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Home My WebLink AboutCDP 14-01; Tabata 10; Coastal Development Permit (CDP) (3)GROUP DELTA: CO.\SULT.\NT,S Geottchnical Engineering Geology Hydrogeology Earthquake Engineering Materiala Testing A Impection Forensic Services Proj. No. / Name: Prepared for: Prepared by: Date: Subject: TECHNICAL MEMORANDUM IR-596 / Tabata 10 Subdivision, Carlsbad, CA Lester Tucker / Lennar Curt Scheyhing, PE, GE August 30, 2013 Geotechnicai Review INTRODUCTION Group Delta Consultants, Inc. (Group Delta) is pleased to present the results of a review of existing geotechnical infornnation ("paper study") performed for the proposed residential development located on an undeveloped parcel southwest of El Camino Real between Camino Hills Drive and Bryant Drive in the City of Carlsbad, California (see Figures lA througli IF). Lennar is considering purchasing and developing the property. Based on our review of existing information, no adverse site or geologic conditions that would preclude development of the site were identified, provided that appropriate geotechnical recommendations are incorporated in the design and construction. Purpose The purpose of our study was to review available information and provide geotechnical input to Lennar as part of their due diligence review for purchase of the property. A geotechnical investigation and report and grading plan prepared by others were provided to Lennar by the seller. These documents were the primary focus of Group Delta's geotechnical review. Pertinent Investigations and Reports The following geotechnical reports provided by the seller were reviewed: • Vinje & Middleton Engineering, Inc., December 13, 2011, "Geotechnical Plan Review Update, Proposed 26-Lot (Tabata 10) Subdivision, Camino Hills Drive, Carlsbad, (A.P.N.'S 212-050-32 & -33)," Job #11-210-P, Prepared For: Tabata Family Trust. • Vinje & Middleton Engineering, Inc., June 23, 2006, "Preliminary Geotechnical Investigation, Proposed 26-Lot Subdivision, Camino Hills Drive, Carlsbad, Califomia, (AP.N.'s 212-050-32 & -33)," Job #06-210-P," Prepared For: Tabata Family Trust. The existing reports are included as Appendix A. 32 Mauchly. Suite B • Irvine. California 92618-233li • (949) 450-2100 voice . (949) 450-2108 fax Torrance (310)330-5100 A Ontario (909) 605-6S00 A San Diego (HSS) .^36-WOO Sacramento (916) 302-2330 A Victorville (7(10) SHI-.1224 www. GroupDella. com Geotechnical Review Tabata - 10, Carlsbad, CA Lennar Homes of California GDC Project No. IR-596 August 30, 2013 Page 2 In addition. Group Delta performed a Phase I Environmental Site Assessment (ESA), which was provided to Lennar under separate cover. Scope of Work Group Delta's geotechnical scope of work included the following: • Site visit and photographic documentation; • Review of existing published geotechnical information including: o Aerial Photographs; o Topographic Maps; o Geologic Maps; o Fault Maps and Seismicity Data; o Existing geotechnical reports and grading plan; • Performing an independent geotechnical assessment based on the data reviewed, commenting on the existing geotechnical report and recommendations, and summarizing our conclusions and comments in this memorandum. Group Delta did not perform additional subsurface investigations or geotechnical laboratory testing for this study. Additional geotechnical field investigation and testing of site soils should be performed during the final design phase of the project. PROJECT DESCRIPTION The site consists of Assessor's Parcel Numbers (APN) 212-050-32 and 212-050-33 and is currently undeveloped. The proposed project consists of rough grading and development of the 10.38 acre site with one or two story wood framed homes with no basements on 26 individual lots. Building pads will be created by cut-fill mass grading. Due to presence of undocumented fill and alluvial soils significant remedial grading (removal and recompaction) is required in portions of the site. Finish grade is generally near the existing grade, with cuts and fills generally within 10 feet of the existing grade, except on the southwest side (Lots 19-22) where excavations up to about 20 to 25 feet below existing grade will be required to remove a small hill. We understand that grading will require import soil. Development will include improvements to Camino Hills Drive, a new "0"-shaped residential street connecting to Camino Hills Drive, retaining walls along Camino Hills Drive, an earthen sound berm adjacent to El. Camino Real, and a bioretention area adjacent to the sound berm. N:\Projects\_A\M50(NR596 Tabata Slte\Geotech\Tabata Development Geotech Letter Report revl.doc Geotechnical Review Tabata - 10, Carisbad, CA Lennar Homes of California GDC Project No. IR-596 August 30, 2013 Page 3 The approximate site latitude/longitude is 33.1439N/ -117.2866W. The project location, topographic map, aerial photographs, and street views of the site are presented in Figures lA through IF, respectively. The tentative tract map is shown in Figure 2. SITE AND SUBSURFACE CONDITIONS Site Conditions I I The site is currently unpaved and undeveloped, and is bounded by El Camino Real on the northeast and by local streets and residential structures on the northwest, southwest, and southeast sides, as shown in Figures lA through IF and Figure 2. Most of the interior of the site is a grassy field gently descending northeasterly toward El Camino Real. The southeast and southwest boundaries ofthe site are ascending 2h: lv graded slopes heavily vegetated with trees and with a maximum height of about 45 feet. A natural hill vegetated with grass and scattered trees is present near the northwest site boundary with a height of up to about 33 feet above the gently sloping portion of the site with slopes of 2h: lv or flatter. A single residential structure formerly occupied this hill (see Figures 1 Cand2); this structure has been removed. Surrounding streets are paved with asphalt concrete (AC) and have sidewalks, light poles, telephone poles, trees, buried utilities, and associated improvements. Street views of the site are shown in Figures ID through IF. Geology Most of western San Diego County, including the project area, lies within the Peninsular Ranges Geomorphic Province of California. The subject site is located in the coastal plain, in a broad transition zone between older Mesozoic granitic and metavolcanic bedrock (to the east) and the younger, terraced coastal sedimentary rock of Quaternary to Tertiary age (to the west). The sedimentary deposits of the coastal plain generally extend between the coastline and the coastal range foothills and mountains to the east. These formational deposits are overlain locally by Holocene (Recent) overburden soils such as alluvium, colluvium, slopewash, and man-placed fill. Erosion of the coastal plain sediments has resulted in topography characterized by mesas, hills, and ridges dissected by a network of alluvial canyon drainages. The primary drainage in the site area is Agua Hedionda Creek located north of the site (Figure IB). The regional geologic setting is shown in Figure 3A. The generalized natural site geology is shown by an overlay of the regional geologic map onto Google Earth imagery in Figure 3B. The project site is at an interface between Tertiary-age (Eocene) soft bedrock of the Santiago Formation (Tsa), Old (late to middle Pleistocene) Alluvial Flood Plain Deposits (Qoa), also referred to as Terrace Deposits (Qt), and young Holocene Alluvium (Qa). Exposures of older Mesozoic granitic rock (Kp, Kl, Kt) and metamorphic rock (Mzu) are not present within the project site but are exposed to the south and east as shown in Figure 3B, and these units form the basement rock underlying N:\Projects\_AWJ500\IR596 Tabata Slte\Geotech\Tabata Developnnent Qeotech Letter Report revl.doc Geotechnical Review Tabata - 10, Carlsbad, CA Lennar Homes of California GDC Project No. IR-596 August 30, 2013 Page 4 the project site at unknown depth. The natural soils at the project site are overlain locally by man placed fill soils, including compacted fills (QcaO and undocumented fills (Qaf). A site geologic map presented in the project geotechnical report is shown in Figure 3C, which is generally consistent with the regional mapping and indicates the location of existing compacted and undocumented fill materials. Seismicity The site is in a seismically active area. At the general latitude of San Diego County, the interaction between the North American and Pacific tectonic plates is considered to take place across a wide area extending from the San Andreas fault in the Imperial Valley, to nearly 100 km offshore to the west (see Figure 4). The main fault zones west of the San Andreas include the San Jacinto and Elsinore fault zones, the Newport Inglewood Rose Canyon fault zone, and a complex system of northwest trending offshore faults include the Coronado Bank, San Diego Trough, and San Clemente faults. A regional fault map is shown in Figure 4. No active faults are known to cross the project site. Major active faults that contribute to the seismic hazard at the site, and calculated deterministic site accelerations are summarized as follows: Fault Name Fault Type Site-Fault Distance (km) Maximum Magnitude, Mmax Deterministic PGA (g's) Rose Canyon Fault Zone (Oceanside section) Strike Slip 11.0 6.8 0.26 Newport-Inglewood Fault Zone (offshore) Strike Slip 13.5 6.9 0.23 Rose Canyon Fault Zone (Del Mar section) Strike Slip 14.4 6.8 0.22 Rose Canyon Fault Zone (San Diego section) Strike Slip 31.7 6.8 0.11 Elsinore Fault Zone (Julian Section) Strike Slip 33.8 7.7 0.16 Elsinore Fault Zone (Temecula Section) Strike Slip 33.8 7.7 0.16 Coronado Bank (alt2) Strike Slip 36.3 7.4 0.13 San Diego Trough (north altl) Strike Slip 51.0 7.3 0.10 Elsinore (Glen Ivy) rev Strike Slip 53.2 7.7 0.11 San Jacinto Fault Zone (Anza section) Strike Slip 73.5 7.7 0.09 Note: Based on Caltrans ARS Online. N:\Projects\_AV\l500\IR596 Tabata Site\Qeotech\Tabata Developnnent Geotech Letter Report revl.doc Geotechnical Review Tabata - 10, Carlsbad, CA Lennar Homes of California GDC Project No. IR-596 August 30, 2013 Page 5 Probabilistic acceleration versus return period (https://qeohazards.usqs.qov/deaqqint/2008/) is estimated as follows: Exceedance Probability 1%/50 years 2% / 50 years 5% / 50 years 10%/50 years 20% / 50 years 50% / 50 years Average Return Period (years) 4975 2475 975 475 224 72 Peak Qround Acceleration, PGA (g's) 0.56 0.46 0.35 0.27 0.20 0.12 Subsurface Soil Conditions Vinje and Middleton Engineering investigated site conditions by drilling four hollow-stem auger borings to depths of 19.5 to 40.5 feet and excavated 10 test pits to depths of 8 to 16.5 feet below existing grades. Standard Penetration Test (SPT) and California (CAL) Split Barrel Sampler penetration resistances were measured in the borings. Bulk and drive samples collected from the test pits and borings were visually classified in the field and selected samples were tested in the laboratory for in-situ moisture content and dry density, laboratory maximum dry density and optimum moisture content, grain size distribution, Atterberg limits, Expansion Index, direct shear, corrosion (pH, sulfate, chloride, minimum resistivity), and R-value. Field and laboratory data are included in Vinje and Middleton's report in Appendix A. Based on the field investigation Vinje and Middleton prepared a geologic map of the site (see Figure 3Q. Geologic cross-sections from their report are reproduced in Figures 5A through 5D, and the cross-section locations are shown in Figure 3C. They classified the site soils sampled into 3 geologic units, listed below in order of increasing age: • Undifferentiated undocumented fill and Holocene alluvium (Qaf / Qal) • Pleistocene Terrace Deposits (Qt) [same as Old Alluvium in Figure 3B] • Eocene Formational Rock (Ts) [same as Santiago Formation (Tsa) in Fig. 3B] All 3 units have variable soil types that can be grouped into broad categories based on color, grain size distribution, and plasticity. The site soils were classified by Vinje & Middleton into 5 general types: • Soil Type 1: Pale brown to red brown lean to fat clay to sandy clay (SC/CIVCH) • Soil Type 2: Pale to dark brown to red brown silty and clayey sand (SWSC) M:\Projects\_AViil500\IR596 Tabata Site\Geotech\Tabata Development Qeotech Letter Report revl .doc Geotechnical Review Tabata - 10, Carlsbad, CA Lennar Homes of California GDC Project No. IR-596 August 30, 2013 Page 6 • Soil Type 3: Tan to red-brown clayey to silty sand with gravel (SC/SM)g • Soil Type 4: Pale to dark gray lean to fat clay and silt (CI7CH/MH) • Soil Type 5: Tan to yellow-tan to off-white-grey silty and clayey sand (SM/SC) Available data for the different geologic units were tabulated and analyzed as shown in Table 1 and summarized as follows: • Qaf / Qal: Undocumented Fill and Holocene AIIuA^um o Covers approximately the eastern 2/3 of the project site o Overlies Qt in northeastern part of site, directly overlies Ts in southeastern part of site o Depth over Qt or Ts mostly ranges from about 1 to 13 feet, but is shown as deep as 24 to 39 feet (Borings B-2 and B-3) toward the north end of site o In boring B-3 undifferentiated Fill / Alluvium is indicated to bottom of borehole at depth 39 feet. However, drilling problems were experienced below groundwater (below 32 feet), and based on other geologic data it seems unlikely alluvium extends this deep. Loose material is indicated on the log below the groundwater. Based on this boring, the bottom of the alluxnum and the liquefaction potential cannot be conclusively determined. o Contains soil types 1-5 (SP, SC, CL/CH, MH) o Coarse grained soils are loose to medium dense (average medium dense) o Fine grained soils are soft to stiff o Limited testing indicates 64 to 70% passing No. 200 sieve o Limited testing indicates Liquid Limit of 45-49 and Plasticity Index of 21-22 o Relative compaction is generally estimated at less than 90% o Existing moisture is generally wet of optimum o Expansion Index is medium to high (measured values are 103-112, "High") o Measured R-Value is 5 (which is very low) o Corrosivity data: • pH=6.2-6.5 • Soluble sulfate=520-600 ppm • Soluble chloride=60-70 ppm • Minimum resistivity=381-504 ohm-cm o Material is generally unsuitable to receive fill or support foundations, requires remedial grading (removal and recompaction) of 6 to 10-I- feet o Wet of optimum moisture may require processing during grading M:\Proiects\_AViJ50(NR596 Tabata Site\Qeotech\Tabata Developnnent Geotech Letter Report revl.doc Geotechnical Review Tabata - 10, Carlsbad, CA Lennar Homes of California GDC Project No. IR-596 August 30, 2013 Page 7 o o o o o o o o o o o o Bottom of overexcavation may require stabilization in some areas with geogrid and rock Qt (Qoa): Pleistocene Alluvial Terrace Exposed at the surface in roughly the western 1/3 of the site Underlies fill in the northeastern portion of site Where present, overlies Ts Contains all soil types 1-5 (SM, SC, GC, CL/CH) Coarse grained soils are medium dense to dense (average dense) Fine grained soils are stiff to very stiff Limited testing indicates 41% passing No. 200 sieve Limited testing indicates Liquid Limit of 32 and Plasticity Index of 16 Existing moisture ranges from wet to dry of optimum (average 3% wet) Expansion Index is medium (measured value 59) No R-Value or corrosion data are available o Material is generally suitable to receive fill or support foundations, more weathered portions may require removal and recompaction o Wet of optimum moisture may require processing during grading Ts: Eocene Formational Bedrock, a.k.a. Santiago Formation o Exposed at the surface in a small area on the west side of the site Underlies Qt in the western and northeastern portions of site Directly underlies Qaf / Qal in the southeastern portion of site Contains soil types 2, 4, and 5 (SM, SC, MH/CH) Ranges from tan-off white-yellow tan silty / clayey sandstone to pale gray-gray siltstone / claystone When classified as soil, sandstone is dense to very dense and claystone is hard Limited testing indicates 32% passing No. 200 sieve Limited testing indicates Liquid Limit of 36 and Plasticity Index of 11 Existing moisture is generally wet of optimum (average 4% wet) Measured Expansion Index is low (measured value 46 in sandstone materials), claystone / siltstone portions were not tested but may be highly expansive No R-Value or corrosion data are available Material is generally suitable to receive fill or support foundations, more weathered portions may require removal and recompaction or undercutting Wet of optimum moisture may require processing during grading o o o o o o o o o o N:\ProjectsVAV\l500\IR596 Tabata Site\Geotech\Tabata Development Qeotech Letter Report revl .doc Geotechnical Review Tabata - 10, Carlsbad, CA Lennar Homes of California GDC Project No. IR-596 August 30, 2013 Page 8 Site soils data sorted according to soil Types 1-5 are presented in Table 2. Generally soil Types 1 and 4 are highly expansive and predominantly fine grained with 50% or more passing No. 200 sieve, while soil Types 2, 3, and 5 are low to medium expansion potential and predominantly coarse grained with less than 50% passing No. 200 sieve. Groundwater Groundwater was encountered only in the two deepest borings (B-2 and B-3) in the northern part of the site. Groundwater was encountered in B-2 at a depth of 33 feet perched in the bedrock materials, and in Boring B-3 was encountered at a depth of 32 feet. Drilling problems in boring B-3 included heaving sand in the auger and caving, so blowcounts and samples in this borehole may not be representative of undisturbed conditions. Although the log suggests this is still in fill / alluvial material, based on the depth and the grain size characteristics of materials indicated on the log and the proximity of the hill comprised of Qt materials, the soils below the groundwater appear that they may be part of the Qt (Qoa) or Ts (Tsa) units. GEOLOGIC AND SEISMIC HAZARDS Ground Rupture The site is not located within or nearby an Alquist-Priolo (AP) earthquake fault zone. Due to lack of any known active fault crossing the site, fault rupture hazard at the site is considered remote. Seismic Shaking Strong shaking should be anticipated during the design life of the project. Nearby active faults and their locations with respect to the site are illustrated in Figure 4. Due to presence of alluvial soils at the site. Site Class D (Stiff Soil Profile) is appropriate for seismic analyses. Seismic shaking estimates based on deterministic and probabilistic methods were presented previously under "Seismicity" section. For facilities designed in accordance with California Building Code (CBC) 2010 and ASCE 7-05, the seismic design recommendations are presented in Table 3. Maximum Considered Earthquake (MCE) horizontal Peak Ground Acceleration (PGA) is 0.48g and design PGA is 2/3 of this value or 0.32g. Note that that the MCE PGA is generally consistent with the value reported for 2500 year return period in the previous "Seismicity" section. Liquefaction and Seismic Compaction liquefaction involves the sudden loss in strength of a saturated, cohesionless soil (sand and non-plastic silts) caused by the build-up of pore water pressure during cyclic loading, such N;\Projects\_AV\l50(NR596 Tabata Site\Qeotech\Tabata Development Qeotech Letter Report revl.doc Geotechnical Review Tabata - 10, Carlsbad, CA Lennar Homes of California GDC Project No. IR-596 August 30, 2013 Page 9 as produced by an earthquake. This increase in pore water pressure can temporarily transform the soil into a fluid mass, resulting in vertical settlement and can also cause lateral ground deformations. Typically, liquefaction occurs in areas where there are loose to medium dense sands and silts, and where the depth to groundwater is less than 50 feet from the surface. In summary, three simultaneous conditions are required for liquefaction: • Liquefaction susceptible soils (loose to medium dense cohesionless soils); • Groundwater within 50 feet of the surface; • Strong Shaking, such as caused by an earthquake. Groundwater at the site appears to be within formational materials that are generally dense and not subject to liquefaction. In general the liquefaction potential at the site appears to be low. However, data from Boring B-3 is inconclusive due to drilling problems resulting from use of hollow stem auger below groundwater and the log indicating that groundwater may be within loose flli / young alluvium. This boring represents an isolated condition generally outside the developed lots, so it may not represent a concern. However, it should be further investigated by rotary boring and/or CPT prior to final design. Soil Collapse Potential Loose sands and silty sands with clay binder, low moisture content, and low dry density may be prone to sudden collapse and ground settlement if suddenly saturated. Alluvial soils in certain environments may contain such collapse-prone materials. Based on grains size characteristics, consolidation test results (indicate expansion rather than collapse), and moisture content and dry density test results, the collapse potential at the site appears to be low. Remedial grading will further reduce the collapse potential, if present. Seismic Slope Stability The site to be developed is relatively level and post-construction slopes will be engineered compacted fill planned at no steeper than 2h: lv. Therefore, slope instability is not considered a significant hazard at the site. Flood Hazard Based on review of FEMA Flood Insurance Rate Maps (FIRM) website, the site is not located within a 100 year or 500 year flood zone. N:\Projects\_AVJ500\IR596 Tabata Site\Geotech\Tabata Development Geotech Letter Report revl .doc Geotechnical Review August 30, 2013 Tabata - 10, Carlsbad, CA Page 10 Lennar Homes of California GDC Project No. IR-596 DISCUSSION AND RECOMMENDATIONS Key Geotechnical Issues Development of the site is generally feasible in general accordance with recommendations in the existing geotechnical reports. The following are considered the key issues for site development: • Remedial Grading: o Removal and recompaction is required to remove and recompact compressible undocumented fill and alluvial soils and to undercut the cut lots, and stabilization fills are required where cutting into existing slopes; o Suggested depth of overexcavation is 6 to 10 feet in the fill area, but final depth is left as a field decision leaving some uncertainty in cost estimation; o Report suggests placing geogrid at the bottom of overex where soft and yielding soils are left in place, but area of stabilization is not clearly enough defined for estimating costs, o Based on boring / trench logs, suggested depth of overexcavation appears to remove all loose / soft undocumented fill and alluvial material to competent native soils except for the following locations: • B-2: 10 ft of removal leaves a total of 14 feet of undifferentiated fill / alluvium in place: 4 ft of soft clay (CL/CH) and 10 feet of loose to medium dense clayey sand (SC) • B-3: 7 ft removal leaves more than 20 ft of undifferentiated fill / alluvium in place, including some material described as loose / firm. o Leaving loose / soft undocumented fill / alluvial materials in place as indicated by Borings B-2 and B-3 may represent a risk; additional investigation by boring and CPT is recommended to better define the required depth of removals and potential for future settlement and need for mitigation. If deeper removals are found to be necessary, an option to reduce removal depths would be surcharging these areas during grading. • Expansive Soil: o Highly expansive soils are present in the site, randomly mixed with low to medium expansion soils o Expansive soils result in high post-tensioned slab requirements and thick pavement and flatwork sections o Selective grading and use of low expansion import may be considered to reduce costs of pavement and slabs • Import Soil: o Low expansion soil is recommended for import o This material should be used to cap lots and pavement areas to reduce cost of slabs and pavement N:\Projects\_AV\l500\lR596 Tabata Site\Qeotech\Tabata Development Qeotech Letter Report revl.doc Geotechnical Review Tabata - 10, Carlsbad, CA Lennar Homes of California GDC Project No. IR-596 August 30, 2013 Page 11 • Selective Grading: o Report suggests placing expansive soils deeper in the fills, lower expansion soils in the shallower portions; due to random presence of materials in the fill / alluvium selective grading and stockpiling materials generated from fill / alluvium may not be practical o Report suggests using Terrace Deposit materials in upper portions of fill to reduce expansion potential o However, terrace deposits do contain clay soils, and no borings are available in the large hill that will be the source of terrace materials, so the expansion characteristics are not known o Additional borings in this area would help to define the properties of the fill that will be generated in this terrace cut o Import soil should be specified as very low expansion and used to cap lots and pavement areas, since selective grading will be easier to control o Quantities and properties of terrace and import soils used to cap lots should be considered and may be used to realize cost savings. Comments on Existing Geotechnical Reports Site characterization and recommendations presented in the existing geotechnical reports generally appear to be reasonable and development of the