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SDP 01-10A; GEOTECHNICAL EVALUATION; 2011-10-24
1104 0~1 EEI leSolutions GEOTECHNICAL EVALUATION Proposed Multi-Family Residential Development Encinas Creek Project North of El Camino Real Carlsbad, California October 24, 2011 EEl Project No. SEA-71249.4 2195 Faraday Avenue + Suite K• Carlsbad, California 92008-7207 +Ph: 760-431-3747+ Fax: 760-431-3748 • www.eeitiger.com I GEOTECHNICAL EVALUATION Prepared for: Ms. Susan Kelly Holly Springs, Ltd. do Mr. Ken Cablay SeaBourne Development 701 Palomar Airport Road Suite 300 Carlsbad, California 92008 Project Site Location: Proposed Multi-Family Residential Development- Encinas Creek Project North of El Camino Real Carlsbad, San Diego County, California EEl Project No. SEA-71249.4 I Prepared and Edited by: No. 2468 Rw William R. Morrison GE 2468 (exp. 12/31/12) Senior Geotechnical Engineer EEl 2195 Faraday Avenue, Suite K Carlsbad, California 92008-7207 EEl Project No. SEA-71249.4 I I I TABLE OF CONTENTS 1.0 INTRODUCTION ................................................................................................................................. 1 1.1 Purpose.......................................................................................................................................1 1.2 Project Description.....................................................................................................................1 1.3 Scope of Services .......................................................................................................................1 2.0 BACKGROUND....................................................................................................................................2 2.1 Site Description..........................................................................................................................2 2.2 Site Topography ....... ................................................................................................................. 2 2.31 Geologic Setting.........................................................................................................................2 2.4 Regional Groundwater ...............................................................................................................3 3.0 FAULTING AND SEISMICITY .........................................................................................................3 Table 1 - Summary of Major Active Faults ....................................................................................3 3.1 Seismic Parameters and Peak Ground Acceleration...................................................................4 3.2 Ground Lurching or Shallow Ground Rupture...........................................................................4 3.3 Liquefaction................................................................................................................................5 3.4 Seismic Induced Settlement .......................................................................................................5 4.0 FIELD EXPLORATION AND LABORATORY TESTING ............................................................5 4.1 Field Exploration........................................................................................................................5 4.2 Subsurface Conditions................................................................................................................6 4.3 Laboratory Testing and Classification ........................................................................................ 6 4.3.1 Moisture Content and Dry Density.............................................................................6 4.3.2 Grain Size Distribution ..............................................................................................6 4.3.3 Maximum Dry Density and Optimum Moisture Content...........................................7 4.3.4 Direct Shear................................................................................................................7 4.3.5 Expansion Index.........................................................................................................7 4.3.6 Sulfate-Corrosion .......................................................................................................7 5.0 CONCLUSIONS....................................................................................................................................7 6.0 RECOMMENDATIONS ......................................................................................................................9 6.1 General .......................................................................................................................................9 6.2 Site Preparation and Grading......................................................................................................9 6.3 Remedial Earthwork .................................................................................................................. 10 6.4 Cut-fill Transition and Cut.......................................................................................................10 6.5 Fill Placement...........................................................................................................................11 7.0 FOUNDATION RECOMMENDATIONS........................................................................................12 7.1 General .....................................................................................................................................12 7.2 Foundation Design ...................................................................................................................13 7.3 Footing Setbacks ......................................................................................................................13 7.4 Construction .............................................................................................................................14 7.5 Concrete Slab-on-Grade ........................................................................................................... 14 7.6 Retaining Walls........................................................................................................................15 7.6.1 Concrete Masonry (CMU) Walls ............................................................................15 7.6.2 Mechanically Stabilized Earth (MSE) Walls ...........................................................16 7.6.2.1 Bearing Capacity..........................................................................................16 7.6.2.2 Seismic Design Parameters ..........................................................................16 7.6.2.3 Back Drainage .............................................................................................17 El I TABLE OF CONTENTS (Continued) 7.6.2.4 Temporary Backcuts.....................................................................................17 7.6.2.5 Foundation Setbacks ...................................................................................... 17 7.6.2.6 Construction Observations and Testing........................................................17 8.0 PAVEMENT DESIGN RECOMMENDATIONS ............................................................................17 Table 2 —Preliminary Pavement Design Recommendations..........................................................18 9.0 DEVELOPMENT RECOMMENDATIONS ...................................................................................18 9.1 Landscape Maintenance and Planting ......................................................................................18 9.2 Site Drainage............................................................................................................................19 9.3 Site Runoff Considerations-Stormwater Disposal Systems .....................................................19 9.3.1 Percolation Testing...................................................................................................19 Table 3 - Percolation Test Results ...................................................................................19 9.4 Additional Site Improvements..................................................................................................20 9.5 Trenching .................................................................................................................................21 9.6 Utility Backfill..........................................................................................................................21 10.0 PLAN REVIEW ...............................................................................................................................21 11.0 LIMITATIONS ................................................................................................................................22 12.0 REFERENCES .................................................................................................................................23 FIGURES Figure 1 - Site Vicinity Map Figure 2 - Aerial Site Map Figure 3 —Boring Location Map APPENDICES Appendix A - Soil Classification Chart and Boring Logs Appendix B - Laboratory Test Data Appendix C - Earthwork and Grading Guidelines Distribution: (4) Addressee (1) Addressee (electronic copy) I I Geotechnical Evaluation - Proposed Multi-Family Residential Development October 24, 2011 Encinas Creek, Carlsbad, California EEl Project No. SEA-71249.4 1.0 INTRODUCTION 1.1 Purpose The purpose of this evaluation was to provide geotechnical information to Holly Springs, Ltd. (herinafier referred to as "Client"), regarding the proposed residential development in Carlsbad, San Diego County, California. The information developed in this evaluation is intended to provide Holly Springs, Ltd. and other members of the design team with an understanding of the physical conditions of site-specific subsurface soils, groundwater, and the regional geologic setting which could affect the cost or design of the proposed development (Site Vicinity Map-Figure 1, Aerial Site Map-Figure 2). This geotehnical evaluation has been conducted in general accordance with the accepted geotechnical engineering principles and in general conformance with the approved proposal and cost estimate for the project by EEl, dated September 19, 2011. EEl conducted an onsite field exploration on September 29, 2011 that included drilling and sampling of six (6) hollow stem auger geotechnical borings for the proposed Enemas Creek residential development We conducted three percolation tests in conjunction with our field exploration. This geotechnical evaluation has been prepared for the sole use of Holly Springs, Ltd. Other parties, without the express written consent of EEl and Holly Springs, Ltd., should not rely upon this geotechnical study. 1.2 Project Description Based on our review of a site plan provided (0' Day Consultants, dated December 2, 2010), the proposed development is for the construction of five (5) multi-family residential buildings that will house 127 units, along with related improvements including graded slopes, paved private streets and drives. The residences are anticipated to be constructed of wood frame and slab-on-grade construction, underground utilities, paved parking and drive areas, and other associated improvements. No foundation plans were available at the time of our preparation of this report; however, foundation loads are anticipated to be typical for the planned residential construction. Based on the referenced plans by O'Day, grading at the site is ant:cipated to include cut and fill depths ranging from approximately five to 15 feet (exclusive of remedial grading) from existing grades. Fill and cut slopes up to approximately 25 feet in height at maximum gradients of 2:1 (horizontal to vertical) are planned. Retaining walls of up to 10 feet in height are also planned. 1.3 Scope of Services The scope of our services included: A review of readily available data pertinent to the subject property, including published and unpublished geologic reports/maps, and soils data for the area (References). The drilling , logging and sampling of eight (8) hollow stem auger (HSA) borings to depths on the order of 20 feet below the existing ground surface across the site, including the conducting of percolation testing at three (3) of the locations. The locations of each of our borings and percolation tests are presented on Figure 3 (Boring Locations and Proposed Site Map). An evaluation of seismicity and geologic hazards that included an evaluation of faulting and Lquefaction potential. I I Geotechnical Evaluation - Proposed Multi-Family Residential Development October 24, 2011 Encinas Creek, Carlsbad, California EEl Project No. SEA-71249.4 I • Completion of laboratory testing of representative earth materials encountered onsite to ascertain their soils engineering properties, including corrosion potential (Appendix B). I . The preparation of this report which presents our findings, conclusions, and recommendations regarding the proposed development. 2.0 BACKGROUND 2.1 Site Description The subject site parcel encompasses approximately 5.8-acres and is situated within the ncrthwestern portion of an approximately 119-acre overall proposed property development named Holly Springs, located south of the eastern terminus of Cannon Road in Carlsbad, California. The subject property is presently undeveloped. The Rancho Carlsbad Estates residential development and associated golf course is located to the south of the subject parcel. The ground surface at the site is moderately to gertly sloping toward the northwest and southwest. The site is also bounded to the north and east generally by vacant undeveloped agricultural land and to the west by vacant land and residential development. A site vicinity map is attached as Figure 1. Current access to the site is afforded by Rancho Carlsbad Drive, which bounds the property to the south. Vegetation varies from sparse to locally heavy. A relatively heavily vegetated drainage located near the southwest portion of the site appears to contain scattered piles of concrete and miscellaneous debris. Based on our review of a site plan by O'Day Consultants, Inc., (dated December 2010), we understand that the proposed multi-family residential development consists of five (5), three (3) story buildings, which are anticipated to include 127 residential units. We also understand that undergrouid utilities, paved parking and drive areas and other associated improvements are included as part of the proposed development at the site. We anticipate the buildings to be slab-on-grade, with wood or steel-frame construction. Foundation loads are assumed to be typical for the type of structures planned. The center of the property is situated at 33.1536° north latitude and 117.2833° west longitude (Google Earth®, 2011). 2.2 Site Topography The subject property is situated within the United States Geological Survey (USGS) San Luis Rey, California 7.5 Minute Quadrangle map (USGS, 1997). A review of this topographic map indicates that the ground surface of the subject property is approximately 85 to 150 feet above mean sea level (msl). The subject site is overall gently to moderately sloping toward the west and south. Surface water appears to drain in both a westerly and southerly direction towards adjacent properties to the west and south. An aerial photo of site is attached as Figure 2. 2.3 Geologic Setting Regionally, the area is situated within the Peninsular Ranges Geomorphic Province of California (CGS, 2002). The Peninsular Ranges are essentially a series of ranges separated by northwest trending valleys, sub-parallel to faults branching from the San Andreas Fault system. The northern portion of t1i5 Province is bounded by the Transverse Ranges Geomorphic Province. The Peninsular Ranges extend into Lower California (and Baja), and are bound on the east by the Colorado Desert. The predominant structural feature that has affected the geologic evolution of the province is the San Andreas Fault. I I Geotechnical Evaluation - Proposed Multi-Family Residential Development October 24, 2011 Encinas Creek, Carlsbad, California EEl Project No. SEA-71249.4 Regional geologic maps of the site vicinity (CGS online geologic interactive maps) indicate the property is underlain by Tertiary-age marine sedimentary deposits. Locally, the property and vicinity is mapped as being underlain by Eocene-aged sedimentary deposits of the Santiago Formation (CDMG, 1996). Regionally, bedding layers within the Santiago Formation in the vicinity of the site are mapped as striking east-west and generally dip gently to the north up to 5 degrees. In the vicinity of the project site, the deposits are locally mantled by artificial fill materials and topsoil/slopewash deposits of varying thicknesses. Due to the proximity of the site area to several nearby active faults, strong ground shaking could occur at the site as a result of an earthquake on any one of the faults. Our review indicates that there are no known active faul:s crossing the site (Jennings, 1994, 2010) and the site is not within a State of California Earthquake Fault Zone (Hart and Bryant, 1997, CDMG, 2000). 2.4 Regional Groundwater Subsurface water was not encountered in any of our exploratory boring excavations performed during our study to the maximum depths explored. Regional groundwater depths are anticipated to be greater 50 feet below the site grades. However, it should be noted that variations in subsurface water including perched water zones and seepage may result from fluctuations in the ground surface topography, subsurface stratification, precipitation, irrigation and other factors that may not have been evident at the time of our subsurface exploration. In general, groundwater is expected to follow the direction of surface topography. Based on topography, regional groundwater flow direction can be expected to generally be in a westerly to southwesterly direction (IJSGS, 1997). 