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Trilogy TR 30023 (Product 1) 2007 Code Update - Geotechnical Engineering ReportEarth Systems �i Southwest August 19, 2010 Shea La Quinta, LLC 60-918 Desert Rose Drive La Quinta, California 92253 Attention: Mr. Perry Devlin Project: Travertine Parcel — TTM 35996 West of Living Stone Drive La Quinta, California Subject: Plan Review Comments 79-81113 Country Club Drive Bermuda Dunes, CA 92203 (760)345-1588 (800)924-7015 FAX (760)345-7315 File No.: 07711-31 Doc. No.: 10-08-759 dZW4, CITY OF LA QUINTA BUILDING & SAFE T Y DEPT. APPROVED FOR CONSTRUCTION I DATE BY R-0 IIII References: 1. Earth Systems Southwest, Geotechnical Engineering Report and Infiltration Testing for Stormwater Retention, Travertine Parcel — TTM 35996, West of Living Stone Drive, La Quinta California, Doc. No.: 08-12-769, dated December 30, 2008. 2. Suncoast Post -Tension, PTD, Sheets PTl, PT1A, PT2, PT2A, PT3, PT3A, PT313, and PTCA, dated June 23, 2010. As requested, Earth Systems Southwest [ESSW], has re -reviewed the above -referenced plans (Reference 2) were found to be in general compliance with the intent of the recommendations presented in Reference 1 subject to the following comments and recommendations. Since the entire site will receive post tension footings/slabs, and since the design is based on the recommended 1.1-inches of differential settlement, it is our opinion that the minimum footing depth of 12-inches is acceptable. Therefore, ESSW "approves" the plans from a geotechnical standpoint. Furthermore, the proposed design will eliminate a different design between the east and west sides of the site, resulting in a more seamless operation in the field during construction. This review was performed specifically with respect to geotechnical factors discussed in Reference 1. Factors related to civil or structural engineering, architecture, drafting or other disciplines are beyond the scope of this review. No attempt was made to resolve every conflict that may exist within the plans or between the plans (Reference 2) and the recommendations contained in Reference 1. AUG 2 0 2010 August 19, 2010 2 File No.: 07711-31 Doe. No.: 10-08-759 We appreciate the opportunity to have provided services for this project and look forward to providing additional services for you in the future. If there are any questions concerning this letter, please do not hesitate to contact us. Sincerely, EARTH SYSTEMS SOUTHWEST Lut unze, P -25801, GE 493 Associate Geotechnical Engineer LTR/csh/cen Distribution: 4/Shea La Quinta, LLC 2/BD File EARTH SYSTEMS SOUTHWEST SHEA LA QUINTA, LLC 60-311 TRILOGY PARKWAY LA QUINTA, CALIFORNIA 92253 I_ GEOTECMUCAL ENGINEERING REPORT AND INFILTRATION TESTING FOR STORM WATER RETENTION TRAVERTINE PARCEL — TTM 35996 WEST OF LIVING STONE DRIVE LA QUINTA, CALIFORNIA December 30 2008 © 2008 Earth Systems Southwest Unauthorized use or copying of this document is strictly prohibited without the express written consent of Earth Systems SouthwesL File No.: 07711-31 Doc. No.: 08-12-769 Earth Systems Southwest 79-811B Country Club Drive Bermuda Dunes, CA 92203 _. (760)345-1588 (800)924-7015 FAX (760) 345-7315 December 30, 2008 File No.: 07711-31 Doc. No.: 08-12-769 Shea Homes La Quinta, LLC 60-311 Trilogy Parkway La Quinta, California 92253 Attention: Mr. Ulrich Sauerbrey Project: Travertine Parcel — TTM 35996 West of Living Stone Drive La Quinta, California Subject: Geotechnical Engineering Report and Infiltration Testing for Stormwater Retention We take pleasure in presenting this geotechnical engineering report prepared for the proposed 36- Lot residential development to be located west of Living Stone Drive in the City of La Quinta, Riverside County, California. This report presents our findings and recommendations for site grading, foundation design criteria, and retention basin/dry well design, incorporating the information provided to our office. The site is suitable for the proposed development, provided the recommendations in this report are followed in design and construction. This report should stand as a whole and no part of the report should be excerpted or used to the exclusion of any other part. This report completes our scope of services in accordance with our agreement, dated October 29, 2008 and authorized on November 4, 2008. Other services that may be required, such as plan review and grading observation, are additional services and will be billed according to our Fee Schedule in effect at the time services are provided. Unless requested in writing, the client is responsible for distributing this report to the appropriate governing agency or other members of the design team. We appreciate the opportunity to provide our professional services. Please contact our office if there are any questions or comments concerning this report or its recommendations. Respectfully submitted, EARTH SYSTEMS SOUTHWEST Joseph E. McKinney GP 1052, PG 8249 SER/jem/csh/ajm Distribution: 6/Shea La Quinta, LLC 2/13D File Reviewed ,v a E 3823411 CE38234 �y E x p .03/31/'q Craig S. �sT c1v1L CE 38234 9TF _,,,�} TABLE OF CONTENTS Page EXECUTIVESUMMARY ......................................................:............................................... Section1 INTRODUCTION.......................................................................................................I 1.1 Project Description....................................................................................................... l 1.2 Site Description.:...........................................................................................................I 1.3 Purpose and Scope of Services.....................................................................................2 Section 2 METHODS OF INVESTIGATION ..................................................................4 2.1 Field Exploration..........................................................................................................4 2.2 Laboratory Testing...................................................................................... ..........4 2.3 Infiltration Testing........................................................................................................5 Section3 DISCUSSION..............................................................................................................8 3.1 Soil Conditions.............................................................................................................8 3.2 Groundwater.................................................................................................................8 3.3 Geologic Setting...........................................................................................................8 3.4 Geologic Hazards..........................................................................................................9 3.4.1 Seismic Hazards...............................................................................9 3.4.2 Secondary Hazards........................................................................................10 3.4.3 Site Acceleration and Seismic Coefficients...................................................I I Section4 CONCLUSIONS.......................................................................................................13 Section 5 .__ RECOMMENDATIONS..........................................................................................14 SITE DEVELOPMENT AND GRADING..............................................................................14 L 5.1 Site Development — Grading.......................................................................................14 5.2 Excavations and Utility Trenches...............................................................................15 5.3 Slope Stability of Graded Slopes., .............................................. ............................... 16 STRUCTURES........................................................................................................................16 5.4 Foundations.................................................................................................................16 5.5 Slabs-on-Grade...........................................................................................................17 5.6 Retaining Walls...........................................................................................................18 5.7 Mitigation of Soil Corrosivit) , Concrete................................................................19 5.8 Seismic Design Criteria..............................................................................................20 5.9 Pavements...................................................................................................................21 Section 6 LIMITATIONS AND ADDITIONAL SERVICES................................................23 6.1 Uniformity of Conditions and Limitations.................................................................23 6.2 Additional Services.....................................................................................................24 REFERENCES.........................................................................................:.............................25 APPENDIX A Figure 1 — Site Location Figure 2 — Boring and Infiltration Test Locations Table I — Fault Parameters Terms and Symbols used on Boring Logs Soil Classification System Logs of Borings Infiltration Test Results Table 2 — Initial Estimated Conductivities Table 3 — Drywell Design and Infiltration Model APPENDIX B Laboratory Test Results EARTH: SYSTEMS SOUTHWEST ii EXECUTIVE SUMMARY Earth Systems Southwest has prepared this executive summary solely to provide a general overview of the report. The report itself should be relied upon for information about the findings, conclusions, recommendations and other concerns. The site is located west of Living Stone Drive in the Trilogy development in the City of La Quinta, Riverside County, California. The proposed development will consist of about 36 residential lots that will include a collector street and two cul-de-sac streets. We understand that the proposed structures will be one- or two -stories and will be of wood -frame and stucco construc tion supported with perimeter wall fou ndations and concrete slabs -on -grade. The proposed project may be constructed as planned, provided that the recommendations in this report are incorporated in the final design and construction. Site development will include clearing and grubbing of vegetation, site grading, building pad preparation, underground utility installation, street construction, and concrete driveway and sidewalks placement. Based on the non -uniform nature and hydrocollapse potential of the near surface soils, remedial site grading is recommended to provide uniform support for the foundations. Due to the presence of a relatively shallow, collapsible dry -silt layer beneath the eastern half of the project site, special foundation recommendations are specified for lots in that area (see Section 5). Laboratory testing of the site soils indicate low levels of sulfate and chloride ion content, therefore normal concrete mixes may be used. However, indications are that the on -site soils exhibit moderate to very severe resistivity resulting in a severe corrosion potential for buried metal pipes. Underground utilities and buried metal pipes will require g p p u re corrosion protection from the 9 surroundingsoil. We consider the most significant geologic hazard to the project to be the potential for moderate to severe seismic shaking that is likely to occur during the design life of the proposed structures. The project site is located in the highly seismic Southern California region within the influence of several fault systems that are considered to be active or potentially active. Structures should be designed in accordance with the values and parameters given within the 2007 California Building Code [CBC] and ASCE 7-05. The seismic design parameters are presented in the following table and within the report. EARTH SYSTEMS SOUTHWEST iii SUMMARY OF RECOMMENDATIONS Design Item Recommended Parameter Reference Section No. Foundations Allowable Bearing Pressure Continuous wall footings Pad Column footings 1,500 psf 2,000 psf 5.4 Foundation Type Spread F oting 5.4 Bearing Materials Engineered fill Allowable Passive Pressure 350 nsf ner foot 5.4 and 5.6 Active Pressure 35 pcf 5.6 At -rest Pressure 55 pcf 5.6 Allowable Coefficient of Friction 0.35 5.4 Soil Expansion Potential Very low EI<20) 3.1 Geologic and Seismic Hazards Liquefaction Potential Low 3.4.2 Significant Fault and Magnitude San Andreas, M7.7 3.4.1 Fault Type and Distance A, 1.4.7 km 3.4.1 Seismic Design C tegoEy D 5.8 Site Class D 5.8 Maximum Considered Earthquake MCE Short Period Spectral Response, Ss 1.50 g 5.8 Second Spectral Response, S1 0.60 g 5.8 Site Coefficient, Fa 1.00 5.8 Site Coefficient, F 1.50 5.8 Pavement TI equal to 5.0 (Light Traffic) 3.0" AC / 4.0" AB 5.9 TI equal to 6.0 (Residential Streets) 3.5" AC / 4.0" AB 5.9 Slabs Building Floor Slabs On engineered fill 5.5 Modulus of Subgrade Reaction 200 pei 5.5 Existing Site Conditions Existing Fill N/A Soil Corrosivity low sulfates low chlorides veryGroundwsevere resistivity 5.7 Depth Presently>50-100 feet 3.2 Estimated Filterl a Estimated Fill and Cut � excludes over -excavation) 6 to 9 feet -cut 1.1 The recommendations contained within this report are subject to the limitations presented in Section 6 of this report. We recommend that all individuals using this report read the limitations. EARTH SYSTEMS SOUTHWEST December 30, 2008 Section 1 INTRODUCTION I GEOTECHNICAL ENGINEERING REPORT AND INFILTRATION TESTING FOR STORM WATER RETENTION TRAVERTINE PARCEL — TTM 35996 WEST OF LIVING STONE DRIVE LA QUINTA, CALIFORNIA 1.1 Project Description File No.: 07711-31 Doc. No.:08-12-769 This geotechnical engineering report has been prepared for the Travertine Parcel of the Trilogy Development located west of Living Stone Drive in the City of La Quinta, Riverside County, California. The proposed development will include about 36 residential lots that will include a collector street and two cul-de-sac streets. We understand that the proposed structures will be one- or two -stories and will be of wood -frame and concrete slab -on -grade construction with stucco exterior. We further understand the structures will be supported by conventional shallow continuous or pad footings. Approximately 6 to 9 feet of native soil will be excavated and exported to lower the overall site elevation. The removed soils will be exported to the adjacent Tract 30023-6, Phase 6B and 6C. Stormwater runoff and nuisance water will be managed with two retention basins: one thirteen - foot deep basin located slightly east of the center of the parcel, and one nine -foot deep basin located at the northeast corner. At least one MaxWelfr" or equivalent dry -well system will be installed in the bottom of each retention basin. Site development will include clearing and grubbing of vegetation, site grading, building pad preparation, underground utility installation, street construction, and concrete driveway and sidewalks placement. Based on existing site topography and ground conditions, site grading is expected to consist of and cuts of about 10 feet (excluding over -excavation and depth of retention basins). We used maximum column loads of 20 kips and a maximum wall loading of 2 kips per linear foot as a basis for the foundation recommendations. All loading is assumed to be dead plus actual live load. If actual structural loading exceeds these assumed values, we would need to reevaluate the given recommendations. 