site is feasible from a geotechnical standpoint if these recommendations are followed. Comments on specific issues are as follows: Remedial grading: o Removal and recompaction, undercutting of bedrock areas, and stabilization fills should be performed as recommended; o Deeper removals may be warranted in the northeastern part of the site near B-2 and B-3, as existing data show some loose / soft undocumented fill and alluvium may be left in place with the existing removal depths, which may pose a risk of future settlement; o Surcharging these deeper alluvial areas by stockpiling may be considered as an alternate to deeper removals; o CPT testing may be considered as a means of better defining required removal depths and surcharge areas across the site; o Soils removed are wet of optimum and may be difficult to compact and require drying; Expansive Soils and Selective Grading: o Import soils are required, and on-site soils range from low to high expansion potential o Savings in slab, hardscape, and pavement design may be realized by importing low expansion soils, selectively grading low expansion on site soils, N:\Projects\_AVy500\IR596 Tabata Slte\Geotech\Tabata Development Oeotech Letter Report revl .doc Geotechnical Review Tabata - 10, Carlsbad, CA Lennar Homes of California GDC Project No. IR-596 August 30, 2013 Page 12 and placing the low expansion import and on-site soils in the upper part of the subgrade o Final values of expansion potential should be determined on each lot after rough grading is complete; • Detailed investigation should be performed including borings and CPTs to supplement existing data and address the following issues: o Refine required depths of removals across the site and areas where deeper removals or surcharge may be warranted o Define or rule out liquefaction potential in saturated alluvium, if present o Expansion potential of borrow soil from the cut areas within the existing hill Should you have any questions regarding this report, please call us at (949) 450-2100. Sincerely, -, ^ GROUP DELTA CONSULTANT^, INC. : - \ Curt Scheyhing, P.E., Associate Geotechnical Engineer Kul Bhushan, Ph.D., GE ' Senior Consulting Principal The following are attached and complete this letter: TABLES Table 1 Table 2 Table 3 HGURES Figure lA Figure IB Figure IC Figure 1 (D-F) Figure 2 Figure 3A Figure 3B Figure 3C Figure 4 Figure 5 (A-D) APPENDICES Appendix A Summary of Soils Data Sorted by Geologic Unit Summary of Soils Data Sorted by Soil Types 1 - 5 CBC 2010 / ASCE 7-05 Acceleration Response Spectra Vicinity Map USGS 7.5' Quadrangle / Google Earth Overlay Aerial Photograph Street View Tentative Tract Map Regional Geologic Map Geologic Map / Google Earth Overiay Site Geologic Map Regional Fault Map Geologic Cross-Sections A, B, C, D, E, X, and Y Geotechnical Reports by Others N:\Projects\_AV\l500\IR596 Tabata Site\Geotech\Tabata Development Geotech Letter Report revl.doc TABLES Field Lab SPT Wet(+)or Depth Sou Geologic Sample N N60 Yd o TdHIMJI ©opt RC Dry(-)of -200 c' MIn. Res. Exptoratlon (ft) Type Unit USCS Color Type (bpf) (bpf) (pcf) (%) (pcf) (%) m Opt. (%) {%) LL PL PI U El (psf) (deg) pH S04 CL (ohm-cm) R-Value T-l 1 1 Qaf/Qal CL/CH pale brown 64 45 24 21 112 6.2 520 70 504 5 T-l 2 1 Qaf/Qal CL/CH pale brown 100.8 18.5 T-3 3 4 Qaf/Qal CL/CH dark grey 88 28.6 110.5 19.8 79.6 8.8 WET 70 49 27 22 0.07 103 280 23 6.5 600 60 381 T-3 5 4 Qaf/Qal ciycH dark grey 88.8 27.8 110.5 19.8 80.4 8 WET T-3 7 5 Qaf/Qal SC off-white-grey 100.6 18.4 119.5 12.5 84.2 5.9 WET T-5 1 1 Qaf/Qal CL pale brown T-5 5 2 Qaf/Qal SC dark brown 109 11.9 129.6 10.4 84.1 1.5 WET T-5 7 2 Qaf/Qal SC dark brown T-5 8 2 Qaf/Qal SC dark brown 110.8 13.1 129.6 10.4 85.5 2.7 WET T-7 4 1 Qaf/Qal CL pale brown 88.9 26.1 T-8 5 2 Qaf/Qal SC red-brown 101.6 11.9 129.6 10.4 78.4 1.5 WET T-8 8 2 Qaf/Qal sc dark brown 113.6 12.7 129.6 10.4 87.7 2.3 WET T-8 11 2 Qaf/Qal sc dark brown 104.1 12.2 129.6 10.4 80.3 1.8 WET B-2 4 5 Qaf/Qal MH grey spt 4 5 B-2 9 1 Qaf/Qal CL/CH red-brown spt 12 15 B-2 14 2 Qaf/Qal SC red-brown cal 36 30 110.1 18.3 129.6 10.4 85.0 7.9 WET B-2 19 2 Qaf/Qal SC pale brown spt 10 13 B-3 4 2,3 Qaf/Qal SC brown to red-brown cal 40 34 113.2 9 129.6 10.4 87.3 -1.4 DRY B-3 9 3,5 Qaf/Qal SM/SC tan to red-brown spt 25 31 B-3 14 2,3 Qaf/Qal SC red-brown cal 40 34 113.8 9.7 129.6 10.4 87.8 -0.7 DRY B-3 19 5 Qaf/Qal SC red-brown to tan spt 24 30 B-3 24 5 Qaf/Qal SC red-brown to tan cal 44 37 109.5 16.2 119.5 12.5 91.6 3.7 WET B-3 29 5 Qaf/Qal SC red-brown to tan spt 27 34 B-3 34 3,5 Qaf/Qal SP/GP red brown cal 70 59 110.7 20.3 119.5 12.5 92.6 7.8 WET B-4 4 3 Qaf/Qal SC red-brown spt 13 16 B-4 9 5 Qaf/Qal SP red-brown cal 28 23 106.2 11.7 119.5 12.5 88.9 -0.8 DRY max= 70 59 113.8 28.6 129.6 19.8 92.6 8.8 70 49 27 22 0.07 112 280 23 6.5 600 70 504 5 mins 4 5 88.0 9.0 110.5 10.4 78.4 -1.4 64 45 24 21 0.07 103 280 23 6.2 520 60 381 5 avgs 29 28 104.4 16.7 124.0 12.3 85.2 3.5 67 47 26 22 0.07 108 280 23 6 560 65 443 5 iGKOUP N:\Proiccts\_AVMSD0\1R59GTabata Slte\Geotec>i\iojk sumnurvJilsii Sort by Unit TABLE 1 SUMMARY OF SOILS DATA SORTED BY GEOLOGIC UNIT Page 1 of 2 Field lab SPT Wet(+)or Depth Soil Geologic Sample N N60 Td a Td-max RC DrY(-)of -200 c' Min. Res. Exploration (ft) Type Unit USCS Color Type (bpf) (bpf) (pcf) {%) (pcf) [%) (%) Opt (%) (%) a PL PI U El (psf) (deg) pH S04 CL (ohm-cm) R-Value T-l 4 2 Qt SC/CL red-brown 104.1 12.9 129.6 10.4 80.3 2.5 WET 41 32 16 16 -0.19 75 32 T-l 7 2 Qt SC/CL red-brown 103.4 15.4 129.6 10.4 79.8 5 WET T-l 9 2 Qt SM/SC dark brown 112.3 8.2 129.6 10.4 86.7 -2.2 DRY T-l 11 2 Qt SM/SC dark brown 119.3 7.8 129.6 10.4 92.1 -2.6 DRY T-l 13 3 Qt SC/GC red-brown 102.8 9.7 T-l 15 3 Qt SC/GC red-brown 103.5 14.1 T-5 10 2 Qt SC red-brown 106.8 13.9 129.6 10.4 82.4 3.5 WET T-5 14 2 Qt SC red-brown 108.5 13.4 129.6 10.4 83.7 3 WET T-6 7 5 Qt SM/SP yellow-tan 105.5 13.3 119.5 12.5 88.3 0.8 WET 59 T-7 7 5 Qt SM/SC tan 99.3 18.9 119.5 12.5 83.1 6.4 WET T-7 10 5 Qt SM/SC tan 92.8 25.2 119.5 12.5 77.7 12.7 WET T-7 12 1 Qt SC/CL brown 98.3 22.5 T-7 14 1 Qt SC/CL brown 95.7 25.7 T-9 5 5 Qt SC yellow-tan 96.1 18.3 119.5 12.5 80.4 5.8 WET T-9 8 5 Qt SC yellow-tan 110.6 12.2 119.5 12.5 92.6 -0.3 DRY T-9 11 5 Qt SC yellow-tan 110.9 13.1 119.5 12.5 92.8 0.6 WET T-9 13 5 Qt SC yellow-tan 99.1 16.9 119.5 12.5 82.9 4.4 WET T-9 15 4 Qt SC yellow-tan 99.3 17.9 119.5 12.5 83.1 5.4 WET B-l 4 2 Qt SC red-brown cal 40 34 113.8 17.4 129.6 10.4 87.8 7 WET B-l 9 4 Qt ciycH olive-brown spt 13 16 B-2 24 5 Qt ciycH dark brown cal 48 40 114.6 16.9 119.5 12.5 95.9 4.4 WET B4 14 2 Qt SC/GC red-brown spt 24 30 B-4 19 3,5 Qt GP red-brown cal 34 28 109.5 5.8 119.5 12.5 91.6 -6.7 DRY max= 48 40 119.3 25.7 129.6 12.5 95.9 12.7 41 32 16 16 -0.19 59 75 32 min= 13 16 92.8 5.8 119.5 10.4 77.7 -6.7 41 32 16 16 -0.19 59 75 32 avg= 32 30 105.1 15.2 123.7 11.6 85.9 2.9 41 32 16 16 -0.19 59 75 32 T-2 3 5 Ts SM/SC tan 101 16.6 119.5 12.5 84.5 4.1 WET T-2 5 5 Ts SM/SC tan 89.8 23.6 119.5 12.5 75.1 11.1 WET 32 36 25 11 -0.13 46 28 166 T-2 8 5 Ts SM/SC tan 107.8 18.8 119.5 12.5 90.2 6.3 WET T-2 10 5 Ts SM/SC tan 114.3 17.4 119.5 12.5 95.6 4.9 WET T-4 5 4 Ts MH/CH grey 106 22 110.5 19.8 95.9 2.2 WET T-4 8 4 Ts MH/CH grey 108 22.4 110.5 19.8 97.7 2.6 WET T-4 10 4 Ts MH/CH grey 106.9 21.2 110.5 19.8 96.7 1.4 WET T-5 16 2 Ts SC off-white 102.5 16 129.6 10.4 79.1 5.6 WET T-8 12 5 Ts SC grey to yeltow-tan 949 13.7 119.5 12.5 79.4 1.2 WET T-9 16 4 Ts MH grey 97.3 24.3 110.5 19.8 88.1 45 WET B-l 14 4 Ts MH pale grey spt 23 29 B-l 18 4 Ts MH pale grey spt 23 29 B-2 29 4 Ts MH pale grey spt 31 39 B-2 34 4 Ts MH pale grey spt 25 31 B-2 39 4 Ts MH pale grey spt 44 55 max= 44 55 114.3 24.3 129.6 19.8 97.7 11.1 32 36 25 11 -0.13 46 28 166 min= 23 29 89.8 13.7 110.5 10.4 75.1 1.2 32 36 25 11 -0.13 46 28 166 avg= 29 37 102.9 19.6 116.9 15.2 88.2 4.4 32 36 25 11 -0.13 46 28 166 ;UKOUI' N:\Proiects\_AV\IS00MRS96Tabati S»te\Geotech\solls MiinmarvJilsx Sort bf Unit TABLE 1 SUMMARY OF SOILS DATA SORTED BY GEOLOGIC UNIT Page 2 of 2 Field Lab SPT Wet (+) or Depth SoH Sample N Neo 7d a Yd-mix RC Dry(-)of -200 c' MIn. Res. Exploration (ft) Type Unit USCS Color Type (bpf) (bpf) (pcf) 1%) (pcf) (%) (%) Opt. (%) {%) LL PL PI U El (psf) (deg) pH S04 CL (ohm<m) R-Value T-l 1 1 Qaf/Qal CL/CH pale brown 64 45 24 21 -1.14 112 6.2 520 70 504 5 T-l 2 1 Qaf/Qal CL/CH pale brown 100.8 18.5 T-5 1 1 Qaf/Qal CL pale brown T-7 4 1 Qaf/Qal CL pale brown 88.9 26.1 T-7 12 1 Qt SC/CL brown 98.3 22.5 T-7 14 1 Qt SC/CL brown 95.7 25.7 B-2 9 1 Qaf/Qal CL/CH red-brown spt 12 15 max= 12 15 101 26 64 45 24 21 -1.14 112 6.2 520 70 504 5 min= 12 15 89 19 64 45 24 21 -1.14 112 6.2 520 70 504 5 avg= 12 15 96 23 64 45 24 21 -1.14 112 6.2 520 70 504 5 T-l 4 2 Qt SC/CL red-brown 104.1 12.9 129.6 10.4 80.3 2.5 WET 41 32 16 16 -0.19 75 32 T-l 7 2 Qt SC/CL red-brown 103.4 15.4 129.6 10.4 79.8 5 WET T-l 9 2 Qt SM/SC dark brown 112.3 8.2 129.6 10.4 86.7 -2.2 DRY T-l 11 2 Qt SM/SC dark brown 119.3 7.8 129.6 10.4 92.1 -2.6 DRY T-5 5 2 Qsf/Qal SC dark brown 109 11.9 129.6 10.4 84.1 1.5 WET T-5 7 2 Qaf/Qal SC dark brown T-5 8 2 Qaf/Qal SC dark brown 110.8 13.1 129.6 10.4 85.5 2.7 WET T-5 10 2 Qt SC red-brown 106.8 13.9 129.6 10.4 82.4 3.5 WET T-5 14 2 Qt SC red-brown 108.5 13.4 129.6 10.4 83.7 3 WET T-5 16 2 Ts SC off-white 102.5 16 129.6 10.4 79.1 5.6 WET T-8 5 2 Qaf/Qal sc red-brown 101.6 11.9 129.6 10.4 78.4 1.5 WET T-8 8 2 Qaf/Qal SC dark brown 113.6 12.7 129.6 10.4 87.7 2.3 WET T-8 11 2 Qaf/Qal sc dark brown 104.1 12.2 129.6 10.4 80.3 1.8 WET B-l 4 2 Qt sc red-brown cal 40 34 113.8 17.4 129.6 10.4 87.8 7 WET B-2 14 2 Qaf/Qal sc red-brown cal 36 30 110.1 18.3 129.6 10.4 85.0 7.9 WET B-2 19 2 Qaf/Qal sc pale brown spt 10 13 B-4 14 2 Qt SC/GC red-brown spt 24 30 B-3 4 2,3 Qaf/Qal sc brown to red-brown cal 40 34 113.2 9 129.6 10.4 87.3 -1.4 DRY B-3 14 2,3 Qaf/Qal sc red-brown cal 40 34 113.8 9.7 129.6 10.4 87.8 -0.7 DRY max= 40 34 119.3 18.3 129.6 10.4 92.1 7.9 41 32 16 16 -0.19 75 32 min= 10 13 101.6 7.8 129.6 10.4 78.4 -2.6 41 32 16 16 -0.19 75 32 avg= 32 29 109.2 12.7 129.6 10.4 84.2 2.3 41 32 16 16 -0.19 75 32 T-l 13 3 Qt SC/GC red-brown 102.8 9.7 T-l 15 3 Qt SC/GC red-brown 103.5 14.1 B-4 4 3 Qaf/Qal SC red-brown spt 13 16 B-3 4 2,3 Qaf/Qal sc brown to red-brown cal 40 34 113.2 9 129.6 10.4 87.3 -1.4 DRY B-3 14 2,3 Qaf/Qal sc red-brown cal 40 34 113.8 9.7 129.6 10.4 87.8 -0.7 DRY B-3 9 3,5 Qaf/Qal SM/SC tan to red-brown spt 25 31 B-3 34 3,5 Qaf/Qal SP/GP red brown cal 70 59 110.7 20.3 119.5 12.5 92.6 7.8 WET B-4 19 3,5 Qt GP red-brown cal 34 28 109.5 5.8 119.5 12.5 91.6 -6.7 DRY max= 70 59 113.8 20.3 129.6 12.5 92.6 7.8 min: 13 16 102.8 5.8 119.5 10.4 87.3 -6.7 avgs 37 34 108.9 11.4 124.6 11.5 89.9 -0.3 GKOUF N:\PrajKti\,AV\l500\lR59« Tabata S)te\Geotech\soik summarv.xisx Sort by Soil Type TABLE 2 SUMMARY OF SOILS DATA SORTED BY SOIL TYPES 1 -5 Page lof 2 Field Ub SPT Wet(+)or Depth Soil Sample N IM60 Td <D Yd^ax RC Dry (•) of -200 c' f Min. Res. Exploration (ft) Type Unit USCS Color Type (bpf) (bpf) (pcf) (%) (pcf) {%) (%) Opt. (%) (%) a PL PI Ll El (psf) (deg) pH S04 CL (ohm-cm) R-Vaiue T-3 3 4 Qaf/Qal CL/CH dark grey 88 28.6 110.5 19.8 79.6 8.8 WET 70 49 27 22 0.07 103 280 23 6.5 600 60 381 T-3 5 4 Qaf/Qal Cl/CH dark grey 88.8 27.8 110.5 19.8 80.4 8 WET T-4 5 4 Ts MH/CH grey 106 22 110.5 19.8 95.9 2.2 WET T-4 8 4 Ts MH/CH grey 108 22.4 110.5 19.8 97.7 2.6 WET T-4 10 4 Ts MH/CH grey 106.9 21.2 110.5 19.8 96.7 1.4 WET T-9 15 4 Qt SC yellow-tan 99.3 17.9 119.5 12.5 83.1 5.4 WET T-9 16 4 Ts MH grey 97.3 24.3 110.5 19.8 88.1 4.5 WET B-l 9 4 Qt ciycH olive-brown spt 13 16 B-l 14 4 Ts MH pale grey spt 23 29 B-l 18 4 Ts MH pale grey spt 23 29 B-2 29 4 Ts MH pale grey spt 31 39 B-2 34 4 Ts MH pale grey spt 25 31 B-2 39 4 Ts MH pale grey spt 44 55 max= 44 55 108.0 28.6 119.5 19.8 97.7 8.8 70 49 27 22 0.07 103 280 23 6.5 600 60 381 min= 13 16 88.0 17.9 110.5 12.5 79.6 1.4 70 49 27 22 0.07 103 280 23 6.5 600 60 381 avg= 27 33 99.2 23.5 111.8 18.8 88.8 4.7 70 49 27 22 0.07 103 280 23 6.5 600 60 381 T-2 3 5 Ts SM/SC tan 101 16.6 119.5 12.5 84.5 4.1 WET T-2 5 5 Ts SM/SC tan 89.8 23.6 119.5 12.5 75.1 11.1 WET 32 36 25 11 -0.13 46 28 166 T-2 8 5 Ts SM/SC tan 107.8 18.8 119.5 12.5 90.2 6.3 WET T-2 10 5 Ts SM/SC tan 114.3 17.4 119.5 12.5 95.6 4.9 WET T-3 7 5 Qaf/Qal SC off-white-grey 100.6 18.4 119.5 12.5 84.2 5.9 WET T-6 7 5 Qt SM/SP yellow-tan 105.5 13.3 119.5 12.5 88.3 0.8 WET 59 T-7 7 5 Ctt SM/SC tan 99.3 18.9 119.5 12.5 83.1 6.4 WET T-7 10 5 Qt SM/SC tan 92.8 25.2 119.5 12.5 77.7 12.7 WET T-8 12 5 Ts SC grey to yellow-tan 94.9 13.7 119.5 12.5 79.4 1.2 WET T-9 5 5 Qt SC yellow-tan 96.1 18.3 119.5 12.5 80.4 5.8 WET T-9 8 5 Qt SC yellow-tan 110.6 12.2 119.5 12.5 92.6 -0.3 DRY T-9 11 5 Qt SC yellow-tan 110.9 13.1 119.5 12.5 92.8 0.6 WET T-9 13 5 Qt SC yellow-tan 99.1 16.9 119.5 12.5 82.9 4.4 WET B-2 4 5 Qaf/Qal MH grey spt 4 5 B-2 24 5 Qt CL/CH dark brown cal 48 40 114.6 16.9 119.5 12.5 95.9 4.4 WET B-3 19 5 Qaf/Qal SC red-brown to tan spt 24 30 B-3 24 5 Qaf/Qal SC red-brown to tan cal 44 37 109.5 16.2 119.5 12.5 91.6 3.7 WET B-3 29 5 Qaf/Qal SC red-brown to tan spt 27 34 B-4 9 5 Qaf/Qal SP red-brown cal 28 23 106.2 11.7 119.5 12.5 88.9 -0.8 DRY B-3 9 3,5 Qaf/Qal SM/SC tan to red-brown spt 25 31 B-3 34 3,5 Qaf/Qal SP/GP red brown cal 70 59 110.7 20.3 119.5 12.5 92.6 7.8 WET B-4 19 3,5 Qt GP red-brown cal 34 28 109.5 5.8 119.5 12.5 91.6 -6.7 DRY max= 70 59 114.6 25.2 119.5 12.5 95.9 12.7 32 36 25 11 -0.13 59 28 166 min= 4 5 89.8 5.8 119.5 12.5 75.1 -6.7 32 36 25 11 -0.13 46 28 166 avg= 34 32 104.1 16.5 119.5 12.5 87.1 4.0 32 36 25 11 -0.13 53 28 166 riKOUP TABLE 2 ri; SUMMARY OF SOILS DATA 1 f SORTED BY SOIL TYPES 1 -5 N;\Pri>iects\_AV\r500\IR596 Tabata Site\6e(itech\5oils summary.xlix Sort by Soil Type Page 2 of 2 TABLE 3 CBC 2010 / ASCE 7-05 Seismic Design Parameters and Response Spectra GDC PROJECT NO. IR-696 Tabata Site, Carlsbad Site Latitude: 33.1439 Site Longitude: -117.2865 Ss- S, Site Class F.H F,- TL' SMS' SMI' So.' SD,' To' 0.438 1.562 1.200 0.456 0.570 g = short period (0.2 sec) mapped spectral response acceleration MCE Site Class B (ASCE7-200S-Flgure22-1) g = 1.0 sec period mapped spectral response acceleration MCE Site Class B (ASCE7-200S-Flgi«'s22-2) = Site Class definition based on ASCE7-200S Section 11.4.2 = Site CoefTicient applied to S, to account for soil type (ASCE7-200S Section 11.4.3 and TaWe 11.4-1) = Site Coefficient applied to S, to account for soil type (ASCE7-2006 Section 11.4.3 and TaWe 11.4-2) sec = Long Period Transition Period (ASCE7-200S Section 11.4.S and Figure 22-16) = site class modified short period (0.2 sec) MCE spectral response acceleration = F, x (ASCE7-200S Equation 11.4-1) = site class modified 1.0 sec period MCE spectral response acceleration = F, x S, (ASCE7-2(H)S Equation 11.4-2) = site class modified short period (0.2 sec) Design spectral response acceleration = 2/3 x SMS (ASCE7-200S Equation 11.4-3) ' site class modified 1.0 sec period Design spectral response acceleration = 2/3 x SMI (ASCE7-2006 Equation 11.4-4) sec - 0.2 SD,/SOS ' Control Period (left end of peak) for ARS Curve (Section 11.4.6 ASCE 7-06) sec = Sm/Sps = Control Period (right encl o! ppak) for ARS Curvi: 'Section 11.4.5 ASCE 7-05) T (seconds) 2.600 3.600 Design Sa (g) 0.652 0.570 0.285 0.217 0.207 0.163 0.157 Sa(g) 1.200 0.684 0.489 0,274 0.221 0.214 0.207 0.201 0.190 2 c o re o 0) o ro k-*^ o a. in 2.0 T 1.0 2.0 Period (seconds) 3.0 4.0 N:\PrqiectsLA\AI500\IR596 Tabata Site\Geotech\2010 CBC Calculation (Tabata).xls FIGURES CARLSBAD t.'.. J " h i School A KHIy tkiTieni»Tr / SrtlOOi / PROJECT SITE -k 4 - MfC'Iflan Palomai Airport 4 7/76 base maps/photos are from Google Maps GROUP DELTA (•()\.sri.T.\\T.< GROUP DELTA CONSULTANTS. INC. ENGINEERS AND GEOLOGISTS 32 MAUCHLY. SUITE B IRVINE. CA 9261B (949)450-2100 PROJECT NAME TABATA-10 Carlsbad. California rir.llRF NUMBER 1A PROJECT NUMBER IR-596 VICINITY MAP 'A Reference: USGS Topographic Map of the San Luis Rey 7.5' Quadrangle / Google Earth. GROUP DELTA tON'SULT.\.NTS GDC Project No. IR-596 Tabata -10 Carlsbad, California USGS 7.5' Quad / Google Earth Overlay Figure 1B Reference: Bing Maps. GROUP DELTA CO.NSUI.T.WTS GDC Project No. IR-596 Tabata -10 Carlsbad, California Aerial Photograph Figure IC EL CAMINO REAL Reference: Google Earth CIE EnSD(IKSnnSi35{2HlJ I . „ I Exit street v P ils? aUBIB (^Bffi Maffi GROUP DELTA (•()NSULTANT.S GDC Project No. IR-596 Tabata -10 Carlsbad, California Street View from North Figure ID EL CAMINO REAL Reference: Google Earth GROUP DELTA CONSULIA.NTS GDC Project No. IR-596 Tabata -10 Carlsbad, California Street View from Middle Figure IE Reference: Google Earth GROUP DELTA CONSULTANTS GDC Project No. IR-596 Tabata -10 Carlsbad, California Street View from South Figure IF FIGURE 2 - TENTATIVE TRACT MAP UD \lla*Ml Howl piaim ikfrnM^ Ihrtr ll<4mTnvi I ...Uhdr ikicwK Hnditidrd <ll«rf«cr«r •nil II. •!.. lrj|!mi:Bi«<«t u» UrrrK t«ih«rfrfi' I ixi'Sflulmol moilrr«ifl\ M,-I i«t|if«til UmMi-k* vnoutn •r*ip .*it^ J- MM.. IM. 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'he s«mM);» l"iMi,ni.'n iiKrtfin ^•r• * rt'i IIK- I »> .ni,.r (.•«mitlh.n .tmi |.*'.•^ S.lfHlMr.itc in ihr I IK IHII.IN .[.ijifciiiifii GROUP DELTA CONSULTANTS GDC Project No. IR-596 Tabata -10 Carlsbad, California Regional Geologic Map Figure 3A Tsa A • 1^ ^ • • TVTsal • Kt Kl * — %--t, Ts^ Reference:: USGS Topographic Map of the San Luis Rey 7.5' Quadrangle / Google Earth / Geologic Map of the Oceanside 30x60" Quadrangle I I Allavial nn.Hl |>laiii Un>*>*il« l>a(r Hokictnv) ' III iai.-iwkM>liilil>i1 »aml\. sili\ iif <\.t\ -Knfiiip alliik nm IKK-V n.^ IIK IIMV: allu.ial fjii ilepi>^» n di»i*l tikJ<> ..f th«incl< ^ I iind«lNli- ilip.i«H« uiHliMded iMatiKrar siid PlrHiMtrnrt-Hii^Mt Inicmcnied i.< Lii^elv i.iheicni l.in.Uli.1. iiepiwu riiti«.^.|i,kiii-.l I., niixlrinietv «wll ^••n.itliiLii.'.l M.IM ni.i|i|vit t4iuKli.li'» .••ni.iin M.Mp .ilea «eri Ji.fc- .k'|«><ii hi >m.i- M .iip "• «hi'«M vp.iMleU M.m* IVia.ivr<H- .tv-c l,w».KItJf* «e»e mtii..iled IM )VI'm cttlirv'K JiiiHn: Uie ((••'.VCIK- M.«I .>I UK- UkKliJc in Ih. •|IK»lf;ill|*V ll«<k .Ktlllla-tl MNhin Iln I .IfnaiiKHi limillHili hiMtrtiT ihcr." me nuiu MiihMi ihy- Mi>ni»Te» IIR.I •uniiiv.. hirmjni<>t\ a» well ^ (N,l .11.* , JI n.M.d ptMn d«-|H.«lU >Mli«M«<-d (UlC 1.1 Nikbllr Plti«liMrm-»—f Inv ul wihmciM. i(epi»ilc«) .m CM>.KI rtrnw*. ( .-wi<.i«l« l.f inr»lcr»»cU -cl! c'-nwIuUlCtl pi«.«ri» tkNlffl. PLfnvrihlc. i.Hiif>ii*ti|\ kh^hil^ tli\>fCK*J V'^^''- '•"•d. MII. mul *la>-lvtiMnf jlUviim Hhcfc imm Ihan «HK mmthci >• «lM>Hn (Cf. Ooj^fl itMH« dcpwM OIC «*idi*Mlnl lFi| )«. SaallH-n FninnMiiin imnlflli- Fnrrnrt—Njmeil h\ \\i.tiilnii>: ami Piifvnue il'»4M h>i livene ilep»Mi\ <•( iKwihuieMjni Sinta \n.i Mouniatn* Thm* ore ihr»v ithanwmr jt\TU. ^ txiKtl ctiemN.-i Ilut ion^«i« huff and hn<wni»h-pij*. mawkAr oui^c-sfatnctl. f»"wH •<*niil 3I1O>.K SJIKS«MK- JIHI nMiylnmcraic tvitHf>l.fM- j,TnvT«ily prcikmim^iingi «iakc k>%'CiUin h> gra* ufkl hfpwniiJi-grnv 1 memhrr thnt c«>n^i^* ol' H>rt. cty WV'II-VKIIMI uilirtte vnkhione tf ol fni>. ruarv-craracil .irt.KU- vMMlM.xie ahl L-n' Thiitu|rhi>*j| lie limnHHti. Niih *cfihiiH. and Uirt.ilh then: e\fts jritvnixh-hnwn ira^^ivc cb>^l(riK- im»iK\K HHifiK's ml li'nv% nl MH,-n l»«ilik*iiMis U;:O>MI;II cLtv^onc and «li*iiw Ttw hmcr pin ol 'he SHnnaco I itmutNm inictfintn-ni *nh the Ivlmjt I .i SarMKianc tn lhe I iH iniij^ (|U3tl'Jiivh: < Ihc hnxH monhcr (vin anil pern*"'I ivn ntedium-iTJineil mmle \n UPIVT nvmlK-r GROUP DELTA CONSULIANTS GDC Project No. IR-596 Tabata -10 Carlsbad, California Geologic Map Google Earth Overlay Figure 3B FIGURE 3C - SITE GEOLOGIC MAP Whittier iversid^ Map -Satellite ~ F—n-Hybrid Terrain Earth Irvine /HuntinglAii / Beach % % Mission ViejoVi: • # / I I I I I I I I \ ^\ % Oceanside % Encrnit^*^ 10 oc Km Rojc Canw I** lonc (iDccaroi*-5<xiio'1 1346 K/iiilL-woil-i>ufc.iw>cxl(Oflshwcl M40 Km Roue CwiyonlM^or* (Del Mar section) 33 82 Km FKnv* <.llA«i) 3382 KmEKino'enemMuiJi 3626 KmCww»*iBanli|ii«l K)73 KmLWowe lOten Nv)iev 7352 Kmr.iiijM><ia(Anni) 50 QC Km San Oiego Trough noftri aNI 31 74 K;n How Canvon laud «nc (San Oiwio sctliow Google 20 ml 50 km San Diegda %. Chula Vista oTijuana Tocate / •^^^ Rosanto Reference: Caltrans ARJ Map data ©2013 Google. GROUP DELTA CONSULTANTS GDC Project No. IR-596 Tabata -10 Carlsbad, California Regional Fault Map Figure 4 PLATE IE B-4(pn>J.] FfmMATIOHALRO€X ~ SCALE: 1"=30' V&M JOB#06-210-P FIGURE 5A PLATE 13 160 • 140- J20- 100 'ATEOMAL MOCE I r 100 IGO - 140- 120 100 - 0 f-120 m mm —^ -100 SCALIi; 1"=30' V&M JOB #06-210-P Orifiinal .t-round .suil'acc upproximuUxi I'rom Couniy of San Diego Topographic Survey Map No. S 354-l(}77 & 354-1683, dated 1975. FIGURE 5B i2M PUlTE 14 B-2 (proi) SCALE: 1"=50' FIGURE 5C SCALE: 1" = 20' 130 - COMPACTED FUL PROPOSED GRADE (LOT 4} FORMATIONAL ROCK ^ 110 I-ICQ Y PROPOSED GRADE fLOT?) FORMATIONAL ROCK 110 -100 PLATE 4 VfisM JOB #06-210-P FIGURE 5D APPENDIXA GEOTECHNICAL REPORTS BY OTHERS TABATA 10 CT 06-13 fiEOTECHMICAL REPORT REC GEOTECHNICAL PLAN REVIEW UPDATE PROPOSED 26-LOT (TABATA 10) SUBDIVISION CAMINO HILLS DRIVE, CARLSBAD (A.P.N.'s 212-050-32 & -33) December 13,2011 Prepared For: TABATA FAMILY TRUST c/o Mr. Gregg Harrington P.O. Box 679 Carlsbad, California 92018 Prepared By: VINJE & MIDDLETON ENGINEERING, INC. 2450 Auto Park Way Escondido, California 92029 Job #06-210-P GEOTECHNICAL PLAN REVIEW UPDATE PROPOSED 26-LOT (TABATA 10) SUBDIVISION CAMINO HILLS DRIVE, CARLSBAD (A.P.N.'s 212-050-32 & -33) I. INTRODUCTION The most current project Grading Plans prepared by REC Consultants, Inc. (not dated) for the proposed 26-lot residential development referenced above, also known as Tabata 10 subdivision, were provided to us for review and comments. The plans are reproduced herein and enclosed with this transmittal as Plates 1-3. The approximate site coordinates are 33.1452''N latitude and 117.2880"W longitude. The subject property was originally studied with respect to surface and subsurface geotechnical conditions performed by this office with findings, conclusions and recommendations summarized In the following written technical report: Preliminary Geotechnical Investigation Proposed 26-Lot Subdivision Camino Hills Drive, Carlsbad, California (A.P.N.'s 212-050-32 & -33) Job #11-210-P, report dated June 23. 2006 The reference report was reviewed in connection with the preparation ofthis update study and a copy is attached herein as Appendix A. The purpose of this work was to review the referenced repori and confirm compatibility of the project current grading plans with the site indicated geotechnical conditions. Additional updated and/oramended recommendations consistent with current codes and engineering standards are also provided in the following sections and will supplement or supersede those given in the referenced report, where specifically indicated. Our efforts in connection with the preparation of this report included a recent site visit conducted by our Engineering Geologist on December 5, 2011. II. SITE DESCRIPTION Existing topographic conditions and proposed development at the project property are shown the enclosed Plate 3. Based on our recent observations, site conditions primarily have remained substantially the same as discussed in the referenced report. In general, much of the study property consists of gently sloping terrain that descends in a northeasterly direction lo Ei Camlno Real. Previous grading activities for off-site developments have modified the property to include large graded slopes that ascend to residential developments along the southerly and easterly site margins. An anomalous hill ViNii-: 8f Mri>i^i.i:iON liN(-,iNi;[;i«iNii, IN*:. • 2450 Auto l^rkWay • Escondido, Ciliforni.T OZOZO-lllO • Phone (760) 743-1214 GEOTECHNICAL PLAN REVIEW UPDATE DECEMBER 13, 2011 TABATHA 10 SUBDIVISION. CAMINO HILLS DRIVE, CARLSBAD PAGE 2 marks the northwest property margin adjacent to Camino Hills Drive. The hill rises nearly 30 feet above surrounding areas with slope gradients that generally approach 2:1 (horizontal to vertical) maximum. The large graded slopes that mark the southerly and easterly site margins were constructed at 2:1 gradients maximum and range to nearly 50 feet high. Drainage terraces were noted in south and northeast portions of the graded embankments. Available pre-development topography indicate the penmeter slopes are largely fill embankments with some fiil-over-cut slopes. The previous residential dwelling located on the hilltop in the northwesterly area of the property has been removed. Elsewhere, the property Is characterized by grass covered gently sloping terrain previously utilized for agricultural purposes. Perimeter graded slopes are well landscaped with large trees, shrubs, and assorted groundcover plants. Site drainage sheetlfows in a northeasterly direction towards El Camino Real. Excessive scouring or erosion Is not in evidence. III. GEOTECHNICAL CONDITIONS Geotechnicai conditions at the project property have remained substantially unchanged from those discussed In the detaiis in the referenced report (see Appendix A). In general, previous grading has modified much of the project site and altered the original surface contours. Old topographic maps of the area indicate that lower, level areas of the site were previously characterized by a naturai canyon that drained northward toward El Camino Real. Grading of the area in the late 1960's leveled the site for agricultural purposes. Graded perimeter slopes in the south and east margins were constructed at a later date in support of the off-site development above. The project site exposes natural formational and Terrace Deposit units that are mantled by surficial alluvial and fill deposits. Eocene age formational rock units are present at shallow to modest depths in south and east portions of the property and found at depth beneath younger soil deposits in northerly areas. Natural Terrace Deposit soiis are present in the north and west portions of the property and thicken northward and pinch out atop formational rocks to the south. Undifferentiated fill and alluvial soils occupy lower elevations of the project site and compacted fill sections mark the south and east perimeter areas of the project site. Groundwater conditions, as encountered during the original site investigation, occur at depths of 32 and 33 feet below ground surfaces in the northwest portions of the property (see Boring Logs B-2 and B-3 in Appendix A). The noted groundwater is sufficiently deep and is not expected to impact the proposed grading orthe futurestability of the developed property provided our recommendations are followed. 