3.0 FAULTING AND SEISMICITY The portion of Southern California that includes the subject site is considered to be seismically active. Due to the proximity of the site area to several nearby active faults, strong ground shaking could occur at the site as a result of an earthquake on any one of the faults. Our review indicates that there are no known active faults crossing the site (Jennings, 1994, 2010) and the site is not within a State of California Earthquake Fault Zone (Hart and Bryant, 1997). It is our opinion, therefore, that the likelihood of surface fault rupture at the site is low. The following table provides a summary of active fault zones within an approximately 50-mile radius of the subject property that may have a considerable effect on the subject property in the event significant activity is experienced. Fault names and approximate distances are based upon information provided in applicable references (Blake, 2000; Jennings, 1994). TABLE 1 Summary of Major Active Faults Fault Name Approximate Distance From Site miles (kilometers) Maximum Moment Magnitude Rose Canyon 7.1 (11.5) 7.2 NewpDrt Inglewood (offshore) 8.5 (13.6) 7.1 Elsinore (Temecula) 21.9 (35.3) 6.8 Elsinore (Julian) 22.0 (35.4) 7.1 Coronado Bank 23.2 (37.4) 7.6 Elsinore (Glen Ivy) 34.1 (54.8) 6.8 I I 11 I I Geotechnical Evaluation - Proposed Multi-Family Residential Development October 24, 2011 Encinas Creek, Carlsbad, California EEl Project No. SEA-71249.4 TABLE 1 Summary of Major Active Faults Fault Name Approximate Distance From Site miles (kilometers) Maximum Moment Magnitude San Joaquin Hills 37.5 (60.4) 6.6 Palos Verdes 39.0 (62.8) 7.3 Earthquake Valley 40.6 (65.4) 6.5 San Jacinto-Anza 44.7 (72.0) 7.2 San Jacinto-San Jacinto Valley 45.7 (73.6) 6.9 Chino-Central Avenue (Elsinore) 48.3 (77.8) 6.7 Newport-Inglewood (L.A. Basin) 48.5 (78.1) 7.1 San Jacinto-Coyote Creek 49.5 (79.7) 6.6 3.1 Seismic Parameters Maximum considered ground motion maps provided in the California Building Code (CBC, 2010) were utilized with coordinates of 33.15360 north latitude and 117.2833° west longitude, to determine the site seismic parameters. EEl utilized seismic design criteria provided in the CBC (2010). In accordance with the guidelines of the CBC (2010), the spectral parameters for the site (based on a Site Class B soil) are estimated to be S = 1.139g and S = 0.432g. Based on the geotechnical data obtained during our subsurface exploration, it is our opinion that the site can be classified as Class C per the 2010 CBC (Table 1613.5.2). Consequently, Site Coefficients Fa= 1.0 and F = 1.368 appear to be appropriate for the site. Based on this information, the adjusted maximum considered earthquake spectral response parameters SMS = 1.139g and SM! = 0.591g are recommended for seismic design of the project. Assuming an occupancy category of II (Table 1604.5), an S0 value of 0.759g and an 5D1 value of 0.394g, the proposed residential buildings at the site can be assigned a seismic design category of D [Table 1613.5.6 (1) and (2)]. Final selection of the appropriate seismic design coefficients should be made by the structural consultant based on the local laws and ordinances, expected building response and desired level of conservatism. Structures should be designed in accordance with seismic design criteria developed by the Structural Engineers Association of California. 3.2 Ground Lurching or Shallow Ground Rupture Based on the geography, topography and site-specific geotechnical conditions encountered during our geotechnical evaluation at the site, we consider the potential for ground lurching or shallow ground rupture at the site to be low; however, due to the active seismicity of California, this possibility cannot be completely ruled out. In light of this, the unlikely hazard of lurching or ground-rupture should not preclude consideration of "flexible" design for onsite utility lines and connections. I I Geotechnical Evaluation - Proposed Multi-Family Residential Development October 24, 2011 Encinas Creek, Carlsbad, California EEl Project No. SEA-71249.4 3.3 Liquefaction Liquefaction is a phenomenon in which the strength and stiffness of a soil is reduced by earthquake shaking or other rapid loading. Liquefaction and related phenomena have been responsible for substantial structural damage in historical earthquakes, and are a design concern under certain conditions. Liquefaction occurs in saturated soils, that is - soils in which the space between individual particles is completely filled with water. This pore water exerts a pressure on the soil particles that influences how tightly the particles themselves are pressed together. Prior to an earthquake, pore water pressure is typically low; however, earthquake motion can cause the pore water pressure to increase to the point where the soil particles can readily move with respect to each other. When liquefaction occurs; the strength of the soil decreases and the ability of a soil deposit to support structural loads are reduced. Due to the observed lack of a near surface static ground water level at the site, along with the relatively dense nature of the encountered materials comprising the Santiago Formation that underlies the site, it appears that liquefaction is not a significant geotechnical concern at the site. 3.4 Seismic Induced Settlement Seismically induced settlement can occur due to the reorientation of soil particles during strong shaking of unsaturated sands, as well as in response to liquefaction of saturated loose granular soils. As noted above, the potential for liquefaction-induced settlement is considered very low. We estimate the total seismic induced settlement within the upper unsaturated soils to be less than 'A-inch across the site. Differential seismic induced settlements are estimated to be less than ¼- inch across a 50-foot span. 4.0 FIELD EXPLORATION AND LABORATORY TESTING 4.1 Field Exploration Field work was conducted on September 29 and September 30, 2011. A total of eight (8) hollow stem auger borings were drilled on the subject property. The borings were placed at various locations across the subject property and were extended to a maximum depth of 20 feet below the existing ground surface. Our exploratory borings were logged under by a representative of EEl. Blow count (N) values were determined utilizing a 140 pound automatic hammer, falling 30-inches onto a Standard Penetration Test (SPT) split-spoon sampler and a Modified California split-tube sampler. A truck mounted Mobile-B61 drill rig was used during field work. The blows per foot (N value) required to advance the 18-inch long SPT and 12-inch long Modified California split-tube samplers was measured at various initial depths followed by 5-foot intervals, recorded on the boring logs, and are presented in Appendix A-Soil Classification Chart and Boring Logs. Relatively "undisturbed" samples were collected in a 2.42-inch (inside diameter) California Modified split-tube sampler for visual examination and laboratory testing. The soils were classified in accordance with the Unified Soil Classification System (ASTM, 2008). Representative bulk samples were also collected for appropriate laboratory testing. I __J Geotechnical Evaluation - Proposed Multi-Family Residential Development October 24, 2011 Encinas Creek, Carlsbad, California EEl Project No. SEA-71249.4 4.2 Subsurface Conditions Subsurface conditions encountered in our exploratory borings consisted of sedimentary deposits of the Eocene aged Santiago Formation, which are locally mantled by approximately two to five feet of topsoil and slopewash materials. As encountered in our exploratory borings, the Eocene Santiago Formation consists of gray and light brown and orange-brown and red-brown, silty and clayey sandstones with interbedded layers of brown and yellow brown, clayey silts and sandy silts. Some localized, poorly graded sand and gravel and cobble layers were also encountered. Locally, the sandstone layers are well indurated and slightly cemented. The sand and sandy silt layers within the Santiago Formation deposits were noted to be typically moist to wet and medium dense to very dense, while the clayey and clayey silt layers were observed to be moist to very moist and stiff to very stiff at the time of our subsurface exploration. The Santiago Formation deposits were observed to be mantled by undifferentiated, disturbed surface (disked) Soils, topsoil and slopewash deposits. As encountered in our exploratory borings, the encountered surficial soils were generally comprised of brown to dark brown silty and clayey sands which were generally damp to moist and loose at the time of our subsurface exploration. Refusal was not encountered within any of our exploratory borings. Detailed descriptions of the encountered soils are provided on the boring logs included as Appendix A. Groundwater was not encountered in any of our exploratory borings during our subsurface exploration. However, it should be noted that variations in groundwater including perched water zones and seepage may result from fluctuations in the ground surface topography, subsurface stratification, precipitation, irrigation and other factors that may not have been evident at the time of our subsurface exploration. 4.3 Laboratory Testing and Classification Representative samples were selected for laboratory testing to confirm their field classification(s). Field descriptions and classifications were visually classified according to the American Society for Testing and Materials (ASTM) D2488 which classifies soils under the Unified Soil Classification System (USCS). Representative soil samples were tested in the lab for grain size distribution to determine actual classifications by ASTM D2487-Standard Practice for Classification of Soils for Engineering Purposes in accordance to the USCS. Final classifications of soils can be found on the boring logs in Appendix A and the laboratory test data in Appendix B. 4.3.1 Moisture Content and Dry Density The in-situ moisture content and dry density of soils was determined for soil samples obtained from the borings. The in-place moisture content and dry density of soils helps to determine engineering design parameters for foundations, retaining walls, and other engineering structures. Moisture content on soil samples was conducted in general accordance with ASTM D2216, and was recorded as a percentage. The in-situ moisture content and dry density for soil samples retrieved from the field can be found on the boring logs located in Appendix A. 4.3.2 Grain Size Distribution To help check field classifications of soils, the grain size distribution of representative soil samples was determined. In order to find the percentages of different sized particles in a particular soil stratum, soils were tested in general accordance to ASTM D 422-Standard Test Method for Particle-Size Analysis of Soils. Grain size distribution curves and gradation results are presented in Appendix B. I I I Geotechnical Evaluation - Proposed Multi-Family Residential Development October 24, 2011 Encinas Creek, Carlsbad, California EEl Project No. SEA-71249.4 4.3.3 Maximum Dry Density and Optimum Moisture Content The maximum dry density and optimum moisture content were determined from bulk samples obtained from borings B3 and P2 at depths of between 1 and 5 feet below existing grade. Our testing was performed in general accordance with ASTM D1557, Method A. Results of our testing are presented in Appendix B. 4.3.4 Direct Shear Direct shear testing was conducted on two representative soil samples that were remolded to 90 percent of their maximum dry density (based on ASTM D1557) and on one undisturbed sample to measure their shear strength characteristics for engineering purposes. The samples were inundated for at least 18 hours prior to testing. The samples were placed in a shear box and a normal load was applied (10, 20, and 40 kilogram weights were used). Each sample was then sheared at a controlled strain rate in a direct shear apparatus that measures horizontal displacement and shear resistance. Shear testing was run in general accordance to ASTM D3080. The results of our testing are presented in Appendix B. 4.3.5 Expansion Index Two representative soil samples from borings P-2 and B-6 within the upper five feet of existing grade were tested for expansion potential. Our expansion index testing was conducted in general accordance to ASTM D4829. The results of our expansion index testing are presented in Appendix B. 4.3.6 Sulfate/Corrosion Three (3) representative samples of the upper onsite earth materials were collected for analysis at HDR-Schiff Associates located in Claremont, California for corrosion/soluble sulfate potential. This corrosion testing included soil minimum resistivity and pH by California Test Method 643, electrical conductivity by AWWA 2510-B and ASTM D1125, alkalinity by U.S. EPA 310.1, AWWA 1320-B, and ASTM D513, and sulfates and chlorides by California Test Method (CTM) 417 and CTM 622 respectively, and nitrates by USEPA 300.0. Results of these tests are presented in Appendix B. It should be understood that the results provided in Appendix B are based upon pre-development conditions. Verification testing is recommended at the conclusion of grading on samples collected at or near finish grade. 5.0 CONCLUSIONS Based on our field exploration, laboratory testing and engineering and geologic analysis, it is our opinion that the site is suitable for the proposed Encinas Creek multi-family residential development from a geotechnical engineering and geologic viewpoint; however, there are existing geotechnical conditions associated with the property that will warrant mitigation and/or consideration during planning stages. If site plans and/or the proposed building locations are revised, additional field studies may be warranted to address proposed site-specific conditions. As a result, EEl is providing the following conclusions: U I Geotechnical Evaluation - Proposed Multi-Family Residential Development October 24, 2011 Encinas Creek, Carlsbad, California EEL Project No. SEA-71249.4 A total of eight (8) exploratory hollow stem auger (HSA) borings were advanced within the subject property during this evaluation. HSA borings extended to a maximum depth of approximately 20 feet below the existing ground surface (bgs). Overall, the subject property is underlain by Eocene Age sedimentary deposits mapped as the Santiago Formation that are mantled by topsoils and slopewash deposits that appear to have an approximate thicknesses on the order of 2 to 5 feet. The encountered materials comprising the Santiago Formation were observed to consist of silty and clayey sandstones with interbedded layers of clayey silts and sandy silts while the topsoils and slopewash deposits were generally comprised of brown to dark brown silty and clayey sands. Although some slow and difficult drilling was encountered in localized layers containing gravels, cobble, and/or cementation, refusal was not encountered in our exploratory borings to the total depths explored. Groundwater was not encountered in our exploratory borings to the maximum depths explored of 20 feet below existing grades. However, it should be noted that variations in groundwater including perched water zones and seepage may result from fluctuations in the ground surface topography, subsurface stratification, precipitation, irrigation and other factors that may not have been evident at the time of our subsurface exploration. Based on our subsurface exploration, laboratory testing and geotechnical engineering analysis, we consider the proposed 2:1 (horizontal to vertical) fill and cut slopes up to maximum heights of 25 feet at the site to be grossly stable in the absence of adverse geologic conditions. We understand that design for planned onsite stonnwater facilities including LID BMP's and bioretention devises are not based on direct infiltration into the underlying earth materials near slope areas and will be lined with an impermeable membrane. As such, the planned slopes are considered grossly stable in the absence of direct infiltration along the top of slope areas. Laboratory test results indicate that native materials are slightly to moderately acidic (pH = 5.8 to 6.5) and are moderately corrosive to extremely corrosive to ferrous metals with minimum resistivity values ranging from 580 ohm-cm to 5,780 ohm-cm. Laboratory testing of the upper soils yielded soluble sulfate concentrations ranging from 7.5 mg/kg to 131 mg/kg, indicating a negligible corrosion potential to concrete. Chloride concentrations were reported ranging from 15 mg/kg to 713 mg/kg, indicating that the upper soils possess a potential for corrosion of steel reinforcement in concrete. Concentrations of nitrate in the soil were reported as ranging from 25 mg/kg to 73 mg/kg, with ammonium concentration reported to be non-detect, while tested levels of ammonium do not appear to pose a corrosion potential to copper piping, the tested levels of nitrate in the soil could be a threat to copper piping. It is recommended that a corrosion engineer be consulted to provide recommendations for proper protection of buried metal pipes at this site (if warranted). Since EEl does not practice corrosion engineering, we recommend that a qualified corrosion consultant be retained to further evaluate the corrosion potential of the upper soils with respect to metallic conduits and reinforced concrete elements, and to provide appropriate recommendations to mitigate the effects of corrosive soils, as warranted. The subject property is located within an area of southern California recognized as having a number of active and potentially-active faults located nearby. Our review indicates that there are no known active faults mapped as crossing the site and the site is not located within an Earthquake Fault Zone. The nearest active faults that could affect the subject site include the Rose Canyon Fault, located approximately 7 miles from the site, and the offshore segment of the Newport Inglewood Fault Zone, located approximately 9 miles from the site. Other nearby seismic sources includes the Temecula and Julian segments of the Elsinore Fault Zone, both located approximately 22 miles from the site. Each of these active faults is capable of generating severe ground shaking at the site. I I Geotechnical Evaluation - Proposed Multi-Family Residential Development October 24, 2011 Encinas Creek, Carlsbad, California EEl Project No. SEA-71249.4 Based on EEl's geotechnical evaluation, earth materials underlying the site of the proposed residential development are not considered susceptible to liquefaction or significant amounts of seismic settlement. Results of our Expansion Index laboratory testing of the upper soils indicate a very low expansion potential. A conventional shallow foundation system appears to be suitable for use to support the structures proposed for residential development, provided the property is graded and improved in general corformance with recommendations presented herein, as well as the California Building Code (CBC, 2010), the City of Carlsbad grading ordinances. EEL evaluated static settlement utilizing results of laboratory testing and subsurface data to I estimate settlement as a result of grading the pads to a proposed finish slab grade, with a minor change in the proposed slab grade elevation from existing grade. Based upon our evaluation and our recommendations for complete removal of potentially compressible soils within the proposed I building footprints (as presented herein); EEl estimates total static settlement of less than 1-inch within the building envelope. Differential settlement is estimated to be approximately '/2-inch or less over a distance of 50 feet. 6.0 RECOMMENDATIONS The recommendations presented herein should be incorporated into the planning and design phases of development. Guidelines for site preparation, earthwork, and onsite improvements are provided in the following sections. 