PERFORMED IF DETERMINED TO BE NECESSARY BY THE SOILS ENGINEER AND/OR ENGINEERING GEOLOGIST. I DAYLIGHT CUT LOT DETAIL RECONSTRUCT COMPACTED RLL SLOPE AT 2:1 OR FLATTER (MAY INCREASE OR DECREASE PAD AREA). OVEREXCAVATE AND RECOMPACT REPLACEMENT RLL NATURAL GRADE AVOID AND/OR CLEAN UP SPILLAGE OF MATERIALS ON THE NATURAL SLOPE ^ BEDROCK OR APPROVED MATERIAL TYPICAL BENCHING r- > m m o NOTE: 1. SUBDRAIN AND KEY WIDTH REQUIREMENTS WILL BE DETERMINED BASED ON EXPOSED SUBSURFACE CONDITIONS AND THICKNESS OF OVERBURDEN. 2. PAD OVER EXCAVATION AND RECOMPACTION SHOULD BE PERFORMED IF DETERMINED NECESSARY BY THE SOILS ENGINEER AND/OR THE ENGINEERING GEOLOGIST. TRANSITION LOT DETAIL CUT LOT (MATERIAL TYPE TRANSITION) NATURAL GRADE COMPACTED RLL OVEREXCAVATE AND RECOMPACT '(/^//'^^//<ly^^^^ 3* MINIMUM* ^ iruuicA-rucDcn DCnonrv np APPROVE^n MATPRI ^ UNWEATHERED BEDROCK OR APPROVED MATERIAL TYPICAL BENCHING CUT-FILL LOT (DAYUGHT TRANSITION) /AW\\Vy/\\VyJ^S^^^^ 3-MINIMUM' y, UNWEATHERED BEDROCK OR APPROVED MATERIAL TYPICAL BENCHING NOTE: * DEEPER OVEREXCAVATION MAY BE RECOMMENDED BY THE SOILS ENGINEER AND/OR ENGINEERING GEOLOGIST IN STEEP CUT-RLL TRANSITION AREAS. PLATE EG~H SETTLEMENT PLATE AND RISER DETAIL 2'X 2'X 1/4' STEEL PLATE ^STANDARD 3/4" PIPE NIPPLE WELDED TO TOP OF PLATE. • 3/4- X 5* GALVANIZED PIPE. STANDARD PIPE \^ THREADS TOP AND BOTTOM. EXTENSIONS THREADED ON BOTH ENDS AND ADDED IN 5" \ INCREMENTS. •3 INCH SCHEDULE 40 PVC PIPE SLEEVE. ADD IN 5* INCREMENTS WITH GLUE JOINTS. FINAL GRADE * ' —I I I 5' I I I I ! y 5* 5* , MAINTAIN 5' CLEARANCE OF HEAVY EQUIPMENT. MECHANICALLY HAND COMPACT IN 2'VERTICAL LIFTS OR ALTERNATIVE SUITABLE TO AND ^ ACCEPTED BY THE SOILS ENGINEER. MECHANICALLY HAND COMPACT THE INITIALS* VERTICAL WITHIN A 5'RADIUS OF PLATE BASE. 2— > \ : •./T^-.-. :./ BOTT BOTTOM OF CLEANOUT PROVIDE A MINIMUM 1'BEDDING DF COMPACTED SAND NOTE: 1. LOCATIONS OF SETTLEMENT PLATES SHOULD BE CLEARLY MARKED AND READILY VISIBLE (RED FLAGGED) TO EQUIPMENT OPERATORS. 2. CONTRACTOR SHOULD MAINTAIN CLEARANCE OF A 5*RADIUS OF PLATE BASE AND WITHIN 5* (VERTICAL) FOR HEAVY EQUIPMENT. RLL WITHIN CLEARANCE AREA SHOULD BE HAND COMPACTED TO PROJECT SPECIRCATIONS OR COMPACTED BY ALTERNATIVE APPROVED BY THE SOILS ENGINEER. 3. AFTER 5'IVERTICAL) OF FILL IS IN PLACE. CONTRACTOR SHOULD MAINTAIN A 51HADIUS EQUIPMENT CLEARANCE FROM RISER. 