11 ViNiiL & MihiM.inON liNniNi-KuiNC, iNt:. • 24S0 Auto IVk Wny • Bscon<liclo,C.iliroi ni.i02029-1229* Plionc (760)743-1214 GEOTECHNICAL PLAN REVIEW UPDATE DECEMBER 13, 2011 TABATHA 10 SUBDIVISION. CAMINO HILLS DRIVE. CARLSBAD PAGE 3 Details of project earth materials are given in the Test Trench and Boring Logs included in Appendix A (Plates 3-11). Approximate locations of the Test Trench excavations and Boring explorations are transferred and are shown on the enclosed Plate 3. IV. PROPOSED DEVELOPMENT The project current Grading Plan (Plate 3) proposes a substantially similar development scheme to the earlier reviewed project Preliminary Site Plan used as a basis of our geotechnical study in 2006 (see Plate 2, Appendix A). The grading plans outline the creation of a 26-lot residential subdivision with associated interior publlc roadways and improvements using minorto relatively significant cut-fill grading. Current plans, however, depict new building pad elevations for some lots. Elevated pad elevations on the order of 4 feet are now proposed for perimeter southeastern lots. Similar grades or minor elevation changes are noted for the remaining lots. Minor graded slopes provide ground elevation transitions between uneven pad surfaces. Additional Cross-Sections showing the proposed new pad elevations and associated new graded embankments are included as Plate 4. Based on the project plans, nearly 26,000 yards of import soil will be required to complete grading and achieve final design grades. A modest sound earthen berm, incorporating relatively short retaining walls, is proposed along the north/northwest margin of the property adjacent to El Camlno Real. Proposed hydro-modification consists of a self-contained vegetated bio-retention/detention area with impermeable liners on sides and bottom, engineered soiis, and perforated and header pipes surrounded with aggregate or crushed rocks, along the northern property margins. The treated stormwater from the bio- retention/detentlon area is discharged via a new 24-inch RCP storm drain pipe into the existing 36-inch RCP pipe beneath the El Camino Real. Future residential construction is anticipated to consist of single and/or two story conventional wood-frame buildings with exterior stucco supported on shallow stiff concrete foundations wilh stem-walls and slab-on-grade floors, slab-on-ground with turned-down footings, or post-tension slab foundations. V. SEISMIC GROUND MOTION VALUES For design purposes, site specific seismic ground motion values were determined as part of this investigation In accordance with the California Building Code (2010 CBC). The following parameters are consistent with the indicated project seismic environment and our experience with similar earth deposits in the vicinity of the project site, and may be utilized for project design work: ViNii. & Miniuin oN IENt;iNi:i=KiN(;, iNt:. • 2450 Auio Park Way • EscoiuWo. Olilornia 92029-1229 • Phone (760) 743-1214 GEOTECHNICAL PLAN REVIEW UPDATE DECEMBER 13, 2011 TABATHA 10 SUBDIVISION, CAMINO HILLS DRIVE. CARLSBAD PAGE 4 TABLE 1 Site Class SB 81 Fa Fv SMa SMI SDS SDI D 1.158 0.439 1.037 1.561 1.201 0.685 0.801 0.457 According to Chapter 16, Section 1613 of the 2010 California Building Code. Expianation: Ss: Mapped MCE, 5% damped, spectral response acceleration parameter at short periods. SI: Mapped MCE, 5% damped, spectral response acceleration parameter at a period of l-second. Fa: Site coefficient for mapped spectral response acceleration al short periods. Fv: Site coefficient for mapped spectral response acceleration at 1 -second period. SMS: The MCE, 5% damped, spectral response acceleration at short periods adjusted for she dass effects (SMS=FaSs). SM1: The MCE, 5% damped, spectral response acceleration at a period of 1-second adjusted for site class effects (SM1=FvS1). SDS: Design, 5% damped, spectral response acceleration parameter al short periods (SDS= %SMS). SD1: Design, 5% damped, spectral response acceleration parameter at a period of 1 -second (SD1 = VaSMI). Site peak ground accelerations (PGA) based on 2 percent probability of exceedance in 50 years defined as Maximum Considered Earthquake (MCE) with a statistical return period of 2,475 years is also evaluated herein in accordance with the requirements of CBC Section 1613 and ASCE Standard 7-05. Based on our analysis, the site PGAMCE was estimated to be 04B.g using the web-based United States Geological Survey (USGS) ground motion calculator. The design PGA determined as two-thirds of the Maximum Considered Earthquake (MCE) was estimated to be 0.32g. VI. HYDRO-MODIFICATIONS Projeci stormwater management should be designed and constructed considering the site indicated geotechnical conditions. The implemented management practice(s) should also have no short and long term impacts on the site building pad surfaces, graded slopes and natural embankments, fills and backfills, structures, and onsite and nearby off improvements and properties. Site hydro-modification, as currently proposed consist of a self-contained vegetated blo- retention/detentlon area with impermeable liners on sides and bottom, engineered soils filter mediai and perforated and header pipes surrounded with aggregates or crushed rocks, along the northern property margins. Treated water from the bio-retention/detention area Is captured and discharged via a new 24-inch RCP pipe into the existing 36-inch RCP storm drain pipe under El Camino Reai. The proposed hydro-modification system represent a feasible design and is considered acceptable from a geotechnical viewpoint. ViNii: & Minni.KTON llNiiiNliliUiNt;. INI:. • 2450 Amo Park Way • Hsrondidi>. C.ilitornia 92029-1229 • Plionc (760) 743-1214 GEOTECHNICAL PLAN REVIEW UPDATE DECEMBER 13, 2011 TABATHA 10 SUBDIVISION> CAMINO HILLS DRIVE. CARLSBAD PAGES Vll. CONCLUSIONS AND RECOMMENDATIONS Project most current Grading Plans reproduced herein as Plates 1 through 3 represent feasible designs and development schemes from a geotechnicai viewpoint. The most significant change from fhe original plans include minorto moderate elevations changes in final pad grades for some lots, the addition of an earthen sound wall adjacent to El Camino Real, and a vegetated blo-retention/detention area as a part ofthe project hydro- modification. The site mostly remains substantially unchanged from conditions presented in the referenced Preliminary Geotechnical Investigation report (Appendix A). All conclusions and recommendations provided In the referenced report (Appendix A) remain valid and should be incorporated into the final plans and implemented during the construction phase except where specifically amended or superseded below. Additional site-specific conclusions and recommendations consistent with the enclosed plans, and current codes, standards and engineering practice are also provided below and should be considered where ever appropriate and as applicable: 1. Landslides, faults or significant shear zones are not present at the project property and are not considered a geotechnicai factor in the planned developments. The study site is not located near or within the Alquist - Priolo earthquake fault zone established by the Slate of California. 2. Soli collapse, liquefaction and seismically induced settlements will not be a factor in the development of the project property provided our remedial grading and foundation recommendations are followed. 3. All existing underground wateriines, sewer lines, storm drains, utilities, tanks, structures, and improvements al or nearby the project construction site should be throughly potholed. Identified, and marked prior to the initiation of the actual excavations, grading and earthworks. Specific geotechnical engineering recommendations may be required based on the actual field locations, invert elevations, backfill conditions and proposed grades in the event of a grading conflict. Utility lines may need to be temporarily redirected, if necessary, priorto earthwork operations and reinstalled upon completion. Alternatively, permanent retocations may be appropriate as shown on the approved plans. Abandoned lines, irrigation pipes, and conduits should be properly removed, capped or sealed off to prevent any potential for future water Infiltrations into the embankments, foundation bearing and subgrade soils. Voids created by the removals of the abandoned underground pipes, tanks and structures should be properly backfilled with compacted fills In accordance with the requirements of this report. ViN|i;& MiiiiiuTON l:N(;tNi:i:RiNi;, INC. ' 2450 Amo Park Way • Kscondido, California 92029-1229* Phone (760) 743-1214 GEOTECHNICAL PLAN REVIEW UPDATE DECEMBER 13, 2011 TABATHA 10 SUBDIVISION, CAMINO HILLS DRIVE. CARLSBAD PAGE 6 4. Remove ail existing surface and subsurface improvements, old foundations and concrete slabs, vegetation, trees, roots, stumps, construction debris, and all other unsuitable materials and deleterious matter from all areas of proposed new fills, embankments, improvements, and structures plus 10 feet outside the perimeter, where possible and as approved in the field. Trash, vegetation, and construction debris shall not be allowed lo occur or contaminate new site fills and backfills. The prepared grounds should be Inspected and approved by the project geotechnical consultant or his designated field representative priorto grading and earthworks. 5. Earthwork and remedial grading operations should be completed as specified In the Remedial Grading and Earthworks section of the referenced report (Page 17 of Appendix A). Site upper fiil and alluvium deposits in the areas of planned new fills, embankments, structures, and improvements plus 10 horizontal feet outside the perimeter should be removed (stripped) to the underlying competent natural soils. Terrace Deposits, and Formational Rock as approved in thefield, and recompacted. Ground slabllization techniques using Tensar Geogrid BX-1100 (orgreaterfrom the same series) earth reinforcement may be required at the yielding botiom of removals, and within the compacted fill mass, in the case of unsuitable exposure and should be anticipated as specified and directed in the fieid. Actual removal depths should be established by the project geotechnical consultant at the time of earthwork operalions based on exposed field conditions. Typical removal depths in the vicinity of the subsurface are given in the referenced report (Table 15, Appendix A) and also depicted on the attached Plate 3. Locally deeper removals may be necessary as directed in the field and should be anticipated. 6. Current plans indicated minor to moderate changes in the final pad elevations. Elevated pad grades are now proposed for the south/southeastern lots with Lots 3-5 raised up to 4 feet above the prior elevations (see Piate 2, Appendix A). Ground transitioning will be accomplished with new graded cuts on the order of 5-8 feet high. Reconstruction of lower sections of the exposed slope in these areas (Lots 4 and 6-10) with stabilization fills, or a toe retaining wall support, as recommended in a referenced report (see Plate 20, Appendix A) may still be necessary. Final recommendations for slope reconstructions for new graded embankments constructed within or al the loe of existing graded slopes will be provided in the field by the project geolechnical engineer based upon actual developed exposures. ViNli: & MiDlJl.in oN ENCiNLiiKiNC, INC. • 2450 Adto P.iik Way • Eiicondido. Cilirornia 92029-1229 • Phone (760) 743-1214 GEOTECHNICAL PLAN REVIEW UPDATE DECEMBER 13, 2011 TABATHA 10 SUBDIVISION. CAMINO HILLS DRIVE. CARLSBAD PAGE 7 7. The project Is an unbalanced grading operation and nearly 26.000 yards of import soil will be required to achieve final design grades. Onsite soils may also may be expected to shrink approximately 10% to 20% on a volume basis when compacted as specified herein. Import soils required to complete grading, should be good quality non-corrosive, very low expansive sandy granular D.G. type soils (100% passing 1-inch sieve, more than 50% passing #4 sieve and less than 18% passing #200 sieve wilh expansion index less than 21), inspected, tested as necessary, and approved by the project geotechnical consultant prior to delivery to the site. Import soils should also meet or exceed the design parameters given in the foliowing sections. Good quality sandy granular D.G. type import soils should be placed within the upper pad grades. Attempts should also be made to bury site potentially expansive clays in deeper fills beiow the upper 4 feet and place, better quality sandy onsite soils wilhin the upper grades using select grading techniques, as specified in the referenced report. 8. The cut portions of cut-fill transition pads should be undercut lo a minimum depth of 3 feet or at least 12 inches below the bottom of the deepest footing(s). whichever Is more and reconstructed to design pad grades with compacled fills, as specified. In the roadways, driveway, parking and on-grade slabs/improvement transition areas, there should be a minimum of 12 inches of compacted soils below rough finish subgrade. 9. Fill malerials. processing, spreading and placement in thin horizontal lifts (less than 8 Inches maximum), moisture conditioning above the optimum levels and compaction procedures, and minimum compaction levels (95% within the upper 3 feet and where specified, and 90% below the upper 3 feet) will remain the same as specified. All grading and earthworks should be completed In accordance with the Chapier 18 and Appendix "J" ofthe California Building Code (CBC). City of Carlsbad Grading Ordinances, the Standard Specifications for Publlc Works Construction, and the requirements ofthe referenced soil report (Appendix) and this update transmittal. 10. New graded slopes, berms, and embankments constructed in connection with the site development are expected minor features on the order of 10 feet high maximum. Graded slopes and embankments should be programmed for 2:1 gradients and constructed as spiffed In the referenced report (see Appendix A). ViNii; & Minnu-TON liNi-iiNi:):UiN»;,, INC. • 24.S0 Amo P.^rk Way • liscondido. Cslifonw 92029-1229 • Phftnc(760)74.^-12l4 GEOTECHNICAL PLAN REVIEW UPDATE DECEMBER 13, 2011 TABATHA 10 SUBDIVISION. CAMINO HILLS DRIVE. CARLSBAD PAGES 11. Excavations and removals of onsite existing fills and alluvium are expected to predominantly generate marginal quality plastic silty to clay-rich deposits which typically require additional processing, mixing and moisture conditioning efforts In order to manufacture a uniform homogeneous mixture suitable for reuse as new site fills. Site potentially expansive soils should be burled in deeper fills and better qualily sandy soils generated from the excavalions of site Terrace Deposits, and good quality sandy Import soils place within upper pad grades, as specified. Plastic silty to clayey soils are also not suitable for wali and trench backfills and good qualily sandy soils should be used for this purpose. For foundation design purposes, however, sandy clay to silty clayey sand (SC/CL) bearing soils with low to high expansion potential (Expansive Index less than 131) based on ASTM D-4829 classification should be considered. Remedial grading and geotechnical foundation design recommendations specified herein are provided lo also mitigate adverse affects of site potentially expansive soils . 12. Soil design parameters, and foundations and slab designs will remain the same as specified in the referenced report. However, the following revised parameters are appropriate based on the anficlpated bearing soils properties and supercede those previously given where specifically applicable: * Design edge moisture variafion distance for edge lift (em) 4.9 feet. * Design edge moisture variation distance for cenler lift (em) 9.0 feet. * Design differential swell occurring at the perimeter of slab for edge lift condition (Ym) 1.32 inches. * Design differential swell occurring at the perimeter of slab for center lift condition (Ym) 2.91 inches. In case of post-tensioned slab foundation system, underslab moisture control should consist of a well-performing vapor barrier/moisture retardant (minimum 15- mil Stego) placed mid-height in a minimum of 4 inches of clean sand (SE of 30 or greater). However, interior underslab moisture control requirements per CGC Section 4.505.2.1 consisting of a minimum 4-inch thick base of ^4-inch or larger clean aggregate, provided with a vapor barrier (minimum 15-mil Stego) in direct conlact with concrete, and a concrete mix design which address bleeding, shrinkage, and curiing may also be considered. 13. All exterior concrete slabs and flatwork (walkways, and patios) should also be constructed as specified in the referenced report (Appendix A). Slab subgrade soils should be compacted to minimum 90% compaction levels. Subgrade soils should be tested for proper moisture and specified compaction levels and approved bythe project geotechnical consultant prior to the placement of concrete. ViNjiL S( Minnu: rrtN ENI:INI;I-RIN.;, INC. • 2450 Amo Park Way • Eseondid... California 92029-1229 • Phone (760) 743-1214 GEOTECHNICAL PLAN REVIEW UPDATE DECEMBER 13, 2011 TABATHA 10 SUBDIVISION, CAMINO HILLS DRIVE, CARLSBAD PAGE 9 Slab reinforcements lying on subgrade will be Ineffecfive and shortly corrode due to lack of adequate concrete cover. Reinforcing bars shouid be correctly placed extending through the construction joinis tying the slab panels. In construction practices where the reinforcements are discontinuous or cut the construction joints, slab panels should be tied together with minimum 16 inches long #3 dowels (dowel baskets) at 18inches on centers placed nearthe mid-height in the slab (9 inches on either side of the joint). Provide thickened slab edge and "tool joint" or "softcut" contraction/control joints for exterior slabs as specified. The larger dimension of any panel shall not exceed 125% of the smaller dimension. All exterior slab designs should be confirmed In the final as-graded compaction report. 14. Preliminary structural seciion esfimates forthe asphalt and PCC paving will remain the same as specified. The minimum asphalt pavement structural section presented In Table 16 of the referenced report (see Page 32 of Appendix A), or the minimum section required by the City of Carlsbad, whichever Is greater, should be considered. Provide "tool joint" or "softcut" contraction/control joints for all PCC paving surfaces also as specified. The larger dimension of any panel shall not exceed 125% of the smaller dimension. Joints shall intersect free edges at a 90° angle and shall extend straight for a minimum of V/x feet from the edge. The minimum angle between any two intersecting joints shall be 80°. Align joints of adjacent panels. Also, align joints in attached curbs with joints in slab panels. Provide adequate curing using approved methods (curing compound maximum coverage rate = 200 sq. ft./gal.). 15. The proposed bio-retention area within the project development is a self- contained system which Incorporates timely removal of the captured water by the perforated subdrain pipe and discharging the treated water into the storm water drainage facilities, \Arithout allowing accumulation or saturation of the surrounding soils. The proposed bio-retention system is considered acceptable from a geolechnical point of view and may be installed at the designaled site locations as shown on the project plans. Added care, however, will be required during the bio-retention constructions to void puncturing the impermeable liner and assure positive outflow of the perforated subdrain pipe. 16. Controi of site surface drainage and potential for post construction subsurface water caused by surface water infiltrations is one of the most significant geotechnical factors at the project building sites. Surface flow, run-off drainage and subsurface water should not impact graded surface, saturate wall backfills, bearing and subgrade soils or cause erosion. All retaining walls should be provided with a back drain as specified. Drainage ditches should be provided at the top and toe of slopes and behind site retaining walls with collected water directed to approved disposal ViNjn & MJIII)I.I;TON liNCiNr-iiitiNt:. INC. • 2450 Amo Park Way • Escondido. Cilifornia 92029-1229 • Phone (760) 743-1214 GEOTECHNICAL PLAN REVIEW UPDATE DECEMBER 13,2011 TABATHA 10 SUBDIVISION. CAMINO HILLS DRIVE, CARLSBAD PAGE 10 location via adequate area Inlets. All wall back drains, fighl pipes and outiet locations should also be shown on the flnal plans. 17. Final grading and foundation plans should reflect preiiminary recommendations given in this report and reviewed and approved by the project geotechnical consultant. Additional or more specific recommendations may be necessary and should be provided at that time, as required. VIII. GEOTECHNICAL ENGINEER OF RECORD (GER^ Vinje & Middleton Engineering, Inc. is the geotechnicai engineer of record (GER) for a specific scope of work or professional service under a contractual agreement unless it is terminated or canceled by either the cllent or our firm. In the event a new geotechnical consultant or soils engineering flrm is hired to provide added engineering services, professional consultations, engineering observations and compaction testing, Vinje & Middleton Engineering, Inc. will no longer be the geotechnical engineer of record. Project transfer should be completed In accordance with the California Geotechnical Engineering Association (CGEA) Recommended Practice for Transfer of Jobs Between Consultants. The new geotechnical consultant or soils engineering firm should review all previous geolechnical documents, conduct an independent study, and provide appropriate confirmations, revisions or desjgn modifications to his own satisfaction. The new geotechnical consultant or soils engineering firm shouid also notify in writing Vinje & Middleton Engineering, Inc. and submit proper notification to the City of Carisbad for the assumption of responsibility in accordance with the applicable codes and standards (1997 UBC Section 3317.8). IX. LIMITATIONS This geotechnical plan review update is not a "Plan Check Review" and does not relieve the responsibility of the project design consuitant(s) and contractor(s) to get completely familiarized with the requirements of the project soil report(s) and fully incorporate its recommendations into the project design, plans and construction works, where appropriate, and as applicable. Our review and comments are for general geotechnicai conformance of the project plans with the Intent of the project soil report and design recommendations. Review of structural and civil engineering calculations, architectural intent and structural and civil engineering design modeling and basis, verification of set back requirements, easements and right-of-ways, as well as code, city and county compliance are beyond geolechnical engineering services. It Is the owner's or his (her) representative's responsibility to provided copies of all pertinent soil report(s), updates, addendum letters and plan review letters to respective design consultant(s), and generai contractor and his (her) subcontractor(s) for full compliance. ViN|i£ it MmiiLin oN liNciiNi.iimNC. INC. • 2450 Amo Park Way * Evimdido, California 92029-1229 • Phone (760) 743-1214 GEOTECHNICAL PLAN REVIEW UPDATE DECEMBER 13. 2011 TABATHA 10 SUBDIVISION. CAMINO HILLS DRIVE. CARLSBAD PAGE 11 This opportunity to be of service again is sincerely appreciated. Should any questions arise concerning this report, please do not hesitate to contact this office. VINJE & MIDDLETON ENGINEERING, INC. ehdi S. Shariat GEN^2885 Steven Melzer CEG# Distribution: Attachments: Steven Melzer X-V <^ Addressee (2, e-mail) x^T" REC Consultants Inc., Atlem" ' Plates 1 - 4 Appendix A X Parra (3, e-mail) VrNll; & MiDDLinoN ENi;iNi;i;HiNf., INC. • 2450 Amo P.irk Way • Escondido, California 92029-1229 • Phone(760)74.VI2l4 »Br KC cinr GKADINC HOTES .Jl AOMTXX m M KoMnorrs or CH«pm is.i< « C'«SB')0 yuMicfM caoc.f m IM suntSDES Ml (»wii fUfS mmua.r APMOI v cwtJM iFBUONC enum SNOM or IMS OT CF PLMS 2. MPfimm. 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NO. 473-7} 5'fecsBtmiue oc. r/'sren NHTENAMW flCR a^-i (LocAfKm MMCS; TO K mOCAKO SECDOn 4* AC/r AS cuircTOR smar FKCm STA 1t*l<ll to STA. t5*l7.SS (Ste arr OH ma 473-7} •' H ooc CUM HW rLDNS OUTLET APf STREET V / fliMnEwnnw CWSS sFnioH CURB OPENING DETAIL H.tS. iiiiM'...aam SECIRK <• «c/»- M M7r m Ti-ID couecnm smrr mem 5TA.i3-*^t7.es TO STA. I»*77.e7 (ser orrom m 472-7} ISBLSSm xcno«4-A^-AS NOT TQ SCALE ti.