6.1 General Grading should conform to the guidelines presented in the California Building Code, 2010 (CBC, 2010) and the grading ordinances of the City of Carlsbad. Additionally, general Earthwork and Grading Guidelines are provided herein as Appendix C. During earthwork construction, removals, excavations, as well as general grading procedures of the contractor should be observed and the fill placed selectively tested by representatives of the geotechnical engineer, EEl. If any unusual or unexpected conditions are exposed in the field, they should be reviewed by the geotechnical engineer and if warranted, modified and/or additional remedial recommendations will be offered. Specific guidelines and comments pertinent to the planned development are provided herein. The recommendations presented herein have been completed using the information provided to us regarding site development. If information concerning the proposed development is revised, or any changes in the design and location of the proposed property improvements are made, the conclusions and recommendations contained in this report should not be considered applicable unless the changes are reviewed and conclusions of this report modified or approved in writing by this office. 6.2 Site Preparation and Grading Debris and other deleterious material, such as organic soils and/or environmentally impacted earth materials should be removed from the site prior to the start of grading. Areas to receive fill should be properly b nched in accordance with current industry standards of practice and guidelines specified in the CBC, 2010. I I Geotechnical Evaluation - Proposed Multi-Family Residential Development October 24, 2011 Encinas Creek, Carlsbad, California EEl Project No. SEA-71249.4 Existing utilities should be removed within the proposed building envelope. Abandoned trenches should be properly backfilled and tested. If unanticipated subsurface improvements (utility lines, septic systems, wells, utilities, etc.) are encountered during earthwork construction, the geotechnical engineer should be informed and appropriate remedial recommendations would then be provided. 6.3 Remedial Earthwork Topsoil was encountered in each of our exploratory borings that were drilled across the site. Slopewash materials were encountered underlying the topsoil in Boring B-6. These surficial materials were encountered to depths of between 2 and 5 feet below existing grade. These materials were observed to be relatively loose during our subsurface exploration and are considered potentially compressible. As such, they are considered unsuitable for the support of settlement-sensitive structures or additional fill in their current condition. Therefore, where they are not already removed by the proposed site grading, any existing fill, the topsoil and slopewash should be completely removed and recompacted in the areas proposed for construction. Following removal of the upper soils, the bottom of the resulting excavation(s) should be observed by a representative of EEl to check that unsuitable materials have been sufficiently removed. It should be understood that based on the observations of our field representative, localized deeper removals may be recommended. Some areas may encounter thicker zones of topsoil, fill or slopewash based on actual field conditions encountered during earthwork. The base of the removal areas should be level to avoid differential fill thicknesses under proposed improvements. This remedial earthwork should extend at least five feet outside the proposed building limits and/or five feet beyond the area to receive fill. Note that vertical sides exceeding five feet in depth may be prone to sloughing and may require laying back to an inclination of 1:1 (horizontal to vertical). After removal of the upper soils and observation of the excavation bottoms, the over-excavated areas should be scarified to a minimum depth of 8-inches, moisture conditioned as needed to achieve at least optimum moisture content and re-compacted to at least 90 percent of the maximum dry density (based on ASTM D1557). The over-excavated areas should then be backfilled with onsite and/or imported soils that are placed and compacted as recommended herein until design finish grades are reached. 6.4 Cut-Fill Transition and Cut Our review of the project plans by O'Day indicates that cut-fill transitions will likely span across several of the proposed lots (Lots 1, 2, 3, 4 and the proposed recreation center lot). It is recommended that where cut-fill transitions (daylight) are planned across the lots, the entire cut portion of the daylight pad should be over-excavated to a minimum depth of three feet below finish grade or 18-inches below the bottoms of the proposed footings (whichever is deeper) and replaced with compacted fill possessing a very low expansion potential. Over-excavation of transition pads is recommended in order to reduce the potential for differential settlements between cut and fill transitions. The overexcavation of the transition cut-fill pads should extend at least 5 feet beyond the proposed building footprints. Our review of the project plans by O'Day Consultants indicates that Lot 5 is situated on a cut lot. In order to provide uniform bearing conditions for the proposed building on Lot 5 at the site, we recommend that consideration be given to over-excavation of the pad to a minimum depth of three feet below finish grade or 18-inched below the bottoms of the proposed footings (whichever is deeper) and replaced with compacted fill possessing a very low expansion potential. This over excavation should extend at least 5 feet beyond the proposed building footprints. 10 I Geotechnical Evaluation - Proposed Multi-Family Residential Development October 24, 2011 Encinas Creek, Carlsbad, California EEl Project No. SEA-71249.4 6.5 Fill Placement Fill material should possess an expansion index of less than 20 (as determined by ASTM D4829) and be free of organic matter (less than three percent organics by weight) and other deleterious material. Much of the onsite materials appear to be suitable for re-use as fill, provided they do not contain rocks greater than six-inches in maximum dimension, organic debris and other deleterious materials. Rock fragments exceeding six-inches in one dimension should be segregated and exported from the site, properly placed in deeper fill areas or utilized for landscaping. If import soils are needed, the earthwork contractor should ensure that all proposed fill materials are approved by the geotechnical engineer prior to use. Representative soil samples should be made available for testing at least ten working days prior to hauling to the site to allow for laboratory tests. Fill materials should be placed in 6- to 8-inch loose lifts, moisture conditioned as necessary to at least optimum moisture and compacted to a minimum of 90 percent maximum dry density according to ASTM D1557. The upper 12-inches of pavement subgrade should be moisture conditioned to at least optimum moisture and compacted to at least 95 percent of the maximum dry density as determined by ASTM D1557. Suitable heavy grading equipment should be utilized to properly mix, spread, moisture condition or dry, and compact each fill lift. Earthwork may be affected by the existing soil moisture content exceeding optimum. Moist to very moist earth materials may be difficult to mix and compact in their native condition, and drying or mixing with drier soils may be warranted to achieve the recommended relative compaction. Those areas to receive fill (including over-excavated areas) or surface improvements should scarified at least 12-inches, moisture conditioned to at least optimum moisture content and recompacted to at least 90 percent of the maximum dry density (based on ASTM D1557). 6.6 Shrinkage and Bulking Several factors will impact earthwork balancing on the site, including shrinkage, bulking, subsidence, trench spoils from utilities and footing excavations, and final pavement section thickness as well as the accuracy of topography. Shrinkage, bulking and subsidence are primarily dependent upon the degree of compactive effort achieved during construction. For planning purposes, the shrinkage factor is estimated to be on the order of 10 to 15 percent for the existing topsoils/slopewash materials to be re-utilized as engineered fill. These shrinkage factors may vary with methods employed by the contractor. Subsidence is estimated to be on the order of 0.1 feet. Losses from site clearing and removal of existing site improvements may affect earthwork quantity calculation and should be considered. Planned excavations into the Santiago Formation materials may result in slight bulking below cut depths of 15 feet. For planning purposes, a bulking factor of 3 to 5 percent may apply to the very dense portions of the Santiago Formation. The previous estimates are intended as an aid for the project engineers in estimating earthwork quantities. It is recommended that the site development be planned to include an area that could be raised or lowered to accommodate final site balancing. 11 I I Geotechnical Evaluation - Proposed Multi-Family Residential Development October 24, 2011 Enemas Creek, Carlsbad, California EEl Project No. SEA-71249.4 6.7 Graded Slopes Based on our laboratory test results and our experience with similar earth materials, proposed cut and fill slopes using onsite materials are expected to be grossly and surficially stable, provided the recommendations contained herein are implemented during site development. All slopes should be designed and constructed in accordance with the minimum requirements of the 2010 CBC and/or City of Carlsbad and the following recommendations: Proposed cut slopes should be constructed at maximum gradients of 2:1 (horizontal to vertical) or flater. Proposed fill slopes should be constructed at a maximum 2:1 gradient (horizontal to vertical) or flatter. Fill slope keys should be excavated into properly compacted, engineered fill materials or competent formational soils approved by the geotechnical engineer and/or geologist. Keyways should be at least 12 feet in width, extend at least two feet into competent materials and sloped away from the face-of-slope (i.e., into slope) a minimum of 2 percent (toe to heel). Depth of keyways should be based upon field conditions encountered during grading; however, the minimum depth should be below surficial soils and old existing fills, if present. Fill slopes should be properly built utilizing horizontal lifts compacted to a minimum relative compaction of 90 percent (ASTM D-1557) throughout, including slope surfaces. If fill slopes are built to grade, the slope face should be track-walked by a dozer at least every 3 feet in elevation. As an option, the fill slope face may be over-built at least 3 feet and trimmed back to grade. All stormwater facilities (including pervious pavement areas) should be designed to avoid direct infiltration and saturation near planned slopes. Direct infiltration and saturation should not be allowed to occur within a minimum horizontal distance to the top of slope equal to the slope height (i.e., for a 20 foot high slope, setback is at least 20 feet from top of slope). While staDilization of the planned cut slopes is not anticipated, locally adverse geologic/geotechnical conditions (i.e., loose granular cohesionless soils, adversely oriented bedding or discontinuities or severely weathered soils) may be encountered which may require remedial grading or laying back of the slope to an angle flatter than the adverse geologic condition. Should any of these materials or conditions be exposed during construction, EEl's geotechnical engineer/engineering geologist would assess the magnitude and extent of the materials and their potential effect on long-term maintenance or possible slope failures. Recommendations would then be made at the time of the field observation. 7.0 FOUNDATION RECOMMENDATIONS 7.1 General In the event that plans concerning the proposed three-story building structures are revised in the project design and/or location or loading conditions of the planned structure are made, conclusions and recommendations contained in this report should not be considered valid unless they are reviewed, revised and/or approved in writing by EEl. The foundation recommendations provided herein are based on the soil materials near finish grade possessing a low expansion potential (El < 50). While the foundaticn design recommendations contained herein anticipate the use of conventional shallow foundaticns, options for post tensioned slab foundations or other alternative foundation systems can also 12 I I U 13 Geotechnical Evaluation - Proposed Multi-Family Residential Development October 24, 2011 Encinas Creek, Carlsbad, California EEl Project No. SEA-71249.4 be provided upon request. Recommendations by the project's design-structural engineer or architect may exceed the following minimum recommendations. Final foundation design should be provided based on the expansion potential of the near surface soils encountered during grading 7.2 Foundation Design The proposed residential structures can be supported on conventional continuous or isolated spread footings bearing entirely upon firm natural materials (i.e., competent formational deposits) or at least 18- inches of properly compacted fill materials. Foundations supporting three story structures should be constructed with an embedment of at least 24-inches below finish grade. At these depths, footings may be designed for an allowable soil bearing value of 2, 500 psf. This value may be increased by one-third for loads of short duration, such as wind and seismic forces. Continuous footings supporting three-story structures should have minimum width of 18-inches. Based on geotechnical considerations, footings should be provided with reinforcement consisting of two No. 4 rebar, one top and one bottom. We recommend a minimum width of 24-inches for isolated spread footings. In order to help reduce the potential for misalignment of proposed garage door openings, we recommend a grade beam be provided at each garage door opening. This grade beam should be designed in accordance with the structural engineer's requirements and have a minimum reinforcement of two No. 4 rebar (one top and one bottom). Horizontal loads acting on foundations and stem walls cast in open excavations against undisturbed native soil or against properly placed and compacted fill will be resisted by friction acting along the base of the footing and by passive earth pressures against the side of the footing and stem wall. The frictional resistance acting along the base of footings founded on suitable foundation soils may be computed using a coefficient of friction equal to 0.35 with the normal dead load. Passive earth pressures acting against the side of footings and stem walls may be assumed to be equivalent to a fluid weighing 300 pounds per cubic foot. Passive pressure in the upper 1.0-foot should be neglected unless confined by concrete slabs- on-grade or asphaltic pavement. The values given above may be increased by one-third for transient wind or seismic loads. 