1.2 Site Description The proposed residential development is to be constructed on the Trilogy at Coral Mountain — Tentative Tract Map No. 35996 development, to be located west of Living Stone Drive in the City of La Quinta, Riverside County, California. The project site presently consists mostly of native, undeveloped land. An approximately 20-foot wide by 15-foot deep temporary drainage channel has been constructed along the north and east boundaries of the parcel. This channel EARTH SYSTEMS SOUTHWEST December 30, 2008 2 File No.: 07711-31 Doc. No.: 08-12-769 will be backfilled and compacted during grading. To the north and east are earlier phases of the Trilogy development, to the east is an existing United States Bureau of Reclamation Levee, approximately 32 feet high (this will be increased as a result of grading and will include a 10- foot terrace). To the south is undeveloped, native land. The site location is shown on Figure 1 in Appendix A. _ The history of past use and development of the property was not investigated as part of our scope of services. Other than the temporary drainage swale, no evidence of past development was observed on the site during our reconnaissance. Nonetheless, some previous development of the site is possible. Buried remnants, such as old foundations, slabs, or septic systems, may exist on the site. There may be underground utilities near and within the building area. These utility lines include, but are not limited to, domestic water, electric, sewer, telephone, cable, and irrigation lines. 1.3 Purpose and Scope of Services The purpose for our services was to evaluate the site soil conditions and to provide professional' opinions and recommendations regarding the proposed development of the site. The scope of work included the following: ➢ A general reconnaissance of the site. ➢ Shallow subsurface exploration by drilling 5 exploratory borings to depths ranging from about 21.5 to 61.5 feet below existing grade. Laboratory testing of selected soil samples obtained from the exploratory borings. ➢ A review of selected published technical literature pertaining to the site and previous geotechnical reports prepared for earlier phases of the Trilogy development. An engineering analysis and evaluation of the acquired data from the exploration and testing programs. ➢ A summary of our findings and recommendations in this written report. This report contains the following: ➢ Discussions on subsurface soil and groundwater conditions. ➢ Discussions on regional and local geologic conditions. ➢ Discussions on geologic and seismic hazards. ➢ Graphic and tabulated results of laboratory tests and field studies. ➢ Recommendations regarding: • Site development and grading criteria. • Excavation conditions and buried utility installations. • Structure foundation type and design. • Allowable foundation bearing capacity and expected total and differential settlements. • Concrete slabs -on -grade. • Lateral earth pressures and coefficients. • Mitigation of the potential corrosivity of site soils to concrete and steel reinforcement. • Seismic design parameters. EARTH SYSTEMS SOUTHWEST December 30,2008- 3 -- File No.: 07711-31 Doc. No.: 08-12-769 • Preliminary pavement structural sections. Not Contained in This Report: Although available through Earth Systems Southwest, the current scope of our services does not include: ➢ A corrosive study to determine cathodic protection of concrete or buried pipes. An environmental assessment. ➢ An investigation for the presence or absence of wetlands, hazardous or toxic materials in the soil, surface water, groundwater, or air on, below, or adjacent to the subject property. The client did not direct ESSW to provide any service to investigate or detect the presence of moisture, mold, or other biological contaminates in or around any structure, or any service that was designed or intended to prevent or lower the risk or the occurrence of the amplification of the same. Client acknowledges that mold is ubiquitous to the environment, with mold amplification occurring when building materials are impacted by moisture. Client further acknowledges that site conditions are outside of ESSW's control and that mold amplification will likely occur or continue to occur in the presence of moisture.. As such, ESSW cannot and shall not be held responsible for the occurrence or recurrence of mold amplification. EARTH SYSTEMS SOUTHWEST December 30, 2008 4 File No.: 07711.-31 Doc. No.: 08-12-769 Section 2 METHODS OF INVESTIGATION 2.1 Field Exploration Five exploratory borings were drilled to depths ranging from about 21.5 to 61.5 feet below the existing ground surface to observe the soil profile and to obtain samples for laboratory testing. The borings were drilled on November 19 and 20, 2008 using 8-inch outside diameter hollow - stem augers, powered by a Mobile B61 HDX truck -mounted drilling rig with an auto -hammer. The boring locations are shown on the Boring and Infiltration Test Location Map, Figure 2, in Appendix A. The locations shown are approximate, established by a hand-held GPS receiver combined with pacing and sighting from existing topographic features. GPS-derived horizontal locations are accurate to within about 10 to 15 feet. Samples were obtained within the test borings using a Standard Penetration [SPT] sampler (ASTM D 1586) and a Modified California [MC] ring sampler (ASTM D 3550 with shoe similar to ASTM D 1586). The SPT sampler has a 2-inch outside diameter and a 1.38-inch inside diameter. The MC sampler has a 3-inch outside diameter and a 2.37-inch inside diameter. The samples were obtained by driving the sampler with a 140-pound automatic hammer, dropping 30 inches in general accordance with ASTM D 1586. Recovered soil samples were sealed in containers and returned to the laboratory. Bulk samples were also obtained from auger cuttings, representing a mixture of soils encountered at the depths noted. The final logs of the borings represent our interpretation of the contents of the field logs and the results of laboratory testing performed on the samples obtained during the subsurface exploration. The final logs are included in Appendix A of this report. The stratification lines represent the approximate boundaries between soil types, although the transitions may be gradational 2.2 Laboratory Testing Samples were reviewed along with field logs to select those that would be analyzed further. Those selected for laboratory testing include soils that would be exposed and used during grading and those deemed to be within the influence of the proposed structure. Test results are presented in graphic and tabular form in Appendix B of this report. The tests were conducted in general accordance with the procedures of the American Society for Testing and Materials [ASTM] or other standardized methods as referenced below. Our testing program consisted of the following: ➢ In -situ Moisture Content and Unit Dry Weight for the ring samples. ➢ Maximum density tests to evaluate the moisture -density relationship of typical soils encountered. ➢ Particle Size Analysis to classify and evaluate soil composition. The gradation characteristics of selected samples were made by hydrometer and sieve analysis procedures. EARTH SYSTEMS SOUTHWEST December 30, 2008 5 File No.: 07711-31 Doc. No.: 08-12-769 ➢ Consolidation (Collapse Potential) to evaluate the compressibility and hydroconsolidation (collapse) potential of the soil. ➢ Chemical Analyses (Soluble Sulfates and Chlorides, pH, and Electrical Resistivity) to evaluate the potential adverse effects of the soil on concrete and steel. 2.3 Infiltration Testing The propose of the infiltration testing was to measure the ultimate infiltration rate to be used with an appropriate factor of safety in designing the onsite storm water disposal facilities. The infiltration test borings were located in the general vicinity of two proposed storm water retention basins, to be located near the center of the parcel, and at the northeast corner. The approximate test locations are shown on Figure 2 in Appendix A. To aid in designing the northeast retention basin; we conducted an open, double ring infiltrometer test on November 21, 2008, in general accordance with ASTM D3385, at the proposed basin location. The test was conducted at the bottom of the existing drainage Swale, at the approximate proposed bottom elevation of the basin. An outer steel ring (24-inch diameter) and an inner steel ring (12-inch diameter) were driven about 5.5 to 6 inches into the soil. The purpose of the outer ring is to create a hydraulic barrier so that the recorded drop in water level of the inner ring measures the vertical infiltration without lateral spreading. Both rings were filled with water to a depth of about 4 inches and maintained. Successive readings of infiltration flow were made over 15- 30- ,and 60-minute periods until a stabilized flow was recorded. A plot of infiltration rates over time is presented on the attached test results. The ultimate infiltration rate measured is presented in the following in metric and equivalent English units. Test Location Depth (feet) cm/hr in/hr gal/sVday 1-1 2 1.8 0.7 10 Two falling head percolation tests, one at each proposed retention basin, were performed within exploratory Borings B-2 and B-4, drilled to depths of approximately 60 feet below the existing ground surface. The tests were conducted to aid in the design of a MaxWell Plus, or equivalent dry well system. A 3'/4-inch diameter perforated pipe with sock was set in the boreholes and the annulus was backfilled with'/4-inch sized gravel for Boring B-2. Soils within Boring B-4 caved around the PVC pipe preventing backfilling of the annulus with gravel. The percolation testing was accomplished on November 20 and 21, 2008. The tests were made in conformance to the Riverside County percolation test method, as described in "Waste Disposal for Individual Homes, Commercial and Industrial," published by the Riverside County Division of Environmental Health [RCDEH]. The boreholes were filled with water and presoaked. Successive readings of drop in water level were made over several, 2- to 30-minute periods until a stabilized drop was recorded. The field percolation test results are presented in the following table: EARTFI SYSTEMS SOUTHWEST December 30, 2008 6 File No.: 07711-31 Doc. No.: 08-12-769 Bottom of Hydraulic Conductivity (k) Hole Test ID (feet) m in/hr) ft/da B-2 60 0.00108 0.78 1.6 B-4 60 0.00056 0.40 0.8 To aid in designing the central retention basin, one shallow pump -in (constant head) infiltration test was conducted within Boring B-5 in the vicinity of the proposed basin, as shown on Figure 2. The test was conducted within the 8-inch diameter, augered borehole made to a depth of 20 feet below existing ground surface. A 3'/4-inch diameter perforated pipe with sock was set in the borehole and backfilled with gravel around the pipe. Water was injected at a relatively constant rate until a stabilized head of water was established. The testing was completed on November 20, 2008 according to the guidelines of the U.S. Bureau of Reclamation Method for Unsaturated Soils above Groundwater. The ultimate test results are presented in the table below: Test ID Bottom of Hole feet Water Head feet Flow Rate m Hydraulic Conductivity in/hr (al/sf/da B-5 20 3.32 0.36 0.99 14.8 Estimated Hydraulic Conductivity In addition to the field infiltration testing, sieve analyses performed on select boring samples were used to estimate the hydraulic conductivity of the soils near Borings B-2 and B-4. The diameter of the finest 10 percent size -fraction of the soil (referred to as the Dio) was used in the Hazen formula to estimate the conductivity of the soils for which the sieve analyses were performed. Multiple samples were