-^ fVtSU STA.ta*77.a7 TO STA. 37*73.27 (srr arr OK wa 473-7J PUH - TYPICAL LOT GRADING PER fiS-15 I'mM' j PLATE 2 1 [ VflAI JOB«06-210~P I ©E©L©0I(D CM© SCALE: 1" = 20' COMPACTED FOL PROPOSED GRADE (LOT 4J FORMATIONAL ROCK ""^ PROPOSED • GRADE fLOT?} PLATE 4 V&M JOB #06-210-P APPENDIXA ViNTE & MIDDLETON ENGINEERING, INC. Job #06-210-P Escondido. Cilifornia 92029-1229 Phone(760)743-1214 June 23, 2006 FM (760)739 0343 Tabata Family Trust c/o Mr. Gregg Harrington P.O. Box 943 Carlsbad, California 92018 PRELIMINARY GEOTECHNICAL INVESTIGATION. PROPOSED 26-LOT SUBDIVISION, CAMINO HILLS DRIVE. CARLSBAD (A.P.N.'s 212-050-32 & 33^ Pursuant to your request, Vinje and Middleton Engineering, Inc. has completed the enclosed Preliminary Geotechnical Investigation Report for the subject site. The following report summarizes the results of our field Investigation, including laboratory analyses and conclusions, and provides recommendations for the proposed development as understood. From a geotechnical engineering standpoint, it is our opinion that the site is suitable for the planned residential subdivision and associated paving and underground improvements provided the recommendations presented in this report are incorporated into the design and construction of the project. The conclusions and recommendations provided in this study are consistent with the indicated site geotechnical conditions and are intended to aid in preparation of final development plans and allow more accurate estimates of development costs. If you have any questions or need clarification, please do not hesitate to contact this office. Reference to our Job #06-210-P will help to expedite our response to your inquiries. We appreciate this opportunity to be of service to you. VINJE & MIDDLETON ENGINEERING, INC. Dennis Middleton CEG #980 DM/jt Preliminary Geotechnical Investigation Proposed 26-Lot Subdivision Camino Hills Drive Carlsbad, California (A.P.N.'s 212-050-32 & 33) June 23, 2006 Prepared For: TABATA FAMILY TRUST c/o Mr. Gregg Harrington P.O. Box 943 Carlsbad, California 92018 Prepared By: VINJE & MIDDLETON ENGINEERING, INC. 2450 Vineyard Avenue, Suite 102 Escondido, California 92029 Job #06-210-P TABLE OF CONTENTS PAGE NO. I. INTRODUCTION 1 IL SITE DESCRIPTION 1 m. PROPOSED DEVELOPMENT 2 IV. SITE INVESTIGATION 2 V. GEOTECHNICAL CONDITIONS 2 A. Earth Materials 3 B. Groundwater and Surface Drainage 4 C. Slope Stability 4 D. Faults / Seismicity 4 E. Geologic Hazards 7 F. Laboratory Testing / Results 7 VI. SITE CORROSION ASSESSMENT 13 VII. CONCLUSIONS 14 VIII. RECOMMENDATIONS 17 A. Remedial Grading and Earthworks 17 B. Foundations and Interior Floor Slabs 26 C. Post-tensioned / Structural Slab-on-Ground Foundations 28 D. Exterior Concrete Slabs / Flatworks 30 E. Soil Design Parameters 31 F. Asphalt and PCC Pavement Design 32 G. General Recommendations 34 IX. LIMITATIONS 36 TABLE NO. Fault Zone 1 Site Specific Seismic Parameters 2 Soil Type 3 Grain Size Analysis 4 TABLE OF CONTENTS (continued) Liquid Limit, Piastic Limit and Plasticity Index 5 Maximum Dry Density and Optimum Moisture Content 6 Moisture-Density Tests (Undisturbed Chunk and Ring Samples) 7 Expansion index Test 8 Direct Shear Test 9 pH and Resistivity Test 10 Sulfate Test 11 Chloride Test 12 R-value Test 13 Years to Perforation of Steel Culverts 14 Removals and Over-excavations 15 Asphalt and PCC Pavement Design 16 PLATE NO. Regional Idea Map 1 Site Plan 2 Test Trench Logs / Boring Logs (with key) 3-11 Geologic Cross-Sections 12-14 Fault - Epicenter Map IS Grain Size Analysis 16-17 Consolidation Tests 18-19 Typical Stabilization Fiil or Retaining Wall 20 Isolation Joints and Re-entrant Corner Reinforcement 21 Retaining Wall Drain Detail 22 REFERENCES PRELIMINARY GEOTECHNICAL INVESTIGATION PROPOSED 26-LOT SUBDIVISION CAMiNO HILLS DRIVE, CARLSBAD (A.P.N. 121-050-32 & 33) I. INTRODUCTION The property investigated in this work includes an approximate 10-acre parcel located at the east terminus of Camino Hills Drive, adjacent to El Camino Real, within the City of Carlsbad. The site location is shown on a Regional Index Map enclosed with this report as Plate 1. We understand that the property is proposed for a 26-lot residential subdivision with associated interior streets and underground improvements. Consequently, the purpose ofthis investigation was to determine soil and geotechnical conditions at the site and to evaluate their influence upon the planned development. Geologic mapping, test trench and boring excavations, as well as soil sampling and testing were among the activities conducted in conjunction with this effort which has resulted in the geotechnical grading and foundation recommendations presented herein. II. SITE DESCRIPTION A Preliminary Review Site Plan depicting existing topographic conditions and the proposed development scheme has been prepared by Pasco Engineering and is reproduced herein as Plate 2. As shown, much of the study property consists of gently sloping terrain that descends in a northeasterly direction to El Camino Real. An anomalous hill marks the northwest property margin adjacent to Camino Hills Drive. Previous grading activities for off-site developments have modified the property to include large graded slopes that ascend to residential developments along the southerly and easterly site margins. The anomalous hill rises nearly 30 feet above surrounding areas with slope gradients that generally approach 2:1 (horizontal to vertical) maximum. The large graded slopes that mark the southerly and easterly site margins were constructed at 2:1 gradients maximum and range to nearly 50 feet high. Drainage terraces were noted in south and northeast portions of the graded embankments. Pre-development topography from San Diego Topographical Sun/ey Maps No.'s 354-1677 and 354-1683 dated 1975 indicate the perimeter slopes are largely fill embankments with some fill-over-cut slopes. This was confirmed fay shallow hand-dug test pits in selected areas of the slopes. Documentation pertaining to slope construction is not available for review. The symetrical hill in the northwesterly portion supports a residential dwelling and associated improvements. Portions of the southwest corner of the property are currently utilized for stockpiling irrigation supplies. Gently sloping areas of the property appear to have been previously used for agricultural purposes, but presently support a modest cover of grass and weeds. Perimeter graded slopes are well landscaped with large trees, shrubs, and assorted groundcover plants. ViN)i; & MiDHi-liTON BNijiNliliHiNC, INC. • 2450 Aiito P.iik Way • liicondido, Cnlilorni.i 92029-1229 • Phone (760) 743-1214 PREUMINARY GEOTECHNICAL INVESTIGATION PAGE 2 26-LOT SUBDIVISION, CAMINO HILLS DRIVE, CARLSBAD JUNE 23, 2006 Site drainage sheetlfows in a northeasterly direction towards El Camino Real. Excessive scouring or erosion is not in evidence. III. PROPOSED DEVELOPMENT The existing dwelling and associated structures and improvements are planned for demolitiori to allow for the development of a 26-lot residential subdivision with interior roadways and underground improvements. Cut-fill grading techniques will be used to construct level building pads and roadway surfaces. Soils generated from the cutting of the northwest hill will be used as compacted fills placed In lower areas ofthe site. Vertical cut and fill depths will approach 30 feet and 15 feet maximum respectively. Planned new graded cut and fill slopes will be modest embankments approaching 10 feet high maximum and are programmed for 2:1 gradients. Perimeter slopes will also be extended at the same gradients (2:1) below the existing toe levels to achieve adjacent pad grades that are approximately up to 6 feet lower. publi'c Interior roadway improvements include a horseshoe-shaped private street that will provide access to individual lots from Camino Hills Drive at two locations. Construction plans are not available. However, future residential constructions are anticipated to consist of conventional wood-framed with exterior stucco buildings supported on shallow foundations with stem-walls and slab-on-grade floors, or slab-on-ground with turned-down footings. IV. SITE INVESTIGATION Subsurface conditions were chiefly determined by the excavation of 10 test trenches dug with a tractor-mounted backhoe and the excavation of 4 small-diameter test borings drilled with a truck-mounted rotary auger drill. A Geotechnical Boring Permit (#LM0N103949 dated May 3, 2006) was issued by the County of San Diego Health Department for the two deep borings. All trenches and borings were logged by our project geologist who also retained representative soil and rock samples at selected locations and intervals for subsequent laboratory testing. Locations of exploratory excavations are shown on the enclosed Preliminary Site Plan, Plate 2. Logs of the excavations are included with this report as Plates 3-11. Laboratory test results are summarized in following sections of this report. V. GEOTECHNICAL CONDITIONS Much of the project site is modified by previous grading which has altered the original surface contours. Old topographic maps of the area indicate that lower, level areas of the site were previously characterized by a natural canyon that drained northward toward El ViNjI: & MlDOI.H'i'ON liNC.INRI-.HINC, INC, • 2450 Aiifo Pnrlt Wn)' • liscondido. Caliloiniii 92029-1229 • Phone (760) 743-1214 PRELIMINARY GEOTECHNiCAL INVESTIGATION PAGE 3 26-LOT SUBDIVISION, CAMINO HILLS DRIVE, CARLSBAD JUNE 23, 2006 Camino Real. Grading of the area in the late 1960's leveled the site for agricultural purposes. Graded perimeter slopes in the south and east margins were constructed at a later date in support ofthe off-site development above. Consequently, the projisct site exposes natural formational and Terrace Deposit units that are mantled by surficial alluvial and fill deposits. A. Earth Materials The following earth deposits are recognized at the project site: Formational Rock (Ts) - Eocene age formational rock units are present at shallow to modest depths in south and east portions of the property and found at depth beneath younger soil deposits in northerly areas. As exposed in our test excavations site formational rock consists predominantly of pale grey colored siltstone with local interbeds of sandstone. The rocks were typically found weathered soft in upper exposures and grade uniformly dense at depth. Project formational rocks are competent deposits with no indication of instability, and will adequately support planned fills, structures, and improvements. Terrace Deposit (Qt) - Natural Terrace Deposit soils were encountered in north and west portions of the property. The Terrace Deposits thicken northward and pinch out atop formational rocks to the south. Site Terrace Deposits largely consist of dark-colored clayey sands and were found in moist and loose to soft conditions near the surface grading more dense at depth. Noted exposures are stable units that will adequately support new fills, structures, and improvements. Fili - Alluvium (af-Qal) - Undifferentiated fill and alluvial soils occupy lower elevations of the project site approximately as shown on Plate 2. These soils consists chiefly of silty sands with clay and occur in a loose, and soft to medium dense condition. Compacted Fill (Caf) - Structural fill sections mark the south and east perimeter areas of the project site as shown on Plate 2. The fills are locally derived compacted sections that support off-site improvements above. Noted fill slopes at the site are provided with a good plant cover and do not evidence instability. Details of project earth materials are given on the enclosed Test Trench Logs and Boring Logs (Plates 3-11) and further defined in a following section herein. The indicated subsurface relationship is depicted on Geologic Cross-Sections enclosed herein as Plates 12-14. ViNji; & MiDnunON ENOINI;I-:UINI;, INC. • 2450 Auto P.nrk Wny • Escnndido. Gililbmi.i 92029-1229 • phone (760) 743-1214 PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 4 26-LOT SUBDIVISION, CAMINO HILLS DRIVE, CARLSBAD JUNE 23.2006 B. Groundwater and Surface Drainage Subsurface water was encountered at depths of 33 and 32 feet below ground surfaces in borings B-2 and B-3 respectively. Elsewhere, groundwater conditions were not encountered to the depths explored. The noted groundwater is sufficiently deep and is not expected to impact the proposed grading as currently planned or the future stability of the developed property provided our recommendations are followed. However, the control of surface run-off and storm water is critical to the continuing stability of the property and graded surfaces. Water should not be allowed to pond on pad surfaces and over-watering of site vegetation may create overiy moist to wet ground conditions near finish pad grades. Development of the property should include improved site drainage and construction of engineered surface drainage and storm runoff control facilities as indicated on the project drainage improvement plans. C. Slope Stability Southeriy and easterly site perimeters are marked by 2:1 gradient graded slopes constructed to support residential developments above. Documentation pertaining to the slope construction is not available for review. Older topographic maps indicate the slopes range from fill slopes to fill over cut slopes. These slopes are well landscaped and were carefully inspected by our project engineering geologist. The graded embankments are performing well and do not evidence slope instability. Pad constructions will lower the grades adjacent to the southeriy and easterly embankments where slopes will continue to descend at 2:1 gradients to an additional maximum height of 6 feet. The new toe embankment should be reconstructed as a graded stabilization fill slope as recommended in the following sections. Altematively, a retaining wall may be constructed at the base of the slope in order to achieve design grades and assure stability ofthe existing embankments. New graded slopes planned in connection with the site development are generally minor to modest embankments programmed for 2:1 gradients. New graded slopes will be grossly stable with respect to shallow and deep-seated failures provided slope construction recommendations, specified in the following sections, are followed. D. Faults / Seismicity Faults or significant shear zones are not indicated on or near proximity to the project site. ViNiK & MiDDLinoN ENOiNr-i;iUNci. INC. • 7.4.SO Am.-, i>iil- u/.... • l^.-.^.v PRELIMINARY GEOTECHNICAL INVESTIGATION 26-LOT SUBDIVISION, CAMINO HILLS DRIVE. CARLSBAD PAGE 5 JUNE 23, 2006 As with most areas of California, the San Diego region lies within a seismically active zone; however, coastal areas ofthe county are characterized by low levels of seismic activity relative to inland areas to the east. During a 40-year period (1934-1974), 37 earthquakes were recorded in San Diego coastal areas by the Califomia Institute of Technology. None of the recorded events exceeded a Richter magnitude of 3.7, nor did any of the earthquakes generate more than modest ground shaking or significant damages. Most of the recorded events occurred along various offshore faults which characteristically generate modest earthquakes. Historically, the most significant earthquake events which affect local areas originate along well known, distant fault zones fo the east and the Coronado Bank Fault to the west. Based upon available seismic data, compiled from California Earthquake Catalogs, the most significant historical event in the area of the study site occijrred in 1800 at an estimated distance of 10.0 miles from the project area. This event, which Is thought to have occurred along an off-shore fault, reached an estimated magnitude of 6.5 with estimated bedrock acceleration values of 0.129g at the project site. The following list represents the most significant faults which commonly impact the region. Estimated ground acceleration data compiled from Digitized California Faults (Computer Program EQFAULT VERSION 3.00 updated) typically associated with the fault is also tabulated: TABLE 1 M^iiurh.um •.;;...,.:;-pf0j^iiite,:,. .• L;: vAicqeifltirtditrt^H^^ Rose Canyon 6.6 miles 0.21 Og Newport-Inglewood 8.2 miles 0.182g Coronado Bank 22.6 miles 0.175g Elsinore-Julian 22.6 miles 0,1508 The location of significant faults and earthquake events relative to the study site are depicted on a Fault - Epicenter Map enclosed with this report as Plate 15. More recently, the number of seismic events which affect the region appears to have heightened somewhat. Nearly 40 earthquakes of magnitude 3.5 or higher have been recorded in coastal regions between January 1984 and August 1986. Most of the earthquakes are thought to have been generated along offshore faults. ViNJi; & MiiiriunoN RNC;INI;I;HINI-., INC. • 2450 Amn l>ark Wiy • liscondido, Olilorni;! 92029-1229 • Phone (760) 74.^-1214 PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 6 26-LOT SUBDIVISION, CAMINO HILLS DRIVE, CARLSBAD JUNE 23. 2006 For the most part, the recorded events remain moderate shocks which typically resulted in low levels of ground shaking to local areas. A notable exception to this pattern was recorded on July 13, 1986. An earthquake of magnitude 5.3 shook County coastaj areas with moderate to locally heavy ground shaking resulting in $700,000 in damages, one death, and injuries to 30 people. The quake occurred along an offshore fault located nearly 30 miles southwest bf Oceanside. A series of notable events shook County areas with a (maximum) magnitude 7.4 shock in the early morning of June 28, 1992. These quakes originated along related segments ofthe San Andreas Fault approximately 90 miles to the north. Locally high levels of ground shaking over an extended period of time resulted; however, significant damages to local structures were not reported. The increase in earthquake frequency in the region remains a subject of speculation among geologists; however, based upon empirical information and the recorded seismic history of County areas, the 1986 and 1992 events are thought to represent the highest levels of ground shaking which can be expected at the study site as a result of seismic activity. In recent years, the Rose Canyon Fault has received added attention from geologists. The fault is a significant structural feature In metropolitan San Diego which includes a series of parallel breaks trending southward from La Jolla Cove through San Diego Bay toward the Mexican border. Test trenching along the fault in Rose Canyon indicated that at that location the fault was last active 6,000 to 9,000 years ago. More recent work suggests that segments of the fault are younger having been last active 1000 - 2000 years ago. Consequently, the fault has been classified as active and included within an Alquist-Priolo Special Studies Zone established by the State of California. Fault zones tabulated in the preceding table are considered most likely to impact the region of the study site during the lifetime of the project. The faults are periodically active and capable of generating moderate to locally high levels of ground shaking at the site. Ground separation as a result of seismic activity is not expected at the property. For design purposes, site specific seismic parameters were determined as part of this investigation in accordance with the California Building Code. The following parameters are consistent with the indicated project seismic environment based on site specific study and our experience with similar earth deposits in the vicinity of the project site, and may be utilized for project design work: ViN)i: & Miniii.i-.TON llNClNl'iilUNC. INC. • 2450 Airio Park W;iy • liscondido. Gililornia 92029-1229 • Phone (760) 743-1214 PRELIMINARY GEOTECHNICAL INVESTIGATION 26-LOT SUBDIVISION, CAMINO HILLS DRIVE. CARLSBAD PAGE 7 JUNE 23. 2006 TABLE 2 >.. Seteinlb?jFles)ji :-5JHPml»^i •':^::} to.:. So 4 0.4 B 1.0 1.0 0.44 0.64 0.582 0.116 According to Chapter 16, Divisions IV & V of the 2001 Califomia Building Code. A site specific probabilistic estimation of peak ground acceleration was also performed using the FRISKSP (T. Blake, 2000) computer program. Based upon Boore et al (1997) attenuation relationship, a 10 percent probability of exceedance in 50 years was estimated to produce a site specific peak ground acceleration of 0.32g (Design-Basis Earthquake, DBE). The results were obtained from the corresponding probability of exceedance versus acceleration curve. E. Geologic Hazards Geologic hazards are not presently indicated at the project site. Perimeter graded slopes are performing well with no indication of gross shalbw or deep-seated instability. The most significant geologic hazards at the property will be those associated with ground shaking in the event of a major seismic event. Liquefaction or related ground rupture failures are considered remote to none provided our remedial grading and ground stabilization recommendations are followed. F. Laboratory Testinq / Results Earth deposits encountered in our exploratory test excavations were closely examined and sampled for laboratory testing. Based upon our test trench and borings, standard perfonning penetration tests (SPT), fleld exposures and site soils have been grouped into the following soil types: TABLE 3 ^^-v'-.^vif -i':-: /;viiii|8!cdBtli)ri-^:.-v. ^ ']•.•.'.'...<'-. v^-\;j: 1 pale brown sandy clay / clayey sand (Fill/Topsoil) 2 red-brown clayey sand (Alluvium) 3 red-brown medium to coarse sand w/ trace clay (Fill/Topsoil/Alluvium) 4 grey silty clay / siltstone/ claystone (Topsoil/Formationai Rock 5 grey / yeltow-tan fine sand w/ trace clay (Topsoil/Formationai Rock/Terrace) VlN|i; & MllWi.l-. rON ENf.lNi;i;i»INci. INC. • 2450 Amo Park Way • liicondido. Cnlifoinia 92029-1229 • Phone (760) 743-1214 PRELIMINARY GEOTECHNICAL INVESTIGATION 26-LOT SUBDIVISION. CAMINO HILLS DRIVE, CARLSBAD PAGE 8 JUNE 23, 2006 The following tests were conducted in support of this investigation: 1. Standard Penetration Tast: Standard penetration tests (SPT) were performed at the time of borehole drilling in accordance with the ASTM standard procedure D-1586. The procedure consisted of a standard 51 MM outside diameter sampler, 457 MM in length and 35 MM in inside diameter, sampler driven by a 140-pound hammer mechanically dropped 30 inches using 5-foot long AW drill rods. The bore hose was 200 MM (8 inches) in diameter and water was added for bore hole support and aiding drilling. The test results are indicated at the corresponding locations on th6 Boring Logs. 2. Grain Size Analysis: Grain size analyses were performed on representative samples of Soil Types 1,2,4, and 5. The test results are presented in Table 4 ahd graphically presented on the enclosed Plates 16 and 17. TABLE 4 Sieve Size %" #10 #40 Location Soil Type Percent Passing T-1 @1' 1 100 99 97 89 T-1 @ 4' 2 100 100 : 97 .:-::-m...-'. 76 T-3 @ 3' 4 100 ;;"icp::::; 100 -. i.-.rr> • 98 . -- ...t -.- .-'.•>-. • T-2 @ 6' 5 100 99 86 .:-TJ}"--J''--:..\~ 3. Liquid Limit. Plastic Limit and Plasticity Index: Liquid limit, plastic limit and plasticity index tests were performed on representative samples of Soil Types 1,2,4, and 5 in accordance with ASTM D-4318. The test results are presented in Table 5. TABLE 5 [ Location ;::$6u;i]iii^^; EiJ^iiqijiif^tiitiJii^'- • / : ; IPIastfetimiif; ' (PL:%); •••/(lyspfile^^LiK^i'i^! T-1 @ 1-1 45 24 21 T-1 @ 4' 2 32 16 16 T-3 @ 3' 4 49 27 22 T-2@5' 5 36 25 11 ViNiii & Mii>Di.|.TON KNCINI-KHINI.. INC.. • 2450 Amo Park Way • Lscondido. Callloinia 92029-1229 • Phooc (760) 74.V1214 PRELIMINARY GEOTECHNICAL INVESTIGATION 26-LOT SUBDIVISION, CAMINO HILLS DRIVE, CARLSBAD PAGE 9 JUNE 23, 2006 4. Maximum Dry Density and Optimum Moisture Content: The maximum dry density and optimum moisture contents of Soil Types 2, 4 and 5 were determined in accordance with ASTM D-1557. The test results are presented in Table 6. TABLE 6 'f?'^:>^^&:^^^di^X<I. : ivl^i(liiiiini>Diy; bptiniutn liljiotijitujrd . . ;^7:;:;i£lo!ii«lriti(fiM6^ .;;. T-1 @4' 2 129.6 10.4 T-3 @ 3* 4 110.5 19.8 T-2 @ 5" 5 119.5 12.5 5. Moisture-Density Tests (Undisturbed Chunk and Rinfl Samples): In-place dry density and moisture contents of representative soil deposits beneath the site were determined from relatively undisturbed chunk samples using the water displacement test method, and undisturbed ring samples using the weights and measurements test method. The test results are presented in Table 7 and tabulated on the enclosed Test Trench Logs and Boring Logs. TABLE 7 :CT%pJti||-|iev-'; J • v-aa/, i-v; j>:'eptttent-a-} r..^J.- '—'-.i X. v',.) ^drPciOiil $9m^A T-1 @ 2' 1 18.5 100.8 -- T-1 @ 4* 2 12.9 104.1 129.6 80.4 T-1 @ 7' 2 15.4 103.4 129.6 79.8 T-1 @ 9' 2 8.2 112.3 129.6 86.7 T-1 @ 11' 2 7.8 119.3 129.6 92.1 T-1 @ 13' 3 9.7 102.8 -- T-1 @ 15' 3 14.1 103.5 -- T-2 @ 3* 5 16.6 101.0 119.5 84.5 T-2 @ 6' 5 23.6 89.8 119.5 75.1 T-2 @ 8' 5 18.8 107.8 119.5 90.2 ViN)i-. & MTIM)II-.ION KNCINHI-UINII, INC. • 2450 Aiiio Park Way • liscondido. Ciiif'orni.i 92029-1229 • Phone (7M)) 743-1214 PRELIMINARY GEOTECHNICAL INVESTIGATION 26-LQT SUBDIVISION, CAMINO HILLS DRIVE. CARLSBAD PAGE 10 JUNE 23, 2006 TABLE 7 (continued) T-2 @ 10' 5 17.4 114.3 119.5 95.6 T-3 @ 3' . 