7.3 Footing Setbacks All footings should maintain a minimum seven-foot horizontal setback from the base of the footing to any descending slope. This distance is measured from the outside footing face at the bearing elevation. Footings should maintain a minimum horizontal setback of H/3 (H=slope height) from the base of the footing to the descending slope face. This setback distance should not be less than seven feet and need not be greater than 40 feet. Footings adjacent to drainage swales, underground utilities (if any) or within 10 feet of stormwater devices should be deepened to a minimum of 6-inches below the invert of the adjacent unlined swale or utilities. Footings near planned stormwater devices (bioswales) that are lined may be deepened to a maximum of 30-inches. This distance is measured from the footing face at the bearing elevation. Footings for structures adjacent to retaining walls should be deepened so as to extend below a 1:1 projection from the heel of the wall. Alternatively, walls may be designed to accommodate structural loads from buildings or appurtenances as described in the retaining wall section of this report. I I I I I I I I I I I I I L I I I Geotechnical Evaluation - Proposed Multi-Family Residential Development October 24, 2011 Encinas Creek, Carlsbad, California EEl Project No. SEA-71249.4 7.4 Construction The following foundation construction considerations are presented as minimum recommendations from a I soils engineering standpoint. Laboratory test results indicate the onsite soils swell (expansion) potential is very low (CBC, 2010). During grading of the site, kve recommend that no potentially expansive soils material (i.e., possessing an El > 20) be placed within 24-inches of finish grade, if possible. Design parameters provided herein, however, assume that finish grade soil materials will have a very low I expansion potential. Recommendations by the project's design-structural engineer or architect, which may exceed the soils I engineer's recommendations, should take precedence over the following minimum considerations. Final foundation design should be provided based on the expansion potential of the near surface soils encountered during grading. I 7.5 Concrete Slab-on-Grade Concrete slabs-on-grade should be a minimum of 4-inches thick. Floor slabs should be suitably reinforced I and jointed (in accordance with Structural Engineer's recommendations) so that a small amount of independent movement can occur without causing damage. Based on the encountered geotechnical conditions, we recommend that floor slabs be reinforced with No. 3 bars spaced on 18-inch centers (each way). The contractor should take the appropriate precautions to make sure that the reinforcement is placed and maintained within the middle one-third of the slab. Control joints should be provided to help reduce the potential for random cracking. Slabs should be underlain by a 4-inch thick capillary break layer consisting of clean sand (Sand Equivalent of at least 30) or rounded fine gravel (pea gravel). Where moisture condensation is undesirable, the slabs should be underlain with a minimum 10-mil visqueen membrane, sandwiched between two layers of clean sand (Sand Equivalent of at least 30) each being at least two inches thick. Care should be taken to adequately seal all seams and not puncture or tear the membrane. The sand should be proof rolled. To reduce the potential for buildup of hydrostatic pressures, the free draining material under the slabs should have positive drainage with no low lying areas (i.e., depressions) created. It should be noted that the above recommendation is based on soil support characteristics only. The structural engineer should design the actual slab and beam reinforcement based on actual loading conditions and possible concrete shrinkage. Exterior slabs, such as walkways and driveways, can be adequately grade supported on firm natural materials (i.e., Santiago formation) or documented structural fill, being a minimum of 12-inches in thickness, which is placed and compacted in accordance with the recommendations contained herein. In preparation for slab or flatwork construction, the earthwork contractor should ensure that the onsite soils have been prepared as recommended and that field density tests have been performed to adequately document the relative compaction of the structural fill. Preparation of the native soils should be documented prior to placement of aggregate, structural components and/or fill. Some minor cracking of slabs can be expected due to shrinkage. The potential for this slab cracking can be reduced by careful control of water/cement ratios in the concrete. The contractor should take appropriate curing precautions during the pouring of concrete in hot or windy weather to reduce the potential for cracking of slabs. We recommend that a slipsheet (or equivalent) be utilized if grouted fill, tile, or other crack-sensitive floor covering is planned directly on concrete slabs. All slabs should be designed in accordance with structural considerations. 14 I Geotechnical Evaluation - Proposed Multi-Family Residential Development October 24, 2011 Enemas Creek, Carlsbad, California EEl Project No. SEA-71249.4 I All dedicated exterior flatwork should conform to standards provided by the governing agency including section composition, supporting material thickness and any requirements for reinforcing steel. Concrete mix proportions and construction techniques, including the addition of water and improper curing, can I adversely affect the finished quality of the concrete and result in cracking and spalling of the slab. We recoinmend that all placement and curing be performed in accordance with procedures outlined by the American Concrete Institute and/or Portland Cement Association. Special consideration should be given to concrete placed and cured during hot or cold weather conditions. Proper control joints should be I provided to minimize any damage resulting from shrinkage. As discussed above, laboratory testing of the upper soils yielded soluble sulfate concentrations ranging from 7.5 mg/kg to 131 mg/kg, indicating a negligible corrosion potential to concrete. Chloride concentrations were reported ranging from 15 mg/kg to 713 mg/kg, indicating that the upper soils possess a potential for corrosion of steel reinforcement in concrete. As such, Type II cement can be used in concrete elements that will be in contact with the upper soils. 7.6 Retaining Walls I The following sections provide geotechnical recommendations for retaining structures at the site. 7.6.1 Concrete Masonry (CMU) Walls The design parameters provided below assume that non-expansive select material (such as gravel wrapped in filter fabric) is used to backfill any retaining walls. If expansive soils are used to backfill the proposed walls, increased active and at-rest earth pressures will need to be utilized for retaining wall design, and can be provided upon request. Building walls below grade should be waterproofed or damp-proofed, depending on the degree of moisture protection desired. The foundation system for retaining walls should be designed in accordance with the recommendations presented in the preceding sections of this report, as appropriate. Footings should be embedded a minimum of 18-inches below adjacent finish grade (excluding 6-inch landscape layer). There should be no increase in bearing for footing width. The design active earth pressure on a retaining wall may be considered equivalent to that produced by a fluid weighing 40 pounds per cubic foot (pcf). This design equivalent fluid pressure of 40 pcf is considered appropriate for cantilevered walls retaining non-expansive soils with a level ground surface, subject to lateral deflection at distances above grade due to lateral earth pressures. A safety factor for sliding and overturning of 1.5 is typically prescribed for a cantilevered structure as described. All retaining structures should be fully free draining. Restrained walls (such as basement walls or re-entrant corners), with a level backfill, should be designed for an equivalent fluid pressure of 60 pcf for at rest lateral earth pressure. For resistance to lateral loads, an allowable coefficient of friction of 0.35 between the base of the foundation elements and underlying material is recommended. In addition, an allowable passive resistance equal to an equivalent fluid weighing 300 pcf acting against the foundation may be used to resist lateral forces. Passive pressure in the upper 1.0-foot should be neglected unless confined by concrete slabs-on-grade or asphaltic pavement. These values may be increased by one-third for transient wind or seismic loads. 15 LI I Geotechnical Evaluation - Proposed Multi-Family Residential Development October 24, 2011 Encinas Creek, Carlsbad, California EEl Project No. SEA-71249.4 I Adequate subdrainage should be provided behind all retaining walls. The subdrainage system should consist of a minimum of a four-inch diameter perforated PVC pipe (schedule 40 or approved equivalent) placed at the base of the retaining wall and surrounded by 3/4-inch clean crushed rock wrapped in a Mirafi 140N filter fabric (or approved equivalent). The crushed rock wrapped in fabric should be at least 12-inches wide and extend from the base of the wail to within two feet of the ground surface. The upper two feet of backfill should consist of compacted native soil. The retaining wall drainage system should be sloped to an outlet into the storm drain system or other appropriate facility. 7.6.2 Mechanically Stabilized Earth (MSE) Walls The geotechnical design parameters provided below pertain to reinforced or MSE type walls (i.e., Keystone, Loffel, Earthstone, Geogrid, etc.) up to maximum heights of ten (10) feet. Based on the geotechnical data and our past experience with similar soils in the general vicinity of the project site, we recommend that the following soils parameters be used for design of the proposed reinforced earth walls: Internal Soil Parameters Friction Cohesion Moist Unit Soil Type Angle (psi) Weight (pct) (Degrees) Reinforced Soil 28 0 125 Compacted onsite SM materials with EI<20 & P1<7. Retained Soil 28 0 125 Compacted onsite SM materials with EI<20 & P1<7. Foundation Soil 28 0 125 Compacted onsite SM materials with EI<20 & P1<7. The backfill materials should be placed in lifts no greater than 8-inches in thickness and compacted at 90 percent relative compaction at optimum moisture content or higher as determined by ASTM test procedure D 1557-00. 7.6.2.1 Bearing Capacity An allowable bearing capacity of 2,500 pounds per square foot, including both dead and live loads, may be used if footings are founded at a minimum of 12 inches below finish grade into properly compacted fill or dense weathered sedimentary formational materials. The allowable bearing may be increased by one-third when considering short-term live loads (e.g. seismic and wind loads). 7.6.2.2 Seismic Design Parameters Seismic design parameters presented in Section 3.0 of this report are based on a soft rock site (Class C), with an SD, value of 0.759g. In keeping with the 2010 CBC (2009 IBC seismic design) criteria, when dividing SD, by 2.5, a peak ground acceleration of 0.30g is obtained. A peak ground acceleration of 0.30g may be used for seismic design purposes. 16 I I Geotechnical Evaluation - Proposed Multi-Family Residential Development October 24, 2011 Encinas Creek, Carlsbad, California EEl Project No. SEA-71249.4 I 7.6.2.3 Back Drainage Retaining walls should be provided with an adequate back drainage system in accordance with the recommendations contained in our referenced report and as required by the wall manufacturer/designer. Proper back drainage can reduce the potential for the accumulation of hydrostatic pressures behind the walls. Location of proposed onsite stormwater facilities (i.e., BMP's) in the vicinity of the walls and the potential for increased hydrostatic pressures should be considered in design of the walls. 7.6.2.4 Temporary Backcuts Temporary excavations or backcuts within the onsite materials should be stable at 1 H: 1Y inclination for short durations during construction but should not exceed 15 feet in height. 7.6.2.5 Foundation Setbacks The following setbacks should apply to the reinforced earth retaining wall foundations, as well as any footings constructed near the walls. Any improvements not conforming to these setbacks may be subject to excessive lateral movements and/or differential settlements: The outside bottom edge of foundations supporting the reinforced earth walls should be set back a minimum of 7 feet from the face of any descending slope. The bottom of all footings for structures near retaining walls should be deepened so as to extend below a 1:1 projection upward from the bottom inside edge of the wall. 7.6.2.6 Construction Observations and Testing All foundation excavations and wall backfilling should be observed and tested by a representative of this office to check for compliance with the recommendations of this report and to check that the soil conditions are consistent with those stated herein. 8.0 PRELIMINARY PAVEMENT DESIGN RECOMMENDATIONS Deleterious material, excessively wet or dry pockets, concentrated zones of oversized rock fragments, and any other unsuitable yielding materials encountered during grading should be removed. Once compacted fill and/or native soils are brought to the proposed pavement subgrade elevations, the subgrade should be proof-rolled in order to check for a uniform firm and unyielding surface. Representatives of the project geotechnical engineer should observe all grading and fill placement. The upper 12-inches of pavement subgrade soils should be scarified; moisture conditioned to at least optimum moisture content and compacted to at least 95 percent of the laboratory standard (ASTM D1557). If loose or yielding materials are encountered during subgrade preparation, evaluation should be performec by EEl. Aggregate base materials should be properly prepared (i.e., processed and moisture conditioned) and compacted to at least 95 percent of the maximum drydensity as determined by ASTM D1557. Aggregate base should conform to Caltrans specifications for Class 2 aggregate base. 17 Geotechnical Evaluation - Proposed Multi-Family Residential Development October 24, 2011 Encinas Creek, Carlsbad, California EEl Project No. SEA-71249.4 All pavement section changes should be properly transitioned. Although not anticipated, if adverse conditions are encountered during the preparation of subgrade materials, special construction methods may need to be employed. A representative of the project geotechnical engineer should be present for the preparation of subgrade and aggregate base. For design purposes we have assumed a Traffic Index (TI) of 5.0 for the proposed interior parking areas and drive areas at the site. This assumed TI should be verified as necessary by the Civil Engineer or Traffic Engineer. Based on the results of our laboratory testing of a representative sample of the upper soils, along with our experience with similar soils in the general vicinity of the subject site, we have utilized an R-Value of 20 for the pavement subgrade during our calculations of pavement structural sections. The modulus of subgrade reaction (K-Value) was estimated at 80 pounds per square inch per inch (psi/in) for an R-Value of 20 (Caltrans, 1974). Flexible pavement design was calculated for the parking areas and drive areas based on structural section requirements for asphaltic concrete in accordance with the guidelines presented in the Caltrans Highway Design Manual. Rigid pavement was evaluated in accordance with ACT 330R-08, based on average daily truck traffic value of 25. TABLE2 Preliminary Pavement Design Recommendations Traffic Index (TI) Pavement Surface I Aggregate Base Material (1) 5.0 3-inches Asphalt Concrete 7-inches Trash Area and Concrete Pavement 6-inches Portland Cement Concrete (2) optional R-Value of 78 for Caltrans Class II aggregate base Reinforcement and control joints placed in accordance with the structural engineer's requirements The recommended pavement sections provided above are intended as a minimum guideline. If thinner or highly variable pavement sections are constructed, increased maintenance and repair could be expected. If the ADT (average daily traffic) or ADTT (average daily truck traffic) increases beyond that intended, as reflected by the assumed and provided traffic indices used for design, increased maintenance and repair could be required for the pavement section. Final pavement design should be verified by testing of soils exposed at subgrade after grading has been completed. If the upper three feet of soils are impacted, EEl may be able to provide a thinner pavement section, assuming soils will have a higher R-Value. 9.0 DEVELOPMENT RECOMMENDATIONS 9.1 Landscape Maintenance and Planting I Water is known to decrease the physical strength of earth materials, significantly reducing stability by high moisture conditions. Surface drainage away from foundations and graded slopes should be maintained. Only the volume and frequency of irrigation necessary to sustain plant life should be applied. I Consideration should be given to selecting lightweight, deep rooted types of landscape vegetation which require low irrigation that are capable of surviving the local climate. From a soils engineering viewpoint, "leaching" of the onsite soils is not recommended for establishing landscaping. If landscape soils are I processed i'or the addition of amendments, the processed soils should be re-compacted to at least 90 percent relative compaction (based on ASTM D1557). I 18 I I I I I I I I I I I I I I I I I Geotechnical Evaluation - Proposed Multi-Family Residential Development October 24, 2011 Encinas Creek, Carlsbad, California EEl Project No. SEA-71249.4 I 9.2 Site Drainage Positive site drainage should be maintained at all times. Drainage should not flow uncontrolled over I slopes or the subject parcel. Runoff should be channeled away from slopes and structures and not allowed to iond and/or seep uncontrolled into the ground. Pad drainage should be directed toward an acceptable outlet. Although not required, roof gutters and down spouts may be considered to control roof I drainage, discharging a minimum of ten feet from the proposed structures, or into a subsurface drainage system. Consideration should be given to eliminating open bottom planters directly adjacent to proposed structures for a minimum distance of ten feet. As an alternative, closed-bottom type planters could be I utilized, with a properly designed drain outlet placed in the bottom of the planter. 9.3 Site Runoff Considerations-Stormwater Disposal Systems It is EEl understanding that current plans call for runoff generated from the development to be disposed of in engineered subsurface facilities onsite. We understand that design for such devices including bioretention facilities are not based on direct infiltration into the underlying earth materials and design will include impermeable liners or equivalent. 