Loading...
HomeMy WebLinkAboutPD 10-01; PALOMAR AIRPORT COMMONS; GEOTECHNICAL EVALUATION; 2010-04-02Ira4 E E U Geotechnical & Environmental Solutions GEOTECHNICAL EVALUATION Proposed Lowe's of Carlsbad SW Corner of El Camino Real and Palomar Airport Road City of Carlsbad, San Diego County, California April 2, 2010 EEl Project No. LOW-70976.2 2195 Faraday Avenue • Suite K - Carlsbad, California 92008-7207 • Ph: 760-431-3747 • Fax: 760-431-3748 • www.eeitiger.com GEOTECHNICAL EVALUATION Prepared for: Ms. Parizaad Holliday Lowe's HIW, Inc. Real Estate, Western Division 1530 Faraday Avenue, Suite 140 Carlsbad, California 92008 Site Location: Proposed Lowe's of Carlsbad SWC El Camino Real and Palomar Airport Road City of Carlsbad, San Diego County, California Prepared and Edited by: C, rn 2466 tOF ///'J.eXffTey P.~l CEG 2248 (exp. 10/31/11) Senior Engineering Geologist EEl 2195 Faraday Avenue, Suite K Carlsbad, California 92008-7207 EEl Project No. LOW-70976.1 William R. Morrison, GE 2468 (exp. 12/31/10) Senior Geotechnical Engineer TABLE OF CONTENTS EXECUTIVESUMMARY ........................................................................................................................ i Table 1 - Summary of Findings from the Preliminary Geotechnical Evaluation..........................iv 1.0 INTRODUCTION............................................................................................................................... 1.1 Purpose ...................................................................................................................................... 1.2 Project Description................................................................................................................... 1.3 Scope of Services...................................................................................................................... 2.0 BACKGROUND..................................................................................................................................2 2.1 Site Description........................................................................................................................2 2.2 Site Topography.......................................................................................................................3 2.3 Geologic Setting........................................................................................................................3 2.4 Groundwater..............................................................................................................................3 2.4.1 Surface Water............................................................................................................4 2.4.2 Hydrologic Flood Plain Information..........................................................................4 2.5 Geologic Hazards......................................................................................................................4 2.6 Soil Characterization.................................................................................................................4 2.7 Review of Previous Geotechnical Report..................................................................................5 3.0 FAULTING AND SEISMICITY ......................................................................................................... 5 Table 2 - Summary of Major Active Faults....................................................................................6 3.1 Seismic Parameters and Peak Ground Acceleration..................................................................6 3.2 Ground Lurching or Shallow Ground Rupture..........................................................................6 3.3 Liquefaction...............................................................................................................................7 3.4 Seismic Induced Settlement.......................................................................................................7 4.0 FIELD EXPLORATION AND LABORATORY TESTING ...........................................................7 4.1 Field Exploration.......................................................................................................................7 4.2 Laboratory Testing and Classification.......................................................................................8 4.2.1 Grain Size Distribution..............................................................................................8 4.2.2 Moisture Content and Dry Density............................................................................8 4.2.3 Maximum Dry Density and Optimum Moisture Content..........................................8 4.2.4 Direct Shear ............................................................................................................... 8 4.2.5 Expansion.. ................................................................................................................. 8 4.2.6 R-Value ...................................................................................................................... 9 4.2.7 Sulfate/Corrosion ....................................................................................................... 9 4.2.8 Consolidation Testing................................................................................................9 4.3 Subsurface Conditions ....................................................................... . ........................................ 9 4.3.1 Fill ........................................................... . ................................................................. 10 4.3.2 Quaternary Alluvium...............................................................................................10 4.3.3 Santiago Form ation ................................................................................................... 10 5.0 PRELIMINARY FINDS AND CONCLUSIONS ............................................................................11 TABLE OF CONTENTS (Continued) 6.0 PRELIMINARY RECOMMENDATIONS ...................................................................................... 12 6.1 General.....................................................................................................................................12 6.2 Site Preparation and Grading...................................................................................................13 6.3 Remedial Earthwork................................................................................................................13 6.4 Fill Yielding Subgrade Conditions..........................................................................................14 6.5 Earthwork Balancing...............................................................................................................14 Table 3—Lowe's Compaction Criteria..........................................................................................15 6.6 Earthwork Balancing...............................................................................................................16 7.0 FOUNDATION RECOMMENDATIONS ....................................................................................... 16 7.1 General.....................................................................................................................................16 7.2 Foundation Design...................................................................................................................16 7.3 Footing Setbacks......................................................................................................................17 7.4 Construction.............................................................................................................................17 7.5 Concrete Slab-on-Grade .......................................................................................................... 18 7.6 Retaining Walls.......................................................................................................................19 8.0 PRELIMINARY PAVEMENT DESIGN RECOMMENDATIONS and EARTHWORK .........19 Table 4— Flexible Pavement Structural Section...........................................................................20 Table 5— Rigid Pavement Structural Section...............................................................................20 9.0 DEVELOPMENT RECOMMENDATIONS ..................................................................................21 9.1 Landscape Maintenance and Planting......................................................................................21 9.2 Site Drainage ........................................................................................................................... 21 9.3 Stormwater Disposal Systems .................................................................................................21 9.3.1 Percolation Testing..................................................................................................21 Table 6— Summary of Percolation Test Results..............................................................22 9.3.2 Summary of Findings..............................................................................................22 9.3.3 Structural Setback from Retention Devices.............................................................22 9.3 Additional Site Improvements.................................................................................................22 9.4 Trenching.................................................................................................................................23 9.5 Backfill .................................................................................................................................... 23 10.0 PLAN REVIEW ...............................................................................................................................23 11.0 LIMITATIONS ................................................................................................................................. 24 12.0 REFERENCES ................................................................................................................................25 TABLE OF CONTENTS (Continued) FIGURES: Figure 1 - Site Vicinity Map Figure 2— Boring and Trench Location and Aerial Site Map Figure 3— Proposed Site Map APPENDICES: Appendix A - Soil Classification Chart Boring and Trench Logs Appendix B - Laboratory Test Data Appendix C - Earthwork and Grading Guidelines Distribution: (6) Addressee (1) Addressee (electronic copy) Geotechnical Evaluation April 2, 2010 Proposed Lowe's of Carlsbad, California El Project No. LOW-70976.1 EXECUTIVE SUMMARY Pursuant to your request and authorization, EEl is providing the following geotechnical evaluation for the proposed Lowe's Home Improvement Warehouse (111W) of Carlsbad which is to be located in the City of Carlsbad, San Diego County, California. The purpose of EEl's geotechnical evaluation was to assess subsurface conditions present within the site and to identify concerns that may substantially affect the cost or practicality of the proposed property improvements, as well as to provide preliminary recommendations for site preparation, earthwork construction and foundation design for the proposed project. The subject property encompasses approximately 12.0 acres of APN 213-020-18-00 that is located at the southwest corner of Palomar Airport Road and El Camino Real in Carlsbad, California. Based on our review of a preliminary site plan provided by Lowe's (REC approved August, 2009, prepared by Adams Engineering), we understand that the proposed Lowe's store is located within the easterly portion of a proposed larger retail development, known as the "Palomar Commons" to be developed by Sudberry Properties. The overall proposed retail development consists of an additional five (5) pads for development, which may include a drug store, pet store, and a gas station located west of the Lowe's parcel. Our evaluation does not include these other parcels. We understand that a Lowe's "103K Superwide Modified" building configuration, which encompasses a 122,256 square-foot (sO single-story Lowe's Warehouse building of slab-on-grade construction with an attached 31,718 sf garden center is planned for the subject site. We also understand that underground utilities, paved parking and drive areas and other associated improvements are included as part of the proposed development at the site. EEl's summary of preliminary findings, conclusions and recommendations provided herein are based upon information provided to EEl regarding the site, as well as our field study conducted from February 23 through February 26, 2010. The property is presently occupied by a building associated with a former hotel and resort along with associated improvements including a paved parking area that is situated within the east portion of the site. Some of the previous structures have been razed. Two (2) swimming pools have been abandoned and backfilled. The west portion of the site includes a former golf driving range. The ground surface at the site is gently sloping toward the southwest. An existing sewer easement traverses the westerly portion of the property and is aligned from southwest to northeast. The sewer alignment crosses Palomar Airport Road. Current access to the site is afforded by El Camino Real, which bounds the property to the east. The site is also bounded to the north by Palomar Airport Road, to the south by an office complex, and to the west by an existing Animal Shelter. McClellan-Palomar Airport is situated further north of the subject property. Based on our review of pertinent regional geologic maps and reports, as well as our field exploration, laboratory testing, geologic and engineering analysis, the proposed development appears to be feasible from a geotechnical and soils engineering viewpoint, provided the recommendations presented herein are incorporated into the design and construction phase of the project. There are, however, existing geotechnical concerns (i.e., potentially compressible soils, expansive soils and differential settlement) onsite that will warrant remediation prior to site development. A summary of EEl's preliminary findings for this geotechnical study are summarized below: Geotechnical Evaluation April 2, 2010 Proposed Lowe's of Carlsbad, California EEl Project No. LOW-70976.2 EEl's review of regional geologic maps and reports of the subject site area indicates the subject property is underlain by Tertiary-aged marine sediments of the Santiago Formation. Quaternary- aged alluvial deposits are mapped generally in the western portion of the overall property. EEl reviewed the California Department of Water Resources Water Data Library (WDL, 2010) Website for information regarding wells and depth to groundwater information. A review indicated that no public water wells are located in the immediate vicinity of the subject property. During our subsurface exploration, however, perched groundwater was encountered at depths of 19- to 23-feet below the ground surface (bgs). Regional groundwater is anticipated at depths of greater than 