4 28.6 88.0 110.5 79.6 T-3 @ 5" 4 27.8 88.8 110.5 80.4 T-3 @ 7' 5 18.4 100.6 119.5 84.2 T-4@5' 4 22.0 106.0 110.5 95.9 T-4 @ 8' 4 22.4 108.0 110.5 97.7 T-4 @ 10' 4 21.2 106.9 110.5 96.7 T-6@5' 2 11.9 109.0 129.6 84.1 T-5 @ 8' 2 13.1 110.8 129.6 85.5 T-5 @ 10' 2 13.9 106.8 129.6 82.4 T-5 @ 14' 2 13.5 108.5 129.6 83.7 T-5 @ 16" 5 16.0 102.6 119.5 85.8 T-6@7' 5 13.3 105.5 119.5 88.3 T-7 @ 4' 1 26.1 88.9 -- T-7 @ 7' 5 18.9 99.3 119.5 83.1 T-7 @ 10' 5 25.2 92.8 119.5 77.6 T-7 @ 12' 1 22.5 98.3 -- T-7 @ 14' 1 25.7 95.7 -- T-8 @ 5' 2 11.9 101.6 129.6 78.4 T-8 @ 8" 2 12.7 113.9 129.6 87.9 T-8 @ 11' 2 12.2 104.1 129.6 80.3 T-8@ 12y»' 5 23.7 94.9 119.5 79.4 T-9 @ 5' 5 18.3 96.1 119.5 80.4 T-9 @ 7' 5 12.2 110.6 119.5 92.6 T-9 @ 10' 5 13.1 110.9 119.5 92.8 T-9 @ 12' 5 16.9 99.1 119.5 83.0 T-9 @ 14' 5 17.9 99.3 119.5 83.1 T-9 @ 15' 4 24.3 97.3 110.6 88.1 ViNiii MiTWi.MTON liNC,rNi-:i:uiNC.. INC. • 2450 Auro Paik W>y • liscondido, Caliiornia 92029-1229 • Phone(760) 743-1214 PRELIMINARY GEOTECHNICAL INVESTIGATION 26-LOT SUBDIVISION, CAMINO HILLS DRIVE, CARLSBAD PAGE 11 JUNE 23, 2006 TABLE 7 (continued) B-1 @ 4' 2 17.4 113.8 129.6 87.8 B-2 @ 14' 2 18.3 110.1 129.6 84.9 B-2 @ 24' 5 16.9 114.6 119.5 95.8 B-3 @ 4' 2 9.0 113.2 129.6 87.3 B-3 @ 14' 2 9.7 113.8 129.6 87.8 B-3 @ 24* 5 16.2 109.5 119.5 91.6 B-3 @ 34' 5 20.3 110.7 119.5 92.6 B-4 @ 9' 5 11.7 106.2 119.5 88.8 B-4 @ 19' 5 5.8 109.5 119.5 91.6 * Designated as relative compaction for structural fills. Minimum required relative compaction for structural fill is 90% unless otherwise specified. 6. Expansion Index Test: Three expansion index tests were performed on representative samples of Soil Types 1, 4, and 5 in accordance with the California Building Code Standard 18-2. The test results are presented in Table 8. TABLE 8 /:$lturiaflit>n: .•••EjkJ»^|i^!ii>-nV • ••:;KVi;l*iitBfttlaL..:i:-- T-1 @ r 1 14.8 51.2 31.8 112 high T-3 @ 3' 4 16.3 50.0 40.1 103 high T-2 @ 5' 5 11.5 49.7 24.4 46 low T-6 @ 6' 5 9.6 51.0 21.2 59 medium (UJ) = moisture content in percent. Direct Shear Test: Three direct shear tests were performed on representative samples of Soil Types 2, 4, and 5. The prepared specimens were soaked overnight, loaded with normal loads of 1, 2, and 4 kips per square foot respectively, and sheared to failure in an undrained condition. The test results are presented in Table 9. ViNiu & Minm.i-TON I;NI-,INIIP.HINI;, INC. • 2450 Am« Pai-k Way • l-.scondido. California 92029-!229 • Phone (760) 743-1214 PRELIMINARY GEOTECHNICAL INVESTIGATION 26-LOT SUBDIVISION, CAMINO HILLS DRIVE, CARLSBAD PAGE 12 JUNE 23, 2006 TABLE 9 ^^i^W^M^:' •': •:••'•• k e;;^v^.^;;4iMiliiiiiti#'j.;:" / • (r: Wat i -•- k(Yw:p!c^)ri /Angi^'cifS ^mtlTrte.-'. ;*t*ji S'-,v.'«-"i"!-'. , fe^^lon^' \=fe*ifl)i:: T-1@4' 2 remolded to 90% of Ym @ % uopt 127.8 32 75 T-3 @ 3' 4 remolded to 90% of Ym @ % uiopt 117.9 23 280 T-2 @ 5' 5 remolded to 90% of Ym @ % (oopt 120.9 28 166 8. pH and Resistivity Test: pH and resistivity of representative samples of Soil Types 1 and 4 were determined using" Method for Estimating the Service Life of Steel Culverts," in accordance with the California Test Method (CTM) 643. The test results are presented in Table 10. TABLE 10 :jSaifiBl^il0feitl^J^ ^ i Miriiiniiitifc 6efallitMty!(bHi*^j^^ 5 ;j>:5.f3iiH!?^v^.: T-1 @ 1' 1 504 6.2 T-3 m 3' 4 381 6.5 9. Sulfate Test: Sulfate tests were performed on representative samples of Soil Types 1 and 4 in accordance with the California Test Method (CTM) 417. The test results are presented in Table 11. TABLE 11 .;^^aria-j|i0-'LQc^^ A|rt6Mntof;Water^oiaW©;Suitfaft/^ T-1 @ 1' 1 0.052 T-3 @ 3' 4 0.060 10. Chloride Test: Chloride tests were performed on representative samples of Soil Types 1 and 4 in accordance with the California Test Method (CTM) 422. The test results are presented in Table 12. ViN)U & MiDDi.iiTON l?NiiiNi:i:HiNC, INC, • 2450 Auto Paik Way • liscondido, Californi.n 92029-1229 • Phone (760) 743-1214 PRELIMINARY GEOTECHNICAL INVESTIGATION 26-LOT SUBDIVISION, CAMINO HILLS DRIVE, CARLSBAD PAGE 13 JUNE 23,2006 TABLE 12 $aitU»l9:kQi^al|^^^ • • ^ * . ' • ~ " > Irribiint6f.\/i6ter^6^^ V; -ifrscjiimbvih^^ .: / r T-1 @ r 1 0.007 T-3 @ 3* 4 0.006 11. Consolidation Tests: Consolidation tests were performed on a representative remolded sample of on-site Soil Type 2. The test result is graphically presented on the enclosed Plate 19-20. 12. R-value Test: One R-value test was performed on a representative sample of Soil Type 1 in accordance with the California Test 301. The test result is presented in Table 13. TABLE 13 ;Lpcatlon . . ;J5«80riDi^^^^ . Rivaliiiei. T-1@1' 1 brown sandy clay/clayey sand 5 VI. SITE CORROSION ASSESSMENT A site is considered to be corrosive to foundation elements, walls and drainage structures if one or more of the following conditions exists: * Sulfate concentration is greater than or equal to 2000 ppm (0.270 by weight). * Chloride concentration is greater than or equal to 500 ppm (0.05 % by weight). * pH is less than 5.5. For structural elements, the minimum resistivity of soil (or water) indicate the relative quantity of soluble salts present in the soil (or water). In general, a minimum resistivity value for soil (or water) less than 1000 ohm-cm indicates the presence of high quantities of soluble salts and a higher propensity for corrosion. Appropriate corrosion mitigation measures for corrosive conditions should be selected depending on the service environment, amount of aggressive ion salts (chloride or sulfate), pH levels and the desired service life of the structure. Laboratory test results performed on selected representative site samples indicated that the minimum resistivity is less than 1000 ohm-cm suggesting a potential for presence of high quantrties of soluble salts. However, test results further indicated pH is greater than ViNil-; & Mini)l.i:TON fiNCiNi-i-iuNt;. INC. • 2450 Amo Park Way • liscondido. California 92029-1229 • Plionc (760) 743-1214 PRELIMINARY GEOTECHNICAL INVESTIGATION 26-LOT SUBDIVISION, CAMINO HILLS DRIVE, CARLSBAD PAGE 14 JUNE 23. 2006 5.5. sulfate concentration is less than 2000 ppm, and chloride concentration is less than 500 ppm. Based on the results of the corrosion analyses, the project site may be considered non-corrosive. Conformation testing should be completed during the actual earthworks and grading operations to further verify site corrosion conditions. The project site is not located within 1000 feet of salt or brackish water. Based upon the result of the tested soil sample, the amount of water soluble sulfate (S04) was found to be 0.052 to 0.060 percent by weight which is considered negligible according to the California Building Code Table No. 19-A-4. Portland cement Type II may be used. Table 14 is appropriate based on the pH-Resistivlty test result: TABLE 14 pesigri;30|>-^yp^^ ••'•'K'^0i:^:.'7^yi^^y' :.:'^\-^?''-' Jl8r^ 1 Years to Perforation of Steel Culveils 5 6 8 11 14 17 4 Years to Perforation of Steel Culverts 6 7 9 13 16 20 VII. CONCLUSIONS Based upon the foregoing investigation, development of the study site info an 26-lot residential subdivision with the associated internal roadway and underground improvements is feasible from a geotechnical viewpoint. Adverse geologic conditions which could preclude site development were not indicated at the property. The following factors are unique to the property and will most Impact project development procedures from a geotechnical viewpoint: * Slope instability or geologic hazards are not present at or near the project site and will not be a factor in site devolvement. * The property is chiefly a graded site developed to its existing lines and grades for agricultural purposes in the late 1960's. Grading documents including engineering observations and compaction testing records of prior earthworks operations at the site, are not available. * Much of the property is occupied by a modest to thick section of undifferentiated fill/alluvial soil (see mapped areas "af-Qal" on Plate 2). These soils occur in a loose to soft condition particularly in near-surface exposures. Post construction compression and settlement ofthe these deposits are considered to be the primary geotechnical concern at the study site. Consequently, ground stabilization and ViNpi! e/ MmiiLin oN RNCINIMIIUNI;. INI:. • 2450 Auto Park Way • liscondido, California 92029-1229 • Phone (760) 743-1214 PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 15 26-LOT SUBDIVISION. CAMINO HILLS DRIVE, CARLSBAD JUNE 23, 2006 remedial grading earthworks mitigation of the underlying loose to soft soils will be required as a part of project development in order to create safe and stable building surfaces as detailed in the following sections. Post construction settlement of site fills/alluvlum after development is not expected to exceed approximately VA inches, and should occur below the heaviest loaded footings. The magnitude of post construction differential settlements of site fills/alluvium (as expressed in terms of angular distortion) is not anticipated to exceed V^-inch between similar elements, in a 20-foot span. * Remaining areas of the site are mostly underlain by formational rocks or Terrace Deposit units (see mapped areas "Ts" and "Qt" on Plate 2). These are suitably dense unrts and will provide adequate support for the planned new fills, structures and improvements. * Perimeter embankments at the project property are predominantly compacted fill stopes (designated as "Caf in Plate 2) constructed as a part of upper development. The existing perimeter embankment slopes are provided with a well-established cover of vegetation, and have performed well since their construction wrth no evidence of gross instability. Some addrtional undercutting is proposed to a maximum height of 6 feet In the south corner of the project (see Plate 20). The lower exposed slopes should be constructed as stabilization fills as recommended in a following section herein. Alternatively, a retaining wall may be constructed in the impacted areas in order to achieve final design grades and enhance the overall gross stability of site embankments. * Soils generated from project fills/alluvium excavations will predominantly consist of marginal quality plastic clay soils which can be detrimental to site structures and improvements if they occur within upper finish pad grades. Excavations of srte Tenrace Deposits underiaying the northwestern hill are expected to generate better quality low expansive sandy soils. Site marginal quality plastic clayey soils should be buried wrthin deeper fills, and better quality sandy soils available from the excavation of project Terrace Deposits may be placed at finish pad grades using select grading techniques. Alternatively, good quality sandy granular import soils may also be considered to cap the building pad areas. * Plastic clayey soils typically require added processing, moisture condrtloning and mixing efforts in order to manufacture a uniform mixture suitable for reuse as new site compacted fills. Potentially expansive clayey soils typically result in thicker pavement sections and will require special geotechnical engineering mitigation and foundations/slab designs which may include presaturation of subgrade soils, deeper foundations and thicker slab-on-grade floors, or post-tensioned / structural ViNji: & M1DIM.KTON KNi'.lNi-P.KiNti. INC. • 2450 Amo Park Way • liscondido, Cilifornia 92029-1229 • Phone (760) 74.V12I4 PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 16 26-LOT SUBDIVISION, CAMINO HILLS DRIVE, CARLSBAD JUNE 23, 2006 slab-on-ground foundations if they occur within upper pad grades. Capping the site with better quality on-site sandy soils or good quality sandy granular import soils will allow the use of more conventional foundations/slab designs and improve pavement structural sections. Moisture sensitive expansive soils and related periodic soil heaving-shrinkage is also considered a major geotechnical concern at the study site. Based on the available laboratory test results and noted site conditions, final bearing and subgrade soils may be anticipated to consist of silty sandy clay to clayey sllty sand (SC/CL) wrth low to high expansion potential (expansion index less than 131) according to the California Building Code classification (Table 18A-I-B). Actual classification and expansion characteristic of the finished grade soil mix can only be provided in the final as-graded compaction report based on proper testing of foundation bearing and subgrade soils when rough finish grades are achieved. Foundation bearing and subgrade soils at finish pad grades should be addrtionally tested at the completion of rough grading to evaluate actual expansion characteristic of final soil mixture and confirm foundations and slab designs. Uniform bearing condrtions should be constructed under the proposed buildings, structures and improvements. For this purpose, added removals of cut ground will be necessary in the case of cut-fill pads which expose formational rock or natural soils, so that uniform soil condrtions are constructed throughout the buildings and improvement surfaces. Groundwater was encountered at the depth of 33 feet below the planned Lot 24 and 32 feet wrthin the alluvial soils (B-3) feet along the easternmost portions of the srte below the planned street improvements measured from the existing ground surfaces. Elsewhere at the site, groundwater was not encountered in our exploratory excavations to the depths explored. Natural groundwater condrtions at the site occur at depth and is not expected to impact project grading or long term stability of the developed property. However, the proper control of surface drainage and storm water is an important factor in the continued stability of the property. Ponding should not be allowed on graded surfaces, and over-watering of site vegetation should be avoided. Subsurface drains should be provided in stability fills and behind retaining walls(if any planned) as recommended below. Site grading and earthwork constructions will not impact the adjacent properties provided our recommendations are incorporated into the final designs and implemented during the construction phase. Appropnate setbacks shall be maintained, and temporary excavation slope constructions completed as recommended below. Added field recommendations, however, may also be ViN|i= & Miniii.iTON liNClNKI-KiNC, INC. • 2450 Amo Park Way • liscondido, Cahfornia 92029-1229 • Phone (760) 743-1214 PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 17 26-LOT SUBDIVISION, CAMINO HILLS DRIVE. CARLSBAD JUNE 23, 2006 necessary and should be given by the project geotechnical consurtant for the protection of adjacent properties and should be anticipated. Local groundwater conditions were found to be deep, and a thick section of overburden soils surcharges the impacted areas. Elsewhere over the majority of the property, groundwater was not recorded to the depths explored and formational units occur at the surface or at shallow to modest depths. Additionally, ground stabilization techniques using earth reinforcement Geogrid, and removal and recompaction of foundation bearing and subgrade soils are recommended in connection with the site development as specified below. Consequently, liquefaction of the locally saturated alluvial soils below the water table (primarily areas of boring B-3, see Plate 2) is not considered a major geotechnical concern at the project property. Liquefaction and secondary affects such as seismically induced settlements, lateral spreading and flow slides are considered unlikely to remote provided our ground stabilization and remedial grading recommendations specified in the following sections are followed. Loose to soft surface fill/alluvial deposits are potentially collapsible and compressible, and should be regraded as recommended below. VIII. RECOMMENDATIONS The following recommendations are consistent with the indicated geotechnical condrtions at the project site and should be reflected In final plans and implemented during the construction phase. Added or modified recommendations may also be appropriate and can be provided at the final plan review phase: A. Remedial Grading and Earthworks The most effective method to mitigate upper loose to soft soils and accelerate compression of the underiying untreated deposits during the construction phase periods is remedial grading removal and recompaction techniques, and compacted fill surcharging as recommended below. All grading and earthworks should be completed in accordance with the Appendix Chapter 33 of the California Building Code, City of Cartsbad Grading Ordinances, the Standard Specifications for Public Works Construction and the requirements of the following sections: ViNjri 6L Mii>r>i.inoN RNtiiNiHiuiNC. INC. • 2450 Amo Park Way • fi«condido. Cilifornia 92029-1229 • Phone (760) 743-1214 PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 18 26-LOT SUBDIVISION, CAMINO HILLS DRIVE. CARLSBAD JUNE 23, 2006 1. Clearing and Grubbing > Surface vegetation, trash, deleterious materials, and construction debris generated from the demolition of existing structures / improvements and other unsurtable materials should be removed from the areas proposed for grading, new fills, structures and improvements plus 10 feet outside the perimeter, or as directed in the field, and properly disposed of. Construction debris and site vegetation shall be allowed to contaminate the new site fills. All irrigation lines and existing leach lines, septic tanks, pipes and structures should be properly removed from the construction areas. Existing underground utilrties in the construction areas should also be pot-holed, identified and * marked prior to the actual work. Abandoned irrigation lines should be properiy capped and sealed off to prevent any future water inflKrations into the foundation bearing and subgrade soils. Voids created by the removals ofthe abandoned underground pipes, tanks and structures should be properly backfilled wrth compacted fills in accordance wrth the requirements of this report. The prepared ground should be inspected and approved by the project geotechnical engineer or his designated field representative prior to remedial grading work. J 2. Removals and Over-excavations - Uniform and stable bearing soils conditions should be constructed under the planned new buildings and site improvements and limrt potential fill soil settlements wrthin tolerable limits as specified. For this purpose, removal and recompaction of the upper fills/alluvlum to firm native ground or competent formation units where these I deposits occur at shallower depths and removal and recompaction with ground J stabilization techniques using earth reinforcement Geogrid placed at the bottom of over-excavations, should be considered. J Approximate removal depths in the vicinity of individual exploratory excavations are summarized in Table 15 and depicted on the enclosed Plate 2 based upon I site soil conditions and proposed grades. The tabulated values are typical and j subject to fleld changes by the project geotechnical consultant based on actual field exposures. Locally deeper removals may be necessary and should be anticipated. J J I I -VlN)li & MiniiLinON I'NCiNl-liKINC,, INC. • 24.50 Aiiio Park Way • Kscondido. California 92029-1229 • Phone (760) 743-1214 PRELIMINARY GEOTECHNICAL INVESTIGATION 26-LOT SUBDIVISION, CAMINO HILLS DRIVE. CARLSBAD PAGE 19 JUNE 23, 2006 TABLE 15 tr-.''*?-^''3* .,:fj.^M-^r-i 9 T-1 not encountered 9' Lot 13 - private street improvement areas. T-2 loin-not encountered 7 Lot 8 areas. Depth of undercut may govern. T-3 s' not encountered 8' Lot 5 areas. Depth of undercut may govem. Reconstruct toe slope as a stability fill. T-4 1014' not encountered 6' Lot 2 areas. Depth of undercut may govem. T-5 1614' not encountered 9' Lot 25 areas. Deptti of undercut may govern. T-6 8' not encountered 3' Lot 22 areas. Depth of undercut may govern. Stockpile better quality sandy soils from Tenace Deposit excavations for capping the pads. T-7 1414' not encountered 7' Fill slope/private street improvement areas. Toe keyway should be a minimum of 3 feet below adjacent ground level. Place Tensar Geogrid earth reinforcement at bottom of slope keyway excavations as specified herein UOA. T-8 15' not encountered 10' Lots 16,17 areas. Place Tensar Geogrid earth reinforcement at soft and yielding bottom of removals in the impacted areas as spedfied herein UOA. T-9 not encountered 7' Private street improvement areas. T-10 15' not encountered 4J4' Private street improvement areas. Depth of undercut may govern. Siodcpile better quality sandy soils from Terrace Deposit excavations for capping the pads. B-1 19%" not encountered 5' Lot 11 areas. Depth of undercut may govern. B-2 4014' 33' 10' Lot 24 areas. Place Tensar Geogrid earth reinforcement at soft and yielding bottom of removals in the impacted areas as specified herein UOA. B-3 39' 32' 7' Private street improvement areas. Place Tensar Geogrid earth reinforcement at bottom of removals in the impacted areas as specified herein UOA. 8-4 20' not encountered 8' Lof 26 areas. Private street improvements. ViNjn & MIDDLETON ENGINEHRING, INC. • 2450 Auro P.irk Way • Fjicondido, Cahforni,! 92029-1229 • Phone (760) 743-1214 PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 20 26-LOT SUBDIVISION. CAMINO HILLS DRIVE. CARLSBAD JUNE 23. 2006 Notes: 1. UOA = Unless Othen/vise Approved. 2. All depths are measured from the existing ground levels. 3. Actual depths may vary at the time of construction based on subsurface exposures. 4. Bottom of all removals should be additionally prepared and recompacted to a minimum depth of 6 inches as directed in the field. 5. Firm native ground is defined as undisturbed natural exposures with in-place densities of 85% or greater as approved in the field. 6. In the case of deeper storm drain or utility trenches where the proposed inverts are below the recommended depths, removals should be further extended a minimum of 12 inches below the bottom of pipe (or pipe bedding) unless otherwise approved. 7. Exploratory trenches excavated in connection with our study at the indicated locations were bacldilled with loose and uncompacted deposits. The loose/uncompacted backfill soils within tiiese trenches shall also be re-excavated and placed back as properly compacted fills as a part of the project grading operations. 8. All grounds steeper than 5:1 receiving fills/backfills should be properly benched and keyed as directed in the field. 3. Ground Stabilization - Fills can only be placed over firm stable native and non-yielding ground (in-place densities of 85% or greater). Ground stabilization techniques using earth reinforcement Geogrid should be used in the areas of the site where yielding soft bottom of removals are exposed at the specified over-excavation depths. Removal and recompaction grading with ground stabilization techniques will also limrt potential fill soil settlements wrthin tolerable limits as specified. For this purpose, a layer of Tensar Geogrid BX-1100 (or greater from the same series) earth reinforcement should be placed at the impacted bottom of over- excavations prepared as directed in the field. Initial fill IHts should then be carefully placed over the Geogrid and compacted. Subsequent fill lifts can continue until design grades are achieved. Additional layers of Geogrid may also be necessary within the compacted fill mass as directed in the field, and should be anticipated. 4. Excavations Characteristics - Proposed cut excavations will approach 25 feet deep in the existing hill knob areas ofthe property underiain by Terrace Deposit units. The cuts and recommended undercuts are expected to be achieved wrth moderate efforts using larger bulldozers (Caterpillar D-8 or equal). Some hard units and cemented beds may also be locally encountered requiring added ripping and more concentrated efforts. However, difficult excavations or the need for special techniques is currently not anticipated. 5. Cut-Fill Transitions and Undercuts - Ground transrtion from excavated cut to compacted fills should not be permitted underneath the proposed structures and improvements. Transition pads will require special treatment. The cut portion of cut-fill pads plus 10 feet outside the perimeter, where possible and VINJE & MIDDLETON ENGINEERING, INC. • 2450 Auro P.irk Way • Escondido, California 92029-1229 • Phone (760) 743-1214 PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 21 26-LOT SUBDIVISION, CAMINO HILLS DRIVE. CARLSBAD JUNE 23, 2006 as directed in the field, should be undercut to a sufficient depth to provide for a minimum of 3 feet of compacted fill mat below rough finish grades, or at least 12 inches of compacted fill beneath the deepest footing(s) whichever is more. In the roadways, driveway, pari<ing and on-grade slabs/improvement transrtion areas there should be a minimum of 12 inches of compacted soils below rough finish subgrade. Cut pad exposing loose to soft soils at final grades should also be undercut to a minimum depth of 3 feet (or 12 inches below the bottom of deepest footing whichever is more unless othenA/ise specified) and reconstructed to design grades wrth compacted fills as specified herein. 