9.3.1 Percolation Testing During our subsurface exploration at the site, EEl conducted percolation testing in our exploratory boring B-i (P-i), P-2 and P-3, which were drilled near or within the some of the areas proposed for stormwater facilities on the site. Our testing was performed at an approximate depth of 5 to 17 feet below the existing ground surface. A minimum 2-inch layer of ¼-inch diameter crushed gravel was placed at the bottom of the excavation prior to testing. The approximate locations of our boring/percolation tests are provided on Figure 3. Percolation testing was onducted by one of EEl's field personnel under the guidance of a California licensed engineering geologist and civil engineer with BET. Percolation test locations were pre-soaked by pouring at least 12-inches of water into the excavation. Testing was started after the holes were allowed to pre-soak for approximately 24 hours. During testing, a minimum of 12-inches of water was placed in the excavation and the rate of the water drop was recorded at approximately 30 minute intervals. This procedure was repeated for the test hole until rates varied generally less than 10 percent for the test hole. Results of percolation testing are presented in the following table, Table 3. TABLE 3 Percolation Test Results Test Boring Depth of Test (feet below existing grade) Stabilized Percolation Rate (mm/in and in/hr) P1 B-i 17 250 and 0.2 P2 P2 5 30 and 2.0 P3 P3 5 33 and 1.8 It is our understanding that a Stormwater Management Plan (SWMP) for the site will be required by the City of Carlsbad. The following items are considerations that should be incorporated into the SWMP: I 19 I I I I I I I I I I I I Geotechnical Evaluation - Proposed Multi-Family Residential Development October 24, 2011 Enemas Creek, Carlsbad, California EEl Project No. SEA-71249.4 I • During and following and grading at the site, the contractor should incorporate the appropriate Best Management Practice (BMP) devices to reduce the potential for erosion and sediment transport as low as practical. Such devices can include (but are not necessarily limited to) the I placement of sand bags, straw bales, geotextiles, fiber rolls and check dams in graded areas that may be subject to erosion and/or sediment transport. Measures to mitigate the potential for post-construction erosion at the site are presented in I Section 9.1 and 9.2 of this report. . As noted above, our subsurface exploration encountered materials comprising the Tertiary age I Santiago Formation. While no groundwater was encountered in any of our exploratory borings, our experience with the Tertiary aged sedimentary rock (and fills derived from it) indicates that it typically possesses relatively poor to moderate infiltration characteristics, due to dense and I indurated sands and silty and clayey layers that are contained within the materials that comprise the bedrock/formation. Our review of the United States Department of Agriculture's soil survey for San Diego County (USDA, 1973) indicates that the soil in the vicinity of the site is referred to as the Cieneba-Fallbrook Rocky Sandy Loams and Olivenhain Cobbly Loam. According to the USDA's Soil Survey (1973), the Cieneba-Fallbrook Rocky Sandy Loam exhibits a high permeability, which is on the order of 1.98- to 5.95-inches per hour. The Olivenhain Cobbly Loam exhibits a very low to moderately low permeability, which is on the order of 0.00 to 0.06 I inches per hour. Consequently, it appears that these materials may not adequately accommodate infiltration devices. It appears that the use of Low Impact Development (LID) site design BMPs can be utilized to reduce the potential for pollutants entering the storm drainage system. Such BMPs can include (but are not necessarily limited to) the utilization of pervious sidewalks, pavements and flatwork in areas where pedestrian or light duty traffic is planned, utilizing roof gutters and downspouts to direct roof runoff into landscaped areas as opposed to directing the runoff onto impermeable surfaces, direct runoff from sidewalks and roads toward landscaped areas where practical and utilize drought tolerant vegetation in landscaped areas if practical. All stormwater disposal systems, including pervious pavement areas should be checked and maintained on regular intervals. Stormwater devices including bioswales that are located closer than 10 feet from any foundations/footings should be lined with an impermeable membrane to reduce the potential for saturation of foundation soils (also refer to Section 7.3). 9.4 Additional Site Improvements Recommendations for additional grading, exterior concrete flatwork design and construction can be provided upon request. If in the future, additional property improvements were planned for the site, recommendations concerning the design and construction of improvements would be provided upon request. I Geotechnical Evaluation - Proposed Multi-Family Residential Development October 24, 2011 Encinas Creek, Carlsbad, California EEl Project No. SEA-71249.4 I 9.5 Trenching All temporary excavations for grading purposes and installation of underground utilities should be I constructed in accordance with OSHA guidelines and local safety codes. Temporary excavations over five feet in height should be evaluated by the project engineer, and could require shoring, sloping, or a combination thereof. Temporary excavations within the onsite materials should be stable at 1:1 I inclinations for cuts less than 10 feet in height. Footing trench excavations for structures and walls should be observed and approved by a representative of the project soils engineer prior to placing reinforcement. Footing trench spoil and excess soils generated from utility trench excavations should be compacted to a minimum relative compaction of 90 percent (based on ASTM D1557) if not removed from the site. All excavations should conform to OSHA and local safety codes. 9.6 Utility Backfill Fill around the pipe should be placed in accordance with details shown on the drawings, and should be placed in layers not to exceed 8-inches loose (unless otherwise approved by the geotechnical engineer) and compacted to at least 90 percent of the maximum dry density as determined in accordance with ASTM D1557 (Modified Proctor). The geotechnical engineer should approve all backfill material. Select material should be used when called for on the drawings, or when recommended by the geotechnical engineer. Care should be taken during backfill and compaction operations to maintain alignment and prevent damage to the joints. The backfill should be kept free from stones, chunks of highly plastic clay, or other objectionable material. Backfill soils should be non-expansive, non-corrosive, and compatible with native earth materials. Backfill materials and testing should be in accordance with the CBC, 2010, the City of Carlsbad and/or County of San Diego specifications. Pipe backfill areas should be graded and maintained in such a condition that erosion or saturation will not damage the pipe bed or backfill. Flooding trench backfill is not recommended. Heavy equipment should not be operated over any pipe until it has been properly backfilled with a minimum two to three feet of cover. The utility trench should be systematically backfilled to allow maximum time for natural settlement. Backfill should not occur over porous, wet, or spongy subgrade surfaces. Should these conditions exist, the areas should be removed, replaced and recompacted. 10.0 PLAN REVIEW Once detafiled site and grading plans are available, they should be submitted to this office for review and comment, to reduce the potential for discrepancies between plans and recommendations presented herein. If conditions were found to differ substantially from those stated, appropriate recommendations would be provided. Additional field studies may be warranted. 21 I I Geotechnical Evaluation - Proposed Multi-Family Residential Development Enemas Creek, Carlsbad, California October 24, 2011 EEl Project No. SE.A-71249.4 11.0 LIMITATIONS This geotechnical evaluation has been conducted in accordance with generally accepted geotechnical engineering principles and practices. Findings provided herein have been derived in accordance with current standards of practice, and no warranty is expressed or implied. Standards of practice are subject to change with time. This report has been prepared for the sole use of Holly Springs, Ltd. (Client), within a reasonable time from its authorization. Site conditions, land use (both onsite and offsite), or other factors may change as a result of manmade influences, and additional work may be required with the passage of time. This evaluation should not be relied upon by other parties without the express written consent of EEl and the Client; therefore, any use or reliance upon this geotechnical evaluation by a party other than the Client should be solely at the risk of such third party and without legal recourse against EEl, its employees, officers, or directors, regardless of whether the action in which recovery of damages is brought or based upon contract, tort, statue, or otherwise. The Client has the responsibility to see that all parties to the project, including the designer, contractor, subcontractor, and building official, etc. are aware of this report in its complete form. This report contains information that may be used in the preparation of contract specifications; however, the report is not designed as a specification document, and may not contain sufficient information for use without additional assessment. EEl assumes no responsibility or liability for work or testing performed by others. In addition, this report may be subject to review by the controlling authorities. 22 Geotechnical Evaluation - Proposed Multi-Family Residential Development October 24, 2011 Encinas Creek, Carlsbad, California EEl Project No. SEA-71249.4 12.0 REFERENCES American Society of Civil Engineers (ASCE), 2005, Minimum Design Loads for Buildings and Other Structures, ASCE Document ASCE/SEI 7-05. American Society for Testing and Materials (ASTM), 2008, Annual Book of ASTM Standards, Volume 04.08, Construction: Soil and Rock (I), Standards D 420 - D 5876. Blake, T., 2000a, "EQFAULT, version 3.0", a Computer Program for Probabilistic Estimation of Peak Acceleration from 3-13 Fault Sources," Thomas F. Blake Computer Services and Software, Newbury Park, California. California Building Code (CBC), 2010, California Code of Regulations, Title 24, Part 2, Volume 2 of 2, California Building Standards Commission, Based on 2009 International Building Code; 2010 California Historical Building Code, Title 24, Part 8; and 2010 California Existing Building Code, Title 24, Part 10, effective January 1. California Division of Mines and Geology (CDMG), 1996, S. Tan and M.P. Kennedy, Geologic Maps of the Northwestern Part of San Diego County, California, Plate 1, Geologic Maps of Oceanside, San Luis Rey, and San Marcos Quadrangles, DMG Open-File Report 96-02. California Division of Mines and Geology (CDMG), 2000, California Department of Conservation, Digital Images of Official Maps of Alquist-Priolo Earthquake Fault Zones of California, Southern Region, DMG CD 2000-003. California Geological Survey (CGS), 2002, Online Interactive Maps, compiled by S. Tan and M.P. Kennedy, Geologic Map of the Oceanside 30 x 60 Minute Quadrangle, California, Regional Geologic Map No. 2, 1: 100,000 scale, California Geological Survey (CGS), 2002, California Geomorphic Provinces Note 36, Electronic Copy, Revised December 2002. California Geological Survey (CGS), 2008, Guidelines for Evaluating and Mitigating Seismic Hazards in California, Special Publication 117, revised and re-adopted September 11, 2008. Coduto, D. P., 2001, Foundation Design Principles and Practices, Second Edition. DeLORME, 1999, 3-13 TopoQuads, California South, Region 7. Google Eath®, 2011, Version 6.0. Geosoils, Inc., 2000, Limited Geotechnical Evaluation Holly Springs Project, Carlsbad, San Diego County, California, W.O. 2929-A-SC, dated October 11. Hart, E.W., and Bryant, W.A. (Hart and Bryant), 1997, Fault-Rupture Hazard Zones in California: California Department of Conservation, Division of Mines and Geology, Special Publication 42. Jennings, C.W., 1994, Fault Activity Map of California and Adjacent Areas: California Division of Mines and Geology, Map Sheet No. 6, scale 1:750,000. 23 Li Li I I I I I I I Li I I I Geotechnical Evaluation - Proposed Multi-Family Residential Development October 24, 2011 Encinas Creek, Carlsbad, California EEl Project No. SEA-71249.4 Jennings, C.W. and Bryant, W.A., 2010, Fault Activity Map of California, California Geological Survey (CGS), California Geologic Data Map Series, Map No. 6. O'Day Consultants, 2010, S.D.P. (A) 01-10, Sheets 2, 3 and 4, scale 1" = 40' and 1" = 201, dated December 2, date of preparation: June 15, 2011. Sowers and Sowers, 1970, Unified Soil Classification System (After U. S. Waterways Experiment Station and ASTM 02487-667) in Introductory Soil Mechanics, New York. United States Geological Survey (USGS), 1997, USGS 7.5 Minute Series Topographic Map, San Luis Rey Quadrangle. United States Geological Survey (USGS), 2002, Earthquake Hazards Program, Interpolated Probalistic Ground Motion for the Conterminous 48 States, http://earthquake.usgs.gov/researchlhazmaps/designl. 24 FIGURES - - - - - - - - - - - - - - - - - - - I I I I I Geotechnical Evaluation - Proposed Multi-Family Residential Development Encinas Creek, Carlsbad, California October 24, 2011 EEl Project No. SEA-71249.4 I I I I I I I I I I I I I I FIGURES Map Source: © 20(7 Dr[ouoe Topo USA SE TO Wt Region SITE VICINITY MAP ENC[NAS CREEK Carlsbad, California Scale: 1" =4000' I EEl Project No. SEA-71249.4 FT 2400 FT 4000 FT 000 FT / treated October 2011 CREATED BY Note: All locations are approximate JAB EE I REVISION DATE: ( REVISION NO FIGURE 1 I I I I I I I I I I I I I I I I I I I I I I I L I I I For ., '• - -. • — 4 :- - • & V v A. a i,. •VIP Map Scure L 2U Iiiiamy WLe 523 2010 I I I I S:ale: 1'= 500' CFY 30C F— 500 FT 1000 FT Note: Al locations are approximate SITE LOCATION MAP ENCINAS CREEK Carlsbad, Cafomia EEl Project NoS-7 1249.4 Created Oc-ober 2011 cgEm)By. I lAB I 111 4EEI EV1CNDATE. FIGURE 2 *t**** 1 FI\EtON NO. I -I 4 Th M up Source Odav Consultants, ants. Tentative Map/Sue 'Ian. SIted 2 ol4. S1001-10, Dee 2. 21)11) LEGEND I Approximate Location of Boring P—Pete Test Scale: 1" = 100 lIFT 50 111 100 FT 2()) F I NOW: All locations aiC 2Il)TOX IlItiltC BORING LOCATION MAP ENCINAS CREEK Carlsbad, California ELI Pi(Jjerl No. SEA-71249.4 Created October2011 tIt F clii) BY JAR I1E,uEIn,rnun Id{\lSloNi)Al1 FIGURE 3 irL\ ISIlIN NI) - - - - - - - - - - - - - - - - - - APPENDIX A - - - - - - - - - - - - - - Geotecbnical Evaluation - Proposed Multi-Family Residential Development October 24, 2011 Encinas Creek, Carlsbad, California EEl Project No. SEA-71249.4 APPENDIX A SOIL CLASSIFICATION CHART AND BORING LOGS SOIL CLASSIFICATION CHART SYMBOLS TYPICAL IIRA GRAPH LETIER DESCRIPTIONS GLEAN • WELL-GRADED GRAVELS, GRAVEL - GRAVEL GRAVELS (3W SAND MIXTURES, LITTLE OR NO AND 40 om FINES GRAVELLY oc -GRADED OJIL SOILS (LITTLE OR NO FINES) tQO < GP POORLY GRAVELS, GRAVEL - SAND MIXTURES, LITTLE OOO C OR NO FINES COARSE GRAINED MORE THAN 50% GRAVELS WITH ° 3ic P°( ni SILTY GRAVELS, GRAVEL - SAND - SOILS FINES °O9j WI SILT MIXTURES OF COARSE FRACTION A7IQ5 RETAINED ON NO. 4 SIEVE (APPRECIABLE CLAYEY GRAVELS, GRAVEL - SAND - AMOUNT OF FINES) '.' CLAY MIXTURES SAND CL SAND s ::::::::::::::::: WELL-GRADED SANDS, GRAVELLY MORE THAN 50% SANDS, LITTLE OR NO FINES OF MATERIAL IS AND LARGER THAN NO 200 SIEVE SANDY SOILS POORLY GRADED SANDS, SIZE (LITTLE OR NO FINES) SP GRAVELLY SAND LITTLE OR NO FINES SANDS WITH I SILTY SANDS SAND - SILT MORE THAN 50% OFCOARSE FINES :./.' Z.:3; . SM MIXTURES FRACTION .. PASSING ON NO. 4:SIEVE (APPRECIABLE , CLAYEY SANDS, SAND-CLAY AMOUNT OF FINES) . •- '" MIXTURES INORGANIC SILTS AND VERY FINE SANDS, ROCK FLOUR, SILTY OR .' CLAYEY FINE SANDS OR CLAYEY SILTS WITH SLIGHT PLASTICITY INORGANIC CLAYS OF LOW TO SILTS FINE AND LIQUID LIMIT ''-' !.L. MEDIUM PLASTICITY. GRAVELLY GRAINED LESS THAN 50 CLAYS CLAYS, SANDY CLAYS, SILTY SOILS CLAYS, LEAN CLAYS rt JL. ORGANIC SILTS AND ORGANIC _-_---_--- SILTY CLAYS OF LOW PLASTICITY MORE THAN 50% OF MATERIAL IS MH INORGANIC SILTS, MICACEOUS OR DIATOMACEOUS FINE SAND OR SMALLERTHAN SILTY SOILS NO. 200 SIEVE SIZE SILTS AND LIQUID LIMIT ,- INORGANIC CLAYS OFHIGH CLAYS GREATER THAN 5O PLASTICITY rn ORGANIC CLAYS OF MEDIUM TO HIGH PLASTICITY, ORGANIC SILTS CLAYSTONE X.x x x CL CLAYSTONE, Pioée Fernando Formation/late Mlocene Puente - X x x x . , Formation • x x x x x x NOTE DUAL SYMBOLS ARE USED TO INDICATE BORDERUNE SOIL CLASSIFICATIONS I I I Number: BOREHOLE LOG 114JEEI BL/P! Client Sheet: Seaboume/ Holly Springs, Ltd. I oil Location: Efl(II13S Creek- Date Started: Date Finished: 9/29/201 1 t 9/29/2011 Carlsbad, CA EEl Rep Project Number Drill RlgfSampling Method Borehole Diameter EH SEA-712494 6" Hollow Stem Auger 6" SAMPLE LOG I BOREHOLE LOG Bulk Sample Blows Dry Unit Moisture Depth1USCS Graphic Geo1ogic Description jype Per 6" Wt.(pcf) (%) Ft Symbol Log (ScilTpe, Color, Cmin Minor Soil ColnponcnUIói5twe, DensiT,Odr Etc) - TOPSOIL - SM @0-2 SILTY FINE TO MEDIUM SAND brown some organics damp loose 2 : - M 23 -24 8 SANTIAGO FORMATION 130 @2 SILTY SAND dark brown, moist dense slight cementation 31 4: 55M M 21 125 10 @5 SILTY-SAND dark brown with trace clay, moist dense 34 6 : M. 9 120 11 8 @75' SILTY. FINE TO COARSE SAND WITH CLAY, red brown, rn0i51 medium - 19 : SM!SC dense, mottled : SP 9 10 10 --- @10 SILTY FINE TO MEDIUM SAND light brown and gray, moist medium dense - - 12 : mottled 12 : 13 - SM 14 - 15 - @145 SIL1YFINESANO dark brown and bghtbrown aridgray moist,rnedium SPIp dense a 16 if : 18 - - 19 - - Total boring depth =17' 20 - - Groundwater not encountered - MC=Modlfled California Sampler 21 - SPT=Standard Penetration Test 22 : - Hoe backThled 9/29/l1. 