tested from each soil horizon, and conductivities derived from these sieve analyses that were deemed to be representative of the sand layers in the overall soil horizon were used as the basis for the infiltration rate evaluation. Drywell depths were identified that would best fit the soil stratigraphy encountered in the borings. Hypothetical water infiltration capacities were estimated using the identified drywell designs. Note that conductivity rates are highly variable between soils types; highly conductive layers can transmit orders -of -magnitude more water than low conductivity layers. Therefore, the availability of high -conductivity layers is the "rate limiting step" from a water disposal _perspective. The distribution and thickness of the more -conductive soil layers and their position in the soil column were used to evaluate the water -disposal characteristics in each area. This was performed by characterizing the soil column at each boring location as generally fitting one of three water disposal models: (A) uniform soils; (B) soils with an underlying boundary condition; and (C) a pervious soil horizon with an overlying and underlying boundary condition. The appropriate model was used to estimate the water disposal capacity of the soil at each location using the conductivity and soil stratigraphy derived during this investigation. In addition, the percent of impermeable soil in each soil horizon was estimated to model the presence of interbedded silt and clay, layers, and was used to decrease the effective thickness of the receiving soil horizons. EARTH SYSTEMS SOUTHWEST. December 30, 2008 7 File No.: 07711-31 Doc. No.: 08-12-769 Results of this analysis are included in Appendix A as Table 2; drywell design recommendations are included in Table 3. Design Infiltration Rate The designer of the storm water management systems should decide on an appropriate factor of safety to apply to reported infiltration rate. Infiltration of storm water through drywells and the bottom of the basin may be significantly less than the value given over time because of siltation and development of films from road oils from paved streets. Maintenance of the storm -water disposal facilities is crucial particularly if no factor of safety is applied. Maintenance may include periodically scarifying the bottom of the basin to open soil pores clogged by siltation, oils, or vegetation growth. A silt and oil trap placed at influent points may be considered to reduce the potential for reduction in the infiltration rate of soils. EARTH SYSTEMS SOUTHWEST December 30, 2008 8 File No.: 07711-31 Doc. No.: 08-12-769 Section 3 DISCUSSION 3.1 Soil Conditions The field exploration indicates that site soils in the upper 10 feet consist generally of medium dense well graded sand with gravel and trace cobbles to medium dense to dense sand with silt (Unified Soils Classification System symbols of SW-SM, SW, SP, and SP-SM). The upper 10 feet of soil were most likely deposited in an alluvial fan environment. Below 10 feet the soils consist generally of medium dense sand with silt, silty sand, sandy silt and silt (SP-SM, SM, and ML), probably deposited in the lacustrine environment of ancient Lake Cahuilla. The boring logs provided in Appendix A include more detailed descriptions of the soils encountered. The soils are visually classified to be in the very low expansion (EI < 20) category. Site soils are classified as Type C in accordance with CaIOSHA. Borehole elevations noted on the boring logs are feet above mean sea level (NAVD29). Elevations were derived from the Revised Rough Grading and Wall Plans provided by MSA Consulting, Inc. Please note that on the rough grading plans, elevations are feet above mean sea level (NAVD29) plus 500 feet. In and climatic regions, granular soils may have a potential to collapse upon wetting. Collapse (hydroconsolidation) may occur when the soluble cements (carbonates) in the soil matrix dissolve, causing the soil to density from its loose configuration from deposition. A dry silt layer was observed in Borings 2 through 5 at a depth of approximately 17 to 30 feet below existing grade. This layer deepens to the west and may thin toward the west. It may be as much as 5 feet thick. One of the consolidation tests performed on this silt layer indicates a 3.6% collapse upon inundation and collapse is therefore considered a moderate to severe site risk. Given the depositional environment of this silt layer, it is assumed to be present under at least the east half of the project site, and probably under the entire site in varying thicknesses. 3.2 Groundwater Free groundwater was not encountered in the borings during exploration. The depth to groundwater in the area is believed to be more than 100 feet using data from borings drilled by ESSW at a site located approximately 0.75 miles east-southeast of the subject site; the depth to groundwater at that site was measured to be about 40 feet below the ground surface. The Travertine Parcel, which is farther up the alluvial fan, is approximately 100 feet higher in elevation. Therefore, even though the water table slightly rises beneath the alluvial fan surface, it does not rise at the same rate as the ground surface, and is most likely deeper than 100 feet. However, there is uncertainty in the accuracy of short-term water level measurements. Groundwater levels may fluctuate with precipitation, irrigation, drainage, regional pumping from wells, and site grading. The absence of groundwater levels detected may not represent an accurate or permanent condition. Groundwater should not be a factor in design or construction at this site. 3.3 Geologic Setting Regional Geology: The site lies within the Coachella Valley, a part of the Colorado Desert geomorphic province. A significant feature within the Colorado Desert geomorphic province is FARTH SYSTEMS SOUTHWEST December 30, 2008 9 File No.: 07711-31 Doc. No.: 08-12-769 the Salton Trough. The Salton Trough is a large northwest -trending structural depression that extends approximately 180 miles from the San Gorgonio Pass to the Gulf of California. Much of this depression in the area of the Salton Sea is below sea level. The Coachella Valley forms the northerly part of the Salton Trough. The Coachella Valley contains a thick sequence of Miocene to Holocene sedimentary deposits. Mountainssurrounding the Coachella Valley include the Little San Bernardino Mountains on the northeast, foothills of the San Bernardino Mountains on the northwest, and the San Jacinto and Santa Rosa Mountains on the southwest. These mountains expose primarily Precambrian metamorphic and Mesozoic granitic rocks. The San Andreas fault zone within the Coachella Valley consists of the Garnet Hill fault, the Banning fault, and the Mission Creek fault that traverse along the northeast margin of the valley. Local Geology: The project site is located approximately 15 to 30 feet below mean sea level in the southwestern part of the Coachella Valley. The sediments within the valley consist of fine - to coarse -grained sands with interbedded clays, silts, gravels, and cobbles of aeolian (wind- blown), lacustrine (lake -bed), and alluvial (water -laid) origin. 3.4 Geologic Hazards Geologic hazards that may affect the region include seismic hazards (ground shaking, surface fault rupture, soil liquefaction, and other secondary earthquake -related hazards), flooding, ground subsidence, and erosion. A discussion follows on the specific hazards to this site. 3.4.1 Seismic Hazards Seismic Sources: Several active faults or seismic zones lie within 62 miles (100 kilometers) of the project site as shown on Table 1. in Appendix A. The primary seismic hazard to the site is strong ground shaking from earthquakes along the San Andreas and San Jacinto faults. The Maximum Magnitude Earthquake (Mmax) listed is from published geologic information available for each fault (Cao et at., CGS, 2003). The Mmax corresponds to the maximum earthquake believed to be tectonically possible. Surface Fault Rupture: The project site does not lie within a currently delineated State of California, Alquist-Priolo Earthquake Fault Zone (Hart, 1997). Well -delineated fault lines cross through this region as shown on California Geological Survey [CGS] maps (Jennings, 1994); however, no active faults are mapped in the immediate vicinity of the site. Therefore, active fault rupture is unlikely to occur at the project site. While fault rupture would most likely occur along previously established fault traces, future fault rupture could occur at other locations. Historic Seismicity: Six historic seismic events (5.9 M or greater) have significantly affected the Coachella Valley in the last 100 years. They are as follows: • Desert Hot Springs Earthquake — On December 4, 1948, a magnitude 6.5 MU (6.OMw) earthquake occurred east of Desert Hot Springs. This event was strongly felt in the La Quinta area. • Palm .Springs Earthquake — A magnitude 5.9 ML (6.2Mw) earthquake occurred on July 8, 1986 in the Painted Hills, causing minor surface creep of the Banning segment of the San EARTH SYSTEMS SOUTHWEST December30, 2008 10 File No.: 07711-31 Doc. No.: 08-12-769 Andreas fault. This event was strongly felt in the La Quinta area and caused structural damage, as as well injuries. J • Joshua Tree Earthquake — On April 22, 1992, a magnitude 6.1 ML (6.1Mw) earthquake occurred in the mountains 9 miles east of Desert Hot Springs. Structural damage and minor injuries occurred in the La Quinta area as a result of this earthquake. • Landers and Big Bear Earthquakes — Early on June 28, 1992, a magnitude 7.5 Ms (7.3Mw) earthquake occurred near Landers, the largest seismic event in Southern California for 40 ears. Surface rupture Y u e occurred just south of the town of Yucca Valle and extended P J Y some 43 miles toward Barstow. About three hours later, a magnitude 6.6 Ms (6.4Mw) earthquake occurred near Big Bear Lake. No significant structural damage from these earthquakes was reported in the La Quinta area. • Hector Mine Earthquake — On October 16, 1999, a magnitude 7.IMw earthquake occurred on the Lavic Lake and Bullion Mountain faults north of Twentynine Palms. While this event was widely felt, no significant structural damage has been reported in the Coachella Valley. Seismic Risk: While accurate earthquake predictions are not possible, various agencies have conducted statistical risk analyses. In 2002 and 2008, the California Geological Survey [CGS] and the United States Geological Survey [USGS] completed of probabilistic seismic hazard maps. We have used these maps in our evaluation of the seismic risk at the site. The recent Working Group of California Earthquake Probabilities (WGCEP, 2008) estimated a 58% conditional probability that a magnitude 6.7 or greater earthquake may occur between 2008 and 2038 along the southern segment of the San Andreas fault. The primary seismic risk at the site is a potential earthquake along the Southern San Andreas fault, located about 14.7 km (9.1 miles) from the site and is considered as fault type A (CGS). Geologists believe that the San Andreas fault has characteristic earthquakes that result from rupture of each fault segment. The estimated characteristic earthquake is magnitude 7.7 for the Southern Segment of the fault (USGS, 2002). This segment has the longest elapsed time since rupture of any part of the San Andreas fault. The last rupture occurred about 1680 AD, based on dating by the USGS near Indio (WGCEP, 2008). This segment has also ruptured on about 1020, 1300, and 1450 AD, with an average recurrence interval of about 220 years. The San Andreas fault may rupture in multiple segments, producing a higher magnitude earthquake. Recent paleoseismic studies suggest that the San Bernardino Mountain Segment to the north and the Coachella Segment may have ruptured together in 1450 and 1690 AD (WGCEP, 1995). 3.4.2 Secondary Hazards Secondary seismic hazards related to ground shaking include soil liquefaction, ground subsidence, tsunamis, and seiches. The site is far inland, so the hazard from tsunamis is non- existent. At the present time, no water storage reservoirs are located in the immediate vicinity of the site. Therefore, hazards from seiches are considered negligible at this time. Soil Liquefaction: Liquefaction is the loss of soil strength from sudden shock (usually earthquake shaking), causing the soil to become a fluid mass. In general, for the effects of liquefaction to be manifested at the surface, groundwater levels must be within 50 feet of the ground surface and the soils within the saturated zone must also be susceptible to liquefaction. The potential for liquefaction to occur at this site is considered negligible because the depth of EARTH. SYSTEMS SOUTHWEST December 30, 2008 11 File No.: 07711-31 Doc. No.: 08-12-769 groundwater beneath the site exceeds 50 feet. No free groundwater was encountered in our exploratory borings. In addition, the project lies in a zone designated by Riverside County for high susceptibility sediments, but deep groundwater resulting in low liquefaction potential. Ground Subsidence: The potential for seismically induced ground subsidence is considered to be low at the site. Dry sands tend to settle and densify when subjected to strong earthquake shaking. The amount of subsidence is dependent on relative density of the soil, ground motion, and earthquake duration. Uncompacted fill areas may be susceptible to seismically induced settlement. Slope Instability: The site is relatively flat. Therefore, potential hazards from slope instability, landslides, or debris flows are considered negligible. Flooding: The project site does not lie within a designated FEMA 100-year flood plain, but is in an area for which flood hazards are undetermined, but possible. The parcel is adjacent to the Trilogy development, which is designated by FEMA as an area protected by levees from a 1% annual chance flood. Given the USBOR levee located immediately to the west of the parcel, this site will most likely be included with the rest of the Trilogy development flood hazard designation. The project site may be in an area where sheet flooding and erosion could occur. Appropriate design, construction, and maintenance by the project civil engineer can minimize the site sheet flooding potential. 