6. Temporary Construction Slopes - Excavations and removals adjacent to existing improvements and graded embankments should be perfomied under inspection of the project geotechnical engineer. Undermining existing improvements, underground utilities to remain, and perimeter graded slopes should not be allowed by the removal operations. Temporary construction slopes should maintain adequate setbacks (minimum of 2 feet) from the toe of existing ascending slopes and adjacent improvements, as directed and approved in the field. Construction slopes, temporary excavations and trenching less than 3 feet high maximum may be constructed at near vertical gradients. Temporary excavations and trenching greater than 3 feet and less than 12 feet high maximum should be laid back at 1:1 gradient unless othenA/ise specrtied or approved. Temporary slopes greater than 12 feet and less than 20 feet high maximum may be constructed at 1:1 wrthin the lower 7 feet and laid back at 1 Vi:1 gradient within the upper portions. The remaining wedge of soil should then be properly benched out and new fills/backfills tightly keyed-in as the backfilling progresses. Temporary trench and constmction slopes greater than 3 feet maximum constructed at near vertical gradients will require shoring/trench shield support unless othenwise approved. All temporary construction slopes require continuous geotechnical inspections during the grading operations. Addrtional recommendations including revised slope gradients, setbacks and the need for temporary shoring/trench shield support should be given at that time as necessary. The project contractor shall also obtain appropriate permrts, as needed, and conform to Cal-OSHA and local governing agencies' requirements for trenching/open excavations and safety of the workmen during construction. Permissions to perform off site grading should also be obtained if necessary and as appropriate. VINJE & MIDDLETON ENGINEERING, INC. • 2450 Amo P.irk Way • Escondido, Cah-fornia 92029-1229 • Phone (760) 743-1214 PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 22 26-LOT SUBDIVISION. CAMINO HILLS DRIVE. CARLSBAD JUNE 23. 2006 7. Soli Properties and Select Grading - Soils generated from the excavations of srte existing fills, alluvium and formational rock units (map symbols af-Qal and Ts) will consist of marginal quality plastic silty to clayey deposrts wrth high expansion potential which can be detrimental to structures and improvements, if they occur at or near finish grades. Plastic silty to clayey soils also required added processing, mixing and moisture condrtloning efforts in order to manufacture a uniform mixture suitable for reuse as site new compacted fills. However, better quality sandy earth deposits which generally work well as compact fills are expected from the excavations of site Terrace Deposits (map symbol Qt). Adverse effects of site highly expansive plastic silty to clayey soils should be mrtigated by selective burial of these deposits, placed a minimum of 4 feet below rough pad grades (or 12 inches below the deepest footing, whichever is more) and a minimum of 10 feet away from the face of slopes wrthin the fill mass. Better quality sandy soils available from the site Terrace Deposrt excavations should to stockpiled and selectively used within the upper pad grades and outer fill embankment slope surfaces. Improvement areas should be provided wrth a minimum 18 inches of better quality sandy soils. On-site plastic clayey soils should also not be used for wall or trench backfills. 8. Shrinkage and Import Soils - Based upon our analyses and experience with similar earth deposits, site soils may be expected to shrink approximately 10% to 20% on a volume basis when compacted to at least the minimum compaction levels specified herein. Import soils, if required to complete grading and achieve final pad grades, should be good quality sandy non-corrosive granular deposits (SM/SW) wrth very low expansion potential (100% passing %-inch sieve, more than 50% passing #4 sieve and less than 20% passing #200 sieve with expansion index less than 21). Import soils should be inspected, tested as necessary, and approved by the project geotechnical engineer prior to delivery to the site. Sandy granular soils should also be considered for wall and trench backfills. 9. Fill Materials and Compaction - Soils generated from the site removals and over-excavations are considered suitable for reuse as site new fills provided they are processed, prepared and placed in accordance wrth the requirements of this report. Project fill soils should be clean deposits free of roots, stumps, vegetation, deleterious matter, trash, demolition debris, and unsuitable materials as approved in the field by the project geotechnical consultant. Uniform bearing soil conditions should be constructed at the site by the remedial grading and earthwori< operations. Site soils should be adequately processed, thoroughly mixed, moisture condrtioned to slightly above VINJE Sd MIDDLETON ENGINEERING, INI;. • 2450 Amo Park Way • Escondido, Cilitornia 92029-1229 • Phone (760) 743-1214 PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 23 26-LOT SUBDIVISION, CAMINO HILLS DRIVE, CARLSBAD JUNE 23, 2006 (approximately 2% for sandy soils and 3% to 5% for clayey soils) the optimum moisture levels as directed in the field, placed In thin (8 inches maximum) uniform horizontal lifts and mechanically compacted to a minimum 90% ofthe corresponding laboratory maximum dry density below 3 feet from the rough finish grades, and minimum 95% ofthe corresponding laboratory maximum dry densrty within the upper 3 feet of final grades per ASTM D-1557, unless otherwise specified. 10. Permanent Graded Slopes - Project graded slopes are programmed for 2:1 orfiatter gradients maximum. Engineered graded slopes constructed at 2:1 or flatter gradients will be grossly stable wrth respect to deep seated and surficial failures for the anticipated design maximum vertical heights provided our recommendations are followed. Engineered slopes should be constructed as follows. Fill Slope Construction - Road embankment fills are planned at the site in connection wtth the private street improvements along the eastern margins. The planned fill slopes should be provided wrth a lower keyway. The keyway should maintain a minimum depth of 3 feet below the adjacent ground surface at the toe into wrth a minimum width of 12 feet as approved by the project geotechnical engineer or his designated representative. Deeper keyway depths may also be required based on actual exposures and should be anticipated. Loose to soft soils may be anticipated at the bottom of keyway excavations requiring mrtigation and stabilization. Stable bottom of keyway excavations can be achieved by placing a layer of Tensar Geogrid BX-1100 (or greater from the same series) earth reinforcement at the impacted bottom prepared as directed in the field. Initial fill lifts should then be carefully placed over the Geogrid and compacted followed wrth subsequent lifts. All keyways should be heeled back a minimum of 2% into the hillside and inspected and approved by the project geotechnical engineer. Addrtional level benches should be constructed into the natural hillside as the fill slope construction progresses. Fill slopes should also be compacted to a minimum 90% (or 95%) of the laboratory standard out to the slope face unless othenA/ise specified. Over-building and cutting back to the compacted core, or backrolling at a minimum of 4 feet vertical increments and "track-walking" at the completion of grading is recommended for site fill slope construction. Geotechnical engineering inspections and testing will be necessary to confirm adequate compaction levels within the fill slope face. VINJE & MIDDLETON ENGINEERING, INC. • 2450 Auco Park Way • Escondido, California 92029-1229 • Phone (760) 743-1214 PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 24 26-LOT SUBDIVISION, CAMINO HILLS DRIVE, CARLSBAD JUNE 23. 2006 Cut Slope Construction - Proposed graded cut slopes are expected to expose stable, competent Terrace Deposits which will be grossly stable at the planned 2:1 gradients. Small cut slopes are also proposed in the form of lowering the existing toe of fill embankments in the south and east perimeter areas to adjacent pad levels are planned at the site. The slopes planned at the rear of Lots 3-6 should be reconstructed as stabilization fills wrth a minimum bottom equipment-width of 15 feet extended at least 2 feet into the underlying competent formational rock as approved in the field. Temporary construction slopes for the stabilization fill should be no steeper than Vi:1. The stability fill should then be reconstructied to design grades soon after by placing fill soils tightly keyed into the construction slopes as the fill placement progress. Recommended Typical Stabilization Fill slope is schematically depicted on the enclosed Plate 16. Alternatively, a retaining wall may be constructed at the base of the perimeter slopes as shown. All cut slopes should be inspected and approved by the project geotechnical consultant during the grading to further confirm stability. More specific or revised recommendations will be provided at that time as necessary and should be anticipated. 11. Surface Drainage and Flood / Erosion Control - A critical element to the continued stabilrty of the graded building pads is adequate surface drainage and flood control. This can most effectively be achieved by installation of appropriate flood and drainage control structures. Building pad surface run-off should be collected in approved drainage facilities and directed to selected locations in a controlled manner. Area drains should be installed. Surface and flood waters should not be allowed to impact site embankments, fills, structures and improvements, or penetrate into the underlying bearing soils. Storm water and surface mn-off shall be diverted from entering the site. The finished slope should be planted soon after completion of grading. Unprotected slope faces will be subject to severe erosion and should not be allowed. Over-watering of the slope faces should also not be allowed. Only the amount of waterto sustain vegetation should be provided. Temporary erosion control facilrties and sirt fences should be installed during the construction phase periods and until landscaping is established as indicated and specified on the approved project erosion plans. VINJE & MIDDLETON ENGINEERING, INC. • 2450 Auio Park Way • liscondido. California 92029-1229 • Phone (760) 743-1214 PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 25 26-LOT SUBDIVISION. CAMINO HILLS DRIVE. CARLSBAD JUNE 23, 2006 12. Engineering Inspections - All grading operations including removals, suitabilrty of earth deposits used as compacted fill, and compaction procedures should be continuously inspected and tested by the project geotechnical consultant and presented in the final as-graded compaction report. The nature of finished subgrade soils should also be confimned in the final compaction report at the completion of grading, Geotechnical engineering inspections shall include but not limrted to the following: * Bottom of over-excavation/keyway inspection - After the bottom of over- excavation or keyway is exposed and prepared to receive fill but before fill Placement is started. * Ground stabilization Geogrid placement - During the actual placement. Geogrid shall conform to the specified specifications. * Excavation inspection - After the excavation is started but before the vertical depth of excavation is more than 3 feet. This includes all temporary excavation slopes and trenching. Safety requirements enforced by the governing agencies for open excavations apply. * Fill/backfill inspection - After the fill/backfill placement is started but before the vertical height of fill/backfill exceeds 2 feet. There should be a minimum of 1-foot in every 100 lineal feet for each 2 feet of vertical gain. Final rough and finish pad grade tests shall be required regardless of the fill/backfill thickness. * Foundation trench inspection - After the foundation trench excavations but before steel placement. * Foundation bearing/slab subgrade soils inspection - Prior to the placement of concrete for proper moisture and specified compaction levels. * Foundation/slab steel inspection - After steel placement is completed but before the scheduled concrete pour. * Subdrain/back drain inspection - During the actual placement. All material shall confomi to the project material specifications and approved by the project soils engineer. VINJE & MIDDLETON ENGINEERING, INC. • 2450 Amo Park Way • liscondido. California 92029-1229 • Phone (760) 743-1214 PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 26 26-LOT SUBDIVISION. CAMINO HILLS DRIVE. CARLSBAD JUNE 23, 2006 Underground utilrty/plumbing trench inspection - After the trench excavations but before installation of the underground facilities. Safety requirements enforced by Cal-OSHA, and governing agencies for open excavations apply. Inspection of the pipe bedding may also be required by the project soils engineer. Underground utility/plumbing trench backfill inspection - After the backfill placement is started above the pipe zone but before the vertical height of backfill exceeds 2 feet. Testing of the backfill within the pipe zone may also be required by the goveming agencies. Pipe bedding and backfill materials shall conform to fhe requirements of goveming agencies and project soils report if applicable. All trench backfills shall be mechanically compacted to the minimum specified compaction levels per ASTM D-1557, unless otherwise superseded. Plumbing trenches over 12 inches deep maximum under the interior floor slabs should also be mechanically compacted and tested for the minimum specified compaction levels. Flooding or jetting techniques as a means of compaction method shall not be allowed. Pavement/improvements base and subgrade inspections - Prior to the placement of concrete or asphalt for proper moisture and specified compaction levels. B. Foundations and Interior Floor Slabs Proposed buildings may be supported on conventional concrete footings and slab- on-grade fioor type foundations. The following recommendations and geotechnical mrtigation are consistent with silty sandy clay to clayey silty sand (SC/CL) foundation bearing and subgrade soils wrth low to high expansion potential (expansion index less than 131) anticipated at finish grade levels. Added or modified recommendations may also be necessary and should be given at the time of foundation plan review phase. All foundations and floor slab recommendations should also be further confinned and / or revised as necessary at the completion of rough grading based on the actual expansion characteristics ofthe foundation bearing and subgrade soils: 1. Perimeter and interior continuous strip foundations should be sized at least 15 inches wide and 24 inches deep for single and two-story structures. Exterior spread pad footings, if any, should be at least 30 inches square and 18 inches deep and structurally tied to the perimeter strip footings wrth tie beams at least in one direction. Tie beams should be a minimum of 12 inches wide by 12 inches deep. Footing depths are measured from the lowest adjacent ground surface, not including the sand/gravel layer beneath floor slabs. ViNjE fit MIDDLETON ENGINEERING, INC. • 2450 Auto IVk Way • Escondido, Cilifornia 92029-1229 • Phone (760) 743-1214 PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 27 26-LOT SUBDIVISION. CAMINO HILLS DRIVE, CARLSBAD JUNE 23. 2006 Exterior continuous footings should enclose the entire building perimeter. Flagpole footings also need to be tied together ifthe footing depth is less than 4 feet below rough finish grade. 2. Continuous interior and exterior foundations should be reinforced wrth a minimum of four #5 reinforcing bars. Place 2-#5 bars 3 inches above the bottom of the footing and 2-#5 bars 3 inches below the top of tiie footing. Tie beams should also be reinforced wrth 2-#4 bars top and bottom and #3 ties at 30 inches on center maximum. Reinforcement details for spread pad footings should be provided by the project architect/structural engineer. 3. The slab subgrade and foundation bearing soils should not be allowed to dry priorto pouring the concrete, as additional ground preparations, moisture re- conditioning and presaturation will be necessary as directed in the field. The required moisture content ofthe bearing soils is approximately 3% to 5% over the optimum moisture content to the depth of 24 inches below slab subgrade. Attempts should be made to maintain as-graded moisture contents in order to preclude the need for presaturation of the subgrade and bearing soils. 4. In the case of presaturation of the slab subgrade and/or non-monolrthic pour (two-pour) system, dowel the slab to the footings using #4 reinforcing bars spaced 18 inches on center extending at least 20 inches into the footings and 20 inches into the slab. The dowels should be placed mid-height in the slab. Alternate the dowels each way for all interior footings. 5. After the footings are dug and cleaned, place the reinforcing steel and dowels and pour the footings. 6. This office should be notified to inspect the foundation trenches, and reinforcing prior to pouring concrete. 7. Once the concrete for the footings has cured and underground utilities tested, place 4 inches of %-inch rock over the slab subgrade. Flood wrth water to the top of the %-inch rock, and allow the slab subgrade to soak until moisture testing indicates that the required moisture content is present. After the slab subgrade soils have soaked, notrty this office and schedule for appropriate moisture testing. 8. When the required moisture content has been achieved, place a well- perfomilng moisture barrier/vapor retardant (minimum 15-mil plastic) over the %-inch rock, and place 2 inches of clean sand (SE 30 or greater) on top of the plastic. VINJE 6; MIDDLETON ENGINEERING, INC. • 2450 Auio Park Way • Escondido, California 92029-1229 • Phone (760) 743-1214 I 1 i i I i i i i I 1 i i I i I I I i i I I I I PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 28 26-LOT SUBDIVISION, CAMINO HILLS DRIVE, CARLSBAD JUNE 23.2006 If suflicient moisture is present, fiooding/presaturation will not be required. The dowels may be deleted, slab underlayment may consist of 2 inches of clean sand over a well perfonning moisture ban^ier/vapor retardant (minimum 15-mil plastic) over 2 inches of clean sand, and the footings and slab may be poured monolithically. This office should be notified to inspect the sand, slab thid<ness, and reinforcing prior to concrete pour. 9. All interior slabs should be a minimum of 5 inches in thickness reinforced with #4 reinforcing bars spaced 18 inches on center each way placed VA inches below the top of slab. 10. Interior slabs should be provided wrth "softcut" contraction/control joints consisting of sawcuts spaced 10 feet on center maximum each way. Cut as soon as the slab will support the weight of the saw, and operate without disturbing the final finish which is normally wrthin 2 hours after final finish at each control joint location or 150 psi to 800 psi. The softcuts should be a minimum of %-inch in depth, but should not exceed 1-inch deep maximum. Anti-ravel skid plates should be used and replaced wrth each blade to avoid spalling and raveling. Avoid wheeled equipment across cuts for at least 24 hours. 11. Provide re-entrant corner reinforcement for all interior slabs. Re-entrant corners will depend on slab geometry and/or interior column locations. Plate 21 may be used as a general guideline. 12. Foundation trenches and slab subgrade soils should be inspected and tested for proper moisture and specified compaction levels and approved by the project geotechnical consultant prior to the placement of concrete. C. Post-tensioned / Structural Slab-on-Ground Foundations Post-tensioned or structural slab-on-ground foundations consistent with the anticipated silty to clayey expansive bearing soils may also be considered. Remedial grading and foundation bearing/slab subgrade soil preparations will remain the same and should be completed as specified. Post-tensioned or structural slab-on-ground foundation design should be completed by the project structural engineer or design/build contractor. The following are appropriate: 1. The foundation design should consider slabs with stiffening beams (ribbed foundation). In the case of uniform slab thickness foundation, the design shall satisfy all requirements of the design procedure for ribbed foundation. The fully ViNiE & MIDDLETON ENGINEERING, INC. • 2450 Auro Park Way • Escondido, Cilifornia 92029-1229 • Phone (760) 743-1214 PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 29 26-LOT SUBDIVISION, CAMINO HILLS DRIVE, CARLSBAD JUNE 23. 2006 conformant ribbed foundation is then converted to an equivalent uniform thickness foundation. In this case, however, perimeter edge beams shall be required as specified in the following sections. 2. All designs shall conform to the latest addition of the Califomia Building Code (CBC), specifications ofthe Posttensioning Instrtute (PTI), local standards, and the specifications given in this report. 3. Foundation bearing soils shouid be inspected and tested as necessary prior to trenching and actual construction by the project geotechnical engineer. The required foundation bearing soils in-place densities, and specified moisture contents should be confirmed prior to the foundation pour. 4. A minimum 4 inches of clean sand (SE greater than 30) should be placed over the approved slab subgrade soils. A well performing moisture barrier/vapor retardant (minimum 15-mil plastic) shall be placed mid-height in the sand. 5. At the completion of ground and subgrade preparations as specified, and approval ofthe project soil engineer, the post-tensioned or stmctural slab-on- ground foundations should be constructed as detailed on the structural/construction drawings. 6. Based upon our experience on similar projects, available laboratory testing and analysis of the test results, the following soil design parameters are appropriate: * * Design predominant clay mineral type Montmorillonite. Design percent of clay in soil 60%. Design effective plasticity index 45. Design depth to constant soil suction 7 feet. Design constant soil suction Pf 3.6. Design velocity of moisture flow 0.70 inch/month. Design edge moisture variation distance for edge lift (em) 3.0 feet. Design edge moisture variation distance for center lift (em) 6.0 feet. Design differential swell occurring at the perimeter of slab for edge lift condrtion (Ym) 1.095 inches. Design differential swell occurring at the perimeter of slab for center lift condition (Ym) 5.677 inches. Design soil subgrade modulus (k) 100 pci. Design net allowable bearing pressure for Post-tensioned or structural slab-on-ground foundations 1000 psf ViNin & MIDDLETON ENGINEERING, INC. • 2450 Auto Park Way • Fj;coiidido, California 92029-1229 • Phone (760) 743-1214 PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 30 26-LOT SUBDIVISION, CAMINO HILLS DRIVE, CARLSBAD JUNE 23, 2006 Notes: The net allowable foundation pressure provided herein applies to dead plus live loads and rnay be increased by one-third for wind and seismic loading. 7, Provide a minimum of 15 inches wide by 24 inches deep perimeter edge beam. Perimeter edge beam should enclose the entire building circumference and reinforced with at least 1^5 continuous bar near the bottom. Provide adequate interior stiffening ribs as necessary. 8. Posttension slab should be a minimum of SYz Inches thick. Use minimum fc=3000 psi concrete. We recommend to consider pre-tensioning in order to preclude early concrete shrinkage cracking. D. Exterior Concrete Slabs / Flatworks 1. All exterior slabs (walkways, patios, etc.) should be a minimum of 4 inches in thickness, reinforced with #3 bars at 16 inches on centers in both directions placed 1 inches below the top of slab. Use 6 inches of 90% compacted clean sand beneath all exterior slabs. 2. Provide "tool joint" or "softcut" contraction/control joints spaced 10 feet on center (not to exceed 12 feet maximum) each way. Tool or cut as soon as the slab will support weight and can be operated wrthout disturbing the final finish which is normally wrthin 2 hours after final finish at each control joint location or 150 psi to 800 psi. Tool or softcuts should be a minimum of %-inch but should not exceed 1-Inch deep maximum. In case of softcut joints, anti-ravel skid plates should be used and replaced wrth each blade to avoid spalling and raveling. Avoid wheeled equipments across cuts for at least 24 hours. 3. In order to enhance performance of exterior slabs and flatworks supported on potentially expansive and moisture sensitive subgrade soils, a minimum 8 inches wide by 12 inches deep thickened edge reinforced with a minimum of 1-#4 continuous bar near the bottom may be considered along the free-ends. 4. All exterior slab designs should be confirmed in the final as-graded compaction report. 5. Subgrade soils should be tested for proper moisture and specified compaction levels and approved by the project geotechnical consultant prior to the placement of concrete. 