23 - - 24 - - 25 - 26 - - 27 - - 28 - - 29— - 30 - - 31 - - 32 - - 33 - - 34— - I I I I I I Number: BOREHOLE LOG B2 ft 'JEEI Client Sheet Seaboume / Holly Springs, Ltd. loft Location: Encinns Creek Date Started Date Finished: 9/29/2011 9/19/2011 Carlsbad CA EEl Rep: Project Number: Drill Rig/Sampling Method: Borehol e Diameter EH SEA-71249A 6 Hollow Stem Auger' 6" SAMPLE LOG BOREHOLE LOG Bulk Sample Blows Dry Unit Moisture Depth In USCS Graphic Geologic Description Type (P4 Feet Symbol Log (SoiiT)pr, Color Grain, ?.linor.SoiI Corponcnt Moiature, Densii; Odot,E1c.) - :- TOPSOIL 1 - SM - A 0-25 SILTY SAND fight brown damp loose 2: MC 7 116 11 SANTIAGO FORMATION - 18 - © 2.5 CLAYEY FINE TO MEDIUM SAND, gray and dark yellow, brown, mottled, : / _________________________________________ M 14 121 9 26 47 8 : SM @55 SILTY SAND gray to yellow brown mottled moist dense : 118 12 --@ 7'CLAYEY-SAND, dark gray, molst, dense, slIghily mottled 23 34 SC M io so 117 7 @10' SILTY FINE TO MEDIUM GRAINED SAND fight brown-gray moist very - 43 11' --':.•dense 12 13- 14 - - SPiN 10 14 9 15 - SM @15' SILTY FINE TO MEDIUM GRAINED SAND, bghtbrown.gray coarse sand V 16 - .: and trace of day, moist,dense 17- 12 SPIV 13 1 19 - @20' SILTY FINE TO MEDIUM GRAINED SAND light brown-gray coarse sand 25 - :: and trace of day, moist, dense 21 - - 22— - — Total boring depth = 20' 23 - - - Groundwater not encountered - MCModilIed California Sampler 24 - - SPT=Standard Penetration Test 25 : - Hole bac$dilled 9129/11. 26 - - 27 - - 28 - 29— - 30 - - 31 - - - -, - Li I I Fl I I I Number: BOREHOLE LOG U EEl Client: Sheet: Seabourne I Holly Springs, Ltd. 1 of I Location: Encinas Creek Data Started: Date Finished. 9/2912011 9/29/201! Carlsbad, CA EEl Rep: Project Number: Drill Rig/Sampling Method: Borehole Dlameter. Eli SEA-71249.4 6' Hollow Stem AUaer 6' SAMPLE LOG I BOREHOLE LOG Bulk Sample Blows Dry Unit Moisture DPth In USCS Graphic Geologic Desosiption Type Per () (°'°) FeetSymbol Log - - (SoilTe, Color; (IÉain,.Mmor Soil Componctss, Moisture, Densit Odor. Etc.) TOPSOIL : SM - @0-2.5' SILTY-SAND, brown, damp, loose, trace organics M 44 124 9 2SANTIAGO FORMATIO : . - 02.6 SILTY FINE TO MEDIUM SAND, gray-brown, recasional gravel, slightly SO for W : moist, very dense —SM MCU 19 , 01r6 so-'9r6" 120 9 5— - -: @5 SILTY FINE TO MEDIUM SAND, gray-brown, occasional gravel, slightly moist, verydense - MC 50 for 6' 88 18 (7.S' SILTY-FINE SAND AND SAN DY-S{LflTH SOME GRAVEL AND 8 - SMIML - . : - COBBLES, yellow-red brown and gray, slightly moist very dense SPTR If M 20 50 ii @9 SILTY FINE TO MEDIUM SAND yellow-redbrown and gray, sightly moist, = Ile - very dense 12— - - Total boring depth = 10 13 - - - Groundwater not encountered - MC=Modied California Sampler 14 : - SPT=Standa,d Penetration Test - .- Hole bacidiRed 9129111. 16 - - - 17— - - 18 - - - 20 - - - 21 - - - 22: I 23 24 - -. 25 - - - 26- - - 27 - - 28 - - - - - 31 - - 32 - 33 34— - I I I I I I I I Number: BOREHOLE LOG EEI Client: Sheet: doom Seaboume/ Holly Springs, Ltd. of I Location: Encinas Creek Date Started: Date Finished: 9/29/2011 9129/2011 Carlsbad, CA EEl Rep: Project Number: Drill Rig/Sampling Method: Borehole Diameter: Eli SEA-71249.4 b" Hollow Stem Auger 6' SANiPLE LOG BOREHOLE LOG Bulk Sample Blows Dry Unit Moisture USCS Graphic Geologic Description e Per 6 Typ In Wt (pet) (%) Feet Symbol Log (SollTpe Color Chain, Manor Sod Component, \Ioisiuxe Densat) Odor Etc TOPSOIL 1 : SM - 0-2.5' SILTY-SAND, gray,-brown, d5fEP toose some organics 2 MC 14 109 11 - SANTIAGO FORMATION - . 20 : SMIML @ 2. SILTY FINE SAND, gray and yeow-btown, moist medium dense M 10 106 15 - - @5SILTYRNEOMEDUJMSANDgrayandbrou,mowedlayersolcoarse — : 21 6 : sand moist medium dense 7 - M 6 19 ii 9 8 - @7.5' SILTY FINE Tb COARSE SAND. gray.brown and orangebrown, moist, - medium dense, mottled SPi1 15 - :-. © 10' SILTY FINE TO COARSE SAND, gray-brownandorange-brown, moist, 13 11 - medium dense, mottled 12: 13— sP'rlc 14 © 15 SILTY FINE TO COARSE SAND gray brown and orange-brown moist _j - ':• medium dense mottled 17 - - - Total boring depth = 15' 18 - - Groundwater not encountered - MCModifled California Sampler 19 = - - SPTStandard Penetration Test 20 : Kale backllited 9129111. 21 - - - - 24 - - 25 - - 26— - 27 - - 28 - - - 29— - 30 - - 31 - - 32 - - - - I I I BOREHOLE LOG Number: B5 EEI Client: Sheet: "Itt ioa Seabourne/ Holly Springs, Ltd. I of I Location: Enemas Creek Date Started: Date Finished: 9/29/2011 9/29120.11 Carlsbad, CA EEl Rep: Project Number:. Drill RiglSampling Method: Borehole Diameter: EH SEA7 1249.4 6" HollàwSleni Auger Of SAMPLE LOG I BOREHOLE LOG Bulk U Sample Blows Dry Unit Moisture Depth IJSCS Graphic Geologic Desciiption Type Per 6 %M. (PCI) (%) Ft Symbol Log (SoiITpe, Color, Grain, hrtnor Soil Component, Moisture, Denait3 Odor, Etc) - . TOPSOIL : SC @o-?.scAYEy-SAND,red-txo,wnhcoarsesandmoist,Ioose MC 15 30 118 6 - SANTIAGO FORMATION r 38 - @25 SILTY FINE TO MEDIUM SAND red brown and gray, moist, dense slightly 10 118 8Is cemented M - @5 SIL1YFINETOMEDIUMSAND fight brown and gray, moist dense with thin - clayey silt layers - - M 10 89 2 8 @7 5 SAND light brown damp to moist, medium dense - 17 9 SP sPTfc 15 8 10 -@ 1 V SILTY FIN E TO COARSE SAND WITH TRACE CLAY, fight gray-brown, 17 11 : moist dense 12 —SM 13 - - 7 - :: @ 13 SILTY FINE TO COARSE SAND W1TI-I TRACE CLAY, light gray-brown, SPI1' 10 14 - :-' moist,.. medium dense JL 14 16 - 17 - - - Total boring depth 15 Groundwater not encountered - MC--Modified California Sampler 19 : - SPlaStaitdard Penetration Test 20 : - Hole backfilted and patched with asphalt concrete 9129/11 21 - - - - - 24 - - 25 - - 26 - - 27 - 28 - - - 29 - - - 30 - - - 31— - - 32- - - - - I I I I I I Number: BOREHOLE LOG EEl B6 Client: Sheet: Seabourne I Holly Springs, Ltd. 1 of I Location: Enemas Creek Date Started: Date Finished: 9/29/2011 9/29/2011 Carlsbad. CA EEl Rep: Project Number: Drill RtgISampling Method: Bo rehole Diameter: EH SEA-71249.4 6' Hollow Stem Auger 6' SA\1PLL LOG BOREHOLE LOG U Bulk Sample Blows Dr Unit Moisture in USCS Graphic Geologic Description Type Per 6" Wt.(pcf) (%) Feet Symbol Log (SoTpt,QoIoi Grain, Minor Soil Componéni Moisiurr, I)cnsil> Odor, Etc.) - - T0PS01USL0PEWAS14 1 : @0-3 CLAYEY SAND brown to ye1low.br'In moist, loose to medium dense SO MC 6 117 13 - - - r @3 FINE TO MEDIUM SAND WITH SILT light brown, trace organics moist to net, 4 - SWSM - •:,: Ioosetomediumdense MC 6 104 17 5 --- - - - - --- -- - -------------------------- SANTIAGO FORMATION - - V 6 - @5 SILTY FINE TO MEDIUM DENSE SAND light gray brown moist to et. L - ..- ... medium dense 7— M 6 • SM - : @ 75 SILTY FINE TO MEDIUM DENSE SAND, light gray-biOwn, mOist medium 20 dense MC 9 12 103 12 10: -- ©1OSANOY-OSILTY-FINE 28 11 - thin layers of silly-clay 12 - - - ML 13 - - 14 - - PT s 17 15 -- -brown, fine to medium sand, moist, 15' SLIGHTLY SILTY, right yellmv and gray = V 19 16 : - dense, trace of clay 17 : SP-SM - 18 - - V\J it 20 19 ML @19 SILTYFINESANDANDSAJ'IDYSILT bghtgray moist medlumdense thin - - :- 21 - - 22 - Total boring depth = 20' 23 - - Groundwater not encountered - MC=Modifled California Sampler 24 - - SPTStandard Penetration Test 25 : - Kolebacklll!ed 9/29111. 26 - - 27— - 28 - - 29— - 30 - - 31 - - 32 - - - - I I I I I I Number: • BOREHOLE LOG P2 EEl Client: Sheet SeabOtxme/ Holly Springs, Ltd. of 1 Location: Encinas Creek Date Started: Date Finished 9129/2011 9/29/2011 Carlsbad, CA EEl Rep: Project Number: Drill Rig/Sampling Method: Borehole Diameter: EH SEA-71249.4 6" Hollow Stem Auger 6" SAMPLE LOG I BOREHOLE LOG Bulk SanpIe Bs. ON Unit Moisture Depth USGS Graphic Geologic Description Type Per 6' WL (pol) (S'o) Feet Symbol Log (SoilT)pe, CotoçGrain Minor Soil Component, Moisturc D6Wtn Odor, EC.) - TOPSOIL : ML - @ 0-2' SANDY-SILT WITH CLAY, brown, damp, soft MC 8 117 4 2 - SANTIAGO FORMATION 23 3 - SC-CL - ( 2' SANDY-CLAY, gray, dark gray with red-brown, moist, stiff to very stiff M 7 120 II - 25 Sc @4' CLAYEY FINE TO COARSE SAND, red brown, moist, medium dense - - - Total boring depth =5 8 - - GroundWater.riot encountered - MC=Modifled California Sampler 9 - - SPT=Standard Penetration Test 10 : - Holebac1dled WWI 1. ii - - 12 - - 13 - - 14 - 16 - - 17 - - 18 - - 19 - - 20 - 21 - 22 - 23 - 24— - 25 - 26 - - 27 - 28- 29 - - 30 - 31 - - 32 - 33 - - 34— - I I I I 1 [I Number: BOREHOLE LOG EEl Client: Sheet: " V Seabourne /Holly Springs Ltd. loft Location: Encinas Creek Date Started: .Date FInished: 9/2912011 9/29/2011 Carlsbad, CA EEl Rep: Project Number Drill Rig/Sampling Method: Borehole Diameter: EH SEA.? 1249.4 6" Hollow Stem Auger 6" SA!PLE LOG I BOREHOLE LOG Bulk U Sample Blows Dry Unit Moisture In USCS Graphic Geologic Description Type Per 6" Wt (pd) (%) Ft Symbol Log (SodT)pe Color 0r3rn, Minor Soil Component Moisture, Density, Odor Etc.) - TOPSOIL : SM @0-2'SILVf-SANDbrownmóltit,1aosé,organics MC 12 122 2 -- SANTIAGO FORMATION - 27 3 - 2 SILTY FINE TO COARSE SAND orange brown moist medium dense M 103 - 6 SM 25 - © 35 SILTY FINE SAND yellow brown toy moist very dense 42 6- 7—. - Total boring depth =5 8 - Groundwater not encountered - MC=Modified California Sampler 9 - SPT=Standard Penetration Test 10 : Hole bacidilled9/29/11. 11 - 12 - 13 - 14 - 15 - 16 - 17 - 18 - 19 - 20 - 21 - 22 - 23- 24- 25 26— - 27 - 28 - 29— - 30 - - 31- 32 - 33 - - 34— - I I I APPENDIX B p - - - - - - - - - - - I I 1 Geotechnical Evaluation - Proposed Multi-Family Residential Development October 24, 2011 Encinas Creek, Carlsbad, California EEl Project No. SEA-71249.4 I I I I I I I APPENDIX B LABORATORY TEST DATA I I I I I I I I I — PARTICLE-SIZE ANALYSIS OF SOILS ASTM METHOD D 422 (SIEVE ANALYSIS) Sample: P-2@5ft. DIO(mm) N/A Total Weight (g) 160.7 .. D30 (mm) N/A Dry Weigh g) 144.4 D60 (mm) 0.40 Wet Sieve Weight 95.6 Cu N/A Initial Moist&ie (%) 1 11.3 Cc N/A According to ASTM D 2487 Unified Sot! Classification System (USCS) and ASTM D 422 (Standard Test Method for Particle -Size test method results soil sample P-2 at 0 to 5 feet is classified as Silt), Sand (SM) >1< Sand >< .... Stand,rdSitc Size; *O3 IlO fQ No to . - tvu- go so so 40 30 20 0 *uIIIIIIIIIIIIllhIIIII1I1IIII$';iiIIIhaiiiiiii PUIIIfflNUhiilIUR1IIllhIPI1IUIlIIuIIllIfl '•uuIuIlluIuuiIIIaaIIlliIuIuuhIIIIuIn iUIIIIIllUIIIillhIII!flhILRIIIflhIIIIUHIll UIlIiilI•IIIllllllhIW!iIIflhi11flIlliiIIliIIiJi .1111111 IUiiHR!UIl1iRUiHhIII•IIIIiiIl uiiiii i iuiiinniiuiuiiiiiiiuuiii lIIIIilI•UIIWhIIIUIIflhIIlRI1lIIIlII•UIIIflhI IIlIIllI•IIIHhIIIIIII1IllILIkHIllIIIIlIIll: IIIIIIll1IIIHIIRIIIIIllI1IithIllUIIIIJII: Ooi Oj . . iO 100 Grain Size (mm) Cumulative Sieve Size (in) Sieve. Size (mm) Weight of dry Percent Retained (%) Percent Passing (%) soil (gm) 3" 762 00 1000 1.5" 38.1 011 inn n 3140 . 19.05 . . 0.0 100.0 - 3/8" 9.53 0.0 100.0 #4 475 09 06 994 48 236 71 49 951 #16 1.18 25.2 17.5 82.5 #30 0.6 . 46.1 31.9 68.1 #50 0.3 68.1, 47.2 52.8 tLgej, Ira EEI Solutions Cc 2195 Faraday'Avemie, Suite K, Carlsbad CA 92008 66.2 I 33.8 lient: Holly Springs. Ltd. )b Name: Encinas Creek . . )b Number: SEA-71249 we: 10/5/ti oring Number: P2 - ocation:0- 5 ft. . escription: SM ested by: BD PARTICLE-SIZE ANALYSIS OF SOILS ASTM METHOD D 422 (SIEVE ANALYSIS) Sample: B-267.5 ft Dio (mm) NA Total Weight (g) 192.1 D30 (mm). NA Dry Weight (g) 171.9 D60 (mm) 0.40 Wet Sieve Weight ... 112.2. Cu NA Initial Moisture (%) 1 11.8 Cc NA According to ASTM D 2487 Unified Soil Classification System (USCS) and ASTM D 422 (Standard Test Method for Particle Size A test method results, soil :sample B-2 at 7.5 feet is classified as Silty sand (SM). ____><...............Sth . >1 . Sfld > f ( Grav tlay > Stand,,,1 Siv, Size ixo Ma ite #a - - 90 00 oe .0 60 C- ox 50 40 C- - 30 20 10 0 iiiiiiiiiuii 00 iiuuiiioiiiiiUhuiiiiihii :IIIIIIlllIIII II1IIIIflflI!iIIIIJIIIllRIIIlIIII iiilliii•IIIli llhIUIIPAhIUILIIIIIIIIIlllI RIIIIIIIIIIIII IlIIRIOhIIUIIIIIHIIRIIIIIllL aiioiiaiiiiiioisiuiiiiii UflhIIIUIIIIIffIJIiI1lllhIIEIItIII1IRIIIIIIlI I1IIIIIII1IIIiII1IIllflhIIIIIIIHIUIIIIIflI UIIIIIIIIIIIUIIIIIIIIIUIIIIIUUIIIIflIIIIIIIII IIIiill•iiiilfluhlilliOiilllllllilllRlllliill lllllllllllfllluhllll1011llUlfflhlllliillll 0.001 .0.01 01 j 10 too Grain Size (mm) Sieve Size (in) Sieve Size (mm) Cumulative Weight of dry soil Own) Percent Retained (%) Percent Passing (%) 3" 76.2 0.0 100.0 . 1.5" 38.1 0.0 100.0 3/4" . 19.05 0.0 100.0 3/8" 9.53 - :o.o 100.0 #100 015 995 579 421 4200 1 0.075 1122 653 347 E E I Geotethnical &.Envfronrnmtal Solutions 2195 Faraday Avenue, Suite K, Carlsbad CA 92008 Client: Holly Springs, Ltd. Project Name: Encinas Creek Job Number SEA 712494 Date: I015I1 I Boring Number: B2 . -. Location: 75feet . . Soil Description: SM Testedbv: BD PARTICLE-SIZE ANALYSIS OF SOILS ASTM METHOD D 422 (SIEVE ANALYSIS) Sample: B1t10 ft D10(mm) NA Total Weight (g) 165.6 D30 (mm) 008 Dry Weight 151.0 D60 (mm) 0.31 Wet Sieve Weight (g) 107.6 Cu NA Initial Moisture (%) 9.7 Cc NA According to ASTM D 2487 Unified Soil Classification System (USCS) and ASTM D 422 (Standard Test Method for Particle-Size test method results, soil sample B! at 10 feet is classified as Silty sand (SM). >1< Siew 03M oleo 00 M 18 04 90 80 ee 70 60 a. tk 50 40 4.. a. 30 20 to 100 - Ii1uhI1RIuhIllhiIiIinuhIuuiikRUiih IIIIIllIUIIII1 IIUIIiIIIIIP'4111111111U1111fl iiiiniiuiiiii iiiiiiiiuuiiniiisiiii IUhIIllRIuI1Illh1IIPillhIIIIIIIIIIflUIIII1III IIIIllllIIIIIliVi1II1llh1UIIIIIIIIIRIIIIllhI RIIUIIHIIIIIffIlI2IIII1ItIuIIII1IIIlIIIIIH mIIIIIIIIaI1IIIllJiiII1luIIII1IIIInhIIIRuII1IH lIIIlIIIIII1HIuIIllI1IIIIIIIIIIllhIIIIIIIH SIIIIIllIUIflHIIIIIIflflhIIIIIIflhllIIIIIIII UllllilllRlllllllllUiilllfluiEuliIilll•IIIiiiH A 0.001 0.01 011 1 10 too Grain Size (mm) Sieve Size (in) Sieve Size (mm) Cumulative Weight of dry soil Percent Retained (%) _(gm) Percent Passing (%) 3" 762 00 1000 151 381 00 1000 3/4" 19.05 0.0 100.0 3/8" 9.53 0.0 100.0 #4 4.75 1.6 1.1 98.9 #8 2.36 9.8 6.5 93.5 #16 1.18 28.2 18.7 81.3 #30 06 452 299 701 #50 0.3 61.8 40.9 59.1 #100 0.15 85.6 56.7 43.3 #200 0.075 107.6 71.3 28.7 Client: Holly Springs, Ltd. EEI Gentechnical & Environmental Solutions 2195 Faraday Avenue, Suite K, Carlsbad CA 92008 Project Name: Encinas Creek Job Number: SEA-71249.4 Date 1015111 Boring Number: B Location: 10 feet Soil Description: SM Tested by: BD 0001 0.01 04 I 10 100 Grain Size (mm) Sieve Size (in) Sieve Size 1.5" Cumulative Weight of dry Percent Retained (%) Percent Passing %) soil (gm) 0.0 100.0 0.0 100.0 0.0 1 100.0 0.0 1 100.0 0.4 1 0.2 1 99.R PARTICLE—SIZE ANALYSIS OF SOILS ASTM METHOD D 422 (SIEVE ANALYSIS) Sample: B-2a7.5 ft Dio (mm) NA Total Weight (g) - 192.1 D30 (mm) NA Dry Weight (g) 171.9 D60 (mm) 0.40 Wet Sieve Weight (g) 112.2 Cu NA Initial Moisture (%) 11.8 Cc NA According to ASTM D 2487 Unified Soil Classification System (USCS) and ASTM D 422 (Standard Test Method for Particle-Size test method results, soil sample B-2 at 7.5 feet is classified as Silty sand (SM). _ si < Sudat Sieve Size: no, Wa 06 ve #a - - 90 so z 70 60 a. so 40 a. 30 20 10 0 100 - IIIHhIIUIIIIIllllhIIIIIIIIIIPgg111flh1fl1hi1 III1IIll•IIIIIllllhIIIIIllIIIILIIIIIUIIIIIIfl UIIIlIIIIUIIIUllhIIIIIJdIIUIFIIIIIUI11IflhI NII1IIIUIIIHfluhIIIiHIIIIIIIIIIIIIRIIIIIIII 1IIIIIII1IIIIAUUtIIOHIUIIIIIIIHIIIIIIII EMIR iiuiintiiiiiniiaiiiuioi•iniiiii NIiiiIiiiIuiiiIluiiiiiHhIiIiuIIiiiuIuliiii II1IIO•IIflh111I1IIIIIIIIIIIIIIHOIIUIIIIIIII IIIlIIflIIIIFIIIIIIIIIllh1IIIIIIIllUIIIIIII RIIIIIIllIIIII11I1IIIIIIIIllI011hJUIIflhIII I I I I I I I I I I I I I I I I I I qj aIsISolutions 2195 Faraday Avenue, Suite K, Carlsbad CA 92008 Client: Holly Springs, Ltd. Pooject Name: Encinas Creek Job Number: SEA-1 1249.4 Date: 10/5/11 Boring Number: B2 Location: 7.5 feet Soil Description: SM Tested by BD O001 0,01 01 I 10 - too PARTICLE-SIZE ANALYSIS OF SOILS ASTM METHOD D 422 (SIEVE ANALYSIS) Sample: _4-3 2.5 ft Dlo (mm) NA, Total Weight (g) 125.4 D30(11un) NA Dry Weight (g) 114.7 . D60 (nun) 0i5 Wet Sieve Weight(g) 65.9 Cu NA Initial Moisture (%) 9.3 Cc NA According to ASTM D 2487 Unified Soil Classification System (USCS) and ASTM D 422 (Standard Test Method for Particle-Size test method results, soil sample 133 at 2.5 feet is classified as Silty sand (SM). ,fiut 4< Standard SM Si.,. 00 90 so u 70 60 $0 .40 A. 30 20 10 IIIIIIIIN.I1IIllh11IuIPu9ituuIIIrniiiihi IIIIIIIIIIIIIl1IIliIllhIIRIIIIlIIIIUIIIIIIII llhl!'Alllllhllllllfflhllllululll, :IIIIIHIIIIII suuiiuiuii iiiiiioiiiiuiiinii•inuiu RIIIIIIIIUIIIIFII!4II1IIllhIIIIIIIlllhIUI1IIII IIIIIIIIIIiIIiIIIIIIIlflhIUIIuIIIIIIlIItI UUIIIlIllIIIIIl1IIIIII1llhIIIIIIIII1IRIIIIIII1 IIIIIIIIIII1HIIIII1IOIIIIIIIIIIIIISIIflhIIl llllllllllllHllullllllllullllliulllllmilli ,RIII1Ill1UIIIIH1UIlIINIIIIIIIUIllIIiIIIflI rim EEI Geotethalcal & Enolionmentat Solutions Client: Holly Springs, Ltd. Project Name: Enemas Creek Job Number: SEA-71249.4 Date: 10/5/11 2.5 feet annual. hiLTS 2195 Faraday Avenue, Suite K, Carlsbad CA 92008 BD I I I I I I I I I I I I I I I I I I I Grain Size (mm) Sieve Size (in) Sieve Size (mm) Cumulative Weight of dry soil (gm) Percent Retained Percent Passing 3" ' 762 00 1000 1.5" 38.1 " 0.0 100.0 3/4" .19.05 0.0 100.0 3/8" 9.53 0.0 100.0 #4 . 4.75 0.7 0.6 99.4 #8 236 14 12 988 #16 118 42 37 963 PARTICLE—SIZE ANALYSIS OF SOILS ASTM METHOD D 422 (SIEVE ANALYSIS) Sample B-3 7.5 ft Dio (mm) NA Total Weight (g) 109.1 D30 (mm) NA Dry Weight (g) 92.8 D60 (mm) NA Wet Sieve Weight (g) 31,9 T Cu NA Initial Moisture (%) 17.6 Cc L NA ording to ASTM D 2487 Unified Soil Classification System (IJSCS) and ASTM D 422 (Standard Test Method for Particle Size Anal test method results, soil sample B-3 at 7.5 feet is. classified as Sandy Clay (CL) )( Sand )I< Swdud SL,,i Sizt .o *o Sid IIlHIIIUIIIIHIIIIflUVIiIIlIIIIRIiIIhII IIIIIlIiIIIIIHIIIIIiNhIIIIIItIIllIRIIlIllhI IIIIIII1RIIIIHIIII011hII1IIIIIIIRIIIllhJJ iiiniouiiiwiiiiiiuioiiiuiiiuiiiiiiiiiiii RIIIIIllIRIIIlHIIIIIIIIIllhIUhIIOIIIIIflhI IIIIIlIIII1IIllflhIUIIIOh1IIUItIIIIIIIII1Ifl IIflhIllIIIIIllflhIIIIIIIIIIIIIIIIllflNIIIIIflI RI1IIIII•III1IllllUIIIIOIIl1II1II1fl1IIlIIII llllflhllullHllllllluhllllllllllllUlllflll I1IflIllBIIIIIllhIIIIIIIIIflhIIIIIIHIIIII1I1U 0,001 001 01 i 10 110 I Grain Size (mm) Sieve Size (in) Sieve Size (mm) Cumulative Weight of dry soil (gm) Percent Retained Percent Passing (% 3" 762 00 1000 38.1 0.0 100.0 3/4" 19.05 0.0 100.0 3/8" 9.53 0.0 100.0 #4 4.75 0.0 100.0 #8 2.36 0.7 0.8 99.2 I Aw 11n, EEl Geotedinlcai & Environmental Scutlons 2195 Faraday Avenue, Suite K, Carlsbad CA 92008 Client: buy Springs, Ltd. Project Name: Encinas Creek Job Number: SEA-i 1249.4 Date: 10/4/I1 Location:. 7.5 feet Soil Description: CL Tested by: BD too 90 - so ss 70 60 50 40 Cl 0. 