50 feet bgs. A total of twenty eight (28) exploratory excavations including trenches and borings were advanced to depths ranging from approximately 10 to 51 Y2-feet bgs. Seventeen (17) exploratory excavations, which included 16 borings and one trench, were excavated within the proposed building footprint and eleven (11) excavations, which included six borings and five trenches, were excavated in the proposed parking lot and driveway areas. Two (2) borings were drilled in the area of the site where an onsite stormwater infiltration system is planned. Fine grained alluvial and formational soils were encountered onsite, consisting predominantly of fine to medium-grained sandy-clay (CL) and silty-clay (CL), sandy-silt (ML), and clayey-silt (ML) and lesser silty-sand (SM). Randomly situated layers of poorly sorted sands (SP) were also encountered. The encountered clayey soils were observed to be moist to very moist and soft, while sandy and silty portions were noted to be moist to saturated and loose to medium dense to a depth on the order of 10 to 15 feet bgs at the time of our subsurface exploration. Below these depths, alluvial soils became either stiff or medium dense. Undocumented fill materials mantle the site with variable thickness generally ranging from approximately 1 to 10 feet. The encountered fill materials consisted of clayey sand (SC), silty sand (SM) with variable amounts of organics and debris. Laboratory soil corrosivity test results indicate that earth materials collected within the upper five feet of the ground surface are acidic to mildly alkaline and are extremely corrosive to ferrous metals. Soils contain negligible to moderate sulfate and chloride concentrations which do not appear to pose a significant threat to concrete durability. Concrete having a compressive strength of 4,000 pounds per square inch (psi) and utilizing Type II cement appears suitable for those concrete elements that will be in contact with the upper soils at the site. Ammonia and nitrate do not pose a corrosion threat to copper piping since both analytes were noted to be present in relatively low levels. A summary of our corrosion test results is included in Table 1. The region of southern California that includes the subject site is known to contain several active seismic faults. EEl observed no fissures and/or fault scarps on the subject parcel; however, a segment of a fault known as the Rose Canyon Fault has been mapped as being situated within 7 miles of the subject site. The subject parcel is not situated within a mapped State of California Seismic Hazard Zone for liquefaction, nor is it situated within a mapped Aiquist-Priolo Earthquake Fault Zone. Strong seismic shaking is expected at the site. Based upon our evaluation, the subject site area does not appear to be susceptible to earthquake-induced liquefaction or significant amounts of seismic-induced ground settlement, due to relatively dense formational materials underlying the site at relatively shallow depths and depth to regional groundwater (groundwater depth of 50 feet or greater bgs). 11 Geotechnical Evaluation April 2, 2010 Proposed Lowe's of Carlsbad, California EEL Project No. LOW-70976.2 A conventional foundation system appears to be suitable for use to support the proposed Lowes building, provided the property is graded and improved in general conformance with guidelines presented herein, as well as the California Building Code (CBC) and the City of Carlsbad grading ordinances. EEl evaluated static settlement utilizing results of laboratory testing and subsurface data to estimate settlement as a result of grading the pad 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 and recompaction of potentially compressible soils within the proposed building footprint (as presented herein); EEL estimates total static settlement of less than 1-inch within the building envelope. Differential settlement is estimated to be approximately V2-inch or less over a distance of 50 feet. Laboratory testing performed during a previous geotechnical evaluation conducted at the site (Leighton, 2006) and our laboratory testing indicate that the upper soils are not susceptible to significant levels of hydro-consolidation. Based on observed subsurface conditions, we anticipate that the onsite soils can be excavated with conventional heavy grading equipment in good operating condition; however, shallow elevated in-place soil moistures coupled with perched groundwater could make remedial earthwork very difficult for rubber tire equipment. Track-mounted heavy equipment may also encounter some difficulty. As such, measures to stabilize the bottoms of excavations that exhibit pumping/yielding may be warranted. In addition, underground utilities that are planned at or near the perched groundwater table may require special backfill procedures and/or dc-watering. Native alluvial and formational materials and fill materials encountered appear to be generally suitable for use as structural fill provided they are free of deleterious materials and are properly moisture conditioned or dried (as needed) and re-compacted to Lowe's criteria. Import soils (if needed onsite to achieve the proposed grade) should contain granular materials with 100 percent finer than 2-inches, 25 to 75 percent passing the No. 4 sieve, contain less than 25 percent passing the No. 200 sieve, have a very low expansion index (EL) potential (EL less than 25) when compacted to 95 percent (based on ASTM D1557), have a liquid limit less than 30 and have a plasticity index less than 10. Our field studies also included the conducting of percolation testing in those borings that were drilled in the area to receive the proposed stormwater infiltration system. Our percolation testing indicated that the clayey sands and silts that were encountered at the test depths possessed poor to moderate percolation characteristics and appears to be conducive to an onsite stormwater infiltration system. Based on the findings and conclusions of this geotechnical evaluation, the proposed development appears to be feasible from a geotechnical and soils engineering viewpoint, provided the recommendations provided herein are properly incorporated into their design/construction. A summary of our determinations is presented in the following table: 111 Geotechnical Evaluation April 2, 2010 Proposed Lowe's of Carlsbad, California EEl Project No. LOW-70976.2 TABLE 1: Summary of Findings from the Geotechnical Evaluation' Major Soil Types - based on the Unified Soil Classification Bearing Capacity —2,500 pounds per square foot (pst) for System (USCS) from laboratory testing - conventional footings with a minimum width of 12- inches sandy-clay and silty-clay (CL), clayey-silt and sandy-silt i4, and a minimum depth of embedment of 18 inches, clayey-sand (SC), and silty-sand (SM) underlain by at least 24-inches of engineered fill. Corrected Maximum Density & Optimum Moisture = Recommended Site Class = D @0-5 feet): 111.5 pounds per cubic feet (pct) 14.5%; (B-9 Recommended Recommended Seismic Design Category = D @ 0-5 feet): 128.6 (pcf) @ 10.4% Design Spectral Response Acceleration Parameters = 5DS (0.2 sec SA) = 0.792g Expansion Index - 12 to 122 (Low to High Expansion 5D1 (1.0 5CC SA) = 0.450g Potential) Estimated Amount of Seismic-Induced Settlement —0 to Percent Passing #200 Sieve = 42.1 to 48 percent 1-inches (total); Approximately 'A inch (differential) Encountered Depth to Ground Water = perched at 19 to 23 feet below existing ground surface (bgs) Recommended Fill Compaction & Moisture Content 92 Friction angle of soils = 14° to 33° to 98%* (ASTM D 1557). Fills compacted to at least 2 percent above the optimum moisture content. Apparent cohesion = 500 psf to 115 psf Pavement Design Parameters Percolation Rate - B-21 (P1) @ 10' = 41.7 minutes per inch (1.4-inch per R-Value = 5 and 13 hour) Subgrade Modulus (k-value) =65 and 75 psi/in (pci) B-22 (P2) @10.5' = 83.3 minutes per inch (0.7-inch per Flexible Pavement hour) Parking Areas - 3-inches of asphalt over 12-inches of aggregate base(') Truck Areas - 4-inches of asphalt over 15.5-inches of aggregate base(') Rigid Pavement Automobile Circulation Areas - 5.0-inches Portland cement concrete over 4-inches aggregate base 2 Truck Areas - 6-inches Portland cement concrete over 4- inches aggregate base(') 'This summary table is not a stand alone document, and should not be utilized without referring to specific technical information contained in the body of EEl's forthcoming geotechnical report, (2) Base materials should meet requirements for a Class 2 aggregate base with an R-Value of 78 or greater. iv Ceotechnical Evaluation April 2, 2010 Proposed Lowe's of Carlsbad, California El Project No. LOW-70976.1 1.0 INTRODUCTION 1.1 Purpose The purpose of this evaluation was to provide geotechnical information to Lowe's HIW, Inc. (Lowe's) regarding a proposed commercial development at the subject property in the City of Carlsbad, San Diego County, California. The information provided in this evaluation is intended to provide Lowe's with an understanding of the physical conditions of subsurface soils, local geotechnical conditions, and the regional geologic setting which could affect the cost or design of the proposed development. Our scope of services is based on generally accepted geotechnical engineering principles and our experience with similar developments in the general vicinity of the subject site. EEl hereby certifies that this geotechnical evaluation has been conducted in general accordance with and conforms with Section 600 - Geotechnical Requirements of the Lowe's Development and Design Criteria, Division 02 Civil - Standard Site Specification and Project Provisions; and with the Site Development Criteria Plan drawing for a 103K Deep Lowe's building The geotechnical evaluation has been prepared for the sole use of Lowe's HIW, Inc. This geotechnical study should not be relied upon by other parties without the express written consent of EEl and Lowe's. 1.2 Project Description The relatively level to gently sloping site is situated in the southeastern portion of Carlsbad, south of Palomar Airport Road and west of El Camino Real in northwestern San Diego County, California (Figure 1- Site Vicinity Map). The former resort property is located at 33.1282° north latitude and 117.2678° west longitude. The preliminary site plan provided by Lowe's (Adams Engineering, REC approved August 6, 2009) indicates that the proposed Lowe's store is planned within the easterly portion of the subject parcel, with parking to the west, east, and north. Overall, the proposed development is a part of a larger retail development, known as the "Palomar Airport Commons" to be developed by Sudberry Properties. The REC approved plan indicates a Lowe's "103K Deep" building configuration, which includes a 122,256 square-foot (sO, single-story Lowe's Warehouse building of slab-on-grade construction with an attached 31,718 sf garden center, which is planned for the subject site. No grading plans were provided to us for our review; however, the preliminary site plan for the project indicates a finish floor elevation for the proposed building at an elevation of 280 feet above mean sea level (amsl). The preliminary site plan indicates that the remainder of the proposed commercial shopping center will be situated west of the Lowe's parcel (Figure 2—Proposed Site Map). Design standards for a typical Lowe's 111W building consist of column loads of 100 kips; wall loads of 6 kips per foot; and floor slab loads of 300 pounds per square foot (psf). Lowe's development criteria indicates that typical pavement design should consider a 15-year life, with traffic patterns of 25 loaded tractor trailers per day and 2,500 vehicles per day (Lowe's, 2006a). 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, geotechnical reports previously prepared for the future "Palomar Airport Commons" shopping center, and soils data for the area (References). Geotechnical Evaluation April 2, 2010 Proposed Lowe's of Carlsbad, California EEl Project No. LOW-70976.2 Drilling and logging of twenty two (22) geotechnical hollow stem auger (HSA) borings and six (6) exploratory trench excavations within the subject property (Appendix A - Soil Classification Chart and Boring and Trench Logs). EEl conducted the fieldwork from March 23 through March 26, 2010. The locations of the borings and trenches are presented on Figure 3 (Boring and Trench Map). Conduct percolation testing within two (2) of the exploratory borings advanced in the area to receive the proposed stormwater infiltration system. Completion of laboratory testing of representative earth materials encountered onsite to ascertain their pertinent soils engineering properties, including corrosion potential (Appendix B - Laboratory Testing Data). R-Value testing and preliminary pavement design. An evaluation of seismicity and geologic hazards to include an evaluation of faulting and liquefaction potential. Engineering and geologic analyses including liquefaction potential and consolidation settlement. Preparation of this report that provides a summary of our field and laboratory data, along with our preliminary findings, conclusions and geotechnical recommendations for the proposed development. 2.0 BACKGROUND 2.1 Site Description The proposed Lowe's of Carlsbad Home Improvement Warehouse (HIW) is located in northwestern San Diego County, California and encompasses 12.0-acres, (Adams, 2009). The currently developed subject property is identified as a portion of Assessor's Parcel Number (APN) 213-020-18-00. The subject property is currently being a part of proposed redevelopment activities, and is identified by the address 6111 El Camino Real (i.e., location of the former Olympic Resort). The former resort property (formerly Olympic Resort), where the retail development is planned, is located to the south of McClellan-Palomar Airport and to the south of Palomar Airport Road, and to the west of El Camino Real. Mixed —use commercial, retail and residential land is situated east of the proposed Lowe's parcel, with commercially developed sites (i.e., Home Depot) located further east. Commercial development is located south of the property. (Figure 1 - Site Vicinity Map and Figure 2 and Boring Location and Aerial Site Map). Prior to our field observation, the subject property was formerly the Olympic Resort, which consisted of tennis courts, a golf practice range, swimming pools, and hotel/spa structures. The site is currently under demolition and the only remaining structure is the main hotel building in the eastern portion of the Lowe's parcel. The property is presently occupied by a building associated with a former hotel and resort along with associated improvements including tennis courts and a paved parking area that are situated within the east portion of the site. Some of the previous structures have been razed. Two (2) swimming pools have been backfilled. The west portion of the site includes a former golf driving range. The ground surface at the site is gently sloping toward the southwest. An existing sewer easement traverses the westerly portion of the property and is aligned from southwest to northeast. The sewer alignment continues to the northeast, where if crosses Palomar Airport Road. Current access to the site is afforded by El Camino Real, which bounds the property to the east. The site is also bounded to the north by Palomar Airport Road, to the south by an office complex, and to the west by an existing Animal Shelter. Geotechnical Evaluation April 2, 2010 Proposed Lowe's of Carlsbad, California EEl Project No. LOW-70976.2 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 on the order of approximately 300 feet above mean sea level (amsl). Overall, the subject site is relatively flat lying, but slopes very gently towards the southwest and surface water appears to drain in a southwest direction towards an unlined drainage. 