1 I ViNlli & MiDDLlTON ENtllNi-.ERINC, INC. • 2450 Amo Park Way * liscondido, Caliiornia 92029-1229 • Phone (760) 743-1214 PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 31 26-LOT SUBDIVISION. CAMINO HILLS DRIVE. CARLSBAD JUNE 23, 2006 E. Soil Desifln Parameters The following soil design parameters are based upon tested representative samples of on-site earth deposits. Expansive clayey soils should not be used for wall backfills. Sandy site soils or good quality granular import soils should be considered within the active zone. Design parameters for import soils can only be given based on actual testing when a representative sample is available. All parameters should be re-evaluated when the characteristics of the final as-graded soils have been specifically determined: * Design wet density of soil = 121 pcf, * Design angle of Internal friction of soil = 28 degrees. * Design active soil pressure for retaining structures = 44 pcf (EFP), level backfill, cantilever, unrestrained walls. * Design active soil pressure for retaining structures = 69 pcf (EFP), 2:1 sloping backfill surface, cantilever, unrestrained walls, * Design at-rest soil pressure for retaining structures = 64 pcf (EFP), non- yielding, restrained walls. * Design passive soli pressure for retaining structures = 335 pcf (EFP), level surface at the toe. * Design coefficient of friction for concrete on soils = 0.34. * Net allowable foundation pressure (minimum 15 inches wide footings extended a minimum of 24 inches into compacted fill) = 2000 psf. * Allowable lateral bearing pressure (all structures except retaining walls) = 150 psf/ft. Notes: * Use a minimum safety factor of 1.5 for wall over-turning and sliding stability. However, because large movements must take place before maximum passive resistance can be devebped, a minimum safety factor of 2 may be considered for sliding stability particulariy where sensrtive structures and improvements are planned near or on top of retaining/basement walls. * When combining passive pressure and frictional resistance the passive component should be reduced by one-third. * The indicated net allowable foundation pressure provided herein was determined based on a minimum 15 inches wkie by 24 inches deep footing and may be increased by 20% for each additional foot of depth and 10% for each VINJE tt MiniH.inoN ENGINEI-KINI-,, INC. • 2450 Auio l»;irk Way • Escondido. Cilifornia 92029-1229 • Phone (760) 743-1214 PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 32 26-LOT SUBDIVISION, CAMINO HILLS DRIVE, CARLSBAD JUNE 23, 2006 addrtional foot of width to a maximum of 4500 psf The allowable foundation pressures provided herein also apply to dead plus live loads and may be increased by one-third for wind and seismic loading. * The lateral bearing earth pressures may be increased by the amount of designated value for each addrtional foot of depth to a maximum of 1500 pounds per square foot. F. Asphalt and PCC Pavement Desiqn 9mm 1. Asphatt Paving: A new pmsts street improvement is planned, and widening of Camino Hills Drive is proposed in connection wtth the site development. All roadway improvements and paving constructions shall be completed in accordance with the City of Carisbad ordinances. The following asphart pavement structural sections are based on a tested R- value of 5 performed on selected on-site earth materials and the indicated assumed traffic indices (Tl), and may be considered for inrtial planning phase cost estimating purposes. A minimum section of 3 inches asphatt (AC) over 6 inches of Class 2 aggregate base (AB) or the minimum structural section required by Crty of Carisbad, whichever is more, will be required and shall govern when a lesser pavement section is indicated by design calculations: TABLE 16 y. '•••'- iy^U-i:B:y:i:-i^^^^^xsi^.M^; Design R-value 4.5 5.0 6.0 6.5 5 3" AC over 8" AB 3" AC over 10" AB 3" AC over 14" AB 4" AC over 14" AB The Class 2 aggregate base shall meet or exceed the cuaent Caltrans specifications. Final pavement sections will depend on the actual R-value test results performed on finish subgrade soils, design Tl and approval of the City of Carisbad. All design sections should be confirmed and/or revised as necessary at the completion of rough pavement subgrade preparations. Revised pavement sections should be anticipated. Base materials should be compacted to a minimum 95% of the maximum dry density. Subgrade soils beneath the pavement base layer should also be compacted to a minimum 95% of the corresponding maximum dry density within the upper 12 inches. Base materials and subgrade soils should be ViNji-: & MIPDLETON ENGINI-.EKING, INC. • 2450 Auto Park Way • liscondido, California 92029-1229 • Phone (760) 743-1214 PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 33 26-LOT SUBDIVISION, CAMINO HILLS DRIVE. CARLSBAD JUNE 23, 2006 tested for proper moisture and minimum 95% compaction levels and approved by the project geotechnical consurtant prior to the placement of the base or asphatt layers. 2. PCC Paving: PCC driveways and parking supported on expansive subgrade soils should be a minimum of 5Vi inches in thkikness, reinforced with #3 reinforcing bars at 16 inches on center each way, placed 2 inches below the top of slab. Subgrade soils beneath the PCC driveways and parking should also be compacted to a minimum 90% ofthe corresponding maximum dry density wtthin the upper 6 inches, unless othenn/ise specified. In order to enhance performance of PCC pavements supported on expansive subgrade, a minimum 8 inches wide by 12 inches deep thickened edge reinforced wtth a minimum 1-#4 continuous bar placed near the bottom is reconrimended to be considered along the outside edges. Provide "tool Joint" or "softcut" contraction/control joints spaced 12 feet on center (not to exceed 15 feet maximum) each way. Tool or cut as soon as the slab will support weight and can be operated wfthout disturbing the final finish which is nonnally within 2 hours after final finish at each control joint location or 150 psi to 800 psi. Tool or softcuts should be a minimum of 1-inch but should not exceed IVi-inches deep maximum. In case of softcut joints, anti- ravel skid plates should be used and replaced wrth each blade to avoid spalling and raveling. Avoid wheeled equipments across cuts for at least 24 hours. 3. General Paving: Base section and subgrade preparations per structural section design, will be required for all surfaces subject to traffic including roadways, travelways, drive lanes, driveway approaches and ribbon (cross) gutters. Driveway approaches within the public right-of-way should have 12 inches subgrade compacted to a minimum of 95% compaction levels, and provided wrth a 95% compacted Class 2 base section per the structural section design. In the case of potentially expansive subgrade (expansion index greater than 20), provide 6 inches of Class 2 base under curb and gutters and 4 inches of Class 2 base (or 6 inches of Class III) under sidewalks with a thickened edge along the free-end as specified. Base layer under curb and gutters should be compacted to a minimum 95%, while subgrade soils under curb and gutters, and base and subgrade under sidewalks should be compacted to a minimum 90% compaction levels unless other\AAse specified. Specific recommendations should be given in the final as-graded compaction report. VINIE & MiiiDun ON ENUINI-ERINC, INC. • 24.50 Auto P.irk Way • liscondido. California 92029-1229 • Phone (76(-)) 743-1214 PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 34 26-LOT SUBDIVISION. CAMINO HILLS DRIVE. CARLSBAD JUNE 23. 2006 Base and subgrade should be tested for proper moisture and specified compaction levels, and approved by the project geotechnical consultant prior to the placement of the base or asphalt/PCC finish surface. G. General Recommendations 1. The minimum foundation design and steel reinforcement provided herein are based on soil characteristics and are not intended to be in lieu of reinforcement necessary for structural considerations. 2. Adequate staking and grading control is a critical factor in properly completing the recommended remedial and site grading operations. Grading control and staking should be provided by the project grading contractor or surveyor/civil engineer, and Is beyond the geotechnical engineering sen/ices. Inadequate staking and/or lack of grading control may resutt in unnecessary additional grading which will increase construction costs. 3. Footings located on or adjacent to the top of slopes should be extended to a sufficient depth to provide a minimum horizontal distance of 7 feet or one-third ofthe slope height, whichever is greater (need not exceed 40 feet maximum) between the bottom edge of the footing and face of slope. This requirement applies to all improvements and stmctures including fences, posts, pools, spas, etc. Concrete and AC improvements should be provided wrth a thickened edge to satisfy this requirement. 4. Open or backfilled trenches parallel wrth a footing shall not be below a projected plane having a downward slope of 1-unrt vertical to 2 unrts horizontal (50%) from a line 9 inches above the bottom edge of tt^ footing, and not closer than 18 inches from the face of such footing. 5. Where pipes cross under-footings, the footings shall be specially designed. Pipe sleeves shall be provided where pipes cross through footings or footing walls, and sleeve clearances shall provide for possible footing settlement but not less than 1-inch all around the pipe. 6. Foundations where the surface ofthe ground slopes more than 1-unrt vertical in 10 units horizontal (10% slope) shall be level or shall be stepped so that both top and bottom of such foundations are level. Individual steps in continuous footings shall not exceed 18 inches in height and the slope of a series of such steps shall not exceed 1-unrt vertical to 2 units horizontal (50%) unless othenA/ise specified. The steps shall be detailed on the structural drawings. The local effects due to the discontinuity of the steps shall also be considered in the design of foundations as appropriate and applicable. L VINJE & MiDni.liTON ENI;INEERINI;, INC. • 2450 Auto l>ark Way • liscondido. California 92029-1229 • Phone (760) 743-1214 PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 35 26-LOT SUBDIVISION, CAMINO HILLS DRIVE, CARLSBAD JUNE 23,2006 7. Expansive clayey soils should not be used for backfilling of any retaining structure. All retaining/basement walls should be provided with a 1:1 wedge of granular, compacted backfill measured from the base of the wall footing to the finished surface, and a well constructed back drainage as shown on Plate 22. 8. All underground utility and plumbing trenches should be mechanically compacted to a minimum 90% of the maximum dry density of the soil unless othenwise specified. Care should be taken not to crush the utilities or pipes during the compaction ofthe soil. Non-expansive, granular backfill soils should be used. Trench backfill materials and compaction beneath pavements within the public right-of-way shall confomn to the City of Carlsbad requirements. 9. On-site soils are expansive clayey deposits subject to continued swelling and shrinkage upon wetting and drying. Maintaining a uniform as-graded soil moisture during the post construction periods is essential in the future perfonnance ofthe site structures and improvements. In no case should water be allowed to pond or accumulate adjacent to the improvements and structures. Due to sensitive expansive plastic clayey soils present at the site, construction of swimming pools, spas, patios, etc. should only be allowed based on a review and specific recommendations provided by the project geotechnical consultant. Planting large trees nearthe building foundations should be avoided. 10. Site drainage over the finished pad surfaces should fiow away from structures onto the street in a positive manner. Care should be taken during the construction, improvements, and fine grading phases not to disrupt the designed drainage pattems. Roof lines ofthe buildings should be provided wrth roof gutters. Roof water should be collected and directed away from the buildings and structures to a suitable location. 11. Final plans should refiect preliminary recommendations given in this report. Final foundations and grading plans may also be reviewed by the project geotechnical consultant for confonnance wrth the requirements of the geotechnical investigation report outlined herein. More specific recommendations may be necessary and should be given when final grading and architectural/structural drawings are available. 12. All foundation trenches should be inspected to ensure adequate footing embedment and confirm competent bearing soils. Foundation and slab reinforcements should also be inspected and approved by the project geotechnical consultant. VINJE & MIDDLIH ON ENI;INI:I;RING, INC. • 2450 Auto Park Way • liscondido. California 92029-1229 • Phone (760) 743-1214 PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 36 26-LOT SUBDIVISION, CAMINO HILLS DRIVE, CARLSBAD JUNE 23,2006 13. The amount of shrinkage and related cracks that occurs in the concrete slab- on-grades, flatworks and driveways depend on many factors the most important of which is the amount of water in the concrete mix. The purpose of the slab reinforcement is to keep nonnal concrete shrinkage cracks closed tightly. The amount of concrete shrinkage can be minimized by reducing the amount of water in the mix. To keep shrinkage to a minimum the following should be considered: * Use the stiffest mix that can be handled and consolidated satisfactorily. * Use the largest maximum size of aggregate that is practical. For example, concrete made with ye-inch maximum size aggregate usually requires about 40-lbs. more (neariy 5-gal.) water per cubic yard than concrete wtth 1-inch aggregate. * Cure the concrete as long as practical. The amount of slab reinforcement provided for conventional slab-on-grade construction considers that good quality concrete materials, proportioning, craftsmanship, and control tests where appropriate and applicable are provided. 14. A preconstruction meeting between representatives ofthis office, the property owner or planner, city inspector as well as the grading contractor/builder is recommended in order to discuss grading/construction details associated wrth site development. IX. LIMITATIONS The conclusions and recommendations provided herein have been based on available data obtained from the review of pertinent reports and plans, subsurface exploratory excavations as well as our experience wtth the soils and formational materials located in the general area. The materials encountered on the project site and utilized in our laboratory testing are believed representative of the total area; however, earth materials may vary in characteristics between excavations. Of necessity we must assume a certain degree of continuity between exploratory excavations and/or natural exposures, tt is necessary, therefore, that all observations, conclusions, and recommendations be verified during the grading operation. In the event discrepancies are noted, we should be contacted immediately so that an inspection can be made and addrtional recommendations issued rt required. VINJE 86 MIDI)I.I-; I ON HNGINI:I:RING, INC. • 2450 Auio Park Way • liscondido, California 92029-1229 • Phone (760) 743-1214 PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 37 26-LOT SUBDIVISION. CAMINO HILLS DRIVE. CARLSBAD JUNE 23, 2006 The recommendations made in this report are applicable to the site at the time this report was prepared. It is the responsibility of the owner/developer to ensure that these recommendations are carried out in the field. It is almost impossible to predict with certainty the future performance of a property. The future behavior of the site Is also dependent on numerous unpredictable variables, such as earthquakes, rainfall, and on-site drainage patterns. The firm of VINJE & MIDDLETON ENGINEERING, INC, shall not be held responsible for changes to the physical conditions of the property such as addrtion of fill soils, added cut slopes, or changing drainage patterns which occur without our Inspection or control. The property owner(s) should be aware that the development of cracks in all concrete surfaces such as floor slabs and exterior stucco are associated with normal concrete shrinkage during the curing process. These features depend chiefiy upon the condrtion of concrete and weather conditions at the time of construction and do not refiect detrimental ground movement. Hairline stucco cracks will often develop at window/door corners, and floor surface cracks up to Ve-inch wide in 20 feet may develop as a result of normal concrete shrinkage (according to the American Concrete Instrtute). This report should be considered valid for a period of one year and is subject to review by our firm following that time. If significant modifications are made to your tentative development plan, especially wrth respect to the height and location of cut and fill slopes, this report must be presented to us for review and possible revision. This report is issued wrth the understanding that the owner or his representative is responsible to ensure that the information and recommendations are provided to the project architect/structural engineer so that they can be Incorporated into the plans. Necessary steps shall be taken to ensure that the project general contractor and subcontractors carry out such recommendations during construction. The project soils engineer should be provided the opportunity for a general review of the project final design plans and specifications in order to ensure that the recommendations provided in this report are property interpreted and implemented. The project soils engineer should also be provided the opportunity to verify the foundations prior the placing of concrete. If the project soils engineer is not provided the opportunity of making these reviews, he can assume no responsibility for misinterpretation of his recommendations. Vinje & Middleton Engineering, Inc., warrants that this report has been prepared within the limits prescribed by our client wrth the usual thoroughness and competence of the engineering profession. No other warranty or representation, either expressed or implied, is included or intended. ViNii; & MIDDLETON ENGiNEi-iUNti, INC. • 2450 Auio Park Way liscondido, Cilifornia 92029-1229 • Phono (760) 74.'\-1214 PRELIMINARY GEOTECHNICAL INVESTIGATION 26-LOT SUBDIVISION, CAMINO HILLS DRIVE. CARLSBAD PAGE 38 JUNE 23. 2006 Once again, should any questions arise concerning this report, please do not hesitate to contact this office. Reference to our Job #06-210-P will help to expedite our response to your inquiries. We appreciate this opportunity to be of service to you. VINJE & MIDDLETON ENGINEERING, INC. Dennis Middleton #980 Steven J. Melzer CEG #2362 DM/SMSS/SJM/jt Distribution: Addressee (5) c-/j(/myfiles/prelifms.06/06-210-P ViNJii & MlDDl.EiON ENGINI-ERING, INC. • 2450 Auio Park Way • liscondido, California 92029-1229 • Phone (760) 743-1214 REFERENCES Annual Book of ASTM Standards, Section 4 - Construction, Volume 04.08: Soil And Rock (I); D 420 - 0 5611. 2005. Annuai Book of ASTM Standards, Section 4 - Construction, Volume 04.09: Soil And Rock (II); D 5714 - Latest, 2005. Highway Design Manual, Caltrans. Fifth Edrtion. Corrosion Guidelines, Caltrans, Version 1.0, Septemtter 2003. California Building Code, Volumes 1 & 2, International Conference of Building Offidals, 2001. "Green Book" Standard Specifications For Publlc Works Construction, Public Works Standards, Inc., BNi Building News, 2003 Edition. California Department of Conservation, Division of Mines and Geology (Califomia Geological Survey), 1997, Guidelines for Evaluating and Mitigating Seismic Hazards in California, DMG Special Publication 117, 71 p. California Department of Conservation, Division of Mines and Geology (Catifornia Geological Sun/ey), 1986 (revised). Guidelines for Preparing Engineering Geology Reports: DMG Note 44. California Department of Coniservation, Division of Mines and Geology (California Geological Survey), 1986 (revised), Guidelines to Geologic and Seismic Reports: DMG Note 42. EQFAULT, Ver. 3.00, 1997, Deterministic Estimation of Peak Acceleration from Digrtized Faults, Computer Program, T. Blake Computer Sen/ices And Software. EQSEARCH, Ver 3.00, 1997, Estimation of Peak Acceleration from California Earthquake Catalogs, Computer Program, T. Blake Computer Services And Software. Tan S.S. and Kennedy, M.P., 1996, Geologic Maps ofthe Northwestern Part of San Diego County, California, Plate(s) 1 and 2, Open File-Report 96-02, California Division of Mines and Geology, 1:24,000. UBCSEIS, Ver. 1.03, 1997, Computation of 1997 Uniform Building Code Seismic Design Parameters, Computer Program, T. Blake Computer Services And Software. "Proceeding of The NCEER Workshop on Evaluation of Liquefaction Resistance Soils," Edited by T. Leslie Youd And Izzat M. Idriss, Technical Report NCEER-97-0022, Dated December 31,1997. "Recommended Procedures For Implementation of DMG Special Publication 117 Guidelines For Analyzing And Mrtigation Liquefaction in Califomia," Southern California Earthquake center; USC, March 1999. "Soil Mechanics,' Naval Facilities Engineering Command, DM 7.01. "Foundations & Earth Structures," Naval Facilities Engineering Command, DM 7.02. "Introduction to Geotechnical Engineering, Robert D. Holtz, William D. Kovacs. "introductory Soil Mechanics And Foundations: Geotechnical Engineering,' George F. Sowers, Fourth Edrtion. "Foundation Analysis And Desjgn," Joseph E. Bowels. Caterpillar Performance Handbook, Edition 29,1998. Jennings, C.W., 1994, Fault Activity Map of Califomia and Adjacent Areas, California Division of Mines and Geology, Geologic Data Map Series, No. 6. Kennedy, M.P.. 1977, Recency and Character of Faulting Along the Elsinore Faurt Zone in Southern Riverside County, California, Special Report 131, California Division of Mines and Geology, Plate 1 (East/West), 12p. Kennedy, M.P. and Peterson, G.L., 1975, Geology of the San Diego Metropolitan Area, California: California Division of Mines and Geology Bulletin 200, 56p. Kennedy, M.P. and Tan, S.S., 1977, Geology of National City, Imperial Beach and Otay Mesa Quadrangles, Southem San Diego Metropolitan Area, Califomia, Map Sheet 24, California Division of Mines and Geology, 1:24,000. Kennedy, M.P., Tan, S.S., Chapman, R.H., and Chase, G.W., 1975, Character and Recency of Faurting, San Diego Metropolitan Areas, Catifornia: Special Report 123,33p. Caterpillar Performance Handbook, Edrtion 29,1998. Jennings, C.W., 1994, Fautt Activity Map of Califomia and Adjacent Areas, California Division of Mines and Geology, Geologic Data Map Series, No. 6. Kennedy, M.P., 1977, Recency and Character of Faulting Along the Elsinore Fault Zone in Southern Riverside County, California, Special Report 131, California Division of Mines and Geology, Plate 1 (East/West), 12p. Kennedy, M.P. and Peterson, G.L., 1975, Geology of the San Dlego Metropolitan Area, California: California Division of Mines and Geology Bulletin 200, 56p. Kennedy, M.P. and Tan, S.S., 1977, Geology of National City, Imperial Beach and Otay Mesa Quadrangles, Southern San Dlego Metropolitan Area, Califomia, Map Sheet 24, California Division of Mines and Geology, 1:24,000. Kennedy, M.P., Tan, S.S., Chapman, R.H., and Chase, G.W., 1975, Character and Recency of Faulting, San Diego Metropolitan Areas, California: Special Report 123, 33p. "An Engineering Manual For Slope Stability Studies," J.M. Duncan, A.L. Buchignani And Marius De Wet, Virginia Polytechnic Instrtute And State University, March 1987. LAT: 33.1452 LONG: 117.2880 PRIMARY DIVISIONS GROUP SYMBOL SECONDARY DIVISIONS COARSE GRAINED SOILS MORE THAN HALF OF MATERIAL IS LARGER THAN NO. 200 SIEVE SIZE GRAVELS MORE THAN HALF OF COARSE FRACTION IS LARGER THAN NO. 4 SIEVE CLEAN GRAVELS (LESS THAN 5% FINES] GW Well graded gravels, gravel-sand mixtures, llllle or no fines. COARSE GRAINED SOILS MORE THAN HALF OF MATERIAL IS LARGER THAN NO. 200 SIEVE SIZE GRAVELS MORE THAN HALF OF COARSE FRACTION IS LARGER THAN NO. 4 SIEVE CLEAN GRAVELS (LESS THAN 5% FINES] GP Poorly graded gravels or gravel-sand mixtures, little or no fines. COARSE GRAINED SOILS MORE THAN HALF OF MATERIAL IS LARGER THAN NO. 200 SIEVE SIZE GRAVELS MORE THAN HALF OF COARSE FRACTION IS LARGER THAN NO. 4 SIEVE GRAVEL WITH FINES GM SUty gravels, gravel-sand-silt mixtures, non-plastic fines. COARSE GRAINED SOILS MORE THAN HALF OF MATERIAL IS LARGER THAN NO. 200 SIEVE SIZE GRAVELS MORE THAN HALF OF COARSE FRACTION IS LARGER THAN NO. 4 SIEVE GRAVEL WITH FINES GC Clayey gravels, gravel-sand-clay mixtures, plasllc fines. COARSE GRAINED SOILS MORE THAN HALF OF MATERIAL IS LARGER THAN NO. 200 SIEVE SIZE SANDS MORE THAN HALF OF COARSE FRACTION IS SMALLER THAN NO. 4 SIEVE CLEAN SANDS (LESS THAN 5% FINES) SW Well graded sands, gravelly sands, litlle or no fines. COARSE GRAINED SOILS MORE THAN HALF OF MATERIAL IS LARGER THAN NO. 200 SIEVE SIZE SANDS MORE THAN HALF OF COARSE FRACTION IS SMALLER THAN NO. 4 SIEVE CLEAN SANDS (LESS THAN 5% FINES) SP Pooriy graded sands or gravelly sands, Iiltle or no fines. COARSE GRAINED SOILS MORE THAN HALF OF MATERIAL IS LARGER THAN NO. 200 SIEVE SIZE SANDS MORE THAN HALF OF COARSE FRACTION IS SMALLER THAN NO. 4 SIEVE SANDS WITH FINES Sl^ Sllty sands, sand-silt mixtures, non-piaslic fines. COARSE GRAINED SOILS MORE THAN HALF OF MATERIAL IS LARGER THAN NO. 200 SIEVE SIZE SANDS MORE THAN HALF OF COARSE FRACTION IS SMALLER THAN NO. 4 SIEVE SANDS WITH FINES SC Clayey sands, sand-clay mixtures, plastic fines. FINE GRAINED SOILS MORE THAN HALF OF MATERIAL IS SMALLER THAN NO. 200 SIEVE SIZE SILTS AND CLAYS LIQUID LIMIT IS LESS THAN 50% ML inorganic sills and very fine sands, roci< flour, siity or clayey fine sands or ciayey silts wilh sllgtit plasticity. FINE GRAINED SOILS MORE THAN HALF OF MATERIAL IS SMALLER THAN NO. 200 SIEVE SIZE SILTS AND CLAYS LIQUID LIMIT IS LESS THAN 50% CL Inorganic clays of low to medium plasticity, gravelly clays, sandy clays, silty clays, lean clays. FINE GRAINED SOILS MORE THAN HALF OF MATERIAL IS SMALLER THAN NO. 200 SIEVE SIZE SILTS AND CLAYS LIQUID LIMIT IS LESS THAN 50% OL Organic silts and organic silly clays of low plaslicity. FINE GRAINED SOILS MORE THAN HALF OF MATERIAL IS SMALLER THAN NO. 200 SIEVE SIZE SILTS AND CLAYS LIQUID LIMIT IS GREATER THAN 50% MH Inorganic sills, micaceous or diatomaceous line sandy or sllty soils, elastic sills. FINE GRAINED SOILS MORE THAN HALF OF MATERIAL IS SMALLER THAN NO. 200 SIEVE SIZE SILTS AND CLAYS LIQUID LIMIT IS GREATER THAN 50% CH Inorganic clays of high plasticity, fat clays. FINE GRAINED SOILS MORE THAN HALF OF MATERIAL IS SMALLER THAN NO. 200 SIEVE SIZE SILTS AND CLAYS LIQUID LIMIT IS GREATER THAN 50% OH Organic clays of medium to high plasticity, organic sills. HIGHLY ORGANIC SOILS PT Peat end other highly organic soils. GRAIN'SIZES U.S. STANDARD SERIES SIEVE 200 40 10 CLEAR SQUARE SIEVE OPENINGS 3/4" 3" 12" SILTS AND CLAYS SAND GRAVEL FINE MEDIUM COARSE FINE COARSE COBBLES BOULDERS RELATIVE DENSITY CONSISTENCY SANDS. GRAVELS AND NON-PLASTIC SILTS BLOWS/FOOT VERY LOOSE 0 - 4 LOOSE 4 - 10 MEDIUM DENSE 10-30 DENSE 30- 50 VERY DENSE OVER 50 CLAYS AND PLASTIC SILTS STRENGTH BLOWS/FOOT VERY SOFT 0- '/4 0 - 2 SOFT • 2 • 4 FIRM •/l -1 4 - 8 STIFF 1 - 2 e - 16 VERY STIFF 2 - 4 16-32 HARD OVER 4 OVER 32 1. Blow count, 140 pound hammer falling 30 Inches on 2 inch O.D. split spoon sampler (ASTM D-1586) 2. Unconfined compressive strength per SOILTEST pocket penetrometer CL-700 • c^,r>H Toc+ M Dull, c I = standard Penetration Test (SPT) (ASTM D-1586) • Sand Cone Test > Bulk Sample | with blow counts per a inches Q Chunk Sample O Driven Rings 11 = California Sampler with blow counts per 6 inches VINJE & MIDDLETON ENGINEERING, INC. 2450 Vineyard Ave., f!