3.4.3 Site Acceleration and Seismic Coefficients Site Acceleration: The potential intensity of ground motion may be estimated by the horizontal peak ground acceleration (PGA), measured in "g" forces. Included in Table 1 are deterministic estimates of site acceleration from possible earthquakes at nearby faults. Ground motions are dependent primarily on the earthquake magnitude and distance to the seismogenic (rupture) zone. Accelerations are also dependent upon attenuation by rock and soil deposits, direction of rupture, and type of fault. For these reasons, ground motions may vary considerably in the same general area. This variability can be expressed statistically by a standard deviation about a mean relationship. The PGA alone is an inconsistent scaling factor and is generally a poor indicator of potential structural damage during an earthquake. Important factors influencing the structural performance are the duration and frequency of strong ground motion, local subsurface conditions, soil -structure interaction, and structural details. The following table provides the probabilistic estimate of the PGA taken from the 2002 CGS/USGS seismic hazard maps/data. Estimate of PGA from 2002 CGS/USGS Probabilistic Seismic MmArd Mnns/Ilntn Risk Equivalent Return Period ( ears) ) PGA ) t 10% exceedance in 50 years 475 =0.46 Notes: t Based on Site Class B/C and soil amplification factor of 1.0 for Site Class D. 2007 CBC Seismic Coefficients: The California Building Code [CBC] seismic design parameters criteria are based on a Design Earthquake that has an earthquake ground motion 2/3 of EARTH SYSTEMS SOUTHWEST December 30, 2008 1.2 File No.: 07711-31 Doc. No.: 08-12-769 the lesser of 2% probability of occurrence in 50 years or 150% of mean deterministic limit. The a PGA estimate given above is provided for information on the seismic risk inherent in the CBC design. The seismic and site coefficients given in Chapter 16 of the 2007 California Building Code are provided in Section 5.8 of this report. Seismic Hazard Zones: The site lies in a low liquefaction potential zone designated by the 2003 Riverside County Integrated Project because of deep groundwater (>50-100 feet), and high susceptibility sediments. This portion of Riverside County has not been mapped by the California - a Seismic Hazard Mapping in Act (Ca. PRC 2690 to 2699). EARTH SYSTEMS SOUTHWEST December 30, 2008 13 File No.: 07711-31. Doc. No.: 08-12-769 Section 4 CONCLUSIONS The following is a summary of our conclusions and professional opinions based on the data obtained from a review of selected technical literature and the site evaluation. General: i ➢ From a geotechnical perspective, the site is suitable for the proposed development, 11 provided the recommendations in this report are followed in the design and construction of this project. Geotechnical Constraints and Mitigation: Y The primary geologic hazard is severe ground shaking from earthquakes originating on nearby faults. A major earthquake above magnitude 7 originating on the local segment of the San Andreas fault zone would be the critical seismic event that may affect the site within the design life of the proposed development. Engineered design and earthquake - resistant construction increase safety and allow development of seismic areas. 7 The underlying geologic condition for seismic design is Site Class D. The site is about 14.7 km from a Type A seismic source as defined in the California Geological Survey. A qualified professional should design any permanent structure constructed on the site. The minimum seismic design should comply with the 2007 edition of the California Building Code. Ground subsidence from seismic events or hydroconsolidation is a potential hazard in the Coachella Valley area. Adherence to the grading and structural recommendations in this report should reduce potential settlement problems from seismic forces, heavy rainfall or irrigation, flooding, and the weight of the intended structures. ➢- The soils are susceptible to wind and water erosion. Preventative measures to reduce seasonal flooding and erosion should be incorporated into site grading plans. Dust control should also be implemented during construction. Site grading should be in strict compliance with the requirements of the South Coast Air Quality Management District [SCAQMD]. ➢ Other geologic hazards, including fault rupture, liquefaction, seismically induced flooding, and landslides, are considered low or negligible on this site. r The upper soils were found to be non -uniform, relatively medium dense to very dense and are unsuitable in their present condition to support structures, fill, and hardscape. The soils within the proposed building and structural areas will require moisture conditioning and compaction to improve bearing capacity and reduce the potential for differential settlement from static loading. Due to the presence of a collapsible dry -silt layer beneath the site, special foundation recommendations are provided for lots located in the eastern half of the parcel. Soils can be readily cut by normal grading equipment. EARTH SYSTEMS SOUTHWEST December 30, 2008 14 File No.: 07711-31 Doc. No.: 08-12-769 Section 5 RECOMMENDATIONS SITE DEVELOPMENT AND GRADING 5.1 Site Development — Grading A representative of Earth Systems Southwest [ESSW] should observe site clearing, grading, and the bottoms of excavations before placing fill. Local 1. p g a variations in soil conditions may warrant increasing the depth of recompaction and over -excavation. Clearing and Grubbing: At the start of site grading, existing vegetation, trees, large roots, pavements, foundations, non -engineered fill, construction debris, trash, and abandoned underground utilities should be removed from the proposed building, structural, and pavement areas. The surface should be stripped of organic growth and removed from the construction area. Areas disturbed during clearing should be properly backfelled and compacted as described below. Dust control should also be implemented during construction. Site grading should be in strict compliance with the requirements of the South Coast Air Quality Management District (SCAQMD). Building Pad Preparation: In order to lower the overall site elevation, approximately 6 to 9 feet of native soil will be excavated and exported to the adjacent Tract 30023-6, Phase 6B and 6C. This will effectively lower the overall site elevation from approximately -12 feet to -20 feet. Due to the relatively non -uniform and under -compacted nature of the site soils, we recommend recompaction of soils in the building areas. The proposed -surface soils within the building pad and foundation areas should be scarified, moisture conditioned, and compacted to at least 90% relative compaction (ASTM D 1557) to a minimum of 2 feet below proposed grade or a minimum of 1 foot below the footing level (whichever is tower). The compaction should extend for 5 feet beyond the outer edge of exterior footings, where possible. Moisture penetration to near optimum moisture should extend at least one foot below existing grade. Compaction should be verified by testing. Auxiliary Structures Subgrade Preparation: Auxiliary structures such as garden or retaining walls should have the foundation subgrade prepared similar to the building pad recommendations given above. The lateral extent of the over -excavation needs to extend only 2 feet beyond the face of the footing. Subgrade Preparation: In areas to receive fill, pavements, or hardscape, the subgrade should be scarified, moisture conditioned, and compacted to at least 90%relative compaction (ASTM D 1557) for a depth of one -foot below finished subgrades or one foot below the bottom of the foundation, whichever is deeper. Compaction should be verified by testing. Engineered Fill Soils: The native soil is suitable for use as engineered fill and utility trench backfill, provided it is free of significant organic or deleterious matter. The native soil should be placed in maximum 8-inch lifts (loose) and compacted to at least 90%relative compaction (ASTM D 1557) near its optimum moisture content. Compaction should be verified by testing. EARTH SYSTEMS SOUTHWEST December 30, 2008 15 File No.: 07711-31 Doc. No.: 08-12-769 Rocks larger than 6 inches in greatest dimension should be removed from fill or backfiIl material. Imported fill soils (if needed) should be non -expansive, granular soils meeting the USCS classifications of SM, SP-SM, or SW-SM with a maximum rock size of 3 inches and 5 to 35% passing the No. 200 sieve. The geotechnical engineer should evaluate the import fill soils before hauling to the site. However, because of the potential variations within the borrow source, import soil will not be prequalified by ESSW. The imported fill should be placed in lifts no greater than 8 inches in loose thickness and compacted to at least 90% relative compaction (ASTM D 1557) near optimum moisture content. Shrinkage: The shrinkage factor for earthwork is expected to be less than 10 percent for the upper excavated or scarified site soils. This estimate is based on compactive effort to achieve an average relative compaction of about 92% and may vary with contractor methods. Subsidence is estimated to be less than 0.1 feet. Losses from site clearing and removal of existing site improvements may affect earthwork quantity calculations and should be considered. Site Drainage: Positive drainage should be maintained away from the structures (5% for 5 feet minimum) to prevent ponding and subsequent saturation of the foundation soils. Gutters and downspouts should be considered as a means to convey water away from foundations if adequate drainage is not provided. Drainage should be maintained for paved areas. Water should not pond on or near paved areas. 5.2 Excavations and Utility Trenches Excavations should be made in accordance with CalOSHA requirements. Using the Cal/OSHA standards and general soil information obtained from the field exploration, classification of the near surface on -site soils will likely be characterized as Type C. Actual classification of site specific soil type per Cal/OSHA specifications as they pertain to trench safety should be based on real-time observations and determinations of exposed soils by the Competent Person during grading and trenching operations. Our site exploration and knowledge of the general area indicates there is a potential for caving of site excavations (utilities, footings; etc.). Excavations within sandy soil should be kept moist, but not saturated, to reduce the potential of caving or sloughing. Where excavations over 4 feet deep are planned, lateral bracing or appropriate cut slopes of 1.5:1 (horizontalwertical) should be provided. No surcharge loads from stockpiled soils or construction materials should be allowed within a horizontal distance measured from the top of the excavation slope and equal to the depth of the excavation. Utility Trenches: Backfill of utilities within roads or public right-of-ways should be placed in conformance with the requirements of the governing agency (water district, public works department, etc.). Utility trench backfill within private property should be placed in conformance with the provisions of this report. In general, service lines extending inside of property may be backfilled with native soils compacted to a minimum of 90% relative compaction. Backfill operations should be observed and tested to monitor compliance with these recommendations. FAKITt SYSTEMS SOUTHWEST December 30, 2008 16 File No.: 07711-31 Doc. No.: 08-12-769 5.3 Slope Stability of Graded Slopes Unprotected, permanent graded slopes should not be steeper than 3:1 (horizontal:vertical) to reduce wind and rain erosion. Protected slopes with ground cover may be as steep as 2:1. However, maintenance with motorized equipment may not be possible at this inclination. Fill slopes should be overfilled and trimmed back to competent material. Slope stability calculations are not presented because of the expected minimal slope heights (less than 5 feet). STRUCTURES In our professional opinion, structure foundations can be supported on shallow foundations bearing on a zone of properly prepared and compacted soils placed as recommended in Section 5.1. The recommendations that follow are based on very low expansion category soils. 