2.3 Geologic Setting The project site is situated within the coastal section of the Peninsular Ranges geomorphic province. The Peninsular Ranges geomorphic province, one of the largest geomorphic units in western North America, extends from the Transverse Ranges geomorphic province and the Los Angeles Basin, south to Baja California. It is bound on the west by the Pacific Ocean, on the south by the Gulf of California and on the east by the Colorado Desert Province. The Peninsular Ranges are essentially a series of northwest- southeast oriented fault blocks (CDMG, 2002). Throughout the last 54 million years, the area known as the "San Diego Embayment" has undergone several episodes of marine inundation and subsequent marine regression, resulting in the deposition of a thick sequence of marine and non-marine sedimentary rocks on the basement rock of the southern California Batholith. During the Pleistocene-age, regional sea levels gradually increased, causing wave-cut platforms, most of which were covered by relatively thin marine and non-marine terrace deposits, formed as the sea receded from the land. Fluvial erosion caused by periods of heavy rainfall, along with lowering sea levels noted during the Quarternary-age, resulted in the existing rolling hills, mesas, and canyons that characterize the setting of the site vicinity. The subject property does not lie within an active fault zone. The nearest fault zone is the northwest- southeast trending Newport-Inglewood - Rose• Canyon Fault zone, which is located off shore approximately 6.9 miles west of the subject property. In addition, the Julian Segment of the Elsinore Fault Zone is approximately 30 miles east of the subject property (Jennings, 1994). A review of regional geologic maps of the site area and pertinent geologic literature indicates that the Lowe's 111W parcel is underlain by Quaternary-aged alluvial deposits and Tertiary aged sedimentary units of the Santiago Formation (CDMG, 1975). 2.4 Groundwater According to the San Diego Regional Water Quality Control Board - Region 9 Basin Plan (SDRWQCB, 1994), the subject property is located within the Carlsbad Hydrologic Unit, and Agua Hedionda Hydrologic Sub Area. Groundwater east of the Interstate 5 Freeway has been designated beneficial for industrial service, commercial and sport fishing, and wildlife and marine habitats. EEl reviewed the California Department of Water Resources Water Data Library (WDL, 2010) Website for information regarding wells and depth to groundwater information. A review indicated that no public water wells are located in the immediate vicinity of the subject property. During our subsurface exploration, however, perched groundwater was encountered at depths of 19- to 23 feet below the ground surface (bgs). Regional groundwater is anticipated at depths of greater than 50 feet bgs. Groundwater reportedly flows to the southwest (toward the ocean). Geotechnical Evaluation April 2, 2010 Proposed Lowe's of Carlsbad, California EEl Project No. LOW-70976.2 Prior studies (Leighton, 2006, and EEl, 20 10) reportedly encountered perched groundwater on the overall property at a depth of 16 to 35 feet bgs. It should be noted that variations in groundwater may result from fluctuations in the ground surface topography, subsurface stratification, rainfall, irrigation, and other factors that may not have been evident at the time of either subsurface exploration. 2.4.1 Surface Water Surface water was not encountered during our field study. Surface water in the vicinity generally is controlled by drainage improvements that channels water flow to the southwest to an unlined drainage. Based on field observation, however, localized shallow remnants of ponding (likely related to recent precipitation) were noted onsite. 2.4.2 Hydrologic Flood Plain Information EEl reviewed the Federal Emergency Management Agency (FEMA) Flood Hazard Map for San Diego County online (2010) to determine if the subject property was located within an area designated as a Flood Hazard Zone. According to the information reviewed on the Flood Insurance Rate Map (FIRM), Community-Panel Numbers 060285, -294 and -297 of 0769 (effective June, 1997), the subject property is located within designated Zone X, which are areas outside the one percent annual chance floodplain; areas of one percent annual chance sheet flow flooding where average depths are less than one-foot; areas of one percent annual chance stream flooding where the contributing drainage area is less than one square-mile, or areas protected from the 1 percent annual chance flood by levees. No Base Flood Elevations or depths are shown within this zone. 2.5 Geologic Hazards The subject property is not situated within a Fault-Rupture Hazard Zone by the California Geological Survey (formerly the California Division of Mines and Geology). The subject property is not located within a State of California Seismic Hazard Zone for liquefaction (CDMG, 1999). The subject property does not appear to be in an area that could be affected by landslides, or rockfalls. Medium to highly expansive soils underlie the site. 2.6 Soil Characterization Soil in the vicinity of the site has been identified by the United States Department of Agriculture - Natural Resource Conservation Service, online Web Soil Survey database as the loamy alluvial land of the Huerhuero complex (USDA, 2010). The complex is defined as residuum material weathered from calcareous sandstone and shale; at 15 to 30 percent slopes; and is moderately well drained. The saturated hydraulic conductivity (Ksat) for the loam is referenced in the USDA-NCRS document as approximately 0.00 to 0.06-inches per hour (in/hr). 4 Geotechnical Evaluation April 2, 2010 Proposed Lowe's of Carlsbad, California EEl Project No. LOW-70976.2 2.7 Review of Previous Geotechnical Reports Two (2) geotechnical reports that were previously prepared by Leighton Consulting, Inc. for an Athletic Club that was once proposed for a portion of the subject proposed retail development that includes the subject site (Leighton, 2006 and 2008) were reviewed as part of our geotechnical evaluation. Leighton's field exploration consisted of drilling eighteen (18) exploratory borings to depths of 4.5 to 51.5 feet bgs and the advancement of twelve (12) exploratory trenches to depths of between 2.5 and 17 feet bgs. Subsurface conditions reported by Leighton in the vicinity of the proposed Lowe's parcel consisted of native alluvial soils that were locally mantled by artificial fill soils. The alluvial soils and fill were underlain by the Santiago Formation. Leighton indicates that the encountered alluvial soils consisted of interbedded silty clays, sandy silts and clayey silts with lesser silty and clayey sands. The sandy portions of the alluvium were noted by Leighton to be slightly moist to moist and loose to very dense, while the more silty layers were indicated by Leighton to be slightly moist to moist and firm to stiff during their subsurface exploration. Leighton (2006 and 2008) indicates that groundwater was encountered during their subsurface exploration at depths of 16 to 28 feet bgs. Leighton's reports (2006 and 2008) recommend that remedial grading at the site should include the removal and recompaction of the upper 5 to 15 feet of soils within building areas. Alternate measures to mitigate for expansive soils, including selective grading of onsite soils, were also recommended. 3.0 FAULTING AND SEISMICITY The southern California area is seismically active. Because of the proximity of the site 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) and the site is not within an Earthquake Fault Zone (CDMG, 2000; Hart and Bryant, 1997. No known fault traces cross the site, and no evidence of surface ground rupture was noted during our site reconnaissance. Therefore, it is our opinion that the likelihood of surface fault rupture at the site is low. Mapped segments of the Rose Canyon Fault zone relative to the subject site are located to the west approximately 7-miles (CDMG, 1998). The following table provides a summary of the these faults, along with other active fault zones in southern California that may have a significant effect on the subject property in the event major activity is experienced. Fault names and approximate distances are based upon information provided in applicable references (Jennings, 1994; CDMG, 1998; Blake, 2000). Geotechnical Evaluation April 2, 2010 Proposed Lowe's of Carlsbad, California EEl Project No. LOW-70976.2 TABLE 2 Summary of Major Active Faults Fault Name Approximate Distance From Site miles (kilometers) Rose Canyon 6.9(11.1) Newport-Inglewood (Offshore) 9.5 (15.3) Coronado Bank 22.6 (36.3) Elsinore (Julian) 22.6 (36.4) Elsinore (Temecula) 22.6 (36.4) Elsinore (Glen Ivy) 35.9 (57.7) San Joaquin Hills 39.4 (63.4) Earthquake Valley 39.9 (64.2) Palos Verdes 40.3 (64.9) San Jacinto-Anza 45.5 (73.3) San Jacinto-San Jacinto Valley 46.9 (75.5) San Jacinto- Coyote Creek 49.5 (79.6) Chino-Central Avenue (Elsinore) 50.3 (81.0) 3.1 Seismic Parameters and Peak Ground Acceleration Maximum considered ground motion maps provided in the California Building Code (CBC, 2007) were utilized with coordinates of 33.1282° north latitude and 117.2678° west longitude, to determine the site seismic parameters. EEl utilized seismic design criteria provided in the CBC, 2007. In accordance with the guidelines of the CBC, 2007, the spectral parameters for the site (based on a Site Class B soil) are estimated to be S =1.136 g and S1 = 0.430.g, utilizing 2005 ASCE 7 Design Standards (ASCE, 2005). Review of the geotechnical data obtained during our subsurface exploration and from subsurface data previously obtained in the vicinity of the site (Leighton, 2006, 2008), however, indicates that the site should be classified as Class D per the CBC (Table 1613.5.2). Consequently, Site Coefficients Fa= 1.046 and F = 1.57 appear to be appropriate for the site. Based on this information, the adjusted maximum considered earthquake spectral response parameters SMS = 1.188g and SM! = 0.675g are recommended for seismic design of the project. Assuming an occupancy category of II (Table 1604A.5), an SD, value of 0.792g and an SD! value of 0.450g, the proposed commercial building 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 engineer based on the local laws and ordinances, expected building response, and desired level of conservatism. 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 this light, the unlikely hazard of lurching or ground-rupture should not preclude consideration of "flexible" design for onsite utility lines and connections. Geotechnical Evaluation April 2, 2010 Proposed Lowe's of Carlsbad, California EEl Project No. LOW-70976.2 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. Using the Tokimatsu and Seed procedure for unsaturated soils (1997), we estimate the total seismic induced settlement within the upper unsaturated soils to be less than ½-inch across the site. Differential seismic induced settlements are estimated to be less than '4- inch across a 50-foot span. These estimates assume that the earthwork recommendations presented herein are properly incorporated into the proposed construction at the site. 4.0 FIELD EXPLORATION AND LABORATORY TESTING 4.1 Field Exploration Fieldwork was conducted between March 23, 2010 and 26, 2010. A total of twenty eight (28) exploratory excavations including trenches and borings were advanced to depths ranging from approximately 10 to 51½-feet bgs. Seventeen (17) exploratory excavations, which included 16 borings and one trench, were excavated within the proposed building footprint and eleven (11) excavations, which included six borings and five trenches, were excavated in the proposed parking lot and driveway areas. Two (2) borings were drilled in the area of the site where an onsite stormwater infiltration system is planned. Borings and trenches were logged under the supervision of EEl's engineering geologist and geotechnical engineer. A truck mounted Mobile-B61 drill rig equipped with 8-inch diameter hollow stem auger was used during fieldwork for the borings. 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. The number of blows (N value) required to advance the 18-inch long SPT and 12-inch long Modified California split-tube samplers a distance of 12 inches was measured at various initial depths followed by 5-foot intervals (recorded on the boring logs), and are presented in Appendix A. Relatively "undisturbed" samples were collected in a 2.42-inch (inside diameter) California Modified split-tube sampler for visual examination and laboratory testing. Trenches were excavated using a light duty rubber tire backhoe. The soils were classified in accordance with the Unified Soil Classification System (ASTM, 2008). Representative bulk samples were also collected for appropriate laboratory testing. Geotechnical Evaluation April 2, 2010 Proposed Lowe's of Carlsbad, California EEl Project No. LOW-70976.2 4.2 Laboratory Testing and Classification Representative samples were selected for laboratory testing to confirm their field classifications. Field descriptions and classifications were visually classified according to the American Society for Testing and Materials (ASTM) D-2488, which classifies soils under the Unified Soil Classification System (USCS). Representative soil samples were tested in the lab for grain size distribution, liquid limits, and plastic limits to determine actual classifications by ASTM D-2487-Standard Practice for Classification of Soils for Engineering Purposes in accordance with the USCS. Final classifications of soils can be found on the boring logs in Appendix A and the laboratory test data in Appendix B. 4.2.1 Grain Size Distribution To check classifications of soils and to help evaluate liquefaction potential at the site, 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 D422-Standard Test Method for Particle-Size Analysis of Soils. Grain size distribution curves and gradation results are presented in Appendix B. 4.2.2 Moisture Content and Dry Density The in-situ moisture content and dry density of soils were determined for soil samples obtained from the borings. Moisture contents and dry densities of soils help to determine engineering design parameters for foundations, retaining walls, and other engineered structures. Moisture content on soil samples was conducted in general accordance with ASTM D-2216, and was recorded as a percentage. In-place moisture content and dry density information for soil samples retrieved from the field can be found on the boring logs located in Appendix A. 4.2.3 Maximum Dry Density and Optimum Moisture Content The maximum dry density and optimum moisture content was determined from bulk soil samples obtained from Borings B1 and B9 within the upper five feet of existing grade. Our testing was performed in general accordance with ASTM D-1557, Method B. Results of our testing are presented in Appendix B. 4.2.4 Direct Shear Direct shear testing was conducted on representative soil samples that was remolded to 92 percent of their maximum dry density (based on ASTM D-1557) to measure their shear strength characteristics for engineering purposes. The sample was then inundated for at least 18 hours. The samples were placed in a shear box and a normal load was applied (10, 20, and 40 kilogram weights were used). The samples were 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 D-3080. The results of our testing are presented in Appendix B. 4.2.5 Expansion Three (3) soil samples obtained from within the upper five feet of existing grade were tested for their expansion potential. Clayey soils can be expansive with the introduction of water and can cause heaving. Our expansion index (i.e., El) testing was conducted in general accordance to ASTM D-4829. The result of our expansion index testing is presented in Appendix B. Geotechnical Evaluation April 2, 2010 Proposed Lowe's of Carlsbad, California EEl Project No. LOW-70976.2 Expansion index testing should be completed at the conclusion of rough grading, and should consist of the evaluation of soils within 4 feet of finish grade. Additional testing, therefore, is recommended after completion of rough building pad grade. 