30 20 10 I I I I. I I I I I I I I I I I I I I I PARTICLE—SIZE ANALYSIS OF SOILS ASTM METHOD D 422 (SIEVE ANALYSIS) Sample B-410ft. DIOmm): NA Total Weight (g) 169.4 D30 (mm) NA Dry Weight (g) 1472 D60 (mm) 0.30 Wet Sieve Weight (g) 91.0 Cu NA Initial, Moisture (%) 1 15.1 F Cc NA ccording to ASTM D 2487 Unified Soil Classification System (USCS) and ASTM D 422 (Standard Test Method for Particle Size test method results, soil sample 84 at 10 feet is classified as Silty Sand (SM) Sr..thzdSirSiz , •I00 0 ,a 90 so iE eaió 60 'I Os 90 4° a. - 30 20 10 0.001 001 0.1 10 too I Grabs Size (mm) - Sieve Size (m) Sieve Size (mm) Cumulative Weight of dry soil (gm) Percent Retained %) Percent Passing (%) 311 72 00 1000 15" 381 00 1000 3/4" 1905 00 1000 3/8" 9.53 0.0 100.0 #4 475 00 1000 .-.., #100 0.15 74.6- 50.7 49.3 #200 1 0.075 910 618 382 Client: Holly Springs, Ltd. Project Name: Encinas Creek Job Number SEA-71249A ' ( EEl Date: i0141ii (l GeotecMlcai & Emranmentai soiulians Boring Number: B4 Location: 10 feet Soil Description: SM 2195 Faraday Avenue, Suite K, Carlsbad CA 92008 Tested by BD 00 - - IilhIIll1lIIHIUIIII1IllJiiiIUiUUIiihll UIIIHIllIIIflhIIIIIIP!iIIUIIIIIflUlIIIIIII UII1IIIllUIIFIIUIIPJ1llhIIUUEIIIHUIIIIlIII IUhI1llUIIIIIflhIIIIPiflhlllhlllltIIIflulIIIIII RIUhIUIII1IFIIIilIIIIIII1Uht1HIIIflhflO RIlIIIIIIIIIIllh!dIIIIOhIIUUIIIIllIRIIIIIIII BIIIIIIIIUIIIHflUIIIIIIIIIIUIIIII 11IIIIIII iiniiiiaiiinoiuinioiiiuuiiiii iaiuiiiiu UIIIIIIllRIIIII#llhII1II1IIIIIIIIIIIllIIIIIIIll lIIIIIllIII1IllllhIII1I011hIIIIIllINIUh1Ill I I I I I LABORATORY COMPACTION ASTM D 1557 4 Sample 1 2 3 Mold and wet soil (Ibi.) 8.550 .9.770 8.960 8.890 Mold (lbs.) 4.380 4.380 4.380 4.380 VetSoil(lbs.) 4.170 4.390 4.580. 4.510 Wet Density (pt) 125.10 131.70 137.40 135.30 Moisture % 5.8 7.8 9.8 11.8 Dry Density (pcf 118.2 122.2 . 125.1 . 121.0 .1 W 135 130 125 120 0. I: 105 100 95 90 0 5 10 15 20 25 30 35 40 Moisture Content (%) Maximum density 125dpcf® 9.8% moisture (EEi q. Gtdui 5 Oal onmnuI S(uns 2195 Faraday, Suite K Carlsbad CA 9206i Client: Holly Springs. Ltd. Project Name: Encinas Creek Procedure Method A Jobw SEA 712494 Bormg Number: B.3 Location: 2.5 .5 feet . Soil Description: SM Tested by: RD DIRECT SHEAR TEST ASTM 1)3080 Job Data EA-71249A My Springs, Ltd, 2111 Sample Data -2 Oa 0-5 ft. LTo:90% Soaked Before Placing in Shear Box LIption:Clayey Sand SC 2195 Faraday Avenue, Suite K, Carlsbad, CA 92008 SHEAR TEST DIAGRAM 2500 2000 U, 150O 1000 U, 500 0 O 500 1000 1500 2000 2500 3000 3500 NORMAL STRESS (PSF) 'Test Results Phi Cohesion LJtllm.de (psI) 33 degrees 214 Average Initial Moisture 9.5% Average Dry Density 115.5 pcf erage Final Moisture J4;4% Ultimate (psf) —Linear (Ultimate (pst)) DIRECT SHEAR TEST ASTM D 3080 Job Data No.:SEA71249.4 nt: Hàlly Springs, Ltd. 10/13/li Sample Data Lple:B-3 (i 25.-5 ft. iolded to 90% iarks: Soaked Before Placi Description: SM EnArmneilfal solutions (; '1 in Shear Box 2195 Faraday Avenue, Suite K, Carlsbad, CA 92008 SHEAR TEST DIAGRAM 2500 2000 11) 1500 1000 ci) 500 0+' 0 500 1000 1500 2000 2500 3000 3500 NORMAL STRESS (PSF) Test Results Phi Cohesion 28 degrees 518 crage initial Moisture 9.8% rerage Dry Density 1126 pcf verage Final Moisture .14.5% In Ultimate (psi) —Linear (Ultimate (psi)) DIRECT SHEAR TEST ASTM D 3080 Job Data Job No.:SEA-7 1249A Client: Holly Springs, Ltd. )ate: 10/11/11 Sample Data Samplo:B-1 R 7.5 ft. Natural Remarks: Soaked Before Placing in Shear Box Soil Description: SM Gic!echn. I & I, cir..nI S':tns re Un 2195 Faraday Avenue, Suite K, Carlsbad, CA 92008 SHEAR TEST DIAGRAM 3500 3000 250O to r'2O00 1500 1000 500 0 L Ultimate (psi) 'Linear (Ultimate (psi)) 0 500 1000 1500 2000 2500 3000 3500 NORMAL STRESS (PSF) Test Results Phi Cohesion Ultimate (pst) 34 degrees 787 psf Average Initial Moisture 10.9% Average Dry Density 115.2 pcf Average Final Moisture 14.3% EXPANSION INDEX TEST ASTM METHOD D 4829 I SAMPLE P-2 c 0-5 ft Moisture Content of Initial Sample Moisture Content of Final Sample Tare No. - S-6 Wt. of Soil and Ring (g) - 601.6 Wt. of Soil and Ring (g) - 629.2 Wet Weight and Tare (g) - 152.1 Ring Weight (g) -. 199.2 Ring Weight (g) ,m 199.2 Dry Weight and Tare (g) - 143.5 Wet Weight of Soil (g) - 402.4 Wet Weight of Soil (g) - 430.0 Tare Weight (g) - 51.0 Dry Weight of Soil (g) - 368.2 Dry Weight of Soil - 368.2 Water Loss (g) - 8.6 Volume of Ring (It3) m 0.0073 Weight of Water (g) - 61.8 Dry Weight (g) - 92.5 Dry Density (pcf) - 111.2 Final Moisture (%) 16.8 Initial Moisture (%) - 9.3 hthital Saturation ('%) - 48.7 1 Final Saturation (9 - 88.0 Expansion Test - UBC (144 PSF) Date Time Reading Add Weight 10/5/2011 12:00 0.000 10 Minutes 1210 0.000 Add Water 1:00 0.012 300 0.015 10/6/2011 5:30 0.017 Initial Reading Final Reading Elmeasured 17 E150 = 16 Expansion Index, El50 Potential Expansion 0-20 Very Low. 21-50 Low 51-90 Medium 91-130 High >130 VeryHigh Client: Holly Springs, Ltd. c'Jf Project Encinas creek Job Number-SEA-71249.4 EEI Date: 10/5111 C , qe'11R--Vj Boring Number: P-2 Depth: 0-5 ft. Soil Description: SC 2195 Faraday Avenue, Suite K, Carlsbad, CA 92008 ITestéd by: BD I EXPANSION INDEX TEST ASTM METHOD D 4829 I SAMPLEB-65ft. Moisture Content of Initial Sample Tare No. - S-6 Wet Weight and Tare (g) - 178.8 Dry Weight and Tare (g) - 169.3 Tare Weight g- 51.0. WaterLoss(g) - 9.5 Dry Weight g- 118.3 Initial Moisture (V/a) - 8.0 %Saturation of Re-molded Sample Wt. of Soil and Ring (g) - 604 Ring Weight(g) - 199.2. Wet Weight of Soil (g) - 404.8 Dry Weight of Soil g) - 374.7 Volume of Ring (ft) - 0.0073 Dry Density (pct) - 113.2 Initital Saturation 016) - 44.4 Moisture Content of Final Sample Mt. of Soil and Ring (g) - 6225 Ring Weight (g) - 199.2 Wet Weight of Soil (g) - 423.3 Dry Weight of Soil (g) - 374.7 Weight of Water (g)- 48.6 Final Moisture (%) /3.0 Final Saturation (Yo) - 71.6 Expansion Test - UBC. (144 PSF) Date Time Reading Add Weight . . 10/6/2011 1:00 0.000 10 Minutes 1:10 0.000 Add Water 2:30 0001 3:30 -0.001 .10/7/2011 .... 5:45..4001 Initial Reading Final Reading Elmeasured = 0 E150 = 0 Expansion Index, El30 Potential Expansion 0-20 . . Very Low 21-50 Low 51-90 Medium 91-130 High >130. Very High 1ient:Ho1ly Springs, Ltd. roject Enemas Creek. ób Number:SEA-71249.4 )ate: 10/6/11 3oring Number: 9-6 )epth: 5 ft. o11 DescriptiOn: SC js 1. E E= I & 2195 Faraday Avenue, Suite K, Carlsbad, CA 92008 ITested by: BD 1-iR I: SCHIFF www.hdrinc.coni Corrosion Control and Condition Assessment (C3A) Department Table 1 - Laboratory Tests on Soil Samples EEl EneJiuis Creek You, #SEA-7.1249.4, HDRSchIff#l1-lO39LAB 1O-OcilI Sample ID P.2 B3 B-6 @0-5' @2.5-5' @ 0-5' SC SW SC/SW Resistivity Units as-received ohm-cm 80,000 38,800 76,000 minimum ohm-cm 2,260 580 5,780 pH 6.5 5.8 6.0 Electrical Conductivity ms/cm 0.1.7 0.57 0.06 Chemical Analyses Cations calcivai Ca2 mg/kg 23 34 28 magnesium Mg2 mg/kg II 29 10 sodium Na I+ mg/kg 187 520 37 potassium K 1+mg/kg 8.6 10 34 Anions carbonate CO32 mg/kg ND ND ND bicarbDnaie HCO' mg/kg 153 61 85 fluorine F" mg/kg 4.9 5.3 1.9 chloride CIb mg/kg 100 713 .15 sulfate S0,2-mg/kg 72 131 7.5 phosphate P0 mg/kg ND ND 26 Other Tests ammonium NH mg/kg ND ND ND nitrate N031 mg/kg 73 25 63 sulfide S 2-qual, na na na RedOx mV .na na na Minimum resistivity per CTM 643 Chlorides per CTM 422 Sulfates per CTM 417 Electrical conductivity in milhisieniens/cm and chemical analysis were made on a 1:5 soil-to-water extract. mg/kg = milligrams per kilogram (parts per million) of dry soil Redox:= oxidation-reduction potential in millivolts ND = not detected na = not analyzed 431 West Baseline Road . Claremont. CA 91711 Phone: 909.626.0967- Fax 909.626.3316 Page 1 of I APPENDIX C - - - - I - - I - mm - - mm Geotechnical Evaluation - Proposed Multi-Family Residential Development October 24, 2011 Encinas Creek, Carlsbad, California EEl Project No. SEA-71249.4 APPENDIX C EARTHWORK AND GRADING GUIDELINES I * 4aEEI ..I Geotechnical & Environmental Solutions EARTHWORK AND GRADING GUIDELINES GENERAL These guidelines present general procedures and recommendations for earthwork and grading as required on the approved grading plans, including preparation of areas to be filled, placement of fill and installation of subdrains and excavations. The recommendations contained in the geotechnical report are applicable to each specific project, are part of the earthwork and grading guidelines and would supersede the provisions contained hereafter in the case of conflict. Observations and/or testing performed by the consultant during the course of grading may result in revised recommendations which could supersede these guidelines or the recommendations contained in the geotechnical report. Figures A through 0 are provided at the back of this appendix, exhibiting generalized cross sections relating to these guidelines. The contractor is responsible for the satisfactory completion of all earthworks in accordance with provisions of the project plans and specifications. The project soil engineer and engineering geologist (geotechnical consultant) or their representatives should provide observation and testing services, and geotechnical consultation throughout the duration of the project. EARTHWORK OBSERVATIONS AND TESTING Geotechnical Consultant Prior to the commencement of grading, a qualified geotechnical consultant (a soil engineer and engineering geologist) should be employed for the purpose of observing earthwork procedures and testing the fills for conformance with the recommendations of the geotechnical report, the approved grading plans, and applicable grading codes and ordinances. The geotechnical consultant should provide testing and observation so that determination may be made that the work is being .completed' as specified. It is the responsibility of the contractor to assist the consultant and keep them aware of work schedules and predicted changes, so that the consultant may schedule their personnel accordingly. All removals, prepared ground to receive fill, key excavations, and subdrains should be observed and documented by the project engineering geologist and/or soil engineer prior to placing any fill. It is the contractor's responsibility to notify the engineering geologist and soil engineer when such areas are ready for observation. 2195 Faraday Avenue • Suite K. Carlsbad, California 92008-7207 • Ph: 760-431-3747 • Fax: 760-431-3748 www.eeitiger.com Earthwork and Grading Guidelines Laboratory and Field Tests Maximum dry density tests to determine the degree of compaction should be performed in accordance with American Standard Testing Materials test method ASTM designation D-1557- 78. Random field compaction tests should be performed in accordance with test method ASTM designations D-1556-82, D-2937 or D-2922 & D-3017, at intervals of approximately two (2) feet of fill height per 10,000 sq. ft. or every one thousand cubic yards of fill placed. These criteria would vary depending on the soil conditions and the size of the project. The location and frequency of testing would be at the discretion of the geotechnical consultant Contractor's Responsibility All clearing, site preparation, and earthwork performed on the project should be conducted by the contractor, with observation by geotechnical consultants and staged approval by the appropriate governing agencies. It is the contractor's responsibility to prepare the ground surface to receive the fill to the satisfaction of the soil engineer, and to place, spread, moisture condition, mix and compact the fill in accordance with the recommendations of the soil engineer. The contractor should also remove all major deleterious material considered unsatisfactory by the soil engineer. It is the sole responsibility of the contractor to provide adequate equipment and methods to accomplish the earthwork in accordance with applicable grading guidelines, codes or agency ordinances, and approved grading plans. Sufficient watering apparatus and compaction equipment should be provided by the contractor with due consideration for the fill material, rate of placement, and climatic conditions. If, in the opinion of the geotechnical consultant, unsatisfactory conditions such as questionable weather, excessive overized rock, deleterious material or insufficient support equipment are resulting in a quality of work that is not acceptable, the consultant will inform the contractor, and the contractor is expected to rectify the conditions, and if necessary, stop work until conditions are satisfactory. The contractor will properly grade all surfaces to maintain good drainage and prevent ponding of water. The contractor will take action to control surface water and to prevent erosion control measures that have been installed. SITE PREPARATION All vegetation including brush, trees, thick grasses, organic debris, and other deleterious material should be removed and disposed of offsite, and must be concluded prior to placing fill. Existing fill, soil, alluvium, colluvium, or rock materials determined by the soil engineer or engineering geologist as unsuitable for structural in-place support should be removed prior to fill placement. Depending upon the soil conditions, these materials may be reused as compacted fills. Any materials incorporated as part of the compacted fills should be approved by the soil engineer. Any underground structures such as cesspools, cisterns, mining shafts, tunnels, septic tanks, wells, pipelines, or other structures not located prior to grading are to be removed or treated in a manner recommended by the soil engineer. Soft, dry, spongy, highly fractured, or otherwise unsuitable ground extending to such a depth that surface processing cannot adequately improve the condition should be over excavated down to firm ground and approved by the soil engineer before compaction and filling operations continue. Over excavated and processed soils which have been properly mixed and moisture-conditioned should be recompacted to the minimum relative compaction as specified in these guidelines. Earthwork and Grading Guidelines Existing ground which is determined to be satisfactory for support of the fills should be scarified to a minimum depth of six (6) inches, or as directed by the soil engineer. After the scarified ground is brought to optimum moisture (or greater) and mixed, the materials should be compacted as specified herein. If the scarified zone is greater than 6 inches in depth, it may be necessary to remove the excess and place the material in lifts restricted to six (6) inches in compacted thickness. Existing grind which is not satisfactory to support compacted fill should be over excavated as required in the geotechnical report or by the onsite soils engineer and/or engineering geologists. Scarification, discing, or other acceptable form of mixing should continue until the soils are broken down and free of large fragments or clods, until the working surface is reasonably uniform and flee from ruts, hollows, hummocks, or other uneven features which would inhibit ccmpaction as described above. Where fills are to be placed on ground with slopes steeper than 5:1 (horizontal to vertical) gradient, the ground should be benched. The lowest bench, which will act as a key, should be a minimum of 12 feet wide and should be at least two (2) feet deep into competent material, approved by the soil engineer and/or engineering geologist. In fill over cut slope conditions, the recommended minimum width of the lowest bench or key is at least 15 feet with the key excavated on competent material, as designated by the Geotechnical Consultant. As a general rule, unless superseded by the Soil Engineer, the minimum width of fill keys should be approximately equal to one-half (Y2) the height of the slope. Standard benching is typically four feet (minimum) vertically, exposing competent material. Benching may be used to remove unsuitable materials, although it is understood that the vertical height of the bench may exceed four feet. Pre stripping may be considered for removal of unsuitable materials in excess of four feet in thickness. All areas to receive fill, including processed areas, removal areas, and toe of fill benches should be observed and approved by the soil engineer and/or engineering geologist prior to placement of fill. Fills may then be properly placed and compacted until design grades are attained. COMPACTED FILLS Earth materials imported or excavated on the property may be utilized as fill provided that each soil type has been accepted by the soil engineer. These materials should be free of roots, tree branches, other organic matter or other deleterious materials. All unsuitable materials should be removed from the fill as directed by the soil engineer. Soils of poor gradation, undesirable expansion potential, or substandard strength characteristics may be designated unsuitable by the consultant and may require mixing with other earth materials to serve as a satisfactory fill material. Fill materials generated from benching operations should be dispersed throughout the fill area. Benching operations should not result in the benched material being placed only within a single equipment width away from the fill/bedrock contact. Earthwork and Grading Guidelines Oversized materials, defined as rock or other irreducible materials with a maximum size exceeding 12 inches in one dimension, should not be buried or placed in fills unless the location of materials and disposal methods are specifically approved by the soil engineer. Oversized material should be taken offsite or placed in accordance with recommendations of the soil engineer in areas designated as suitable for rock disposal. Oversized material should not be placed vertically within 10 feet of finish grade or horizontally within 20 feet of slope faces. To facilitate trenching, rock should not be placed within the range of foundation excavations or future utilities unless specifically approved by the soil engineer and/or the representative developers. If import fill material is required for grading, representative samples of the material should be analyzed in the laboratory by the soil engineer to determine its physical properties. If any material other than that previously analyzed is imported to the fill or encountered during grading, analysis of this material should be conducted by the soil engineer as