«102 Escondido, CA 92029-1229 KEY TO EXPLORATORY BORING LOGS Unified Soil Classification System {ASTM D-2487) PROJECT NO. KEY Date: 4-11-06 Logged by: SJM 1 DEPTH (ft) SAMPLE T-1 uses SYMBOL FIELD MOISTURE 1%) FIELD DRY DENSITY (pel) REUTIVE COMPACTION CA) 1 DEPTH (ft) SAMPLE DESCRIPTION uses SYMBOL FIELD MOISTURE 1%) FIELD DRY DENSITY (pel) REUTIVE COMPACTION CA) 3 - • • FILL: Sandy clay. Pale brown color. Moist to very moist. Soft. Plastic. ST-1 CL/CH 18.5 100.8 - 5 -• • • TERRACE DEPOSIT (0+): Clayey sand. Red-brown color. Moist Somewhat blocky. Loose to medium dense. Includes sub-angular pebbles. ST-2 SC/CL 12.9 15.4 104.1 103.4 80.4 79.8 i 1 -10-• Silty fine to medium sand with clay. Dark brown color. Medium dense to dense. Grades fine to coarse grained at 10'. Trace of clay. ST-2 SM/SC 8.2 7.8 112.3 119.3 86.7 92.1 - 15- • Q 1 Coarse sand. Clay binder. Some gravel and small rock. Red-brown color. Moist. Medium dense. ST-3 SC/GC 9.7 14.1 102.8 103.5 - - 15- • Q 1 Clay fine to medium sand. Brown color. Moist. Somewhat blocky. Medium dense. ST-2 \ SC 9.7 14.1 102.8 103.5 - -Clay fine to medium sand. Brown color. Moist. Somewhat blocky. Medium dense. ST-2 \ SC -20- Clay fine to medium sand. Brown color. Moist. Somewhat blocky. Medium dense. ST-2 \ SC -20- End Test Trench at 16J4' - extent of backhoe. No caving. No groundwater. Date: 4-11-06 Logged by: SJM ' PTH .ft) SAMPLE T-2 uses SYMBOL FIELD MOISTURE (%) FIELD ORY DENSITY (pcf) RELATIVE COMPACTION I'A) ' PTH .ft) SAMPLE DESCRIPTION uses SYMBOL FIELD MOISTURE (%) FIELD ORY DENSITY (pcf) RELATIVE COMPACTION I'A) - 0 • FILL/TOpSOlU: Sandy clay. Pale brown color. Moist. Soft. Plastic. ST-1 CL - FILL/TOpSOlU: Sandy clay. Pale brown color. Moist. Soft. Plastic. ST-1 CL - 5 - - 10- u • • Q • • FORIVI ATIONAL ROCK (Ts): Claystone. Grey color. Weathered. "Popcorn" texture. ST-4 CL/CH 1 16.6 23.6 18,8 17,4 101.0 89.8 107.8 114.3 84.5 75.1 90.2 95.6 - 5 - - 10- u • • Q • • Silty sandstone. Finegrained. Trace of clay. Tan with rust-colored staining. Inciudes clasts of claystone. Weathered. Friable. Moderately to poorly cemented. No discernable structure. ST-5 SM/SC i 16.6 23.6 18,8 17,4 101.0 89.8 107.8 114.3 84.5 75.1 90.2 95.6 - 15- - 20- Silty sandstone. Finegrained. Trace of clay. Tan with rust-colored staining. Inciudes clasts of claystone. Weathered. Friable. Moderately to poorly cemented. No discernable structure. ST-5 SM/SC i - 15- - 20- End Test Trench at 1014. No caving. No groundwater. VINJE & MIDDLETON ENGINEERING, INC 2450 Vineyard Avenue, Suite 102 Escondido, Californta 92029-1229 Office 760-743-1214 Fax 760-739-0343 TEST^REKR5H LQOa. CAMINO HILLS DRIVE, CARLSBAD PROJECT NO, 06-210-P PLATE 3 T Sand Cone Test Bulk Sample • Chunk Sample Q Driven Rings Date: 4-11-06 Logged by: SJM DEPTH (ft) SAMPLE T-3 uses SYMBOL FIELD MOISTURE (%) FIELD DRY DENSITY (pel) RELATIVE COMPACTION (V.) DEPTH (ft) SAMPLE DESCRIPTION uses SYMBOL FIELD MOISTURE (%) FIELD DRY DENSITY (pel) RELATIVE COMPACTION (V.) 0 -FILL/ALLUVIUM (af-Qal): Sandy clay. Pale brown color. Moist. Soft. ST-1 CL/CH ^ - 5 - • • • FILL/ALLUVIUM (af-Qal): Sandy clay. Pale brown color. Moist. Soft. ST-1 CL/CH ^ 28.6 27.8 88.0 88.8 798 80.4 - 5 - • • • Silty clay. Dark grey color. Moist. Soft to stiff. Plastic. ST-4 CUCH 28.6 27.8 88.0 88.8 798 80.4 -• Fine sand. Trace of clay. Off-white to grey color. Somewhat hlnrky Mprliiim dp.n.qR ST-5 SC 18.4 10.6 84.2 FORMATIONAL ROCK (Ts): Fine sandy siltstone/claystone. Grey color. Weathered. Fractured. Blocky. ST-4 MH/CH -10- -15- -20- ! FORMATIONAL ROCK (Ts): Fine sandy siltstone/claystone. Grey color. Weathered. Fractured. Blocky. ST-4 MH/CH -10- -15- -20- ! End Test Trench at 9, No caving. No groundwater. Date: 4-11-06 Logged by: SJM PTH (ft) SAMPLE 1-4 DESCRIPTION USCS SYMBOL FIELD MOISTURE (%) FIELD DRY DENSITY (pef) RELATIVE COMPACTION - 0 FILL (af): Sandy clay. Brown color. Moist. Soft. ST-1 CL 5 - -10- • • • FORMATIOt^AL ROCK (Ts): Fine sandy siltstone. Grey color. Deeply weathered. Soft ST-4 MH Pinch-out lens of medium sand. Trace of clay. Red-brown color. Friable. Some gravel and small rock. ST-3 SC/GC Fine sandy siltstone / claystone. Grey color. Maroon colored staining. Polished surfaces. Fractured. Grades blocky at 9'. ST-4 MH/CH 21.2 106.0 108.0 106.9 95.5 97.7 96.7 -15- - 20- End Test Trench at 10V4. No caving. No groundwater. VINJE & MIDDLETON ENGINEERING, INC 2450 Vineyard Avenue, Suite 102 Escondido, Califomia 92029-1229 Office 760-743-1214 Fax 760-739-0343 TEST TRENCH LOGS CAMINO HILLS DRIVE, CARLSBAD PROJECT NO. 06-210-P PLATE 4 T Sand Cone Test Bulk Sample • Chunk Sample O Driven Rings Date: 4-11-06 Logged by: SJM DEPTH (ft) SAMPLE T-5 uses SYMBOL FIELD IVIOISTURE (%) FIELD DRY DENSITY (pcf) RELATIVE COMPACTION m DEPTH (ft) SAMPLE DESCRIPTION uses SYMBOL FIELD IVIOISTURE (%) FIELD DRY DENSITY (pcf) RELATIVE COMPACTION m 0 - • FILL-ALLUVIUM (af-Qal): Sandy clay. Pale brown color. Moist Soft. ST-1 CL 0 - • Clayey sand. Fine grained. Dark brown color. Moist. Loose to medium dense. ST-2 SC 1 - 5 -Q • • Clayey sand. Fine grained. Dark brown color. Moist. Loose to medium dense. ST-2 SC 1 11.9 13.1 109.0 110.8 84.1 85.5 - 5 -Q • • TERRACE DEPOSIT IQtl: Clayey sand. Red-brown color. Moist. Medium dense. White carbonate stringers and 3"-6" diameter sub-angular roclc below 11'. ST-2 1 SC 11.9 13.1 109.0 110.8 84.1 85.5 -10- -15- • Q TERRACE DEPOSIT IQtl: Clayey sand. Red-brown color. Moist. Medium dense. White carbonate stringers and 3"-6" diameter sub-angular roclc below 11'. ST-2 1 SC 13.9 13.4 106.8 108.5 82.4 83.7 -10- -15- • Q FORMATIONAL ROCK (Ts): Clayey sandstone. Fine grained. Off-white color. Moderately cemented. Somewhat blocky. No apparent structure. ST-2 SC 13.9 13.4 106.8 108.5 82.4 83.7 -p FORMATIONAL ROCK (Ts): Clayey sandstone. Fine grained. Off-white color. Moderately cemented. Somewhat blocky. No apparent structure. ST-2 SC 16.0 102.5 85.5 -20- FORMATIONAL ROCK (Ts): Clayey sandstone. Fine grained. Off-white color. Moderately cemented. Somewhat blocky. No apparent structure. ST-2 SC -20- End Test Trench at 16V4' - extent of backhoe. No caving. No groundwater. Date: 4-11-06 Logged by: SJM T-6 uses FIELD FIELD DRY RELATIVE EPTH (ft) SAMPLE DESCRIPTION SYMBOL MOISTURE (%) DENSiTY (pcf) COMPACTION m - 0 -FILL(af): Clayey sand. Tan color. Moist. Loose. ST-2 SC - 5 - • TERRACE DEPOSIT (nL+ ) Fine sand. Silty. Yellow-tan color. Somewhat blocky. Friable. Moderately cemented. No structure. ST-5 SM/SP 13.3 105.5 88.3 - 10- -15- End Test Trench at 8'. No caving. No groundwater. - 20- VINJE & MIDDLETON ENGINEERING, INC 2450 Vineyard Avenue, Suite 102 Escondido, Califomia 92029-1229 TEST TRENCH LOGS VINJE & MIDDLETON ENGINEERING, INC 2450 Vineyard Avenue, Suite 102 Escondido, Califomia 92029-1229 CAIVIINO HILLS DRIVE, CARLSBAD Office 760-743-1214 Fax 760-739-0343 PROJECT NO. 06-210-P PLATE 6 V Sand Cone Test B Bulk Sample • Chunk Sample O Driven Rings Date: 4-11-06 Logged by: SJM DEPTH (ft) SAMPLE T-7 uses SYMBOL FIELD MOISTURE (%) FIELD DRY DENSITY (pef) RELATIVE COMPACTION (•-4) DEPTH (ft) SAMPLE DESCRIPTION uses SYMBOL FIELD MOISTURE (%) FIELD DRY DENSITY (pef) RELATIVE COMPACTION (•-4) 0 - • FILL-ALLUVIUM (af-Qal): Sandy clay. Pale brown color. Moist. Soft. Stiff at 3'. ST-1 CL 26,1 88.9 - 5 - - 10- • • TERRACE DEPOSIT (Qt): Fine sand. Trace of clay. Tan color. Somewhat blocky. Loose to medium dense. Locai clean sand lenses. ST-5 SM/SC 18.9 25.2 99.3 92,8 83.1 77.6 -• n Sandy clay / clayey sand. Brown color. Some rust - colored staining. Blocky. Medium dense. ST-1 SC/CL 22.5 25.7 98.3 95.7 • -15- -20- Sandy clay / clayey sand. Brown color. Some rust - colored staining. Blocky. Medium dense. ST-1 SC/CL -15- -20- End Test Trench at 14V4'. No caving. No groundwater. Date: 4-11 -06 Logged by: SJM 1 -PTH (ft) SAMPLE T-8 uses SYMBOL FIELD MOISTURE (•/.) FIELD DRY DENSITY (pcf) RELATIVE COMPACTION 1 -PTH (ft) SAMPLE DESCRIPTION uses SYMBOL FIELD MOISTURE (•/.) FIELD DRY DENSITY (pcf) RELATIVE COMPACTION - 0 - - 5 -• FILL- ALLUVIUM (af-Qal): Clayey sand. Fine to medium grained. Red-brown color. Moist. Very loose to loose. ST-2 SC 11.9 101.6 78.4 - 0 - - 5 -• Clayey sand. Dark brown color. Moist Blocky. Medium dense. Color changes to red-brown color at 10'. ST-2 SC 11.9 101.6 78.4 - 10- • • Clayey sand. Dark brown color. Moist Blocky. Medium dense. Color changes to red-brown color at 10'. ST-2 SC 12.7 12.2 113.6 104.1 87.9 80.3 - 10- • • FORMATIONAL ROCK/Ts): Sandstone. Finegrained. Trace of clay. Grey to yellow- tan. Deeply weathered. Weakly to moderately cemented. Friable. Local rust-colored staining. ST-5 1 SC 12.7 12.2 113.6 104.1 87.9 80.3 15. • FORMATIONAL ROCK/Ts): Sandstone. Finegrained. Trace of clay. Grey to yellow- tan. Deeply weathered. Weakly to moderately cemented. Friable. Local rust-colored staining. ST-5 1 SC 13.7 94.9 79.4 1 w - 20- End Test Trench at 15'. No caving. No groundwater. VINJE & MIDDLETON ENGINEERING, INC 2450 Vineyard Avenue, Suite 102 Escondido, Califomia 92029-1229 Office 760-743-1214 Fax 760-739-0343 TEST TRENCH LOGS CAMINO HILLS DRIVE, CARLSBAD PROJECT NO. 06-210-P PLATE 6 • Sand Cone Test Bulk Sample • Chunk Sample Q Driven Rings Date: 4-11-06 Logged by: SJM DEPTH (ft) SAMPLE T-9 uses SYMBOL FIELD MOISTURE (%) FIELD DRY DENSITY (pet) RELATIVE COMPACTION (%) DEPTH (ft) SAMPLE DESCRIPTION uses SYMBOL FIELD MOISTURE (%) FIELD DRY DENSITY (pet) RELATIVE COMPACTION (%) 0 -FILL-ALLUVIUM faf-Qal): Sandy clay. Pale brown color. Moist Soft. ST-1 CL - — \ FILL-ALLUVIUM faf-Qal): Sandy clay. Pale brown color. Moist Soft. ST-1 CL - — \ Fine sandy silt Grey color. Moist Soft ST-4 MH - 5 - - 10- \ • • • • Fine sandy silt Grey color. Moist Soft ST-4 MH 18.3 12.2 13.1 16.9 17.9 96.1 110.6 110.9 99.1 99.3 80.4 92.6 92.8 83.0 83.1 - 5 - - 10- \ • • • • TERRACE DEPOSIT (Ot): Sandstone. Fine grained with clay. Yellow-tan color. Moist. Weakly cemented. Weathered. Becomes somewhat blocky at 7'. Local rust - colored staining below 11". ST-5 -/ SC 18.3 12.2 13.1 16.9 17.9 96.1 110.6 110.9 99.1 99.3 80.4 92.6 92.8 83.0 83.1 - 5 - - 10- \ • • • • FORMATIONAL ROCK (Ts): Fine sandy siltstone. Grey color. Deeply weathered. Plastic ST-4. MH / 18.3 12.2 13.1 16.9 17.9 96.1 110.6 110.9 99.1 99.3 80.4 92.6 92.8 83.0 83.1 - 15-u •• \ FORMATIONAL ROCK (Ts): Fine sandy siltstone. Grey color. Deeply weathered. Plastic ST-4. MH / 24.3 97.3 88.1 -20- \ FORMATIONAL ROCK (Ts): Fine sandy siltstone. Grey color. Deeply weathered. Plastic ST-4. MH / -20- \ End Test Trench at ISVa. No caving. No groundwater. Date: 4-11-06 Logged by: SJM ;PTH .ft) SAMPLE T-10 uses SYMBOL FIELD MOISTURE (%) FIELD ORY DENSITY (pcf) RELATIVE COMPACTION (%) ;PTH .ft) SAMPLE DESCRIPTION uses SYMBOL FIELD MOISTURE (%) FIELD ORY DENSITY (pcf) RELATIVE COMPACTION (%) - 0 -FILL/TOPSOIL: Clayey sand. Red-brown color. Moist Loose. ST-2 CL - 0 - TERRACE DEPOSIT fQt): Silty fine sand. Trace of clay. Red-brown color. Locally blocky. Friable. Some rust-colored staining. ST-5 SM/SC - 6 - TERRACE DEPOSIT fQt): Silty fine sand. Trace of clay. Red-brown color. Locally blocky. Friable. Some rust-colored staining. ST-5 SM/SC - 6 - Clayey medium to coarse sand. Red-brown color. Medium dense. ST-3 SC - 10 Clayey medium to coarse sand. Red-brown color. Medium dense. ST-3 SC - 10 Sandy clay. Dark grey color. Moist. Blocky. Moderately plastic. Polished surfaces. ST-4 CH \ Sandy clay. Dark grey color. Moist. Blocky. Moderately plastic. Polished surfaces. ST-4 CH \ - 1 Sandy clay. Dark grey color. Moist. Blocky. Moderately plastic. Polished surfaces. ST-4 CH \ - 1 Clayey sand. Brown color, Rust-colored staining. Local polished surfaces. Blocky. Medium dense. ST-2 SC 15 \ Clayey sand. Brown color, Rust-colored staining. Local polished surfaces. Blocky. Medium dense. ST-2 SC - 20- \ Fine sandy silt Grey color. Blocky. Polished surfaces. Medium dense. ST-4 MH / - 20- \ End Test Trench at 15". No caving. No groundwater. VINJE & MIDDLETON ENGINEERING, INC 2450 Vineyard Avenue, Suite 102 Escondido, California 92029-1229 Office 760-743-1214 Fax 760-739-0343 TESTTRENCH LOGS CAMINO HILLS DRIVE, CARLSBAD PROJECT NO. 06-210-P PLATE 7 T Sand Cone Test Bulk Sample • Chunk Sample Q Driven Rings BORING LOG B-1 DEPTH FT SAMPLE Description USGS SYMBOL MOISTURE (•/.) DRY DENSiTY (PCF) RELATIVE COMPACTION (%) - 0 -FILL (af|: Clayey sand. Brown color. Slightly moist. Loose. SC -ST-2 17.4 113.8 87.8 • 17.4 113.8 87.8 - 5 -o 12.20 B TERRACE DEPOSIT (Qt): Medium to coarse sand. Clay binder. Red-brown color. Moist. ST-3 SC 1 -10-1 5.9,4 Sandy clay. Olive-brown color. Moist Stiff. Plastic. Local grey-colored staining. Weathered reflection of underlying siltstone. CL/CH -15-II ST-4 1 -15-6.10,13 II 5.10,13-| 1 ! FORMATIONAL ROCK fTs): Sandy siltstone. Pale grey color. Weathered. Friable. Firm. ST-4 MH -20- 6.10,13 II 5.10,13-| 1 ! -25-End Boring at IOVJ. No caving. No groundwater. -30- -35- -40- Proiect CAMINO HILLS DRIVE. CARLSBAD Bulk Sample • Ring Sample O SPT Sample || Groundwater PLATE 8 Proiect No: 06-210-P Date Drilled: 5-25-06 Loaaed Bv: SM Bulk Sample • Ring Sample O SPT Sample || Groundwater PLATE 8 Truclt-mounted rotary drill. 8" hollow-stem auger. Drill, Sample Method: 140-lb. Hammer, 30" hydraulic drop. 5' A\N Rods. Bulk Sample • Ring Sample O SPT Sample || Groundwater PLATE 8 VINJE & MIDDLETON ENGINEERING, INC. BORING LOG B-2 DEPTH FT SAIUIPLE Description USGS SYMBOL MOISTURE (%) DRY DENSITY (PCF) REUTIVE COMPACTION (%) - 0 -FILL-ALLUVIUM (af-Qal): Clayey sand / sandy clay. Brovm color. Slightly moist. Soft. ST-1 SC/CL - 5 - -10- II 3,2.2 II • 3.6.7 Clayey silt. Grey color. Moist Soft. ST-5 Sandy clay. Red-brown color. Moist to very moist. Soft. Plastic. ST-1 MH CUCH -15- -20- O 9.16 II 4.4.6 Clayey sand. Red-brown color. Moist Loose to medium dense. Color Chang es to pale brown at 18'. ST-2 SC 18.3 110.1 84.9 -25-O 12,24 TERRACE DEPOSIT (Qt): Sandy clay. Dark brown color. Moist. Stiff. Plastic, ST-1 CL/CH 16.9 114.6 95.8 -30- -35- -40- II 8.13,18 II 10.11.14 FORMATIONAL ROCK (Ts): Sandy siltstone. Pale grey color. Weathered soft and plastic in upper exposures. Fractured and friable below. Local rust-colored staining. Medium dense. Groundwater encountered at approximately 33'. Becomes somewhat blocky and dense at 39'. Continued .rust-colored staining. ST-4 MH ... -30- -35- -40- II 8.13,18 II 10.11.14 End Boring at 401/2'. No caving. Groundwater encountered at 33'. ... 19,20,24 End Boring at 401/2'. No caving. Groundwater encountered at 33'. Project Project Drill, Ss CAMINO HILLS DRIVE. CARLSBAD Bulk Sample • Ring Sample O SPT Sample || Groundwater ^ PLATE 9 Project Project Drill, Ss No: 06-210-P Date Drilled: 5-25-06 Logged Bv: SM Bulk Sample • Ring Sample O SPT Sample || Groundwater ^ PLATE 9 Project Project Drill, Ss Truck-mounted rotary drill. 8" hollow-stem auger, imple Method: 140-lb. Hammer, 30" hydraulic drop. 5'A\A/Rods. Bulk Sample • Ring Sample O SPT Sample || Groundwater ^ PLATE 9 BORING LOG B-3 DEPTH FT SAMPLE Description USGS SYMBOL MOISTURE (%) DRY DENSITY (PCF) RELATIVE COMPACTION (%) - 0 -FILL-ALLUVIUM faf-Qal): Clayey sand. Brown color. Slightly moist Loose. ST-2 sc - 5 -O 13,20 Medium to coarse sand. Clay binder. Red-brown color. Friable. Medium dense. ST-3 SC 9.0 113.2 97.3 - Medium to coarse sand. Clay binder. Red-brown color. Friable. Medium dense. ST-3 SC - Silty fine sand. Tan color. Firm to medium dense, ST-5 SM -10-II 11,12,13 O Silty fine sand. Tan color. Firm to medium dense, ST-5 SM -10-II 11,12,13 O Medium sand. Trace of clay. Red-brown color. Friable, Medium dense. ST-3 SC -10-II 11,12,13 O Clayey fine sand. Red-brown to tan color. Medium dense. Local rust and grey colored staining. Massive. ST-5 sc -15- -20- -25- -30- 18,20 II 6,10,14 o 13,22 1 .7,13,14 .. Clayey fine sand. Red-brown to tan color. Medium dense. Local rust and grey colored staining. Massive. ST-5 sc 9.7 16.2 113.8 109.5 87.8 91.6 -15- -20- -25- -30- 18,20 II 6,10,14 o 13,22 1 .7,13,14 .. Medium to coarse sand. Includes gravel and pebbles. Red-brown color. Very moist Groundwater at approximately 32'. Loose to firm. Blow counts for 34' sample inflated due to pebbles. Water added to aid drilling. Caving below 32' prohibited further sampling. ST-3 SP/GP 9.7 16.2 113.8 109.5 87.8 91.6 -35-O 12,35, 1 Medium to coarse sand. Includes gravel and pebbles. Red-brown color. Very moist Groundwater at approximately 32'. Loose to firm. Blow counts for 34' sample inflated due to pebbles. Water added to aid drilling. Caving below 32' prohibited further sampling. ST-3 SP/GP 20.3 1107 92.6 -35-O 12,35, 1 End Boring at 39'. Caving 35' - 39'. Groundwater at 32'. 1 20.3 1107 92.6 -40- End Boring at 39'. Caving 35' - 39'. Groundwater at 32'. 1 P roject Project Drill, Sa CAMINO HILLS DRIVE. CARLSBAD Bulk Sample • Ring Sample O SPT Sample || Groundwater ^ PLATE 10 P roject Project Drill, Sa No: 06-210-P Date Drilled: 5-25-06 Logged By: SM Bulk Sample • Ring Sample O SPT Sample || Groundwater ^ PLATE 10 P roject Project Drill, Sa Truck-mounted rotary drill. 8" hollovi/-stem auger, mple Method: 140-lb. Hammer, 30" hydraulic drop. 5" AW Rods. Bulk Sample • Ring Sample O SPT Sample || Groundwater ^ PLATE 10 VINJE & MIDDLETON ENGINEERING, INC. BORING LOG B-4 DEPTH FT SAMPLE Descnption USGS SYMBOL MOISTURE (•/.) DRY DENSITY {PCF) RELATIVE COMPACTION (%) - 0 -FILL-ALLUVIUM faf-Qal): Clayey sand. Brown color. Slightiy moist Loose. ST-2 SC - 5 -II 9,8,5 Medium to coarse sand. Clayey sand. Red-brown color. Loose to firm. ST-3 SC -10-o 11,14 Fine sand. Red-brown color. Weakly cemented. Friable. Massive. Medium dense. ST-5 SP 11.7 106.2 88.8 - o 11,14 TERRACE DEPOSIT (Qti: Clayey sand. Includes gravel and pebbles. Red- brown color. Medium dense. ST-2 1 SC/GC -15-II TERRACE DEPOSIT (Qti: Clayey sand. Includes gravel and pebbles. Red- brown color. Medium dense. ST-2 1 SC/GC -15-9,10,14 o Medium to coarse sand with gravel and pebbles. Red-brown color. Medium dense. ST-3 GP 5.8 109.5 91.6 8,12,17 ! Medium to coarse sand with gravel and pebbles. Red-brown color. Medium dense. ST-3 GP -25- -30- End Boring at 20'. No caving. No groundwater. -35- -40- Proiect: CAMINO HiLLS DRIVE. CARLSBAD Bulk Sample • Ring Sample O SPT Sample || Groundwater ^ Proiect No: 06-210-P Date Drilled: 5T25-06 Loaaed Bv: SM Bulk Sample • Ring Sample O SPT Sample || Groundwater ^ Bulk Sample • Ring Sample O SPT Sample || Groundwater ^ Trucl<-mounted rotary drill. 8" hollow-stem auger. Drill, Sample Method: 140-lb. Hammer, 30" hydraulic drop. 5' AW Rods. PLATE 11 VINJE & MIDDLETON ENGINEERtNG, INC. Jio ei^©.is-i PLATE 12 B-4 (proj.) -1^ SCALE: 1"=30' V&M JOB #06-210-P PLATE 13 160 140 120 - 100 > • 120 100 160 140 120 IOO SCALE: J"=3()' V&IVI JOI^/(06-210-P Original ground .surface approximaLKtl rrom Couniy of San Diego Topographic Survey Map No. s 354-ll-i77Ss 354-1688, dn led J 975. PL/\TE 14 -i _L , B-2 (proj.) SCALE: 1"=50' FAULT - EPICENTER MAP SAN DIEGO COUNTY REGION INDICATED EARTHQUAKE EVENTS THROUGH 75 YEAR PERIOD (1900-1974) Map data is compiled from various sources including California Division of Mines and Geology, California Institude of. Technology and the National Oceanic and Atmospheric Administration. Map is reproduced from California Division of Mines and Geology, "Earthquake Epicenter Map of California; Map Sheet 39." L Earthquake Magnitude o 4.0 TO 4.9 O 5.0 TO 5.9 6.0 TO 6.9 CD 7.0 TO 7.9 Fault. PROJECT: Job #06-210-P PLATE: CAMINIO HILLS DRIVE. CARLSBAD 15 U. S. STANOARO SIEVE IN INCHES - SB U.S. STANDARO E NUMBERS o p o HYDROMETER SOO 100 50 1 0.5 GRAIN SIZE MILLIMETERS 0.01 0.005 0.001 Cobt>les Gravel Coarse Fine Sand C03SM to medhm Rns SILT OR CLAY SAMPLE # - DEPTH (FEET) SYMBOL CLASSIRCATION NAT W% U. PL PI PROJECT: 06-210-P T-1 1 • CL/CH -45 24 23 ADDRESS: CAMINO HILLS DRIVE T-1 4 A SC/CL 12.9 32 16 16 CARLSBAD DATE: JUNE, 2006 PLATE 16 VINJE AND MIDDLETON ENGINEERING, INC. U. S. STANDARD SIEVE IN INCHES 100 90 80 70 a S. STANDARD E NUMBERS O Q O HYDROMETER 1 1 j ~ i s 1 1 T 1 -—t \ \ \ 1 —' \ \ \ \ 'N 11 \ ll 1 1 1 1 \ \ 1 1 1 t 1 10 20 30 60 50 40 40 O z m <n < fi. Z IU o a IU c o 50 H g 60 m 30 20 10 70 80 90 J 100 500 Cobbles Grave! Sand SILT OR CLAY Coarae Rne Coaese to medium Fine SILT OR CLAY SAMPLE # DEPTH (FEEn SYMBOL CLASSIFICATION NAT W% LL PL PI PROJECT: 06-210-P T-2 5 « SC/SM 23.6 36 25 11 ADDRESS: CAMINO HILLS DRIVE T-3 3 .CL/CH 28.6 49 27 22 CARLSBAD DATE: JUNE, 2006 PLATE 17 VINJE AND MIDDLETON ENGINEERING, INC. PEPTH (FEET) SYRflBOL eXPLAMATHON T-1 4 • ====--—=— FIELD MOISTURE _ = ^ SAMPLE SATURATED REBOUND Sample condition j 1.070 1.060 1.050 1.040 1.030 1.020 1.010 1.000 0.990 0.980 0.970 0.960 0.950 0.940 0.930 o o o e o o w o o o 9 w s o o o o S o ooo CM rt Tf in o o o o o o o o CM OOO ooo ooo eoo o s NORMAL LOAD<PSF) 06-210-P LOAD CONSOLIDATION TEST PLATE PLATE 18 VINJE & MIDDLETON ENGINEERING, INC. SAMPLE DEPTH (FEET) SYMBOL EXPLANATION T-3 3 A FIELD MOISTURE SAMPLE SATURATED REBOUND Sample condition j 1.070 1.060 1.050 1.040 1.030 1.020 1.010 1.000 0.990 0.980 0.970 0.960 0.950 0.940 0.930 s o ooo o ooo M CO Tt IO i o o e _ o oeo 8 s $s NORMAL LOAD (PSF) \ ^ 1 \ \ \ N •K. m ooo " — o o e o ogo W § IB geo -OB #06-210-P LOAD CONSOLIDATION TEST PLATE PLATE 19 VINJE & MIDDLETON ENGINEERING, INC. RETAINING WALL (See report for backcut specifications and bearing soil preparation) Wall drain Bench as direcied in the field Minimum epuiptment width 15' min. TYPICAL STA]BSLIgATI©M FULL ©M IfSimiMlIM© WALL EL CAMINO REAL AT CAMINO HILLS DRIVE, CARLSBAD OONSTRUCTION NOTES * Construct back-cut at 1/2:1 gradient * Heel keyway into hillside 2% * Recompact soil to minimum 90% of laboratory standard * Trim excess soil to finish grade PLATE 20 06-210-P ISOLATION JOINTS AND RE-ENTRANT CORNER REINFORCEMENT Typical - no scale RE-ENTRANT CORNER—- REINFORCEMENT NO. 4 BARS PLACED I.5" BELOW TOP OF SLAB RE-ENTRANT CORNER CRACK NOTES: 1. Isolation joints around the colunnns should be either circular as shown in (a) or diamond shaped as shown in (b). If no isolation joints are used around columns, or if the corners of the isolation joints do not meet the contraction joints, radial cracking as shown in (c)may occur (reference ACI). 2. In order to control cracking at the re-entrant corners (±270° comers), provide reinforcement as shown in (c). 3. Re-entrant corner reinforcement shown herein is provided as a general guideline only and is subject to verification and changes by the project architect and/or structural engineer based upon slab geometry, location, and other engineering and construction factors. VINJE & MIDDLETON ENGINEERING, INC. PLATE 21 RETAINING WALL DRAIN DETAIL Typical - no scale • • Gronulor, non-exponsive • backfill. Compacled. Walerproofing Perforated droin pipe -77--^ droinoge Filter Maleriol. Crushed rock (wrapped in filler fabric) or Cioss 2 Permeable Maierial (see specifications below) Competent, opproved ^•'^ soils or bedrock :::::: ;::.::it :;; Sand Equivalent > 75 CONSTRUCTION SPECIFICATIONS: 1. Provide granular, non-expansive backfill soil in 1:1 gradient wedge behind wall. Compact backfill to minimum 90% of laboratory standard. 2. Provide back drainage for wall to prevent build-up of hydrostatic pressures. Use drainage openings along base of wall or back drain system as outlined below. 3. Backdrain should consist of 4" diameter PVC pipe (Schedule 40 or equivalent) with perforations down. Drain to suitable ouflet at minimum 1%. Provide V* - VA' crushed gravel filler wrapped in filter fabric (Mirafi 140N or equivalent). Delete filter fabric wrap if Caltrans Class 2 permeable material is used. Compact Class 2 material to minimum 90% of laboratory standard. 4. Seal back of wall with waterproofing in accordance with architect's specifications. 5. Provide positive drainage to disallow ponding of water above wall. Lined drainage ditch to minimum 2% flow away from wall is recommended. * Use 1V4 cubic foot per foot with granular backfill soil and 4 cubic foot per foot if expansive backfill soil is used. VINJE & MIDDLETON ENGINEERING, INC. PLATE 22