4.2.6 R-Value Representative bulk samples from the upper five-feet of the proposed parking area were collected for R-Value testing. Pavement design is based upon these test results. The samples were sent to the GeoSoils, Inc. soils laboratory in Carlsbad, California. Test procedures were conducted in general accordance with the Department of Transportation, State of California, and Materials & Research Test Method No. 301. The R-Value test results are presented in Appendix B. Verification testing is recommended at the conclusion of grading on samples collected at (or near) finish grade. 4.2.7 Sulfate/Corrosion Two representative samples of onsite earth material were collected for analysis for corrosion/soluble sulfate potential, consisting of minimum resistivity and pH by California Test Method 643, electrical conductivity by AWWA 2510-B and ASTM D-125, alkalinity by USEPA 310.1, AWWA 1320-B, and ASTM D -13, and sulfate, chloride, 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. 4.2.8 Consolidation Testing Consolidation properties of soils were determined to evaluate soil potential for compression and long-term settlement. The consolidation test method includes measuring the amount and rate of consolidation of soil when subject to loading. The test was run with relatively undisturbed soil samples in 1-inch thick brass rings, collected from the Modified California sampler. The samples were placed in a consolidometer with porous stones at the top and bottom of the sample and placed in a loading frame. Weights were added and measurements of height were recorded from a dial indicator as the sample was compressed. Measurements of height were also recorded during the "rebound" period of removal of the weights. Consolidation testing was performed in general accordance to ASTM D-2435. Results of our consolidation testing are presented in Appendix B. 4.3 Subsurface Conditions Subsurface conditions encountered in our exploratory borings and trenches were observed to be generally consistent with those previously reported by Leighton Consulting Group (Leighton, 2006, 2008). The subsurface materials encountered in our exploratory borings consisted of undocumented fill, Quaternary alluvial deposits, and the Tertiary aged Santiago Formation. Discussions of each of these materials (from youngest to oldest) are presented below. Geotechnical Evaluation April 2, 2010 Proposed Lowe's of Carlsbad, California EEl Project No. LOW-70976.2 4.3.1 Fill Undocumented artificial fill materials of variable thickness were encountered in our exploratory excavations at various locations and appear to be associated with minor fills that were utilized to create the building pad areas of former structures previous driving range features and utility and backfill of the former swimming pools. In addition, recently imported fill materials also appear to underlie portions of the westerly edge of the subject site area. In general, the fill materials were observed to be comprised of light brown silty and clayey sands with some organics consisting of scattered roots and rootlets. Miscellaneous debris consisting of concrete, plastic and wood was also noted within the fill in some areas. These materials were noted to be typically slightly moist to wet and loose at the time of our subsurface exploration and are not considered suitable for the support of additional fills and/or structures in their current condition. A more detailed description of the encountered soils is provided on the boring and trench logs included as Appendix A. 4.3.2 Quaternary Alluvium Quaternary-aged alluvium deposits were encountered in our exploratory borings to maximum depths of approximately 20 feet below the existing ground surface. In general, the encountered portions of these deposits were observed to be comprised of brown, dark brown and orange- brown sandy clays, clayey sands, and lesser amounts silty sands, sandy silts and silty clays. The sandy portions of these materials were noted to be typically slightly moist to very moist and loose to medium dense, while the clayey portions were observed to be moist to wet and medium stiff to stiff at the time of our subsurface exploration. Zones of concentrated organics were observed locally within the alluvium. A more detailed description of the encountered soils is provided on the boring logs included as Appendix A. 4.3.3 Santiago Formation The sedimentary bedrock unit underlying the undocumented fill and alluvium is the Tertiary-aged Santiago Formation. The Santiago Formation was encountered in all of our exploratory borings and in our exploratory test pits to maximum depths of 51% feet below the existing ground surface. In general, the encountered portions of these deposits were observed to be comprised of gray, green and brown to olive brown silty claystones, clayey siltstones and clayey to silty sandstones. The sandy portions of these materials were noted to be typically slightly moist to very moist and medium dense to dense, while the clayey portions were observed to be moist to wet and medium stiff to hard at the time of our subsurface exploration. A more detailed description of the encountered soils is provided on the boring logs included as Appendix A. During our subsurface exploration, however, perched groundwater was encountered at depths of 19- to 23 feet below the ground surface (bgs). Regional groundwater is anticipated at depths of greater than 50 feet bgs. Groundwater reportedly flows to the southwest (toward the ocean). Prior studies (Leighton, 2006, and EEl, 2010) reportedly encountered perched groundwater on the overall property at a depth of 16 to 35 feet bgs. It should be noted that variations in groundwater may result from fluctuations in the ground surface topography, subsurface stratification, rainfall, irrigation, and other factors that may not have been evident at the time of either subsurface exploration. 10 Geotechnical Evaluation April 2, 2010 Proposed Lowe's of Carlsbad, California EEl Project No. LOW-70976.2 5.0 PRELIMINARY FINDINGS AND CONCLUSIONS Based on our fieldwork, laboratory testing and engineering and geologic analysis, it is our opinion that the site is suitable for the proposed commercial development from a geotechnical engineering and geologic viewpoint; however, there are existing geotechnical conditions associated with the property that will require consideration during planning stages and mitigation during grading. The predominant geological considerations at this site include the presence of soft compressible alluvial soils and moderately to highly expansive earth materials. EEl's findings appear to be somewhat consistent with other recent studies associated with the existing proposed retail development immediately to the west of the proposed Lowe's. If site plans and/or the proposed building location are revised, or if finish grade elevations are raised more than 2 feet above existing topography, additional field studies may also be warranted to address proposed site-specific conditions. Based on the geotechnical data obtained to date, EEl is providing the following preliminary findings and conclusions relative to the proposed development: The subject property overall, is underlain by fine-grained, potentially compressible alluvium consisting predominantly of sandy-clays, clayey-sands, sandy-silts, and clayey-silts to a depth on the order of 15 feet bgs. Expansion test results completed by EEl indicate that clayey near- surface soils at the site have a medium to high expansion index (El) potential, with tested Els ranging from 53 to 122. During EEl's field exploration, groundwater was encountered across the site at depths of between 19 and 23 feet below the existing ground surface (bgs). This groundwater condition is considered a perched condition and review of pertinent references indicates historic regional groundwater depth in the vicinity is on the order of 50 feet bgs. There are no apparent geologic hazards that would place unusual constraints on the project; however, the site is located in a seismically active area and moderate to strong ground shaking from earthquakes should be anticipated and incorporated into project design. Additionally, the expansive nature of onsite materials will impact foundations and flatwork construction. The cohesionless nature of sandy alluvial soils may represent trench safety issues that will require consideration. To provide relatively uniform foundation support underlying the future building envelope and to reduce the potential for excessive post-construction settlement, remedial earthwork appears to be warranted to provide a sufficient layer of engineered fill beneath the footings/foundations. 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 crossing the site and the site is not within a Special Studies zone relative to active faulting. There are a number of faults in southern California that are considered active and could generate severe ground shaking, should they be the source of an earthquake. The closest of these faults is the Rose Canyon fault within approximately 7-miles west of the subject property. To provide relatively uniform foundation support underlying the future building envelope and to reduce the potential for excessive post-construction settlement, remedial earthwork appears to be warranted to provide a sufficient layer of engineered fill beneath the footings/foundations. Soils are likely to contain elevated moisture contents, which could potentially make earthwork very difficult for rubber tire heavy equipment. 11 Geotechnical Evaluation April 2, 2010 Proposed Lowe's of Carlsbad, California EEl Project No. LOW-70976.2 A conventional foundation system appears to be suitable for use to support the proposed Lowe's HIW Inc. building, provided the property is graded in general conformance with guidelines of the 2007 California Building Code (CBC), the City of Carlsbad and/or San Diego County, as well as guidelines presented in Lowe's Development Criteria, and the recommendations provided herein. Footings should be founded entirely in compacted fill material. Provided earthwork recommendations provided herein are adhered to during grading, EEl estimates that the maximum post construction settlement will be less than 1-inch. The maximum differential settlement estimated for the proposed Lowe's building is less than 4-inch over a horizontal distance of 50 feet. Decreasing the depth of THE remedial earthwork recommended herein may increase the total and differential amount of settlement to the point where they could exceed Lowe's 111W, Inc. construction tolerances. Laboratory test results indicate that native materials range from strongly acidic (pH 5.4) to mildly alkaline (pH 7.4), and are extremely corrosive to ferrous metals with minimum resistivity values of 352 ohms-cm and 1,080 ohms-cm. A Soluble sulfate concentration of between 168 mg/kg and 973 mg/kg, along with a chloride concentration of between 90 mg/kg and 337 mg/kg were reported, indicating a negligible to moderate corrosion potential to concrete. Consequently, Type II cement can be used in concrete that will be in contact with the encountered soils. Nitrate concentrations within the two tested samples were reported to be non-detect and 27 mg/kg, while the ammonium levels within the samples were reported as non-detect. These nitrate and ammonium concentrations are not considered to pose a corrosion threat to copper piping. 6.0 PRELIMINARY 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 most recent Division 02 Civil - Standard Site Specification and Project Special Provisions provided by Lowe's. 6.1 General Grading should conform to the guidelines presented in the 2007 California Building Code (CBC), the City of Carlsbad, and/or the requirements of San Diego County. Guidelines for site preparation, earthwork, and onsite improvements are provided in Division 02 Civil - Standard Site Specification and Project Provisions, Section 02300 (Earthwork) provided by Lowe's (2009). Additionally, general grading guidelines are provided herein and in Appendix C. During earthwork construction, removals and reprocessing of fill materials, as well as general grading procedures of the contractor should be observed and the fill placed should be selectively tested by representatives of the geotechnical engineer. 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 the 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 shall not be considered applicable unless the changes are reviewed and conclusions of this report modified or approved in writing by this office. 12 Geotechnical Evaluation April 2, 2010 Proposed Lowe's of Carlsbad, California EEl Project No. LOW-70976.2 It should be understood that if another firm besides EEl performs these functions, that firm would then assume responsibility as Geotechnical Engineer-of-Record. In this case, the firm should provide Lowe's and EEl with a letter indicating they have reviewed EEl's geotechnical report and accept the conclusions and recommendations. The letter should also provide any revisions to the recommendations deemed appropriate by the other firm. 6.2 Site Preparation and Grading Debris and other deleterious material, such as vegetation and organic topsoil, should be stripped from the site prior to the start of grading. Only soils containing 3 percent organic content (or less) may be re-used as fill soils onsite. EEl recommends that all foundations, elevator shafts, underground utilities, septic systems, cisterns, and cesspools be completely removed or abandoned following the City of Carlsbad and/or San Diego County Department of Health guidelines. Subsurface areas disturbed by building foundation, elevator shaft, and utility demolition should be properly backfilled. Areas to receive fill should be properly benched in accordance with current industry standards of practice and guidelines specified in the CBC, 2007. Existing utilities should be removed from the site. 