5.4 Foundations To accommodate potential settlement due to hydrocollapse of the silt layer, separate recommendations are provided for the west and east halves of the project site. We recommend additional drilling to further constrain the areal extent of the silt layer. This may result in a decrease in the number of adversely impacted building pads. Footing design of widths, depths, and reinforcing are the responsibility of the Structural Engineer, considering the structural loading and the geotechnical parameters given in this report. A minimum footing depth of 12 inches below lowest adjacent grade should be maintained for building pads located in the west half of the project site. For pads located in the east half, a minimum footing pth of 15 inches below lowest adjacent grade should be maintained A representative of ESSW should observe foundation excavations before placement of reinforcing steel or concrete. Loose soil or construction debris should be removed from footing excavations before placement of concrete. Conventional Spread Foundations: Allowable soil bearing pressures are given below for foundations bearing on recompacted soils as described in Section 5.1. Allowable bearing pressures are net (weight of footing and soil surcharge may be neglected). ➢ Continuous wall foundations, 12-inch minimum width and 12 inches below lowest adjacent grade for building pads located in the west half of the project site, 15 inches below lowest adjacent grade for the east half: 1500 psf for dead plus design live loads Allowable increases of 200 psf per each foot of additional footing width and 300 psf for each additional 0.5 foot of footing depth may be used up to a maximum value of 2500 psf. Isolated pad foundations, 2 x 2 foot minimum in plan and 18 inches below grade: 2000 psf for dead plus design live loads Allowable increases of 300 psf per each foot of additional footing width and 400 psf for each additional 0.5 foot of footing depth may be used up to a maximum value of 2500 psf. FARTEI SYSTEMS SOUTI-YWEST December 30, 2008 17 File No.: 07711-31 Doc. No.: 08-12-769 A one-third (%) increase in the bearing pressure may be used when calculating resistance to wind or seismic loads. The allowable bearing values indicated are based on the anticipated maximum loads stated in Section 1.1 of this report. If the anticipated loads exceed these values, the geotechnical engineer must reevaluate the allowable bearing values and the grading requirements. Minimum reinforcement for continuous wall footings for building pads located in the west half of the project site should be two No. 4 steel reinforcing bars, one placed near the top and one placed near the bottom of the footing. Minimum reinforcement for continuous wall footings; for pads in the east half should be four No 5 steel rein orciny bars two placed near the top and two placed near the bottom of the footing. This reinforcing is not intended to supersede any structural requirements provided by the structural engineer. Expected Settlement: Estimated total static settlement should be less than one -inch, based on footings founded on firm soils as recommended. Differential settlement between exterior and interior bearing members should be less than V2-inch, expressed in a post -construction angular distortion ratio of 1:480 or less. Settlement induced from hydrocollapse, based on a 5-foot thick silt layer and 3.6% settlement at 2.0 ksf, may be up to approximately 2.2 inches with surface reaction estimated to be about one- half this value. Utility connections to structures should be flexible and able to accommodate this potential movement. Frictional and Lateral Coefficients: Lateral loads may be resisted by soil friction on the base of foundations and by passive resistance of the soils acting on foundation walls. An allowable coefficient of friction of 0.35 of dead load may be used. An allowable passive equivalent fluid pressure of 350 pcf may also be used. These values include a factor of safety of 1.5. Passive resistance and frictional resistance may be used in combination if the friction coefficient is reduced by one-third. A one-third (%3) increase in the passive pressure may be used when calculating resistance to wind or seismic loads. Lateral passive resistance is based on the assumption that backfill next to foundations is properly compacted. 5.5 Slabs -on -Grade Subgrade: Concrete slabs -on -grade and flatwork should be supported by compacted soil placed in accordance with Section 5.1 of this report. Vapor Retarder: In areas of moisture sensitive floor coverings, an appropriate vapor retarder should be installed to reduce moisture transmission from the subgrade soil to the slab. For these areas, an impermeable membrane (10-mil thickness) should underlie the floor slabs. The membrane should be covered with 2 inches of sand to help protect it during construction and to aid in concrete curing. The sand should be lightly moistened just prior to placing the concrete. Low -slump concrete should be used to help reduce the potential for concrete shrinkage. The effectiveness of the membrane is dependent upon its quality, the method of overlapping, its protection during construction, and the successful sealing of the membrane around utility lines. EARTH SYSTEMS SOUTHWEST December 30, 2008 1.8 File No.: 07711-31 Doc. No.: 08-12-769 The following minimum slab recommendations are intended to address geotechnical concerns such as potential variations of the subgrade and are not to be construed as superseding any structural design. The design engineer and/or project architect should ensure compliance with SB800 with regards to moisture and moisture vapor. Slab Thickness and Reinforcement: Slab thickness and reinforcement of slabs -on -grade are contingent on the recommendations of the structural engineer or architect and the expansion index of the supporting soil. Based upon our findings, a modulus of subgrade reaction of approximately 200 pounds per cubic inch can be used in concrete slab design for the expected very low expansion subgrade. Concrete slabs and flatwork should be a minimum of S inches thick (actual, not nominal). We suggest that the concrete slabs be reinforced with a minimum of No. 3 rebars at 18-inch centers, both horizontal directions, placed at slab mid -height to resist potential cracking. Concrete floor slabs may either be monolithically placed with the foundations or doweled after footing placement. The thickness and reinforcing given are not intended to supersede any structural requirements provided by the structural engineer. The project architect or geotechnical engineer should continually observe all reinforcing steel in slabs during placement of concrete to check for proper location within the slab. Control Joints: Control joints should be provided in all concrete slabs -on -grade at a maximum spacing of 36 times the slab thickness (12 feet maximum on -center, each way) as recommended by American Concrete Institute [ACI] guidelines. All joints should form approximately square patterns to reduce the potential for randomly oriented shrinkage cracks. Construction joints in the slabs should be tooled at the time of the concrete placement or saw cut (%< of slab depth) as soon as practical but not more than 8 hours from concrete placement. Construction (cold) joints should consist of thickened butt joints with '12-inch dowels at 18-inches on center or a thickened keyed joint to resist vertical deflection at the joint. All construction joints in exterior flatwork should be sealed to reduce the potential of moisture or foreign material intrusion. These procedures will reduce the potential for randomly oriented cracks, but may not prevent them from occurring. Curing and Quality Control: The contractor should take precautions to reduce the potential of curling of slabs in this and desert region using proper batching, placement, and curing methods. Curing is highly affected by temperature, wind, and humidity. Quality control procedures may be used, including trial batch mix designs, batch plant inspection, and on -site special inspection and testing. Typically, for this type of construction and using 2500-psi concrete, many of these quality control procedures are not required. 5.6 Retaining Walls The following table presents lateral earth pressures for use in retaining wail design. The values are given as equivalent fluid pressures without surcharge loads or hydrostatic pressure. EARTH sYs'rEMs sour iwEs'r December 30, 2008 19 File No.: 07711-31 Doc. No.: 08-12-769 Lateral Pressures and SlidingResistance r Granular Backfill Passive Pressure 350 pcf - level ground Active Pressure (cantilever walls) Use when wall is permitted to rotate 0.1 to 0.2% of wall 35 pcf - lever ground height for granular backfill At -Rest Pressure restrained walls 55 pcf - level ground Dynamic Lateral Earth Pressure' Acting at 0.6H, 15 pcf Where His height of backfill infect Base Lateral Sliding Resistance Dead load x Coefficient of Friction: 0.50 1VOres: These values are ultimate values. A factor of safety of 1.5 should be used in stability analysis except for dynamic earth pressure where a factor of safety of 1.2 is acceptable. 2 Dynamic pressures are based on the Mononobe-Okabe 1929 method, additive to active earth pressure. Walls retaining less than 6 feet of soil and not supporting inhabitable structures need not consider this increased pressure (reference: CBC Section 1630A. 1. 1.5). Upward sloping backfill or surcharge loads from nearby footings can create larger lateral pressures. Should any walls be considered for retaining sloped backfill or placed next to foundations, our office should be contacted for recommended design parameters. Surcharge loads should be considered if they exist within a zone between the face of the wall and a plane projected 45 degrees upward from the base of the wall. The increase in lateral earth pressure should be taken as 35% of the surcharge load within this zone. Retaining walls subjected to traffic loads should include a uniform surcharge load equivalent to at least 2 feet of native soil. Drainage: A backdrain or an equivalent system of backfill drainage should be incorporated into the retaining wall design, whereby, the collected water is conveyed to an approved point of discharge. Our firm can provide construction details when the specific application is determined. Backfill immediately behind the retaining structure should be a free -draining granular material. Waterproofing should be according to the designer's specifications. Water should not be allowed to pond near the top of the wall. To accomplish this, the final backfill grade should be such that all water is diverted away from the retaining wall. Backfill and Subgrade Compaction: Compaction on the retained side of the wall within a horizontal distance equal to one wall height should be performed by hand -operated or other lightweight compaction equipment. This is intended to reduce potential lockedAn lateral pressures caused by compaction with heavy grading equipment. Foundation subgrade preparation should be as specified in Section 51. 5.7 Mitigation of Soil Corrosivity on Concrete Selected chemical analyses for conosivity were conducted on soil samples from the project site as shown in Appendix B. Sulfate and other salts can attack the cement within concrete causing weakening of the cement matrix and eventual deterioration by raveling. This attack can be in the form of a physical attack or chemical attack whereby there may be a chemical reaction between the sulfate and the cement EARTH SYSTEMS SOUTHWEST December 30, 2008 20 File No,: 07711-31 Doc. No.: 08-12-769 used in the concrete. According to ACI 318 as referenced by the 2007 California Building Code, if sulfate concentrations exceed 1000 ppm there will be special requirements. For this project, the results of those samples tested suggest a low sulfate ion concentration (78-20 ppm). Normal concrete mixes may be used. Electrical resistivity is a process whereby metal (ferrous) objects in direct contact with soil may be subject to attack by electrochemical corrosion. This typically pertains to buried metal pipes, valves, culverts, etc. made of ferrous metal. To avoid this type of corrosion or to slow the process, buried metal objects are generally protected with waterproof resistant barriers, i.e. epoxy corrosion inhibitors, asphalt coatings, cathodic protection, or encapsulating with densely consolidated concrete. Electrical resistivity testing of the soil suggests that the site soils may present a moderate to very severe potential for metal loss from electrochemical corrosion processes. Chloride ions can cause corrosion of reinforcing steel. For this project, the results of those samples tested suggest a low chloride ion concentration (28-51 ppm). ACI 318 is referenced by the California Building Code, and provides commentary relative to the effects of chlorides present in the soil; from both internal and external sources. It is possible that long term saturation of foundations with chloride rich water could allow the chloride access to the reinforcing steel. The soils encountered on this site consist of relatively free draining material over fairly fractured bedrock. Therefore, if the site is adequately drained in accordance with sound engineering practice and the applicable codes, this should be a low threat. A minimum concrete cover of cast -in -place concrete should be in accordance with Section 7.7 of the 2007 edition of ACI 318. Additionally, the concrete should be thoroughly vibrated during placement. The information provided above should be considered preliminary. These values can potentially change based on several factors, such as importing soil from another job site and the quality of construction water used during grading and subsequent landscape irrigation. Earth Systems does not practice corrosion engineering. We recommend that a qualified corrosion engineer evaluate the corrosion potential on metal construction materials and concrete at the site to provide mitigation of corrosive effects, if further guidance is desired. 