soon as practical. Fill material should be placed in areas prepared to receive fill in near-horizontal layers that should not exceed six (6) inches compacted in thickness. The soil engineer may approve thicker lifts if testing indicates the grading procedures are such that adequate compaction is being achieved. Each layer should be spread evenly and mixed to attain uniformity of material and moisture suitable for compaction. Fill materials at moisture content less than optimum should be watered and mixed, and "wet" fill materials should be aerated by scarification, or should be mixed with drier material. Moisture conditioning and mixing of fill materials should continue until the fill materials have uniform moisture content at or above optimum moisture. After each layer has been evenly spread, moisture-conditioned and mixed, it should be uniformly compacted to a minimum of 90 percent of maximum density as determined by ASTM test designation, D 1557-78, or as otherwise recommended by the soil engineer. Compaction equipment should be adequately sized and should be reliable to efficiently achieve the required degree of compaction. Where tests indicate that the density of any layer of fill, or portion thereof, is below the required relative compaction or improper moisture content, the particular layer or portion will be reworked until the required density and/or moisture content has been attained. No additional fill will be placed in an area until the last placed lift of fill has been tested and found to meet the density and moisture requirements, and is approved by the soil engineer. Compaction of slopes should be accomplished by over-building the outside edge a minimum of three (3) feet horizontally, and subsequently trimming back to the finish design slope configuration. Testing will be performed as the fill is horizontally placed to evaluate compaction as the fill core is being developed. Special efforts may be necessary to attain the specified compaction in the fill slope zone. Final slope shaping should be performed by trimming and removing loose materials with appropriate equipment. A final determination of fill slope compaction should be based on observation and/or testing of the finished slope face. 4 Earthwork and Grading Guidelines If an alternative to over-building and cutting back the compacted fill slope is selected, then additional efforts should be made to achieve the required compaction in the outer 10 feet of each lift of fill by undertaking the following: .Equipment consisting of a heavy short-shanked sheepsfoot should be used to roll (horizontal) parallel to the slopes continuously as fill is placed. The sheepsfoot roller should also be used to roll perpendicular to the slopes, and extend out over the slope to provide adequate compaction to the face slope. Loose fill should not be spilled out over the face of the slope as each lift is compacted. Any loose fill spilled over a previously completed slope face should be trimmed off or be subject to re-rolling. Field compaction tests will be made in the outer two (2) to five (5) feet of the slope at two (2) to three (3) foot vertical intervals, subsequent to compaction operations. After completion of the slope, the slope face should be shaped with a small dozer and then re-rolled with a sheepsfoot to achieve compaction to near the slope face.. Subsequent to testing to verify compaction, the slopes should be grid-rolled to achieve adequate compaction to the slope face. Final testing should be used to confirm compaction after grid rolling. Where testing indicates less than adequate compaction, the contractor will be responsible to process, moisture condition, mix and recompact the slope materials as necessary to achieve compaction. Additional testing should be performed to verify compaction. Erosion control and drainage devices should be designed by the project civil engineer in compliance with the ordinances of the controlling governmental agencies, and/or in accordance with the recommendations of the soil engineer or engineering geologist. EXCAVATIONS Excavations and cut slopes should be observed and mapped during grading by the engineering geologist. If directed by the engineering geologist, further excavations or over-excavation and refilling of cut areas should be performed. When fills over cut slopes are to be graded, the cut portion of the slope should be observed by the engineering geologist prior to placement of the overlying fill portion of the slope. The engineering geologist should observe all cut slopes and should be notified by the contractor when cut slopes are started. If, during the course of grading, unanticipated adverse or potentially adverse geologic conditions are encountered, the engineering geologist and soil engineer should investigate, evaluate and make recommendations to mitigate (or limit) these conditions. The need for cut slope buttressing or stabilizing should be based on as-grading evaluations by the engineering geologist, whether anticipated previously or not. Unless otherwise specified in soil and geological reports, no cut slopes should be excavated higher or steeper than that allowed by the ordinances of controlling governmental agencies. Additionally, short-term stability of temporary cut slopes is the contractor's responsibility. Earthwork and Grading Guidelines Erosion control and drainage devices should be designed by the project civil engineer and should be constructed in compliance with the ordinances of the controlling governmental agencies, and/or in accordance with the recommendations of the soil engineer or engineering geologist. SUBDRAIN DISTALLATION Subdrains should be installed in accordance with the approved embedment material, alignment and details indicated by the geotechnical consultant. Subdrain locations or construction materials should not be changed or modified without approval of the geotechnical consultant. The soil engineer and/or engineering geologist may recommend and direct changes in subdrain line, grade and drain material in the field, pending exposed conditions. The location of constructed subdrains should be recorded by the project civil engineer. COMPLETION Consultation, observation and testing by the geotechnical consultant should be completed during grading operations in order to state an opinion that all cut and filled areas are graded in accordance with the approved project specifications. After completion of grading and after the soil engineer and engineering geologist have finished their observations, final reports should be submitted subject to review by the controlling governmental agencies. No additional grading should be undertaken without prior notification of the soil engineer and/or engineering geologist. All finished cut and fill slopes should be protected from erosion, including but not limited to planting in accordance with the plan design specifications and/or as recommended by a landscape architect. Such protection and/or planning should be undertaken as soon as possible after completion of grading. ATTACHMENTS Figure A - Transition Lot Detail Cut Lot Figure B - Transition Lot Detail Cut - Fill Figure C - Rock Disposal Pits Figure D - Detail for Fill Slope Toeing out on a Flat Alluviated Canyon Figure E - Removal Adjacent to Existing Fill Figure F - Daylight Cut Lot Detail Figure G - Skin Fill of Natural Ground Figure H - Typical Stabilization Buttress Fill Design Figure I - Stabilization Fill for Unstable Material Exposed in Portion of Cut Slope Figure J - Fill Over Cut Detail Figure K - Fill Over Natural Detail Figure L - Oversize Rock Disposal Figure M - Canyon Subdrain Detail Figure N - Canyon Subdrain Alternate Details Figure 0— Typical Stabilization Buttress Subdrain Detail Figure P - Retaining Wall Backfill TRANSITION LOT DETAIL CUT LOT - MATERIAL TYPE TRANSITION Grade 51 Minimum Pad Grade XXX Overexcavate and Recompact / Compacted Fill Ix __-_---_- : 3 Miuimum Unweathered Bedrock or Approved Material 'I'pical Beliching * The soils engineer and/or engineering geologist may recommend deeper overexcavation in steep cut fill transitions. EARTHWORK AND GRADING GUIDELINES TRANSITION LOT DETAIL CUT LOT - MATERIAL TYPE TRANSITION 4 EEI FIGURE A Note: Figure not to scale 0,7, Expertise. Service. . Sohilions TRANSITION LOT DETAIL CUT - FILL - DAYLIGHT TRANSITION Compacted Fill - - - - - -- - - -Oil -- - -- - = - - - - - -- - - - -- - - - - - - - - - - - - °1 AI e.0' - - - - - - Unweathe Ve0 - - O - - ........ * The soils engineer and/or engineering geologist may recommend deeper overexcavation in steep cut-fill transitions. Note: Figure not to scale ROCK DISPOSAL PITS Large Rock/Boulder Note: (1) Large rock is defined as having a diameter larger than 3 feet in maximum size. Pit shall e excavated into compacted fill to a depth equal to half of the rock size. Granular soil shall be pushed into the pit and then flooded around the rock using a sheepsfoot to help with compaction. A minim am of 3 feet of compacted fill should be laid over each pit. Pits shall have at least 15 feet of separation between one another, horizontally. Pits shall be placed at least 20 feet from any fill slope. Pits shall be used only in deep fill areas. Note: Figure not to scale DETAIL FOR FILL SLOPE TOEING OUT ON FLAT ALLUVIATED CANYON Toe of slope as shown on grading plan HI Original ground to be restored with compacted fill. Compacted fill Original ground surface ------------------------------------------------------------------- Anticipated alluvial removal depth per soils engineer. Backcut varies for deep removals. A backcut shall not be made steeper than a slope of 1:1 or as necessary for safety Provide a 1:1 minimum projection from the toe of the slope as shown on considerations, the grading plan to the recommended depth. Factors such as slope height, site conditions, and/or local conditions could demand shallower projections. Note: Figure not to scale Qaf (Existbg compacted fill) REMOVAL ADJACENT TO EXISTING FILL Adjoining Canyon Fill Compacted fill limits line, Proposed additional compacted fill To be before placing additional compacted fill Legend Qaf- Artificial Fill Qal - Alluvium EARTHWORK AND GRADING GUIDELINES REMOVAL ADJACENT TO EXISTING FILL Note: Figure not to scale EEI I FIGURE E Expertise. Service. .Soiulions DAYLIGHT CUT LOT DETAIL Fill slope shall be recompacted at a 2:1 ratio (this may increase or - - - - - - - - - - - decrease the area of the pad) C"09 OF - - - - - - - ----- Overexcavate and recompact fill - - - - - - - - - - - -- Proposed finish grade Avoid and/or clean up spillage of materials on the natural 2% gradient 2' minimum key depth Note: (1) Subdrain and key width requirements shall be determined based on exposed subsurface conditions and the thickness of overburden. (2) Pad overexcavation and recompaction shall be completed if determined as necessary by the soils engineer and/or engineering geologist Note: Figure not to scale 3' minimum blanket fill Bedrock or aunroved material SKIN FILL OF NATURAL GROUND 15 minimum to be maintained from proposed finish Original slope Note: (1) The need and disposition of drains will be determined by the soils engineer and/or engineering geologist based on site conditions. (2) Pad overexcavation and recompaction shall be completed if determined as necessary by the soils engineer and/or engineering geologist Note: Figure not to scale TYPICAL STABILIZATION BUTTRESS FILL DESIGN Outlets shall be spaced at 100' maximum intervals, and should extend 12" beyond the face of the slope at the finish of of rough grading 15' minimum Blanket fill if recommended by the soils engineer and/or engineering geologist / Design finish slope 10' 25' benching 15' is typical Buttress or sidehill till diameter non-perforated outlet pipe and backdrain (see alternatives) I gradient 1'-2' clear .- Toe Reel I I Gravel-fabric drain material 3' key depth W = 11/2 or a Note: Figure not to scale - - - - - - - - - - - - - - - - - - - STABILIZATION FILL FOR UNSTABLE MATERIAL EXPOSED IN PORTION OF CUT SLOPE Remove unstable material - - - - 15' minimum - - - --- - - Proposed finished grade X. M. Unweathered bedrock or approved material Remove. unsta le material Compacted stal nil X. V minimum tilted back - -- - ff recommended ly the soils engineer and/or engineering geologist, the remaining cut - - - W2 portion of the slope may require removal and replacement with compacted fill ji Wi Note: (1) Subdrains are required only if specified by the soils engineer and/or engineering geologist. (2) "W" shall be the equipment width (15') for slope heights less than 25 feet. For slopes greater than 25 feet "W" EARTHWORK AND GRADING GUIDE shall be determined by the project soils engineer and/or the engineering geologist. "W" shall never be less than H12. QT A TLTT T7 A TTflN PTT T 101Z I 1NSTA 1T P. M Note: Figure not to scale FILL OVER CUT DETAIL Cut/Fill Contact: As shown on grading plan Maintain minimum 15' 1111 section from backeut to Cut/Fill Contact- As shown on as built face of finish slope Compacted fill Note: 100 Original topography 2' minimum Cut slope iX Bench width may vary Lowest bench width 15' minimum or ff/2 Bedrock or approved material The cut sectioin shall be excavated and evaluated by the soils engineer/engineering geologist prior to constructing the fill portion. Note: Figure not to scale minimum FILL OVER NATURAL DETAIL SIDE}IEELL FILL Compacted Fill Proposed Grade Maintain Minimum IS' Width _- Toe of slope as shown on grading plan Provide a 1:1 minimum projection from design toe of slope to toe of key as shown on as built / - - - - - - - - - - - - Natural slope to beored with compacted fill Width May Bench Vary 15' Minimum key width 2'X 3' Minimum key depth 2' minimum in bedrock or approved material Note: (1) Special recommendations shall be provided by the soils engineer/engineering geologist where the natural slope approaches or exceeds the design slope ratio. (2) The need for and disposition of diuins would be determined by the soils engineer/engineering geologist based upon exposed conditions. Note: Figures not to scale Minimum OVERSIZE ROCK DISPOSAL View Normal to Slope Face Proposed Finish Grade Bedrock or Approved Material View Parallel to Slope Face Proposed Finish Grade 4 10' minimum (5) "600 (4) Bedrock or Approved Material Note: (I) One Equipment width ora minimum of15feet Height and width may vary depending on rock size and type of equipment used. Length of windrow shall be no greater than 100 feet maximum. If approved by the soils engineer and/or engineering geologist. Orientation of windrows may vary but shall be as recommended by the soils engineer and/or engineering geologist Unless recommended staggering of windrows is not necessary. Areas shall be cleared for utility trendies, foundations, and swimming pools. Voids in windrows shall be filled by flooding granular soil into place. Granular soil shall be any soil which has a unified soil classification system (Universal Building Code (UBC) 29-1). Designation of SK SP, SW, UP, or GW. After fill between windrows is placed and compacted with the lift of fill covering windrow, windrow shall be proof rolled with a D-9 dozer or equivalent. Oversized rock is defined as larger than 12', and less than 4 feet in size. Approximate Scale: 1" = 30' OFT I8FT 30FT 60 FT Note: All distances are approximate CANYON SUBDRAIN DETAIL Type A rut Type B Note: Alterratives, locations, and extent of subdrains should be determined by the soils engineer and/or engineering geologist during actual grading. Note: Figures not to scale Minimum T erla 6" CANYON SUBDRAD ALTERNATE DETAILS Alternate 1: Perforated Pipe and Filter Material Filter material: Minimum volume of 9 feet3/linear foot. 6" diameter ABS or PVC pipe or approved substitute with minimum 8 (¼" diameter) perforations per linear foot in bottom half of pipe. ASTM D 2751, SDR 35 or ASTM D 1527, Schedule 40. ASTM D 3034, SDR 35 or ASTM D 1785, Schedule 40: For continuous run in excess of 500 feet use 8' diameter pipe. Minimum Filter Material 12" Minimum 6" Minimum Sieve Size Percent Passine 1" 100 N" 90-100 3/8' 40-100 No.4 25-40 No. 8 18-33 No. 30 5-15 No. 50 0-7 No. 200 0-3 Alternate 2: Perforated Pipe, Gravel and Filter Fabric Minimum Bedding Gravel material 9 feet3/linear foot Perforated pipe: see alternate 1. Gravel: Clean N" rock or approved substitute. Filter Fabric: Mirafi 140 or approved substitute. 6" Minimum Cover linimum Bedding Note: Figures not to scale 4" ml imum 2" minimum TYPICAL STABILIZATION BUTTRESS SUBDRAIN DETAIL 2' minimum 3' minimum 2' minimum 4" minimum -pipe 2"minimum Filter Material: Minimum of S &/!inear foot of pipe or 4 tt3/linear foot of pipe when placed in square cut hunch. Alternative In Lieu Of Filter Material: Gravel may be encased in approved filter fabric. Filter fabric shall be mirafi 140 or equivalent. Filter fabric shall be lapped a minimum of 12' on all joints. Minimum 4" Diameter Pipe: ABS-ASTM D-2751, SDR 35 or ASTM D-1527 schedule 40 PVC-ASTM D-3034, SDR 35 or ASTM D-1785 schedule 40 with a crushing strength of 1,000 pounds minimum, and a minimum of 8 uniformly spaced perforations per foot of pipe installed with perforations at bottom of pipe. Provide cap at upstream end of pipe. Slope at 2% to outlet pipe. Outlet pipe shall be connected to the subdrain pipe with tee or elbow. Note: (1) Trench for outlet pipes shall be backfilled with onsite soil. (2) Backdrains and lateral drains shall be located at the elevation of every bench drain. First drain shall be located at the elevation just above the lower lot grade. Additional drains maybe required at the discretion of the soils engineer and/or engineering geologist Filter Material - Shall be of the following Gravel - Shall be of the following specification or specification or an approved equivalent: an approved equivalent: Filter Material Filter Material Note: Figures not to scale Sieve Size Percent Passing Sieve Size Percent Passing EARTHWORK AND GRADING GUIDELINES 1" 100 1'/z" 100 No.4 50 TYPICAL STABILIZATION BUTTRESS SUBDRAIN 3/" 90-100 3/8" 40-100 No. 200 8 DETAIL No.4 25-40 No. 8 18-33 No. 30 5-15 No. 50 0-7 No. 200 0-3 Sand equivalent: Minimum of 50 EEI I FIGURE 0 Expertise Service.. Soiutiw,s I