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 All undocumented fill and the upper portions of the alluvial deposits at the site appear to be relatively variable in moisture content and somewhat variable in relative density. As such, they are considered unsuitable for the support of settlement-sensitive structures or additional fill in their current condition and should be removed and recompacted in the area of the proposed buildings and other settlement-sensitive improvements. Based on the results of our subsurface exploration, we anticipate that the removal and recompaction will extend to depths on the order of 8 to 10 feet below existing site grades. To provide uniform bearing conditions for the proposed building foundations, we recommend that the removals extend at least 24-inches below the bottoms of the proposed foundations or to the removal depth recommended above (whichever is deeper). In pavement areas, the 18-inches of pavement subgrade should be moisture conditioned to at least optimum moisture and be compacted to at least 95 percent of the maximum dry density (based on ASTM D-557). 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. The base of the removal areas should be level to avoid differential fill thicknesses under proposed improvements. 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 12-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 D-1557). 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. 13 Geotechnical Evaluation April 2, 2010 Proposed Lowe's of Carlsbad, California EEl Project No. LOW-70976.2 Based on the preliminary plans by Adams Engineering (2009) and existing topography, a cut-fill transition is anticipated to traverse to the proposed building pad area. In order to provide a uniform compacted fill beneath the building foundation and to reduce the potential for differential settlement across the cut-fill transitions, over excavation depths should extend to a minimum of 3 feet below finish pad grade or to such depths that to provide at least 24-inches of compacted fill beneath the bottom of footings (whichever is deeper). The over excavation limits should extend laterally beyond the building footprint at least 5 feet. Fill should be compacted by mechanical methods to at least 90 percent of the maximum dry density as determined by ASTM D1557. Where practical, over-excavation and/or removals should be excavated, extended at least ten feet outside the edge of footings/foundations, as well as ten feet outside the edge of the entryway and canopy, loading docks, and other appurtenances attached to the main building (Lowe's, 2006a). The limits of any over- excavation should be determined once a precise grading plan for the site with finish grade elevation(s) is made available. 6.4 Yielding Subgrade Conditions The soils encountered at the site can often exhibit "pumping" or yielding once they become saturated. This can often occur in response to periods of significant precipitation, such as during the winter rainy season, or if the bottom of an excavation is situated relative close to the groundwater level. In order to help stabilize the yielding subgrade soils within the bottom of the removal areas, the contractor can consider the placement of uniform sized, %- to 2-inch crushed rock within areas exhibiting the "pumping" conditions. The crushed rock should be properly tracked into the underlying soils such that it is adequately intruded into and interlocks with the soils. We expect that a 6- to 12-inch thick section of the crushed rock will be required. Following the placement and tracking of the gravel layer into the underlying "pumping" soils, it is recommended that Mirafi 600X stabilization fabric (or approved equivalent) then be placed upon the gravel layer. Fill soils, which should be placed and compacted in accordance with the recommendations presented herein, should then be placed upon the fabric until design finish grades are reached. The gravel and stabilization fabric should extend at least 5 feet laterally beyond the limits of the "pumping" areas. These operations should be performed under the observation and testing of a representative of EEl in order to evaluate the effectiveness of these measures and to provide additional recommendations for mitigative measures, as warranted. 6.5 Fill Placement Lowe's guidelines, Section 02300-Earthwork, specify that "clean" fill shall consist of well graded granular soils which are non-expansive and non-collapsible, and shall have less than 20-percent by weight passing the #200 sieve (Lowe's, 2007). Soils onsite exceed 20-percent fines, (by weight); however, Lowe's criteria allows for the use of onsite soils as fill materials provided they are identified in the geotechnical report. It is EEl's opinion that most of the onsite soils may be reused as fill soils within the building envelope onsite, excluding fat clays, highly expansive soils, organic debris and other deleterious materials. EEl recommends fill soils within the upper four feet should have a very low to low expansion potential (i.e., El < 50). Native soils with a medium expansion potential (i.e., El 90) may be placed as fill onsite, provided soils are placed at least 4 feet below finish grades or in areas away from improvements (such as buildings) that may be sensitive to differential vertical movement with a moisture content of at least 3 percent over optimum moisture content (based upon ASTM D-1556). As an option, fill soils that are expansive should be mixed with non-expansive soils to reduce the potential of swelling. Moisture conditioning the fill soils to at least three percent over optimum is recommended to help reduce post- grading expansion and/or consolidation. Maximum lift thickness should be 8-inches (uncompacted), and individually tested. Lowe's Development Criteria indicates that fill materials placed at depths below 11/2- 14 Geotechnical Evaluation April 2, 2010 Proposed Lowe's of Carlsbad, California EEl Project No. LOW-70976.2 foot of finish grade are to be compacted to a minimum of 92 percent of the maximum dry density according to ASTM D- 1557. Fill materials placed within 1 4-feet of finish grade should be compacted to at least 95 percent of the laboratory standard (ASTM D-1557) within the building envelope, walkways, and pavement areas. As a second option, select non-expansive import soils may be placed to cap the building envelope, to a depth of four feet. Characteristics of import soils should follow Lowe's criteria (Section 02300), and recommendations provided herein. Onsite earth materials containing rock fragments less than 6-inches in one dimension may be placed at depths of at least 3 feet below proposed finish grade within the building envelope, and at least 11/2 feet below proposed subgrade outside the building envelope. No fill materials should contain rock fragments exceeding 2-inches in one dimension within 3 feet of proposed finish grade within the building envelope and within 1 /2 feet of subgrade outside the building envelope (Lowe's, 2006a). Unless approved by Lowe's and/or EEl, rock fragments exceeding 12-inches in one dimension (if encountered) should not be placed within fill materials onsite. If import soils are to be used, the earthwork contractor should ensure that 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. The following table presents Lowe's earthwork guidelines for compaction and testing criteria. TABLE 3 LOWE'S COMPACTION CRITERIA Location or Area Lowe's Density per ASTM D 1557 Testing Frequency 1 Per Lift Per: Structures and Walkways 92% 20,000 sf Retaining Walls 92% 1,000 sf Trenches 92% 1501f Lawn and Unimproved Areas 90% 20,000 sf Building and Pavement Subgrades (Top 18 inches) 95% 10,000 sf Building and Pavement Subgrades (Below Top 18 inches) 92% 15,000 sf 4-inches of Building Base 98% 10,000 sf Asphalt and Concrete Base 98% 10,000 sf Out-Parcels 92% 20,000 sf Lowe's minimum compaction and testing requirements were taken from Section 600 Geotechnical Requirements of Lowe's Development Criteria; Section 02300-Earthwork and Section 02400-Aggregate Base Coarse. Lowe's did not provide a testing frequency for the base materials, EEl's recommendations are listed NA = Not Available During earthwork construction, removals and reprocessing of fill materials, as well as general grading procedures of the contractor should be observed and the fill placed selectively tested by representatives of EEl. 15 Geotechnical Evaluation April 2, 2010 Proposed Lowe's of Carlsbad, California EEl Project No. LOW-70976.2 6.6 Earthwork Balancing 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 onsite natural soils to be utilized as fill. This shrinkage factor 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. The above estimates are intended as an aid for project engineers in estimating earthwork quantities. It is recommended that site development be planned to include an area that could be raised or lowered to accommodate final site balancing. 7.0 FOUNDATION RECOMMENDATIONS 7.1 General In the event that plans concerning the proposed Lowe's FIIW building 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 following foundation recommendations assume that remedial earthwork will be performed at the site as described in Section 6.0 of this report to mitigate the potential for expansion and/or differential settlement. If, based on Lowe's cost-benefit analysis, alternative foundation systems for building support (such as a mat foundation system, waffle foundation system, etc.) are considered in lieu of complete remedial earthwork, EEl would be pleased to evaluate such systems upon request. 7.2 Foundation Design Conventional shallow foundations can be adequately supported on at least 24-inches of engineered fill compacted to at least 92 percent relative compaction (ASTM D 1557), which is underlain by improved onsite soils, as described in Section 6.0 of this report. In preparation for foundation construction, the earthwork contractor should ensure that the site has been prepared as recommended, and that field density tests have been performed to document the relative compaction of all structural fill. Footings can be designed to impose dead plus long term live load bearing pressures of 2,500 pounds per square foot (psf). The allowable soil bearing value is based on a footing having a minimum width of 12- inches and a minimum depth of 18-inches embedment below lowest adjacent finish grade. The allowable soil bearing pressure can be increased by 175 psf for each additional foot of embedment to a maximum value of 3,000 psf. The allowable soil bearing value can also be increased by one-third when considering load combinations that include transient loading, including wind or earthquake loads. 16 Geotechnical Evaluation April 2, 2010 Proposed Lowe's of Carlsbad, California EEl Project No. LOW-70976.2 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 0.25 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 225 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. Be advised that as part of the foundation design election process, there is always a cost/benefit evaluation. Although, we are recommending a specific foundation type, we have not accomplished the cost/benefit evaluation. Footing/foundation and slab reinforcement should be provided by the project structural engineer 7.3 Footing Setbacks All footings should maintain a minimum 7-foot horizontal setback from the base of the footing to any descending slope. This distance is measured from the outside footing face at the bearing elevation. Footings should maintain a minimum horizontal setback of H13 (H=slope height) from the base of the footing to the descending slope face and should be no less than 7 feet, and it need not be greater than 40 feet. Footings adjacent to unlined drainage swales or underground utilities (if any) should be deepened to a minimum of 6-inches below the invert of the adjacent unlined swale or utilities. 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. 7.4 Construction The following foundation construction considerations are presented as minimum recommendations from a soils engineering standpoint. Laboratory test results indicate the onsite soils' swell (expansion) potential is generally low to medium (i.e., 205 El <90). During grading of the site, we recommend that medium or highly expansive soils material (i.e., El> 50 percent) encountered should not be placed within 4 feet of finish grade, if possible. Design parameters provided herein, therefore, assume that finish grade soil materials will have a low expansion potential. Recommendations by the project's design-structural engineer or architect, which may exceed the soils engineer's recommendations, should take precedence over the following minimum recommendation. Final foundation design should be checked based on the expansion potential of the near surface soils encountered during grading. 17 Geotechnical Evaluation April 2, 2010 Proposed Lowe's of Carlsbad, California EEl Project No. LOW-70976.2 7.5 Concrete Slab-on-Grade Cast-in place concrete guidelines are provided in Lowe's criteria, Section 03300 (2008a). Interior slabs should be supported solely by competent structural fill possessing a very low to low expansion potential, whose placement has been observed/tested by the EEl (i.e., the project soils engineer/engineering geologist). Lowe's building design criteria (Section 300) specify that the concrete slab shall be at least 5- inches. The concrete slab should have steel reinforcement designed by the structural engineer, per Lowe's requirements, or in accordance with the guidelines of the local governing jurisdiction. For slab- on-grade concrete areas that will be impacted by heavy storage racks and fork-lift traffic, a modulus of subgrade reaction of 125 psi/in can be used in design. The concrete slab should be placed over at least 4- inches of free draining, crushed rock or gravel or Caltrans Class 2 aggregate base material compacted to 98 percent relative compaction (AS1'M D-1557) (Lowe's, 2006a, 2008a). To reduce the potential for potential buildup of hydrostatic pressures, the free draining material under the slabs should have positive drainage with no depressions created. In-place density testing of the aggregate slab base should be completed no more than 48 hours prior to concrete placement (Lowe's, 2008a). Exterior slabs, such as walkways and driveways, can be adequately supported on approved structural fill that is a minimum of 12-inches in thickness, and is compacted to at least 95 percent relative compaction (ASTM D-1557) with at least two percent over optimum moisture content. 