5.8 Seismic Design Criteria This site is subject to strong ground shaking due to potential fault movements along the San Andreas and San Jacinto faults. Engineered design and earthquake -resistant construction increase safety and allow development of seismic areas. The minimum seismic design should comply with the 2007 edition of the California Building Code and ASCE 7-05 using the seismic coefficients given in the table below. EARTH SYSTEMS SOUTHWEST December 30, 2008 21 2007 CBC (ASCE 7-05) Seismic Parameters Seismic Category: D Site Class: D Maximum Considered Earthquake [MCE] Ground Motion Short Period Spectral Response Ss: 1.50 g 1 second Spectral Response, SI: 0.60 g Site Coefficient, Fa: 1.00 Site Coefficient, F,: 1.50 Design Earthquake Ground Motion Short Period Spectral Response, SDs 1.00 g 1 second Spectral Response, SDI 0.60 g File No.: 0771 I-31 Doe. No.: 08-12-769 Reference Table 1613.5.6 Table 1613.5.2 Figure 1613.5 Figure 1613.5 Table 1613.5.3(i) Table 1613.5.3(2) The intent of the CBC lateral force requirements is to provide a structural design that will resist collapse to provide reasonable life safety from a major earthquake, but may experience some structural and nonstructural damage. A fundamental tenet of seismic design is that inelastic yielding is allowed to adapt to the seismic demand on the structure. In other words, damage is allowed. The CBC lateral force requirements should be considered a minimum design. The owner and the designer may evaluate the level of risk and performance that is acceptable. Performance based criteria could be set in the design. The design engineer should exercise special care so that all components of the design are fully met with attention to providing a continuous load path. An adequate quality assurance and control program is urged during project construction to verify that the design plans and good construction practices are followed. This is especially important for sites lying close to the major seismic sources. . Estimated peak horizontal site accelerations based upon a probabilistic analysis (10% probability of occurrence in 50 years) is approximately 0.46 g for a stiff soil site. Actual accelerations may be more or less than estimated. Vertical accelerations are typically '/3 to % of the horizontal accelerations, but can equal or exceed the horizontal accelerations, depending upon the local site effects and amplification. 5.9 Pavements Since no traffic loading was provided by the design engineer or owner, we have assumed traffic loading for comparative evaluation. The design engineer or owner should decide the appropriate traffic conditions for the pavements. Maintenance of proper drainage is advised to prolong the service life of the pavements. Water should not pond on or near paved areas. The following table provides our preliminary recommendations for pavement sections. Final pavement sections recommendations should be based on design traffic indices and R-value tests conducted during grading after actual subgrade soils are exposed. EARTH SYSTEMS SOUTHWEST December30, 2008 22 File No.: 07711-31 Doc. No.: 08-12-769 PRELIMINARY RECOMMENDED PAVEMENTS SECTIONS R-Value Subgrade Soils - 50 (assumed) Design Method — CALTRANS Flexible Pavements Rigid Pavements Aggregate Portland Aggregate Traffic Pavement Use Base Cement Base Index Zhe Thickness Concrete Thickness (Assumed)((Inches Inches Inches) 5.0 Auto Parkin Areas 4.0 4.0 4.0 6.0 Residential Streets 3.5 4.0 5.0 4-0 '.. Notes: 1. Asphaltic concrete should be Caltrans, Type B, Ys-in. or 3/o in. maximum -medium grading and compacted to a minimum of 95% of the 75-blow Marshall density (ASTM D 1559) or equivalent. 2: Aggregate base should be Caltrans Class 2 (3/. in. maximum) and compacted to a minimum of 95% of ASTM D1557 maximum dry density near its optimum moisture. 3. All pavements should be laced on 12 inches of moisture -conditioned u P p d s bgrade, compacted to a minimum of 90 /o of ASTM D 1557 maximum dry density near its optimum moisture. 4. Portland cement concrete should have a minimum of 3250 psi compressive strength at 28 days. 5. Equivalent Standard Specifications for Public Works Construction (Greenbook) may be used instead of Caltrans specifications for asphaltic concrete and aggregate base. EARTH SYSTEMS SOUTHWEST December 30, 2008 23 File No.: 07711-31 Doc. No.: 08-12-769 Section 6 LIMITATIONS AND ADDITIONAL SERVICES 6.1 Uniformity of Conditions and Limitations Our findings and recommendations in this report are based on selected points of field exploration, laboratory testing, and our understanding of the proposed project. Furthermore, our findings and recommendations are based on the assumption that soil conditions do not vary significantly from those found at specific exploratory locations. Variations in soil or groundwater conditions could exist between and beyond the exploration points. The nature and extent of these variations may not become evident until construction. Variations in soil or groundwater may require additional studies, consultation, and possible revisions to our recommendations. Findings of this report are valid as of the issued date of the report. However, changes in conditions of a property can occur with passage of time, whether they are from natural processes or works of man, on this or adjoining properties. In addition, changes in applicable standards occur, whether they result from legislation or broadening of knowledge. Accordingly, findings of this report may be invalidated wholly or partially by changes outside our control. Therefore, this report is subject to review and should not be relied upon after a period of one year. In the event that any changes in the nature, design, or location of structures are planned, the conclusions and recommendations contained in this report shall not be considered valid unless the changes are reviewed and the conclusions of this report are modified or verified in writing. This report is issued with the understanding that the owner or the owner's representative has the responsibility to bring the information and recommendations contained herein to the attention of the architect and engineers for the project so that they are incorporated into the plans and specifications for the project. The owner or the owner's representative also has the responsibility to verify that the general contractor and all subcontractors follow such recommendations. It is further understood that the owner or the owner's representative is responsible for submittal of this report to the appropriate governing agencies. As the Geotechnical Engineer of Record for this project, Earth Systems Southwest [ESSW] has striven to provide our services in accordance with generally accepted geotechnical engineering practices in this locality at this time. No warranty or guarantee is express or implied. This report was prepared for the exclusive use of the Client and the Client's authorized agents. ESSW should be provided the opportunity for a general review of final design and specifications in order that earthwork and foundation recommendations may be properly interpreted and implemented in the design and specifications. If ESSW is not accorded the privilege of making this recommended review, we can assume no responsibility for misinterpretation of our recommendations. EARTH SYSTEMS SOUTHWEST December 30, 2008 24 File No.: 07711-31 Doc. No.: 08-12-769 Although available through ESSW, the current scope of our services does not include an environmental assessment or an investigation for the presence or absence of wetlands, hazardous a or toxic materials in the soil, surface water, groundwater, or air on, below, or adjacent to the subject property. 6.2 Additional Services This report is based on the assumption that an adequate program of client consultation, 1 construction monitoring, and testing will be performed during the final design and construction phases to check compliance with these recommendations. Maintaining ESSW as the geotechnical consultant from beginning to end of the project will provide continuity of services. The geotechnical engineering firm providing tests and observations shall assume the responsibility of Geotechnical Engineer of Record. Construction monitoringand testing would be additional services provided b r firm. our The g P Y costs of these services are not included in our present fee arrangements, but can be obtained from our office. The recommended review, tests, and observations include, but are not necessarily limited to, the following: • Consultation during the final design stages of the project. • A review of the building and grading plans to observe that recommendations of our report have been properly implemented into the design. • Observation and testing during site preparation, grading, and placement of engineered fill as required by CBC Sections 1704.7 and Appendix J or local grading ordinances. • Consultation as needed during construction. -000- Appendices as cited are attached and complete this report. EARTH SYSTEMS SOUTHWEST December 30, 2008 25 File No.: 07711-31 Doc. No.: 08-12-769 REFERENCES Abrahamson, N., and Shedlock, K., editors, 1997, Ground motion attenuation relationships: Seismological Research Letters, v. 68, no. 1, January 1997 special issue, 256 p. American Concrete Institute [ACI], 2004, ACI Manual of Concrete Practice, Parts 1 through 5. American Concrete Institute (2004) `Building Code Requirements for Structural Concrete (ACI 318-05) and Commentary (ACI 318R-05)." American Society of Civil Engineers [ASCE], 2006, Minimum Design Loads for Buildings and Other Structures, ASCE 7-05. California Department of Water Resources, 1964, Coachella Valley Investigation, Bulletin No. 108, 146 pp. California Geologic Survey (CGS), 1997, Guidelines for Evaluating and Mitigating Seismic Hazards in California, Special Publication H 7. Cao, T, Bryant, W.A., Rowhandel, B., Branum. D., and Wills, C., 2003, The Revised 2002 California Probabilistic Seismic Hazard Maps, California Geologic Survey [CGS], June 2003. Frankel, A.D., et al., 2002, Documentation for the 2002 Update of the National Seismic Hazard Maps, USGS Open -File Report 02-420. Hart, E.W., 1997, Fault -Rupture Hazard Zones in California: California Division of Mines and Geology Special Publication 42. International Code Council [ICC], 2007, California Building Code, 2007 Edition. Jennings, C.W, 1994, Fault Activity Map of California and Adjacent Areas: California Division of Mines and Geology, Geological Data Map No. 6, scale 1:750,000. Petersen, M.D., Bryant, W.A., Cramer, C.H., Cao, T., Reichle, M.S., Frankel, A.D., Leinkaemper, J.J., McCrory, P.A., and Schwarz, D.P., 1996,.Probabilistic Seismic Hazard Assessment for the State of California: California Division of Mines and Geology Open -File Report 96-08. Riverside County Planning Department, 2002, Geotechnical Element of the Riverside County General Plan —Hearing Draft. Rogers, T.H., 1966, Geologic Map of California - Santa Ana Sheet, California Division of Mines and Geology Regional Map Series, scale 1:250,000. Tokimatsu, K, and Seed, H.B., 1987, Evaluation of Settlements in Sands Due To Earthquake Shaking, ASCE, Journal of Geotechnical Engineering, Vol. 113, No. 8, August 1987. United States Department of Homeland Securities, FEMA Map Center, flood map number 06065C2925G, Riverside CO, dated August 28, 2008. Wallace, R. E., 1990, The San Andreas Fault System, California: U.S. Geological Survey Professional Paper 1515, 283 p. Working Group on California Earthquake Probabilities, 1995, Seismic Hazards in Southern California: Probable Earthquakes, 1994-2024: Bulletin of the Seismological Society of America, Vol. 85, No. 2, pp. 379-439. EARTH SYSTEMS SOUTHWEST 116015'22"IV 1160W22"IV 0 568000 568500 569000 569500 570000 570500 571000 571600 0 O O 1l4 I �I ?7 i _.J M uoi 11 ce c�htni l '. q� I - i„ w N 1' :Cci my l ut VIPER 0U d L 0 0 0 1 III, 1 1y I 1 S \ IJ40. r� 0o La �_. r Q `iwimnuag P,oiQ°1 l `i1 3 33 34 -Proj c it E 1 l ;:{{ i- M -'V 11YD .0M M1 S I a i- i ° lttl'rca Colte; ( n Into 5o ( IN L{I A•N I I � Lem h 568000 568500 569000 569500 570000 570500 571000 571500 116015'22"IN IWI4'22"IP LEGEND N Figure 1 Project Site Location Project Site Travertine Parcel - TTM 35996 West of Living Stone Drive La Quinta, Riverside County, California 0 500 1,000 3,000 3,000 1'000 5,OW RAI Earth Systems I`00! Southwest 12/30/08 1 File No.: 077 t 1-31 DESCRIPTIVE SOIL CLASSIFICATION Soil classification is based on ASTM-Designations D 2487 and D 2488 (Unified Soil Classification System). Information on each boring log is. a compilation of subsurface conditions obtained from the field as well as from laboratory testing of selected samples. The indicated boundaries between strata on the boring logs are approximate only and may be transitional. SOIL GRAIN SIZE U.S. STANDARD SIEVE BOULDERS COBBLES GRAVEL V SAND SILT CLAY COARSE FINE COARSE MEDIUM FINE fr.ra c.uu u.4� U.1314 U.UO2 SOIL GRAIN SIZE IN MILLIMETERS RELATIVE DENSITY OF GRANULAR SOILS (GRAVELS, SANDS, AND NON -PLASTIC SILTS) Very Loose *N=0.4 RD=0-30 Easily push a 1/2-inch reinforcing rod by hand Loose N=5-10 RD=30-50 Push a 1/2-inch reinforcing rod by hand Medium Dense N=11-30 RD=50-70 Easily drive a 1/2-inch reinforcing rod with hammer Dense N=31-50 RD=70-90 Drive a 1/2-inch reinforcing rod 1 foot with difficulty by a hammer Very Dense N>50 RD=90-100 Drive a 1/2-inch reinforcing rod a few inches with hammer *N=Blows per foot in the Standard Penetration Test at 60% theoretical energy. For the 3-inch diameter Modified California sampler, 140-pound weight, multiply the blow count by 0.63 (about 213) to estimate N. If automatic hammer is used, multiply a factor of 1.3 to 1.5 to estimate N. RD=Relative Density (%). C=Undrained shear strength (cohesion). CONSISTENCY OF COHESIVE SOILS (CLAY OR CLAYEY SOILS) Very Soft *N=0-1 *C=0-250 psf Squeezes between fingers Soft N=24 C=250-500 psf Easily molded by finger pressure Medium Stiff N=5-8 C=500.1000 psf Molded by strong finger pressure Stiff. N=9-15 C=1000-2000 psf Dented by strong finger pressure Very Stiff N=16-30. C=20004000 psf Dented slightly by finger pressure Hard N>30 C>4000 Dented slightly by a pencil point or thumbnail MOISTURE DENSITY Moisture Condition: An observational term;. dry, damp, moist, wet,. saturated. Moisture Content: The weight of water in a sample divided by the weight of dry soil in the soil sample expressed as a percentage. Dry Density: The pounds of dry soil in a cubic foot. MOISTURE CONDITION RELATIVE PROPORTIONS Dry .....................Absence of moisture, dusty, dry to the touch Trace... .......... minor amount (<5%) Damp......, ......... Slight indication of moisture with/some....