4. PLACE AND MECHANICALLY HAND COMPACT INITIAL 2'OF RLL PRIOR TO ESTABLISHING THE INITIAL READING, 5. IN THE EVENT OF DAMAGE TO THE SETTLEMENT PLATE OR EXTENSION RESULTING FROM EQUIPMENT OPERATING WITH IN THE SPECIFIED CLEARANCE AREA. CONTRACTOR SHOULD IMMEDIATELY NOTIFY THE SOILS ENGINEER AND SHOULD BE RESPONSIBLE FOR RESTORING THE SETTLEMENT PLATES TO WORKING ORDER. 6. AN ALTERNATE DESIGN AND METHOD OF INSTALLATION MAY BE PROVIDED AT THE DISCRETION OF THE SOILS ENGINEER. PLATE EG-U TYPICAL SURFACE SETTLEMENT MONUMENT RNISH GRADE 'r-B" *-6- DIAMETER X 3 1/2" LENGTH HOLE 3/8- DIAMETER X 6" LENGTH CARRIAGE BOLT OR EQUIVALENT CONCRETE BACKFILL PLATE EG-15 TEST PIT SAFETY DIAGRAM SIDE YIEW ^ TEST PIT ( NOT TO SCALE ) TOP VIEW 100 FST 50 FEET V&HCLE III APPROXIMATE CENTER OF TESTPIT ( NOT TO SCALE ) Dl ATC 1FJ OVERSIZE ROCK DISPOSAL VIEW NORMAL TO SLOPE FACE PROPOSED FINISH GRADE oo MINIMUM (E) CO oa 15'MINIMUM (A) oo C30 (G) lO'MINIMUM CO J5'MINIMUM (AU CO oo oolF) ^5' MINIMUM (C) BEDROCK OR APPROVED MATERIAL . VIEW PARALLEL TO SLOPE FACE PROPOSED FINISH GRADE FROM MINIMUM fC) BEDROCK OR APPROVED MATERIAL NOTE: lA) ONE EQUIPMENT WIDTH OR A MINIMUM OF 15 FEET. (B) HEIGHT AND WIDTH MAY VARY DEPENDING ON ROCK SIZE AND TYPE OF EQUIPMENT. LENGTH OF WINDROW SHALL BE NO GREATER THAN 100* MAXIMUM. IC) IF APPROVED BY THE SOILS ENGINEER AND/OR ENGINEERING GEOLOGIST. WINDROWS MAY BE PLACED DIRECTLY ON COMPETENT MATERIAL OR BEDROCK PROVIDED ADEQUATE SPACE IS AVAILABLE FOR COMPACTION. ID) ORIENTATION OF WINDROWS MAY VARY BUT SHOULD BE AS RECOMMENDED BY THE SOILS ENGINEER AND/OR ENGINEERING GEOLOGIST. STAGGERING OF WINDROWS IS NOT NECESSARY UNLESS RECOMMENDED. (E) CLEAR AREA FOR UTILITY TRENCHES. FOUNDATIONS AND SWIMMING POOLS, (n ALL RLL OVER AND AROUND ROCK WINDROW SHALL BE COMPACTED TO 9 0% RELATIVE COMPACTION OR AS RECOMMENDED. IG) AFTER FILL BETWEEN WINDROWS IS PLACED AND COMPACTED WITH THE LIFT OF RLL COVERING WINDROW. WINDROW SHOULD BE PROOF ROLLED WITH A D-9 DOZER OR EQUIVALENT. VIEWS ARE DIAGRAMMATIC ONLY. ROCK SHOULD NOT TOUCH AND VOIDS SHOULD BE COMPLETELY RLLED IN. PLATE RD"—1 ROCK DISPOSAL PITS VIEWS ARE DIAGRAMMATIC ONLY. ROCK SHOULD NOT TOUCH AND VOIDS SHOULD BE COMPLETELY RLLED IN. RLL LIFTS COMPACTED OVER ROCK AFTER EMBEDMENT r I I GRANULAR MATERIAL COMPACTED RLL SIZE OF EXCAVATION TO BE COMMENSURATE WITH ROCK SIZE ROCK DISPOSAL LAYERS GRANULAR SOIL TO RLL VOIDS,^OMPACTED RLL DENSIRED BY FLOODING LAYER ONE ROCK PROPOSED FINISH 6RADF ^0* MINIMUM OR BELOW LOWEST UTIU PROFILE ALONG LAYER AYER OVERSIZE LAYER -j, s,- FRt)10SSLOPE FACE COMPACTED FILL -T- OOaococc«oooc)cccocccx33coc?c>^^ Jp'MINIMUM sCXSOCXXXXXXi ^CLEAR ZONE 20'MINIMUM LAYER ONE ROCK HIGH PLATE RD-2