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 by EEl to 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. The moisture content of fill materials should be maintained until footings/foundations are poured and a vapor barrier is installed (if required by the plans). Lowe's Criteria dictate that Portland cement concrete should have a minimum 28 day compressive strength of at least 4,000 pounds per square inch (psi). As noted above, soluble sulfate results were reported to be between 168 and 973 milligrams per kilogram (mg/kg) with a chloride concentration of between 90 and 337 mg/kg (or ppm). As a result, onsite soils appear to have a moderate corrosion potential to concrete. Based on this information, Type II cement can be used in concrete that will be in contact with the encountered soils. 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 adversely affect the finished quality of the concrete and result in cracking and spalling of the slab. We recommend 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 windy, hot or cold weather conditions. Proper control joints and/or reinforcing steel should be provided in accordance with the structural engineer's requirements to reduce the potential for damage resulting from shrinkage. 18 Geotechnical Evaluation April 2, 2010 Proposed Lowe's of Carlsbad, California EEl Project No. LOW-70976.2 Due to the potential for lateral vapor migration to occur associated with seasonal moisture change and differences between the building interior and exterior ambient conditions, consideration should be given to the use of a vapor inhibitor in areas of the building where floor coverings are proposed. Lowe's criteria Section 03300 (2008) dictates that at least 10 millimeter visqueen should be used. For slab-on-grade, the visqueen layer should be placed on top of the crushed gravel or aggregate base and protected from puncturing by a minimum 2-inch layer of clean sand. To reduce the potential for curling, a 2-inch layer of sand with a minimum sand equivalent (SE) of 25 should be placed between the concrete slab and visqueen (or equivalent). 7.6 Retaining Walls The design parameters provided below assume that non-expansive granular 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 may be provided upon request. Building walls below grade should be water-proofed 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 12-inches below adjacent grade (excluding 6-inch landscape layer). There should be no increase in bearing capacity for footing width. Recommendations pertaining to "landscape" walls (i.e., Crib, Loffel, Earthstone, Geogrid, etc.) may vary from those provided herein, and shall be provided upon request. 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 appropriate for cantilevered walls retaining level backfill soils comprised of non-expansive granular soils, subject to lateral deflection at distances above grade due to earth pressure. A safety factor for sliding and overturning of 1.5 is typically utilized in the design of a cantilevered structure as described. Restrained walls, with a level backfill, should be designed for an equivalent fluid pressure of 60 pcf for at-rest pressure and 225 pcf for passive pressure. Drainage should be provided behind all retaining walls. The drainage system should consist of a minimum of four-inch diameter perforated PVC pipe (schedule 40) placed at the base of the retaining wall and surrounded by washed 3/4-inch drain rock wrapped in a Mirafi 140N filter fabric, or equivalent approved by the geotechnical engineer. The drain rock wrapped in fabric should be at least 12 inches wide and extend from the base of the wall 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 tied to the storm drain system or other suitable outlet. 8.0 PRELIMINARY PAVEMENT DESIGN RECOMMENDATIONS and EARTHWORK Deleterious material, excessively wet or dry pockets, concentrated zones of oversized concrete and/or rock fragments, and other unsuitable yielding materials encountered during grading should be removed. Once existing compacted fill and/or native soils are brought to proposed pavement subgrade elevations, the subgrade should be proof-rolled in order to check that a uniform firm and unyielding surface is exposed. All grading and fill placement should be observed by representatives of EEl. 19 Geotechnical Evaluation April 2, 2010 Proposed Lowe's of Carlsbad, California EEl Project No. LOW-70976.2 As indicated in the Lowe's development criteria, the upper 18-inches of pavement subgrade soils should be moisture conditioned to at least optimum moisture content and compacted to at least 95-percent of the laboratory standard (ASTM D-1557). Rock fragments over 2-inches in one dimension are not allowed within the upper 18-inches of subgrade (Lowe's, 2008a). If loose materials are encountered during subgrade preparation, evaluation should be performed by the project geotechnical engineer at that time. Class 2 aggregate base used in the pavement structural section should be properly prepared (i.e., processed and moisture conditioned) and compacted to at least 98 percent of the representative laboratory standard ASTM D-1557 (Lowe's, 2006a). Aggregate base material should conform to Caltrans specifications for Class 2 aggregate base (minimum "R" value = 78). 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, base rock, asphalt, and/or asphalt concrete. Laboratory testing of upper earth materials obtained from the proposed pavement areas indicated a R- Values of 15 and 13 (Appendix B). Pavement design was calculated for the parking lot structural section requirements for flexible and rigid pavement using Lowe's development guidelines. Based upon the nature of materials anticipated to be exposed at subgrade and the anticipated traffic loadings for a fifteen year design life, EEl recommends the pavement structural sections presented in Tables 4 and 5. For design purposes, Traffic Index (TI) values of 5.5 and 7.0 were utilized for parking areas and truck areas, respectively. An R-Value of 5 was used in our calculations. A modulus of subgrade reaction (k-value) was estimated at 65 pounds per square inch per inch (psi/in) for an R-Value of 5 (Lindeburg, 1994). I . TABLE 4: FLEXIBLE PAVEMENTSTRUCTUALSECTION Design Location Daily Vehicles Ti Aggregate Base Material Asphalt Concrete Parking Areas 2,500 Passenger Vehicles 5.5 12.0-inches 3.0-inches Truck Areas 25 Trucks 7.0 15.5-inches 4.0-inches Note: Minimum thickness per Lowe's Development Criteria, Section 600. TABLE 5 RIGID PAVEMENT STRUCTURAL SECTION Design Location Daily Vehicles Base Material Portland Cement Concrete (4,000 psi)(') Automobile Circulation 2,500 Passenger Vehicles 4.0-inches (I 5.0-inches Area Truck Circulation Area 25 Trucks 4.0-inches 6.0-inches Note: Minimum thickness per Lowe's Development Criteria, Section 600. (2) Reinforcement to be provided in accordance with structural engineer's requirements 20 Geotechnical Evaluation April 2, 2010 Proposed Lowe's of Carlsbad, California EEl Project No. LOW-70976.2 The recommended pavement sections provided 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 ADTI' (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 checked by testing of soils exposed at subgrade after grading has been completed. This final pavement design could result in thinner or thicker pavement structural sections than the preliminary recommendations presented above. 9.0 DEVELOPMENT RECOMMENDATIONS 9.1 Landscape Maintenance and Planting 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. 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 processed for the addition of amendments, the processed soils should be re-compacted to at least 90 percent relative compaction (based on AS1'M D- 1557). 9.2 Site Drainage Positive site drainage should be maintained at all times. Drainage should not flow uncontrolled over slopes or the subject parcel. Runoff should be channeled away from slopes and structures and not allowed to pond and/or seep into the ground. Pad drainage should be directed toward an acceptable outlet. Although not required from a geotechnical standpoint, roof gutters and down spouts may be considered to control roof drainage, discharging a minimum often-feet from proposed structures, or into a subsurface drainage system. 9.3 Stormwater Disposal Systems It is EEl understanding that current plans call for runoff generated from the facility to be disposed of in engineered subsurface features onsite. 9.3.1 Percolation Testing As noted above, our subsurface exploration program for the proposed Lowe's 1-11W included the drilling, logging and sampling of two (2) exploratory borings to the south of the existing building, in the area to receive the proposed stormwater infiltration system. Boring B-21 (P-i) was advanced to an approximate depth of 10 feet below the existing ground surface, while boring B- 22 (P-2) was extended to a depth of approximately 10.5 feet below existing grade. A minimum 2-inch layer of V2-inch diameter crushed gravel was placed at the bottom of the excavations prior to testing. The approximate locations of our borings/percolation tests are provided on Figure 3. 21 Geotechnical Evaluation April 2, 2010 Proposed Lowe's of Carlsbad, California EEl Project No. LOW-70976.2 Percolation testing was conducted by one of EEl's engineering technicians under the guidance of a California licensed engineering geologist and civil engineer with EEl. 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 10 minute intervals. This procedure was repeated for the test hole until rates varied generally less than 10 percent for the test hole. Upon conclusion of testing, the perforated pipe was removed and the test excavation was backfilled. Results of percolation testing are presented in the following table, Table 6. TABLE 6 Summary of Percolation Test Results T Test Test Depth of Test Stabilized Percolation Rate Recommended Percolation Pit/Boring (feet below existing grade) (mm/in and in/hr) Rate for Design (in/hr) P1 B-21(P1) 10 42 and 1.4 1.4 P2 B-22 (P2) 10.5 83 and 0.7 0.7 9.3.2 Summary of Findings Measured results, completed in soils underlying the proposed locations to receive subsurface stormwater retention/disposal devices (see Figure 3), indicate soils with poor to moderate percolation rates (approximately 1.4-inches per hour at a depth of 10 feet bgs and 0.7-inches per hour at a depth of 10.5 feet. As noted in Section 4.2.3 of this report, groundwater was encountered in some of our exploratory borings at depths of 19 to 23 feet bgs. As such, it is anticipated that groundwater will be at least 10 feet below the bottom of the proposed stormwater infiltration system, assuming the infiltration system will be installed at depths comparable to those where percolation testing was performed. 9.3.3 Structural Setback from Retention Devices It is recommended that retention/disposal devices be situated at least three times their depth, or a minimum of 15-feet (whichever is greater), from the outside bottom edge of structural foundations. Structural foundations include (but are not limited to) buildings, loading docks, retaining walls, and screen walls. 9.3 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 are planned for the site, recommendations concerning the design and construction of improvements would be provided upon request. 22 Geotechnical Evaluation April 2, 2010 Proposed Lowe's of Carlsbad, California EEl Project No. LOW-70976.2 9.4 Trenching Shallow vertical excavations exposing compacted fill may be unstable, and should be properly shored and/or sloped at a minimum temporary gradient of 1:1 (horizontal to vertical) to a maximum height of 5 feet without further evaluation. Temporary excavations over 5 feet in height should be evaluated by the project engineer, and will likely require shoring, sloping, or a combination thereof. Deeper vertical excavations below the fill materials are anticipated to encounter soft and/or saturated alluvial soils and should be evaluated by the project soils engineer. Sloping at a minimum gradient of 1:1 (horizontal to vertical), shoring, or a combination of the two will likely be required. 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 92 percent (based on ASTM D-1557) if not removed from the site. All excavations should conform to OSHA and local safety codes. 9.5 Backfill Any underground utilities excavated at or near the perched groundwater surface, encountered at a depth of 19 to 23 feet bgs during our recent field exploration, should be anticipated to require special backfill procedures and/or de-watering. Tentatively, the utilization of gravel backfill wrapped with filter fabric, or slurry backfill may be considered. The method and means of backfill proposed by the contractor should be evaluated by the owner and geotechnical consultant prior to the start of construction. 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 92 percent of the maximum dry density as determined in accordance with ASTM D-1557 (Modified Proctor). The geotechnical engineer should approve all backfill material. Select material should be used when called for on the drawings, or when required by the geotechnical engineer. Rock fragments greater than 3-inches in one dimension are not allowed per Lowe's standard criteria (Section 02300, Part 2). 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. All pipe backfill areas should be graded and maintained in such a condition that erosion or saturation will not damage the pipe bed or backfill. 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 backfihled 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 detailed site grading and foundation 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 are found to differ substantially from those anticipated herein, appropriate recommendations would be provided. Additional field studies may be warranted. 23 Geotechnical Evaluation ' April 2, 2010 Proposed Lowe's of Carlsbad, California EEl Project No. LOW-70976.2 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 Lowe's (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 shall 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 which 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. 24 Geotechnical Evaluation April 2, 2010 Proposed Lowe's of Carlsbad, California EEl Project No. LOW-70976.2 12.0 REFERENCES Adams Engineering, 2009, "Preliminary Site Plan, Lowe's of: Carlsbad, CA," dated August 6. 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., 2000, "EQFAULT, version 3.0", a Computer Program for Probabilistic Estimation of Peak Acceleration from 3-D Fault Sources," Thomas F. Blake Computer Services and Software, Newbury Park, California. Blake, T., 2000b, "FRISKSP, version 4.00", a Computer Program for Probabilistic Estimation of Peak Acceleration and Uniform Hazard Spectra Using 3-D Faults as Earthquake Sources," Thomas F. Blake Computer Services and Software, Newbury Park, California. California Building Code (CBC), 2007, California Code of Regulations, Title 24, Part 2, Volume 2 of 2, California Building Standards Commission, Based on 2006 International Building Code; 2007 California Historical Building Code, Title 24, Part 8; and 2007 California Existing Building Code, Title 24, Part 10, effective January 1. California Department of Transportation (Caltrans), 1974, Highway Design Manual, dated October 1. California Department of Water Resources (CDWR), Water Data Library (WDL) Website, accessed January 2010 (http://wdl.water.ca.gov/gw/map/index.cfin). California Division of Mines and Geology (CDMG), 1995, Landslide hazards in the Northern part of the San Diego Metropolitan Area, San Diego County, California, Open File Report 95-04. California Division of Mines and Geology (CDMG), 1997, Guidelines for Evaluating and Mitigating Seismic Hazards in California, Special Publication 117, adopted March 13, revised and re-adopted by California Geological Survey September 11, 2008. 