-significant amount Moist.................Color change with short period of air exposure (granular soil) modifier/and... sufficient amount to Below optimum moisture content (cohesive soil) influence material behavior Wet_..................High degree of saturation by visual and touch (granular soil) (Typically >30%) Above optimum moisture. content (cohesive soil) Saturated .......... Free surface water LOG KEY SYMBOLS PLASTICITY Bulk, Bag or Grab Sample DESCRIPTION FIELD TEST Nonplastic A 1/8 in. (3-mm) thread cannot be rolled I7 Standard Penetration at any moisture content. ' ` Split Spoon Sampler Low The thread can barely be rolled. `s (2" outside diameter) Medium The thread is easy to roll and not much ' Modified California Sampler time is required to reach the plastic limit. Moutside diameter) High The thread can be rerolled several times after reaching the plastic limit. GROUNDWATER LEVEL No Recovery Water Level (measured or after drilling) Terms and Symbols used on Boring Log Water Level (during drilling) Travertine Parcel - TI'M 35996 077I1-31 Table 1 Fault Parameters & DMI'MilliStle EStimatfS of Mean Peale Gennad Aeeeloratian rPV.A) Fault Name or - Seismic Zone Distance front Site (,Ili) then) 6anlf Type iMaximnnt Magnitude Motu (Mhv) Avg Slip Rate (mntiyrl Avg Return Period (yrs) Panic Length (kill) Mean Site PGA, (9) ReferenceNotes: (1) (2) Q) (4) (2) (2) (2) (5) San Andreas - Southern 9.2 14.7 SS A 7.7 24 220 199 0.33 San Jacinto (Hot Spgs - Buck Ridge) 12.2 19.6 SS C 6.5 2 354 70 0.16 San Andreas - Banning Branch 12.3 19.9 SS A 7.2 10 220 98 0.23 San Andreas - Mission Crk. Branch 12.3 -19.9 SS A 7.2 25 220 95 0.23 San Jacinto-Anza 16.5 26.6 SS A 7.2 12 250 91 0.18 San Jacinto -Coyote Creek 18.1 29.2 SS B 6.8 4 175 41 0.13 Blue Cut 21.0 33.8 SS C 6.8 1 760 30 0.12 Burnt Mtn. 24.6 39.6 SS B 6.5 0.6 5000 21 0.09 Eureka Peak 25.5 41.1 SS B 6.4 0.6 5000 19 0.08 San Jacinto - Borrego 28.1 45.3 SS B 6.6 4 175 29 0.08 Earthquake Valley 35.0 56.4 SS B 6.5 2 351 20 0.06 Morbngo 35.7 57.4 SS C 6.5 0.0 1170 23 0.06. Brawley, Seismic Zone 35.8 57.7 SS B 6A 25 24 42 0.06 Pinto Mountain 37.3 60.0 SS B 7.2 2.5 499 74 0.09 Emerson So. - Copper Mtn. -- 38.3 61.0 SS B 7.0 0.6 5000 54 0.08 Pisgah -Bullion Mtn. -Mesquite Lk 39.3 63.2 SS. B 7.3 0.6 5000 89 0.09 San Jacinto -San Jacinto Valley 39.6 63.E SS 'B 6.9 12 83 43 0.07 Ganders 39.7 63.9 SS - B 7.3 0.6 5000 83 0.09 Elsinore-Adian 39.8 64.0 SS A 7.1 5 340 76 0.08 Elmore Ranch 43.4 69.9 SS B 6.6 1 225 29 0.05 Elsinore -Coyote Mountain 44.7 72.0 SS B 6.8 4 625 39 0.06 North Frontal Fault Zone (East) 45.8 73.6 RV B 6.7 0.5 1727 27 0.07 Superstition Mtn. (San Jacinto) 46.2 74.4 SS B 6.6 5 500 24 0.05 Elsinore=l'emeeula 46.9 75.4 SS B 6.8 5 240 43 0.05 Superstition I[ills (San Jacinto) 47.2 76.0 SS B 6.6 4 250 23 0.05 Johnson Valley(Not-them)50.5 81.3. SS B 6.7 0.6 5000 35 0.05 Calico -Hidalgo 52.0 83.6 SS B 7.3 0.6 5000 95 0.07 Lenwood-Lockhart-Old Woman Sprgs 56.3 905 SS B 7.5, 0.6 5000 145 0.07 North Frontal Fault Zone (West) 56.4 90.8 RV 11 7.2 1 1314 50 0.07 Weinert (Superstition Hills) ,. 59.5 95.7 SS C 6.6 4 2504s. 22 0.04 Imperial a>; 61.8 99A SS A 7.0 20 79 62 0.05 Notes: I. Jennings (1994) and California Geologic Survey (COS) (2003) 2. CGS(2003), SS=Strike-Slip; RV =Reverse, DS = Dip Slip (normal), B'r= BlindThrust 3. 2001 CBC, where'rype A faults: Mmm> 7 & slip rate>5 nunfyr & Type C faults: Minas <6.5 & slip rate <2 nuWyr 4. CGS (2003) 5. The estimates of the mean Site PGA are based on the following ahenualion. relationships: Average of (1) 1997 Boore, Joyner &. Fumai; (2) 1997 Sadigh et at; (3) 1997 Campbell , (4) 1997 Abrahamson & Silva (mean plus sigma values are about 1.5 to L6 times higher) Based oil Site Coordinates: 33.605 N Latitude, 116.247 W Longtade and Site Soil Type D EARTH SYSTEMS SOUTHWEST MAJOR DIVISIONS GRAPHIC LETTER TYPICAL DESCRIPTIONS SYMBOL SYMBOL Well -graded gravels, gravel -sand CLEAN GW mixtures, little or no fines GRAVELS r+ra!e!ri:!� s?ri• <5%FINES GRAVEL AND ir.•r•r •r •r: r: r: r• +:.:•:+:++:+:+ GIP Poorl raded ravels, revel -sand GRAVELLY +:+!:•:+.•,+:•. mixtures. Little or no fines SOILS GM Silty Silty gravels, gravel -sand -silt COARSE More than 50% of GRAVELS GRAINED SOILS coarse fraction WITH FINES ............ retained on No. 4 > 12% FINES sieve GC Clayey gravels, gravel -sand -clay mixtures SW Well -graded sands, gravelly sands, SAND AND CLEAN SAND little or no fines SANDY SOILS (Little or no fines) iiii>;t;.i%>z>%>'>� •�••��•"•� 5% SP Poorly -graded sands, gravelly More than 50% of sands, little orno fines material is lancer than No. 200 sieve size SAND WITH FINE SM Silty sands, sand -silt mixtures More than 50% of (appreciable ,: coarse fraction amount of fines) passing No. 4 sieve 12% � 11 - NNIUMN SC Clayey sands, sand -clay mixtures Inorganic silts and very fine sands, ML rock flour, silty low clayey fine sands or clayey silts with slight plasticity Inorganic clays of low to medium FINE-GRAINED LIQUID LIMIT SOILS LESS THAN 50 CL plasticity, gravelly clays, sandy clays, silty clays, lean clays OL Organic silts and organic silty � ' � ' ' � � � � � � ' clays Ysof low plasticity SILTS AND Inorganic silty, micaceous, or CLAYS MH diatomaceous fine sand or silty soils 50% or more of —"�"— material is smaller LIQUID LIMIT %� CH Inorganic clays of high plasticity, than No. 200 GREATER fat clays sieve size THAN 50 R-11 NUNN OH Organic clays of medium to high plasticity, organic silts HIGHLY ORGANIC SOILS YYYYYYYYYYYYe YYYYY•YYYYYYY YYYYY Y YYYJ' PT Peat, humus, swamp soils with YY.iYYYYYYYYY high organic contents YYYYYYYYYYYY VARIOUS SOILS AND MAN MADE MATERIALS Fill Materials MAN MADE MATERIALS Asphalt and concrete Soil Classification System Earth Systems i Southwest 0Earth Systems -- 1"=Southwest 79-811 B ConuayClub Drive, bAN CA Phone (M) 345-1588. Fax (760) 345-7315 Boring No.: B-1 - "'x"Onalion Date: November 19, 2009 Project Name: Travertine Parcel,'17M 35996, La Quinta, CA Drilling Method:. 8" fISA FileNumber: 07711.31 13quipment'1'yp" Mobile B61 HDX wJAuto Hammer Boring Location: See Figure 2 Elevation -1 I' MSL Logged By: Joseph E. McKinney v Sample Type Penetration — -- �� -- - > lageluft Description of Units '9 Resistance N q c L Now 17rc stratification lines shown represent the 0 a o (131ows/G" } vE approximate boundary between soil andlor rock types Grephic'rmad m rn p U and the transition may be gradational. Blow Dry Count Density -0 SM SILTY SAND: light olive gray, dense, damp to 7.1 t,22 115 4 moist, fine to coarse grained sand with silt _' S 12,13,15i 113 2 j} T SP SAND: moderate olive brown, medium dense, damp to moist, fine to coarse grained sand with trace sw, 10 8,11,13 112 2 gravel 24,31,40 _..... WELL GRADED SAND: moderate olive brown, 8,12,12 - _ SPlSM 121 5 - 15 4 4 G medium dense, damp to moist, fine to coarse - grained sand with gravel, cobble lenses -- 20 5,5,7 SAND WITH SILT: light olive gray, medium dense, dry to damp, fine to coarse grained sand with - silt, trace of gravel, 4-inch lenses of silty sand — 25 -- 30 Boring completed at 21.5 feet _ Backfilled with cuttings - No groundwater encountered - 35 - 40 _ 45 - 50 - 55 - - - 60 - 65 - 70 75 90 # Earth Sp Southwest f- 79-81In Comury Chib Ww, nemuxla Dunes, 1'bone (760) 345-1588, Fax (760) 345-7M5 Boring Project No.: B-2 Name: Travertine Parcel, TPM 35996, La Quinta, Exploration Date: November 20, 2008 CA Drilling Method: 8" HSA Pile Number: 07711-31 EquipmentTYpe: Mobile B61 HDX w/Auto Ilammei Boring vrypc Smnple Location: See Figure Penetration 2 Elevation -23' MSL Logged By: Joseph 13. McKinney ------...-. Description of Units . CPage 1 of 1 Resistance E U =4 q a o Note: The stratiftution tines shown represent the q m --3a H p o (Blows/G") rn approximate boundary between soiland/or rock types Graphic Trend U and the transition ma Y be g,adalional. Blow Ihy COnnt I)ensily. 3 WELL GRADED SAND WITH SILT: light olive - 10,14,34 SW-SM 123~ S,t3,7 110 3 gray, dense, dry to damp, with cobbles sw -5 102 14 SW-SM WELL GRADED SAND: light olive gray, medium 7,11,16 toe 3 dense, dunp to moist, with trace oFcobbles - 10 7,12, 13 --- 2 WELL GRADED SAND WITH SILT: light olive gray, dense; dry to damp, with cobbles - 15 - Al 30,15,17 - 20 15,24,30 SM 93 4 SILTY SAND: light olive gray, very dense, dry, fine to coarse grained sand ML - 25 4 8 t9 sp SM SILT: yellowish gray, hard, dry - 30 WELL GRADED SAND WITH SILT: P: yellowish 6 9 12 SM— gray, dense, dry, fine to coarse grained sand with silt, trace of gravel - 35 8,10 18 SILTY SAND: yellowish gray, dense, dry, fine to coarse grained sand with I" well graded sand lease, _ 40 6" ML Tense at tip SW-SM 9,13,26 _ WELL GRADED SAND WITH SILT: yellowish - 45 gray, dense, dry, fine to coarse grained, with I" well _ SM �I 12,18,21 graded sand Tense, 3" ML loose 50 SILTY SAND: yellowish gray, very dense, dry, fine b,2a,29 to coarse grained sand with silt, 3" silt lenses, 3" sand lenses, trace gravel - 55 9,14,17 �'-- ML SANDY SILT: yellowish gray, dense, dry to damp, fine grained sand, 4" dusky yellow silty clay lense, - b0 12,14,20 trace of gravel - 65 Boring completed at 61.5 feet No groundwater encountered - 70 Perforated PVC Pipe set with sock in boring; backfilled with gravel 75 - 80 - 85 % Earth S Southwest 79-8118 CMIlrY Chub I)EM, Bamada vanes, CA Phone(760)345-1588, Fax(760)345-73t5 Boring No.: B-3 Exploration Date: November 19, 2008 Project Name: Travertine Parcel, TEM 35996, La Quints, CA Drilling Method`.. 8" 1ISA File Number: 0771 I-31 Equipment Type: Mobile 1361 liDX w/Auto l lammer Boring Location: See Figure 2 Elevation .13 MSI, Logged By: Joseph E. McKinney v Sample'-' 'Type PenetrationTE�U `o i Description of Units Page — I of 1 oResistance q na .'o« Note:'fhe stratification lines shown represent the (Blows/6") approximate boundary between soil and/or rock types (iraphicTrend tl q U and the transition may be gradational- BlowDry _ Count Density S1i1 SILTY SAND: yellowish gray, fine to coarse _ �1 6,6, I 1 116 1 grained sand, medium dense, dry, gravel near top — 5 7,12,21 t SW-SM GRAVELLY SAND WITH SILT: light olive gray, 7 dense, dry, fine to coarse grained sand, cobble in — 10 �i 8,17,19 --- I sample 6,7,13 -- ) - 20,22,34 . I - - 15 - 5 SP-SM SAND WITH SILT: yellowish gray, medium dense, 1 fine to coarse grained sand, silty sand lense at tip 20 5,5,7 1.5"gravel tense 25 7,7,8 SM SILTY SAND WITH GRAVEL: yellowish gray, medium dense, dry to damp, fine to coarse grained - 30 5,8,17 sand, trace gravel Mil SILT: yellowish gray, dense, dry to damp, fine to - 35 medium grained sand Bowing completed at 31.5 feet - 40 Backfilled with cuttings - 45 No groundwater encountered - 50 - 55 - 60 - 65 70 75 80 85 _.. OEarth Systems`) *aw Southwest 79-81 IBCountq•Clubnriw,Bernwda Dmxs, CA Phone(760) 345-1588, Fas (760) 3454315 Boring DSO.: B-4 Exploration Date: November 19, 2008 Project Name: Travertine Parcel,1"1'M 35996, La Quanta, CA Drilling Method:, 8" HSA Pile Number: 07711-31. Equipment'rype: Mobile B61 HDX tv/Auto hammer Boring Location: See Figure 2 Elevation -15 MSL Logged By: Joseph E. McKinney -----_..--- ---- ------- ---- v Sam plo 'Type Penetration r � \ iRe, lP�age 1 of2 Description of Units `—_ s � Resistance '� N q y H � a�i —.� T Note: he stratification tines shown represent the 'rrend q o (Blows/6') E, � Z,�' S o approximate boundary between soil and/or rocl: types Graphic ti 5 Ca U and the transition may be gradational Blow Dry Count Density a SM SILTY SAND: light olive gray, dense, dry, fine to 10,15,23 105 1 medium grained sand, with gravel at top t \ ', 1 5,12,I7 117 1 5 1 — 10 7,8,13 IL - I SP-sM SAND WITH SILT: yellowish gray, medium dense,' dry, fine to coarse grained sand with silt, trace of 8,15,12 sW-SM -- I gravel 12,1422 WELL GRADED SAND WIT SILT: yellowish gray, medium dense, dry, with silt _ 15 6,6,8 sly-sM SAND WITH SILT: light olive gray, medium dense, dry, fine to coarse grained sand with silt, 3" gravel louse — 20 �.. 3,6,11 ML SILT: yellowish gray, sitff, dry, fine to coarse grained sand with trace of gravel - 25 7 8 13 SM SILTY SAND: yellowish gray, medium dense, dry, fine to medium grained, trace of gravel 30 G G 16 SM SILTY SAND: yellowish gray, medium dense, dry, fine grained sand, trace of gravel, 2" silty clay lenses 35 7,8,13 gM _----- SILTY SAND: yellowish gray, mediurrtm dense, dry, fine to corase, grained sand, 4" and 1" silty clay lenses 40 7,16,19 MI- SANDY CLAYEY SILT: dusky yellow, hard, dry, fine grained SW-sM i WELL GRADED SAND WITH SILT: yellowish gray, very dense, dry, fine to coarse grained sand, 1 45 15,18,24 ( trace of gravel r LJ' I.'. Earth S � Southwest 79d 1113 Comnp C60r Vnwe, nenanda tonnes, CA Phone (760) 345-1588, tax (760) 3g5a315 Boring No.: B-4 Exploration Date: November 19, 2008 Project ame: Travertine Parcel, T"fM 35996; La Quinta, CA Drilling Method: 8" NSA Pile Number: 07711-31 Equipment Type: Mobile 1161 1-IDX w/Auto Hammer Boring Location: See Figure 2 Elevation -15 MSL Logged By: Joseph E. McKinney F Sample Type Penetration E Description of Units Pitge 2 of 2� a w Resistance o p q, o NOW 'file stratification lines shown represent the t7 .