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 Department of Conservation Division of Mines and Geology (CDMG), 1998, Maps of Known Active Fault Near-Source Zones in California and Adjacent Portions of Nevada, published by International Conference of Building Officials, dated February. California Geological Survey (CGS), 2002, California Geomorphic Provinces Note 36, Electronic Copy, Revised December 2002. CivilTech Software (CivilTech), 2003, LiquefyPro: Liquefaction and Settlement Analysis, Version 5 and Later, dated February 3. Coduto, D. P., 2001, Foundation Design Principles and Practices, Second Edition. 25 Geotechnical Evaluation April 2, 2010 Proposed Lowe's of Carlsbad, California EEl Project No. LOW-70976.2 DeLORME, 1999, 3-1) TopoQuads, California South, Region 7. EEl, 2010, Geotechnical Evaluation, Proposed Retail Development, Palomar Airport Commons, SWC of Palomar Airport Road and El Camino Real, Carlsbad, San Diego County, Project No. SUD-70986.1, dated January 13, 2010 Google Earth®, 2008, Version 4.0. 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 (CDMG), Map Sheet No. 6, scale 1:750,000. Leighton Consulting Group, Inc., 2006, Geotechnical Investigation, Proposed Athletic Club, Southwest of Palomar Airport Road and El Camino Real, Carlsbad, California, Project No. 600854-002, dated June 23, 2008. Leighton Consulting Group, Inc., 2008, Geotechnical Plan Review and Addendum Recommendations, Proposed Athletic Club, Carlsbad, California, Project No. 600853, dated January 22, 2008. Lindeburg, Michael, R., 1994, Civil Engineering Reference Manual, Sixth Edition, Appendix C, Professional Publications, Inc. Lowe's HIW, Inc., 2005, Building Design Criteria - Section 300, Lowe's Development Criteria, dated September 6. Lowe's HIW, Inc., 2006a, Geotechnical Requirements - Section 600, Lowe's Development Criteria, dated October 23. Lowe's HIW, Inc., 2007, Site Specifications, Sections 02300, 02305, 02400 and 02800, dated October 9. Lowe's HIW, Inc., 2008a, Cast-In-Place Concrete - Section 03300, dated March. Lowe's HIW, Inc., 2008b, Site Design Criteria - Section 200, Lowe's Development Criteria, dated February 8. Lowe's HIW, Inc. 2008c, Site Development Criteria Plan 103K Deep, Drawing No. SP-1, dated March 1. Seed, R.B., Cetin, K.O., Moss, R.E.S., Kammerer, A.M., Wu, J., Pestana, J.M., Riemer, M.F., Sancio, M.F., Bray, J.D., Kayen, R.E., and Fans, A., 2003, Recent Advances in Soil Liquefaction Engineering: A Unified and Consistent Framework, Earthquake Engineering Research Center, 26th Annual ASCE Los Angeles Geotechnical Spring Seminar, Keynote Presentation, H.M.S. Queen Mary, Long Beach, California, Report No. EERC 2003-06, College of Engineering-University of California, Berkeley, dated April 30. San Diego Regional Water Quality Control Board (SDRWQCB), Region 9, 1994, Water Quality Control Plan: California State Water Resources Control Board Publication. Sowers and Sowers, 1970, Unified Soil Classification System (After U. S. Waterways Experiment Station and ASTM 02487-667) in Introductory Soil Mechanics, New York. 26 Geotechnical Evaluation April 2, 2010 Proposed Lowe's of Carlsbad, California EEl Project No. LOW-70976.2 Tokimatsu, K. and Seed, H.B., 1997, "Evaluation of Settlements in Sands Due to Earthquake Shaking," American Society of Civil Engineers Journal of Geotechnical Engineering. Vol. 113, No. 8, PP. 861-878. United States Geological Survey (USGS), 1997, 7.5 Minute Topographic Map, San Luis Rey, California Quadrangle, Scale 1:24,000. United States Geological Survey (USGS), 2002, Earthquake Hazards Program, Interpolated Probalistic Ground Motion for the Conterminous 48 States, http://earthquake.usgs.gov/research/hazmaps/design/ United States Geological Survey (USGS), 2007, Earthquake Ground Motion Parameters, Version 5.0.8, dated November 20, 2007. United States Department of Agriculture (USDA), Natural Resources Conservation Center Website, Web Soil Survey, accessed January 2010 (http://websoilsurvey.nrcs.usda.gov/appfWebSoilSurvey.aspx). Weber, F.H., 1982, Recent Slope Failures, Ancient Landslides and Related Geology of the Northern- central Coastal Area, San Diego County, California: California Division of Mines and Geology, Open File Report 82-12LA, Tip. Youd, et.al., 2001, "Liquefaction Resistance of Soils: Summary Report from the 1996 NCEER and 1998 NCEER/NSF Workshops on Evaluation of Liquefaction Resistance of soils", American Society of Civil Engineers, Journal of Geotechnical and GeoEnvironmental Engineering, Vol. 127, No. 10, pp. 817-833. 27 Geotechnical Evaluation April 2, 2010 Proposed Lowe's of Carlsbad, California EEl Project No. LOW-70976.2 FIGURES , VICINITY - LIJ /,>1 .Le J PL VI Cerro eICaaera \ el ' It AM CA WAY\ , P 0 10 06 1-- OQ- 540 DE RJ t?i kit Hinton JT[faI; mw OR 7 4vjf--- k1t .rror / Z IL 4/ <I SITE VICINITY RD VA ml \\ \ -ILI -I— < 0 -\ COor 4Cte 9Iar CR CJSMOSCT rn JZ Lu ca 0 72> IM 7GOLD FLQRRJL f m L~-J G bOVE j OR N ;' AA F ALGA RDul NA S7,4 J_ I u Pont t;p L7 RL/NG v5 ' Ils/J1ri Map Source: 2007 DeLornie. Topo USA 7.0 West Region SITE VICINITY MAP [OWES HIW Palomar Airport Road Scale: I 4000 Carlsbad, California = EEl Project No. LOW-70976.2 I) V 24(0) II' 4000 FT 80()0 FT Created March 2010 Note: All locations are approximate El.. - FIGURE 1 RI kit I) RI: clv SUlk i)\IF JAB RI 515111k No Scale: 1" =200' a rr 120 FT 200 FT 400 FT Note: All locations are approximate AERIAL SITE MAP LOWE'S HIW Palomar Airport Road Carlsbad, California EEl Project No. LOW-70976.2 Created March 2010 (RI AIIDR, U' JAB REVISION DA1 F gEEI. RF\ O,I(IN No FIGURE 2 Geotechnical Evaluation April 2, 2010 Proposed Lowe's of Carlsbad, California EEl Project No. LOW-70976.2 APPENDIX A SOIL CLASSIFICATION CHART AND BORING AND TRENCHLOGS TRENCH LOGS Project No. LOW-70976.2 Date: February 23, 2010 Equipment: Case 580 SL 4X4 backhoe Logged by: JB Trench No. T-1 Depth USCS Description @0-4.5' CL Alluvium Gray and orange- brown, wet, sandy CLAY, appears soft to firm, abundant scattered roots and rootlets; porous; with some calcium carbonate stringers @ 4.5-7.5' SC Light Gray, wet, Clayey SAND, mottled; root hairs; some calcium carbonate @7.5'- 10' CL-MI Santia2o Formation (Weathered) Gray and olive-brown, moist to very moist, clayey Siltstone, appears stiff; oxidized ; weathered Bulk sample® 1'-5' Total Depth = 10 feet No groundwater encountered No caving Back.fihled 2 -23 -10 1 TRENCH LOGS Project No. LOW-70976.2 Date: February 23,2010 Equipment: Case 580 SL 4X4 backhoe Logged by: ffi Trench No. T-2 Depth IJSCS Description @0-1' SC Eu Orange-brown, clayey SAND, moist, loose, some scattered roots and rootlets; a few scattered cobbles up to 4 inch noted SM Light gray, moist to wet, loose, some rootlets @39-69 CL Orange-brown, wet, sandy CLAY, a few scattered roots up to 1" thick @61-12' SM Alluvium Gray, silty SAND, trace clay, saturated, loose, with zones of porous; abundant organics; heavy organic layer at 7-81; large roots up to 1-1/2" thick @12'- 15.5' SC Yellow gray, clayey fine SAND, moist, appears loose, mottled; scattered roots and rootlets Total Depth = 15.5 feet (maximum reach of backhoe) Slight seepage @ 8 feet Some caving @ 3 feet Backfilled 2 -23 -10 2 TRENCH LOGS Project No. LOW-70976.2 Date: February 23, 2010 Equipment: Case 580 SL 4X4 backhoe Logged by: j Trench No. T-3 DeDth USCS Soil Description Fill @0-6.5' SM Brown to orange brown, silty SAND, moist to very moist, loose, some scattered cobbles up to 4-inch in size; piece of plastic PVC pipe noted @6.59- 8' SC Gray brown, clayey SAND, moist to wet, porous; scattered wood fragments; rootlets Alluvium @8'-10' CL Gray and orange-brown sandy CLAY, wet, root hairs; porous @10'- 15' SC Bulk sample @ 11,-15' Total Depth = 15 feet No groundwater encountered No caving Backfihled 2-23 -10 Gray to dark gray, silty and clayey fine to medium SAND, wet, abundant organic layers with roots up to 1" thick. 91 TRENCH LOGS Project No. LOW-70976.2 Date: February 23,2010 Equipment: Case 580 SL 4X4 backhoe Logged by: ffi Trench No. T-4 Depth USCS Soil Description Fill @0-2' SM Gray brown, silty SAND, damp to moist, loose, some organics; scattered rootlets @29- 4' CL Gray-green, silty CLAY, wet SC Gray and orange brown, clayey SAND, moist to very moist, mottled @59- 7' CL Orange-Brown and gray, sandy CLAY, wet, mottled Alluvium @7'-10' SM Gray, silty SAND, trace clay, wet, loose; scattered rootlets and roots @109-13' CL-SC Dark gray, sandy Clay and clayey fine SAND; very moist to wet, appears soft; abundant organics; roots up to 1" thick noted 13'-15' SC Gray and yellow gray, clayey fine SAND, wet, mottled; some roots; possible highly weathered formation at 15' Total Depth =15 feet Minor seepage at 15 feet No caving Backfihled 2-23-10 4 TRENCH LOGS Project No. LOW-70976.2 Date: February 23, 2010 Equipment: Case 580 SL 4X4 backhoe Logged by: ffi Trench No. T-5 Depth USCS Soil Description Fill @0-3' SC Light brown, clayey fine SAND, wet, loose, abundant scattered roots near surface Topsoil/Residual soil @3-5' CL Orange-gray silty CLAY with some fine sand, damp to moist, stiff, porous; some scattered rootlets and root hairs CL-CU Light brown, silty CLAY, wet, stiff SantiaEo Formation (weathered) @7'- 11' ML Light gray-yellow, clayey silt, wet, appears medium stiff mottled, very weathered and fractured siltstone; oxidized Bulk sample @ 8'-10' Total Depth = 11 feet No groundwater encountered No caving Backfiiled 2-23-10 TRENCH LOGS Project No. LOW-70976.2 Date: February 23, 2010 Equipment: Case 580 SL 4X4 backhoe Logged by: j Trench No. T-6 Depth USCS Soil Description Fill @0-3' SC Brown, clayey SAND, moist to wet, loose, some scattered pieces of plastic, wood, branches, and concrete noted up to 8 inches in size @ 3'-5' CL Dark gray, sandy CLAY, wet, abundant organics; roots/ rootlets Santiago Formation (weathered) SM/SC Orange-brown and gray, silty and clayey fine SAND, moist, mottled, minor iron oxide staining; very weathered Bulk sample @ 5-8' @8-10' CL Total Depth = 10 feet No groundwater encountered No caving Backfihled 2-23-10 Orange-gray and gray, silty CLAY, wet, mottled; very weathered; oxidized Geotechnical Evaluation April 2, 2010 Proposed Lowe's of Carlsbad, California EEl Project No. LOW-70976.2 APPENDIX B LABORATORY TEST DATA EXPANSION INDEX TEST ASTM METHOD D 4829 Sample T6@5ft : Moisture Content of Initial Sample Tare No. Wet Weight and Tare (g) - Dry Weight and Tare (g) - Tare Weight (g)- 8.1 Water Loss (g) - 11.2 DiyWeight(g) - 91.4 Initial Moisture (Vo) - 12.3 % Saturation of Re-molded Sample Wt. of Soil and Ring (g):561.2 Ring Weight 199.1 Wet Weight of Soil (g) - 362.1 Dry Weight of Soil (g) - 322.6 Volume of Ring (&) - 0.0073 Dry Density (pcf) - 97.4 Initital Saturation f%) - 45.4 Moisture Content of Final Sample Vt. of Soil and Ring (g) - 603j RingWeight(g) - 199.1 Wet Weight of Soil (g) - 403.9 Dry Weight of Soil (g) - 322.6 Weight of Water (g) - 81.3 Final Moisture ('/o) 25.2 Final Saturation (%) - 93.3 Expansion Test - USC (144 PSF) Date Time Reading Add Weight 10 Minutes .:.:::: 10:•i5 IAdd Water j-: 1140 0050- - 0053 [nitial Reading Final Reading Elmeasured = 53 El50 = 50 Expansion Index, E150 Potential Expansion 0-20 Very Low 21-50 Low 51-90 Medium 91-130 High >130 Very High Client: Lowe's rc c trou-9j,' E E I Geotethnlcaf & Environmental Solutions 2195 Faraday Avenue, Suite K, Carlsbad, CA 92008 Name: Lowe's Carlsbad Job Number: LOW-70976.2 Date: 3-11-10 Boring Number: T6 Depth: 5 feet Soil Description: Lean clay with sand, CL Tested by: BD EXPANSION INDEX TEST ASTM METHOD D 4829 Moisture Content of Initial Sample Tare No. - Wet Weight and Tare (g) - Dry Weight and Tare (g) - Tare Weight (g)- 8.1 WaterLoss(g) - 11.6 Dry Weight (g)- 80.3 Initial Moisture (%) - 14.4 % Saturation of Re-molded Sample Wt. of Soil and Ring (g) - Ring Weight (g) ::. Wet Weight of Soil (g)- 357.0 DryWeightofSoil(g) - 311.9 Volume of Ring (ft3) - 0.0073 Dry Density (pcf) - 94.2 Initital Saturation (%) - 49.5 Moisture Content of Final Sample Wt. of Soil and Ring (g) - 617. 1 Ring Weight (g) - 199.2 Wet Weight of Soil (g) - 417.9 DryWeightofSoil(g) - 311.9 Weight of Water (g) - 106.0 Final Moisture (Vo) 34.0 Final Saturation (%) - 116.3 Expansion Test - UBC (144 PSF) Date Time Reading Add Weight 3/10/2010 - 11 33 ... - 0 000 -. 10 Minutes . . .: Add Water . .- - - 12 15 0 039 0102-- -. [nitial Reading Final Reading Elmeasured = 123 El50 = 122 Expansion Index, E150 Potential Expansion 0-20 Very Low 21-50 Low 51-90 Medium 91-130 High >130 Very High Client: Lowe's Project Name: Palomar Commons It c EEl Geotethnlcal & Envlronmentai Solutions Job Number: LOW-70976 Date: 3-10-10 Boring Number: BI Deoth: 0-5 feet CL 2195 Faraday Avenue, Suite K, Carlsbad, CA 92008 EXPANSION INDEX TEST ASTM METHOD D 4829 Sample: B9@O-5ft : Moisture Content of Initial Sample Tare No. - Wet Weight and Tare (g) - iO4.1 Dry Weight and Tare (g) - .95.0 Tare Weight (g) - 8.2 Water Loss (g) - 9.1 Dry Weight (g)- 86.8 Initial Moisture (Yo) - 10.5 % Saturation of Re-molded Sample Wt. of Soil and Ring (g) Ring Weight (g) - Wet Weight of Soil (g) - 410.3 Dry Weight of Soil (g) -371.4 Volume of Ring (&) - 0.0073 Dry Density (pcf) - 112.2 Inilital Saturation V/0) - 56.4 Moisture Content of Final Sample Wt. of Soil and Ring (g) - 6197 Ring Weight (g) - 189.1 Wet Weight of Soil (g) - 430.6 Dry Weight of Soil (g) - 371.4 Weight of Water (g) - 59.2 Final Moisture (V/o) 16.0 Final Saturation ('%) - 85.7 Expansion Test - UBC (144 PSF) Date Time Reading Add Weight 10 Minutes :•• 3:21.—: Add Water 0-.007 745 0009 - 915 - 0009 [nitial Reading Final Reading Elmeasured = 9 El50 = 12 Expansion Index, Elso Potential Expansion 21-50 Low 51-90 Medium 91-130 High >130 Very High Client: Lowe's SEEI Geotethnical & Environmental Solutions Project Name: Lowe's Carlsbad Job Number: LOW-70976.2 Date: 3-9-10 Boring Number: B9 DeDth: 0-5 feet Soil SM 2195 Faraday Avenue, Suite K, Carlsbad, CA 92008 1 Tested by: BD SAMPLE INFORMATION Sample Location: B-17 © 0-5' Sample Description:Light Yellow Brown Clay Notes: Lowe's, LOW-70976 Notes:Palomar Airport 0% Retained on 314 inch sieve Test Method: Cal-Trans Test 301 R-Value By Exudation DESIGN CALCULATION DATA Traffic index, assumed 5.0 Gravel equivalent factor, assumed 1.25 Expansion, stability equilibrium 1.21 R-Value by expansion 5 R-Valuey exudation 6 R-Value at equilibrium S Expansion, Stability Equilibrium 3.00 0.00 0.00 0.50 1.00 1.50 2.00 2.50 3.00 Cover Thickness by Expansion Pressure (ft) "NONE 0 00 0 MEN EMMEMEMEMEM ••au•••u•u ••• R•UU••W4• Ilion::1 11111110 ::: viuiupoji III1IINI S•• U .• _...._.....• •••UU•UU•U UUUUUUUU•UUU•!UU•UUUU•N•U• MWINMMMMMI -...........,........... u. MISEEME u•u•••Uu•uuu•uuu••••U MMIFF a INURE•NU•u•••••U•••••UUU••UUU MEMO 00 00 EMMIM U :_rlU YRUU••••UUUURUUU•U•U•U••U U ....:::::i TEST SPECIMEN A B C D Compactor air pressure PSI 180 130 70 Water added % 1.9 49 - 5.8 Moisture at compaction % 16.1 21.1 22.0 Height of sample IN 2.46 2.6 2.52 Dry density PCF 108.6 102.8 100.8 R-Value by exudation 9 8 5 R-Value by exudation, corrected 9 - 8 5 Exudation pressure PSI 557 414 285 Stability thickness FT 1.16 1.18 1.22 Expansion pressure thickness FT 2.57 - 2.07 1.10 GeoSoils, mo. 4015741 Palmer Way Carlsbad, CA 92008 Telephone: (760) 430-3155 Fax: (760) 931-0915 R - VALUE TEST RESULTS Project EEl -. Number: 5932.11-A-SC Date: Mar-ID Figure: 1 2.50 2.00 ra.U••u•I.a.•umU•uu ..•• 0.00.. , 0.00 0.50 1.00 1.50 .00 2.50 3.00 Cover Thickness by Expansion Prassure (ft) •••••I• ........ U•••UUUUUU!4N MEMEME auuua.......uiiium ••uw ..•.iii NU.Ul.U..IUNUIli.... ....suI. .U.uuIiWi•iu... wuuu.. UR1UIl...UU...IIUI!41UUUU. SIIIU..wu..uu.u•rAuU....u. lIIIau1u..IIUuii........ ON sIuuNu....uI'1ua.u.... OEM" IU •U UU U IIIU • IIIUUM.urlU*UlII••I..... 1IIN•U1UUUUNII•uU•uUU III...rl.uNIiIuu... No IN. U IU lUll UUlUUII1RkuIUuI.I UrNUIIUI.*u....m.I r...u.lu.m.u.....IIu MEMMIN •u.....uuIu•u!u. .UpUB •...muIIBPa•....u. UI UI NI •• u p NEEIREM UIU UU U OW U•U Nis" U.... ..... N•Ui R-Value By Exudation 100 90 80 70 60 50 40 30 20 10 0 TEST SPECIMEN A Compactor air pressure PSI 270 - 180 - 150 - Water added % 3.0 4.0 5.1 Moisture at compaction - % 14.0 15.0 16.1 Height of sample IN 2.41 2.5 2.5 Dry density PCF 116.5 112.8 - 111.9 R-Value by exudation 16 13 10 R-Value by exudation, corrected 15 13 10 Exudation pressure PSI 451 300 209 Stability thickness FT 1.08 1.11 1.15 Expansion pressure thickness FT 0.93 0.33 0.13 SAMPLE INFORMATION DESIGN CALCULATION DATA Traffic index, assumed 5.0 Gravel equivalent factor, assumed 1.25 Expansion, stability equilibrium 0 R-Value by expansion NA R-Value by exudation 13 R.-Value at equilibrium 13 Expansion, Stability Equilibrium Sample Location: B-20 @ 0-5' Sample Description: Gray BrownSandy Clay Notes: Lowe's, LOW-70976 Notes:Palomar Airport 0% Retained on 3/4 Inch sieve Test Method: Cal-Tisna Test 301 800 700 600 500 400 300 200 100 0 Exudation Pressure (psi) GeoSoils, Inc. , 1•c%c 5741 Palmer Way GoiSta1,. Carlsbad, CA 92008 Telephone: (760) 438-3155 Fax: (760) 931-0915 R - VALUE TEST RESULTS Number 5932.1 1-A-SC Date: Mar-10 2 DESIGN CALCULATION flATA Traffic index, assumed 5.0 Gravel equivalent factor, assumed 1.25 Expansion, stability equilibrium 1.19 R-Value by expansion 7 R-Value by exudation 5 R-Value at equilibrium 5 TEST SPECIMEN A n Compactor air pressure PSI 170 80 70 - Water added % 5.2 9.9 11.1 Moisture at compaction % 21.2 25.9 27.1 Height of sample IN 2.48 2.64 2.65 Dry density PCF 102.6 9.7 92.8 R-Value by exudation 11 5 4 R-Value by exudation, corrected 11 5 4 Exudation pressure psi 7331 3321 212 Stability thickness I 1.14 —1.221 1.23 Expnsion pressure thickness FT 2.471 0.401 0.20 SAMPLE INFORMATION 3.00 g2.50 2.00 0.00 0.00 0.50 1.00 1,50 2.00 2.50 3.00. Cover Thickness by Expansion Pressure (ft) Expansion, Stability Equilibrium M MEN MMMM.um.u....a.r. .....ME MEN ME 0 ENE! flUUU uuuI1N NMI Ii Ia05 .ulIU No U. .UUU. U ilmom U UU !U ..aUU'IU'Iu...u...Ul.•.IWA •uu•i UU.U1ll...p.UNUUa UU• uIIIUl... U. •• ..UU•IUrUuIIUUl lul ...1•UuI .MMIMIMMI UWUUUUUaUUBUIUa..0 ••UUI•U4UIUIUUWUU• E U.mauUuUuur•uuUUUuuI$*u 0 lum UIUN Im ON ME Uu•ulU•Ni••••uIIImu.... ME= I.0 U ME UU.MMEM U UUIUU*aU..u MINE IMEMMI U P.0 N U UN I•UUUNUU ••UUUI..U.UUUUUNN....U. Ur MMl UU U. INN U N.UpIUUU•u.u.puIUUal.u.Uu ill Sample Location: TI @ 0-5 Sample Description: Light Yellow Brown Clay Notes: Lowe's,LOW-70976 Notes:Palomar Airport 0% Retained on 314 inch sieve Test Method: .Cal-Trans Test 301 R-Value By Exudation GeoSoils, Inc. 5741 Palmer Way 4@ Carlsbad, CA 92008 Telephone: (760) 438-3155 Fax: (760) 931-0915 R - VALUE TEST RESULTS Project EEl Number: 5932.11-A-SC Date: Mar-10 Figure: 3 SCHIFFASSOCIATES - .---FIFTY YEARS OF PROFESSIONALISM www.scnittassoclaies.com Consulting Corrosion Engineers - Since 1959 Table 1 - Laboratory Tests on Soil Samples EEl Palomar Airport Your #Low-709 76.2, SA #10-0205L4B 5-Mar-JO Sample ID B-i B-9 @ 0-5' @ 0-5- CL SM -. Resistivity Units as-received ohm-cm 760 28,800 minimum ohm-cm 352 1,080 pH 5.4 7.4 Electrical Conductivity ms/cm. 0.71 0.20 Chemical Analyses Cations calcium C2 mg/kg 112 30 magnesium Me mg/kg 29 10 sodium Na' mg/kg 616 183 potassium K' mg/kg 28 8.1 Anions carbonate C032 mg/kg ND ND bicarbonate HC031 mg/kg 58 92 flouride F' mg/kg 0.9 4.7 chloride Cl' mg/kg 337 90 sulfate SO4 2-mg/kg 973 168 phosphate P043. mg/kg ND 2.5 Other Tests ammonium NH.' mg/kg ND ND nitrate N031 mg/kg ND 27 sulfide S2 qual na na Redox mV na na - -. Minimum resistivity per CTM 643 Electrical conductivity in millisiemens/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 1 Geotechnical Evaluation April 2, 2010 Proposed Lowe's of Carlsbad, California EEl Project No. LOW-70976.2 APPENDIX C EARTHWORK AND GRADING GUIDELINES AV E E I I) .J Geotothnlcai & Envlronmentai 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 ovethized 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, colluviuni, 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. 2 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 free from ruts, hollows, hummocks, or other uneven features which would inhibit compaction 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 slopç 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 AS1'M 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. SUBDRAJN INSTALLATION 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 6 ANN— — — — — TRANSITION LOT DETAIL CUT LOT - MATERIAL TYPE TRANSITION 5! MinImum 44 No I Compacted Fill Unweathered bedrock or ApprGVCG Matenhl 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 EEI FIGURE A Note: Figure not to scale 4u,5ai1c . .SoNon, JNL— — — - — TRANSITION LOT DETAIL CUT - FILL - DAYLIGHT TRANSITION - - - - - - - - - - - - - 5' MInimum Pad Grade - - - - - - - - - - - - - - - - - - Overexcavate and Recompact Compacted Fill dc -- _- - - - -- Cos -- -- - •O - - - - - Unweathered Bedrock or Approved Material - - - - - 3, Typical Benching The soils engineer and/or engineering geologist may recommend deeper overexcavation in steep cut-fill transitions. EARTHWORK AND GRADING GUIDELINES TRANSITION LOT DETAIL CUT - FILL - DAYLIGHT TRANSITION fa M EEI FIGURE B Note: Figure not to scale Expertise.. SeMcr. .Soludos 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 be 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 minimum 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. EARTHWORK AND GRADING GUIDELINES ROCK DISPOSAL PITS 11 EEI Note: Figure not to scale I HG C Exp,e. . ScMce. .Sohdions DETAIL FOR FILL SLOPE TOEING OUT ON FLAT ALLUVIATED CANYON Toe of slope as shown on grading plan Original ground surface to be restored with compacted fill. ZorigiaWground Compacted fill ------------------------------------------ Anticipated alluvial removal depth per soils engineer. Baciccut varies for deep removals. A backcut shall not be made steeper than a slope of 1:1 or as necessary forsafety 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. EARTHWORK AND GRADING GUIDELINES DETAIL FOR FILL SLOPE TOEING OUT ON A FLAT ALLUVIATED CANYON Note: Figure not to scale 4 EEI FIGURED nZp5C.. Savicc..SoI,dimu REMOVAL ADJACENT TO EXISTING FILL Adjoining Canyon Fill ------------------ Compacted fill limits line Qaf (Existing compacted filO ------------------------------------------------------------- posed additional compacted fill A Temporary compacte,.'' T fill for drainage only --------------- Qf Qal (To beremoved) A To be removed before placing additional compacted fill Legend Qaf - Artificial Fill Qal - Alluvium EARTHWORK AND GRADING GUIDELINES REMOVAL ADJACENT TO EXISTING FILL I Note: Figure not to scale I $EEI Expertise. Sivioe..Sotuo,u FIGURE E DAYLIGHT CUT LOT DETAIL Fill slope shall be recompacted at a 2:1 ratio (this may increase or decrease the area of the pad) ereicavate and recompact fill - Proposed finish grade 3' minimum blanket fill Avoid and/or clean up spillage of materials on the natural slope Id9 On Bedrock or approved material Typical benching 21 minimum key depth Note: (1) Subdrain and key width requirements shall be determined based on exposed subsurface conditions and the thickness of (2) Pad overexcavatlon and recompaction shall be completed if determined as necessary by the soils engineer and/or EARTHWORK AND GRADING GUIDELINES engineering geologist DAYLIGHT CUT LOT DETAIL EEI FIGURE F Eulisc. Note: Figure not to scale Scivice . .Sdoju SKIN FILL OF NATURAL GROUND Note: The need and disposition of drains will be determined by the soils engineer and/or engineering geologist based on site conditions. Pad overexcavation and recompaction shall be completed if determined as necessary by the soils engineer and/or engineering geologist EARTHWORK AND GRADING GUIDELINES SKIN FILL OF NATURAL GROUND Note: Figure not to scale EEI & I ' FIGURE G TYPICAL STABILIZATION BUTTRESS FILL DESIGN Outlets shaft 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 1111 If recommended by the soils engineer and/or I p.] engineering geologist / Design finish slope benching is, is typical-- Buttress or sidehifi fill diameter non-perforated outlet pipe and backdraln (see alternatives) I gradient 11-2' clear _- Toe Heel I Gravel-fabric drain material Bedrock 3' minI urn key depth 1V2 or EARTHWORK AND GRADING GUIDELINES PICAL STABILIZATION BUTTRESS FILL DESF Note: Figure not to scale T. all ; EEl Expertse. FIGURE H STABILIZATION FILL FOR UNSTABLE MATERIAL EXPOSED IN PORTION OF CUT SLOPE Remove unstable mateilal -- -- I 15' minimum Proposed finished grade Compacted stabdon fill Ueatbered bedrock or approved material Remove: nosta le mate minimum tilted back If recommended by the soils engineer and/or engineering geologist, the remaining cut portion of the slope may require removal and replacement with compacted fill 31111111 -HI I 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 GUIDELINES shall be determined by the project soils engineer and/or the engineering geologist. "W" shall never be less than Hn. STABILIZATION FILL FOR UNSTABLE MATERIAL EXPOSED IN PORTION OF CUT SLOPE Note: Figure not to scale IE El FIGURE I 07 Expthe. SeMce - FILL OVER CUT DETAIL Cut/Fill Contact: As shown on grading plan Maintain minimum 15' fill section from backcut to face of finish slope shown on as built Original topography Lowest bench width 15' minimum or H/2 Bedrock or approved material Note: The cut sectioin shall be excavated and evaluated by the soils engineer/engineering geologist prior to constructing the fill portion. EARTHWORK AND GRADING GUIDELINES FILL OVER CUT DETAIL EEI FIGURE J Note: Figure not to scale Expass. 5cM0e..So!gfio,,, — — — — FILL OVER NATURAL DETAIL SIDEHILL FILL Compacted Fill Proposed Grade N Toe of slope as shown on grading plan slope to toe of key as shownon as built /'At __- Provide a 1:1 minimum projection from design toe of Maintain Minimum 15' Width Minimum Natural slope to be 91 favao WOO - - - - - - restored with compacted fill IN Bench 'Width May Vary _ Backeut Varles - 3' Minimum 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 engmcer/cngineenng geologist where the natural slope approaches or exceeds the design slope ratio. (2) The need for and disposition of drains would be determined by the soils engineer/engineering geologist based upon exposed conditions. EARTHWORK AND GRADING GUIDELINES FILL OVER NATURAL DETAIL SIDEHILL FILL Note: Figures not to scale EEI I FIGURE K Expatiac. ScMcc..S6oju I OVERSIZE ROCK DISPOSAL View Normal to Slope Face Proposed Finish Grade Bedrock or Approved Material View Parallel to Slope Face Proposed Finish Grade rnrmir€ r•:•:'•:•__ 5' minimum (3) Bedrock or Approved Material Note: (1) One Equipment width or a minimum of 15 feet 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. 11 approved by the soils engineer and/or engineering geologist Orientation of windrows may vary but shall bear recommended by the soils engineer and/or engineering geologist Unless recommended staggering of windrows is not necessary. Areas shall be cleared for utility trenches, 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 SM, SP, SW, GP, 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. .1 Approximate Scale: 1" = 30' OFT 18FF 301717 60 Fr Note: All distances are approximate EARTHWORK AND GRADING GUIDELINES OVERSIZE ROCK DISPOSAL EEI FIGURE L Sctvicc..Sdudoju CANYON SUBDRAIN DETAIL Type A Type B Note: Alternatives, locations, and extent of subdrains should be determined by the soils engineer and/or engineering geologist during actual grading. EARTHWORK AND GRADING GUIDELINES CANYON SUBDRAIN DETAIL I EEI FIGURE M Note: Figures not to scale S Expa1ie. Seivice .SaJWios CANYON SUBDRAIN ALTERNATE DETAILS Alternate 1: Perforated Pipe and Filter Material Filter material: Minimwn volume of 9 fee?/linear foot 6" diameter ABS or PVC pipe or approved substitute with minimum 8 ('4" 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. I Minimum Filter Material 12" Minimum 6" Minimum Sieve Size Percent Passinu 1 100 V4., 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 rlap 6" Minimum Cover Minimum Bedding Ilnimum Bedding Gravel material 9 feet3/linear foot Perforated pipe: see alternate 1. Gravel: Clean %" rock or approved substitute. Filter Fabric: Mirafi 140 or approved substitute. Note: Figures not to scale TYPICAL STABILIZATION BUTTRESS SUBDRAIN DETAIL 3' minimum 2' minimum 4" minin 4' m Imum Filter Material: Minimum of 5 f 3/linear foot of pipe or 4 ft3/lincar foot of pipe when placed in square cut trench Alternative In Lieu Of Filter Material: Gravel may be encased in approved filter fabric. Filter fabric shall be mirafi 140 or equivalent. Filter fabric shall be lapped a minimum of 12" on all joints. Minimum 4" Diameter Pine: ABS-ASTM D-2751, SDR 3501 ASThI D-1 527 schedule 40 PVC-ASThf D-3034, SDR 35 or ASTM 1)4785 schedule 40 with a crashing 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 may be required at the discretion of the soils engineer and/or engineering geologist Filter Material— Shall be of the following Qci - 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 EARTHWORK AM) GRADING GUIDELINES Sieve Size Percent Pasahig in 100 11/2' 100 No.4 50 TYPICAL STABILIZATION BUTTRESS SUBDRAIN '4" 90-100 No. 200 8 DETAIL 3/8" 40-100 No.4 25-40 No. 8 18-33 _________________________ EEI No. 30 5-15 No. 50 0-7 Sand equivalent Minimum of 50 No. 200 0-3 I" FIGURE 0 Eisc. 5awcc . . Sdonn PROVIDE DRAINAGE SWALE OR PROVIDE HOLES AS RED * OR AS REQUIRED FOR SAFETY NOTES () 4-INCH PERFORATED PVC SCHEDULE 40 OR APPROVED ALTERNATE. PLACE PERFORATION DOWN AND SURROUND WITH A MINIMUM OF I CUBIC FOOT PER LINEAL FOOT (1 FT. /FT) OF 314 INCH ROCK OR APPROVED ALTERNATE AND WRAPPED IN FILTER FABRIC. PLACE DRAIN AS SHOWN WHERE MOISTURE MIGRATION THROUGH THE WALL IS UNDESIRABLE. EARTHWORK & GRADING GUIDELINES TYPICAL RETAINING WALL BACKFILL NOTE: FIGURE NOT TO SCALE I EEI I flGLE P c..Sice..Soc*, RECEIVED ADR 28 2010 ENGINEERING DEPARTMENT