< o (Blows(6") >,. cn p v ❑ 5 approximate boundary between soil and/or rock types Graphic Trend m ti U mid the transition may be gradational. Blow Dry Count Density 50 sM/ML SILTY SAND: dusky yellow, dense, dry, fine to coarse grained sand to fine to coarse sandy silt, trace of gravel - 55 10,13,27 _'_'__ Sw :SM WELL GRADED SAND WITH SILT: yellowish gray, Very dense, dry, fine to coarse grained sand with silt, 3" silt lenses at tip, trace of gravel - 60 12,20,38 M1. - '— --`— SANDY SILT: dusky yellow, hard, dry, fine to coarse grained sand, trace of gravel, silty sand tenses at tip -. - 65 - 70 Boring completed at 61.5 feet - No groundwater encountered Perforated PVC Pipe with sock set in boring; hole caved - around pipe; no gravel; backfflled - -75 - 80 -85 -- ------------- - Earth S Southwest 79-8118 Cowry Char Drive, Ocmuela D,m Phone (760)345-1SM. Evc(760) 345-7315 Boring No.: B-5 Bxploratiion Date: November 19. 2009 Project Name: Travertine Parcel,'ITM 35996, La Quinta, CA Drilling Method: 8" HSA Pile Number: 07711-31 Equipment Type: Mobile B61 HDX wlAuto Hammer Boring Location: See Figure 2 Elevation -16 MSL- Logged By: Joseph)". McKinney wjype Sample Penetrationti E Tl¢S¢Clpttori ofnitS. Page 1 of I Resistance o E rn y ❑ q a,e+ 3 « Nose: The Stratification lines shown represent the m Q x q o (Blows/6") >, rn �,�o approximate boundary between soil and/or rock types Graphic Trend m Q U and ilia transition may be gradational. 13I01v Dry _ Camu Density = Sw-SM WELL GRADED SAND WITH SILT: light olive 6,8.9 7 gray, medium dense, dry, gravel - 5 6,8,13 -_ l gravel SP-SM — SAND WITH SILT: light olive gray, medium _ 10,18,38 123 1 dense, dry, fine to coarse grained sand, trace of 15 10,18,38 __ 92 2 gravel _- Sw-SM 9,9,2s GRAVELLY SAND WITH SILT: yellowish gray, - 20 4 9 M!" very dense, dry, fine to coarse grained sand, cobbles SILT: light olive gray, very stiff, dry, some with I" = - 25 silty clayey lense, gastropod shells - 30 - 35 Boring completed at 21.5 feet ' No groundwater encountered - 40 Perforated PVC Pipe with sock set in boring; hole caved . around pipe; no gravel; backfilled - 45 - 50 - 55 _ - 60 -65 70 -75' - 90 - 85 o � U ^ c- � II r—I � U p _ CN w j¢ {I N "' E C L M v o E T C.. :.. .. .... .. E. ...... -. ,. O U N x (a (llpwa) iey Uopenlput IQ U O ^ to E O O O O O co M M O CM O M h co M O U p ¢ O U N N vi M M W N u7 h h O W M M N V O N C6 N CV 11 E t0 E O M M d U M M O a s E^ ¢ y I` x � tr J F v U v V G ?' O O 7 r M W !fl u) M u) M C O V' p O N MUJ �' v O Vh' h N O c6 CO 4 O O O N M N N M (O c0 SU) h C N M C a a1M W 6 6 V. VV VN Mr rr(OV WCV rVNM QO,C C N U L6 M MNh c0VEO Q N co Q N A c _= U. (ho M E F- W y Q' c0 Z O C E ZO V —O N Uti(O O O W V' ifl V W c0 V; V Uf u7 M c(Y Y V V 'Q 0 0 V' �U.. O F C ... c0 (O COMMAtO c0 c0 (6 M 0 O In V' M (fl V'cV O CD Nr-�OOSA O (4 M O M c0 MIh c0 1f1 to u) u) In M M N M M U.1 iL C (- 0 E V' c0 r N Q M rz m v Z M U UC E O u7 u) O M O M O O O O O Uj M M 0 p O p Q J F W M Iu cc' �`22 �� r2 rG ��rc'��G2 2 2O M m E ¢¢¢¢¢¢¢¢¢¢¢¢¢¢¢¢¢aaaaa�. O u�oo n noo o� n� NN n V7 nu u)NN oco o N V' <t u)U0r "N V i NNNNN O_ co 0 w co W W 6) 6)&i6>63OOOOr.r-� aN-re-(y G C S' M II W 41 N Q N us (nwmwCOWmWcnwcnW(nWr�w�wmW(nw �zO wm � 00~ V Lt— N a_O o Table 2 - Initial Estimated Conductivities Boring 2 Borin 4 Reference Elevation current gs current gs Interval t Top 25 25 Bottom 35 30 Thickness 10 5 D,o Size (mm) 0.09 0.04 K Value (cm/sec) 8.1 E-03 1.6E-03 K Value (ft/day) 23.0 4.5 K Value (gal/day/ftz) 172 34 Interval 2 Top 40 45 Bottom 55 50 Thickness 15 5 D,o Size (mm) 0.05 0.06 K Value (cm/sec) 2.5E-03 3.6E-03 K Value (ft/day) 7 10 K Value (gal/daylft) 53 77 Interval 3 Top 55 Bottom 60 Thickness 5 D,o Size (mm) 0.06 K Value (cm/sec) 3.6E-03 K Value (ft/day) 10 K Value (gal/day/ft2) 77 a. Table 3 - Drywell Design and Infiltration Model Reference Elevation Boring 2 Boring 4 Current gs Current gs Drywell Construction Depth Main Drywell Pilot Hole 20 55 20 60 Upper Soil Interval Top feet 25 8 Bottom feet 35 30 Thickness feet 10 22 Estimated K Value (ft/da) 22.9 2.5 al/da /ft2 172 20 Model Type (see below) C C Estimated Disposal Capacity (gal/day) 103,184 11,098 Estimated Disposal Capacity AF/da 0.32 0.03 Deeper Soil Interval (if an Top feet 40 45 Bottom feet 55 50 Thickness feet 15 5 Estimated K Value (ft/da) 7.1 10.3 al/da /ft2 53 77 Model Type (see below) C C Estimated Disposal Capacity (gal/day) 80,408 58,648 Estimated Disposal Capacity AF/da 0.25 0.2 Deeper Soil interval (if an Top feet 55 Bottom feet 60 Thickness feet "" 5 Estimated K Value (ft/da) x 10.3 al/da Ift2 °r' 77 Model Type (see below) ,' C Estimated Disposal Capacity (gal/day) 75,404 Estimated Disposal Ca acit AF/da r 0.2 Model Types A = Unconfined with no underlying barrier B = Unconfined with underlying barrier C = Overlying and underlying barrier File No.: 07711-31 December 30, 2008 I,ab No.: 08-0465 UNIT DENSITIES AND MOISTURE CONTENT ASTM D2937 & D2216 Job Name: Travertine Parcel, TTM35996 Unit Moisture USCS Sample Depth Dry Content Group Location (feet) Density (ef) (%) Symbol B1 2 115 4 SM B1 4 113 2 SP B1 9 112 2 SP B1 13 121 5 SW B2 1 123 3 SW-SM B2 3 110 3 SW B2 6 102 14 SW-SM B2 8 102 3 SW-SM B2 10 -- 2 SW-SM B2 20 93 4 ML B3 2 116 1 SM B3 4 --- 1 SM B3 9 --- 1 SP-SM B3 II I SP-SM B3 13 --- 1 SW-SM B4 1 105 1 SM B4 3 117 1 SM B4 9 --- I SP-SM B4 11 I SW-SM B5 2 _ 7 SP-SM B5 4 --- 1 SP-SM B5 10 --- I SP-SM B5 14 123 1 Sw-SM B5 I7 92 2 ML EARTH SYSTEMS SOUTHWEST File No.: 07711-3 1 December 30, 2008 Lab No.., 08-0465 PARTICLE SIZE ANALYSIS ASTM D-422 Job Name: Travertine Parcel, TTM 35996 Sample ID: B2 @ 25 feet Description: Yellow Brown Well Graded Sand w/Silt (SW-SM) Sieve Percent Size Passing 1-1/2" 100 ? 100 3/4-1 100 1/2" 98 3/8" 98 #4 93 48 83 #16 69 % Gravel: 7 430 45 % Sand: 85 #50 25 % Silt: 7 filoo 14 % Clay (3 micron): 1 #200 8 (Clay content by short hydrometer method) 100 90 80 70 521 to PO a, 30 20 10 0 ICI' m ��I II I, TIi j � �� ill � . ........ . I � I li �' I 10 1 0.1 Particle Size (MM) EARTH SYSTEMS SOUTHWEST 0.01 0.001 File No.: 07711-31 Lab No.: 08-0465 PARTICLE SIZE ANALYSIS December 30, 2008 ASTM D-422 Job Name: Travertine Parcel, TTM 35996 Sample ID: B2 @ 30 feet Description: Yellowish Brown Silty Fine to Coarse Sand w/Gravel (SM) Sieve Percent Size Passing 1-1/2" 100 1" 100 3/4" 89 1/2" 89 3/8" 89 #4 84 #8 78 416 68 % Gravel: 16 430 54 % Sand: 59 #50 43 % Silt: 17 #100 32 % Clay (3 micron): 8 #200 25 (Clay content by short hydrometer method) 100 90 80 70 %f T W, 20 10 0 .- f _._"---. .- - ---"-- � � i �I i - ----- 10 1 Particle Size{ mm). 0.01 0.001 EARTH SYSTEMS SOUTHWEST Pile No.: 07711-31 December 30, 2008 Lab No.: 08-0465 PARTICLE SIZE ANALYSIS ASTM D-422 Job Name: Travertine Parcel, TTM 35996 Sample 1D: B2 @ 40 feet Description: Brown Well Graded Sand w/Silt & Gravel (SW-SM) Sieve Percent Size Passing 1-1/2" 100 1" 100 3/4" 100 1/2" 97 3/8" 96 #4 89 #8 76 #16 63 % Gravel: 11 #30 46 % Sand: 77 #50 30 % Silt: 12 # 100 18 % Clay (3 micron): 0 #200 12 (Clav content by short Irvdrometer method) 100 90 80 70 &0 c N go C �o N a 30 20 10 0 10 1 0.1 Particle Size ( MM) 0.01 0.001 EARTH SYSTEMS SOUT14W EST File No.: 07711-31 December 30, 2008 Lab No.: 08-0465 PARTICLE SIZE ANALYSIS ASTM D-422 Job Name: Travertine Parcel, TTM 35996 Sample ID: B2 @ 45 feet Description: Yellowish Brown Silty Tine to Coarse Sand w/Gravel (SM) Sieve Percent Sire Passing 1-1/2" 100 „ 1 100 3/4" 100 1/2" 98 3/8" 97 #4 92 #8 81 #16 70 % Gravel: 8 #30 56 % Sand: 78 #50 40 % Silt: 12 #100 24 % Clay (3 micron): 2 #200 14 (Clay content by short hydrometer method) 100 90 80 70 &o to CL a 30 20 10 0 ............. i 10 1... Particle Size ( 0.1 0.01 0.001 EARTH SYSTEMS SOUTHWEST File No.: 07711-31 December 30, 2008 Lab No.: 08-0465 PARTICLE SIZE ANALYSIS ASTM D-422 Job Name: Travertine Parcel, TTM 35996 Sample 1D: B4 @ 25 feet Description: Brown Silty Fine to Coarse Sand w/Gravel (SM) Sieve Percent Size Passing 1-1/2" 100 1ff 100 3/4" 100 1/2" 95 3/8" 95 #4 92 #/8 85 #16 76 % Gravel: 8 #30 57 % Sand: 78 #50 37 % Silt: 11 #100 24 % Clay (3 micron): 3 #200 14 (Clay content by short hydrometer method) 100 90 so 70 &0 Obu a 30 20 10 0 ' I I 1 I i i 10 1 Particle Size (mm) 0.1 0.01. 0.001 EARTH SYSTEMS SOUTHWEST File No.: 07711-31 Lab No.: 08-0465 PARTICLE SIZE ANALYSIS December 30, 2008 AS'I'M D-422 Job Name: Travertine Parcel, TTM 35996 Sample ID: B4 @ 35 feet Description: Brown Silty Fine to Medium Sand (SM) Sieve Percent Size Passing 1-1/2" 100 1" 100 3/4" 100 1 /2" 100 100 #4 98 #8 94 916 88 % Gravel: 2 t#30 79 % Sand: 63 #50 65 %Silt: 35 #100 49 % Clay (3 micron): 0 #200 35 (Clay content by short hydrometer method) 100 90 80 70 AO C *0 d C po 0 ❑. 30 20 10 0 10 1 0.1 Particle Size ( mm) O.Ot OA01 EARTH SYSTEMS SOUTHWEST File No.: 07711-31 December 30, 2008 Lab No.: 08-0465 PARTICLE SIZE ANALYSIS ASTM D-422 Job Name: Travertine Parcel, TTM 35996 Sample ID: B4 @ 45 feet Description: Yellowish Brown Well Graded Sand w/Silt (SW-SM) Sieve Percent Size Passing 1-1/2" 100 111 100 3/4" 100 1/2" 100 3/8" 100 #4 96 #8 87 #16 74 % Gravel; 4 #30 58 % Sand: 84 950 39 % Silt: 10 #100 23 % Clay (3 micron): 2 #200 12 (Clay content by short hydrometer method) 100 90 80 70 Poo 30 20 10 0 - - - - - - - - -- - ........ - --- - - ------ ---- --- --- -7- 4- LI 10 1 0.1 0.01 0�001 Particle Size ( Min) EARTH SYSTEMS SOUTHWEST File No.: 07711-31 December 30, 2008 Lab No.: 08-0465 PARTICLE SIZE ANALYSIS ASTM D-422 Job Name: Travertine Parcel, TTM 35996 Sample ID: B4 @ 55 feet Description: Yellowish Brown Well Graded Sand w/Gravel (SW-SM) Sieve Percent Size Passing 1-1/2" 100 1" 100 3/4" 100 1/2" 100 3/8" 98 #4 96 #8 90 #16 81 % Gravel: 4 430 65 % Sand: 84 #50 42 % Silt: 12 #100 22 % Clay (3 micron): 0 #200 12 (Clay content by short hydrometer method) 100 90 80 70 Ao c y to a. ��CNy G O 0Y a 30 20 10 0 10 particle Size ( mm) EARTH SYSTEMS SOUTHWEST 0.01 0.001 File No.: 07711-31 December 30, 2008 Lab No.: 08-0465 CONSOLIDATION TEST ASTM D 2435 & D 5333 Travertine Parcel, TTM 35996 Initial Dry Density: 88.6 pcf 132 @ 20 feet Initial Moisture, %: 3.9% Yellowish Gray Silt (ML) Specific Gravity (assumed): 2.67 Initial Void Ratio: 0.881 Ring Sample Hydrocollapse: 3.6% @ 2.0 ksf % Change in Height vs Normal Presssure Diagram 0.1 �- Before Saturation • --- Hydrocollapse ■ After Saturatioi Rebound 1.0 Vertical Effective Stress, kst 10.0 EARTH SYSTEMS SOUTHWEST File No.: 07711-31 December 30, 2008 Lab No.: 08-0465 CONSOLIDATION TEST ASTM D 2435 & D 5333 Travertine Parcel, TTM 35996 Initial Dry Density: 90.4 pef 135 @ 17 feet Initial Moisture, %: 1,6% Grey Fine Silt (ML) Specific Gravity (assumed): 2.67 Initial Void Ratio: 0.844 Ring Sample Hydrocollapse: 1.1%@2.0ksf % Change in Height vs Normal Presssure Diagram 8- Before Saturation Hydrocollapse N After Saturation *—Rebound 0 — --- --- -- ----- ---- . ..... ..... -2 . ..... . .... ........ -3 .. . ..... .. .. -4 -------- - _- _ -5 . ........ ------ . ... . ....... ... ... ,11 2 -7 . ...... . ........ . .. . - - - ----------- 4 ---- -- -9 . . ..... . . . ............. ... ...... ... ... -10 -11 -12 0.1 q'o 10.0 Vertical Effective Stress, ksf EARTH SYSTEMS SOUTHWEST File No.: 07711-3I December 30, 2008 Lab No.: 08-0465 MAXIMUM DENSITY / OPTIMUM MOISTURE; ASTM D 1557-91 (Modified) Job Name: Travertine Parcel, TTM 35996 Procedure Used: A Sample ID: 1 Preparation Method: Moist Location: B1 @ 1-4 feet Rammer Type: Mechanical Description: Brown Fine to Coarse Sand w/Silt Lab Numbe 08-0465 & Gravel (SM) Sieve Size % Retained Maximum Density: 130 pef 3/4" 1.4 Optimum Moisture: 9% 3/8" 4.4 #t4 9.0 140 135 130 125 115 110 105 100 k 0 <----- Zero Air 2.75 5 10 15 20 25 Moisture Content, percent 30 35 EART14 SYSTEMS SOUTHWEST File No.: 07711-31 December 30, 2008 Lab No.: 08-0465 MAXIMUM DENSITY / OPTIMUM MOISTURE ASTM D 1557-91 (Modified) Job Name: Travertine Parcel, TTM 35996 Procedure Used: A Sample ID. 2 Preparation Method: Moist Location: Bl @ 8-11 feet Rammer Type: Mechanical Description: Olive Will Graded Sand w/Gravel Lab Numbe 08-0465 (SW) Sieve Size % Retained Maximum Density: 128.5 pef 3/4" 4.3 Optimum Moisture: 8% 3/8" 9.5 #4 16.3 140 135 130 Imi 115 110 105 100 + 0 <----- Zero Air Voids Linee sp =2.65, 2.70. 2.75 5 10 15 20 25 Moisture Content, percent 30 35 EARTH SYSTEMS SOUTHWEST Pile No.: 07711-31 December 30, 2008 Lab No.: 08-0465 MAXIMUM DENSITY / OPTIMUM MOISTURE ASTM D 1557-91 (Modified) Job Name: Travertine Parcel, TTM 35996 Procedure Used: A Sample ID: 3 Preparation Method: Moist Location: B4 @ 1-4 feet Rammer Type: Mechanical Description: Brown Silty Pine to Medium Sand Lab Numbe 08-0465 w/Gravel (SM) Sieve Size % Retained Maximum Density: 115 pef 3/41, 0.0 Optimum Moisture: 11.5% 3/8" 0.1 #4 1.0 140 136 130 125 C Q N 120 c m i7 0 115 110 105 100 4 0 <----- Zero Air Voids Lines, sg =2.65, 2.70, 2.75 5 10 15 20 25 Moisture Content, percent 30 35 EARTH SYSTEMS SOUTHWEST File No:: 07711-31 Lab No.: 08-0465 SOIL CHEMICAL ANALYSES December 30, 2008 Job Name: Travertine Parcel, TTM 35996 Job No.: 07711-31 Sample ID: B1 B4 Sample Depth, feet: 1-4 1-4 DP RL Sulfate, mg/Kg (ppm): 78 20 1 0.50 Chloride, mg/Kg (ppm): 51 l 28 l 0.20 NH, (pH Units): 8.70 8.20 1 0.41 Resistivity, (ohm -cm): 650 2,800 N/A NIA Conductivity, (µmhos -cm): 1 2.00 Note: Pests performed by Subcontract Laboratory: Surabian AG Laboratory DF: Dilution Factor 105 Tesori Drive RL: Reporting Limit Palm Desert, California 92211 Tel: (760) 200-4498 General Guidelines for Soil Corrosivity Chemical Agent Amount in Soil Degree of Corrosivii. Soluble 0 -1000 mg/Kg (ppm) [ 0-,1%] Low Sulfates 1000 - 2000 rng/Kg (ppm) [0.1-0.2%] Moderate 2000 - 20,000 mg/Kg (ppm) [0.2-2.0%] Severe > 20,000 m K ( m) [>2.0%] Very Severe Resistivity 1-1000 ohnrcm Very Severe 1000-2000 ohm -cm Severe 2000-10,000 ohm -ern Moderate I — + ohm -cm Low EARTIF SYSTEMS SOUTHWEST i1G`;4'S2M! 5597100 ii.*.5'eSii - a"o98 101 569900 Legend m Site Boundary ® Boring E Infiltration Test Boring & Infiltration Test r:l LNJ O O m 0 25 50 100 150 200 66JII00 115`14'52MJ