Loading...
HomeMy WebLinkAboutCT 06-13; Tabata 10; Tentative Map (CT) (6)Preliminary Geotechnical Investigation Proposed 26-Lot Subdivision Camino l-lills Drive Carlsbad, California (AP.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 Job #06-210-P June 23, 2006 ViNTE & MIDDLETON ENGINEERING, INC. 2450 Vineyard Avenue Escondido, Califomia 92029-1229 Phone(760) 743-1214 Fax (760) 739-0343 Tabata Family Trust c/o Mr. Gregg Harrington P.O. Box 943 Carlsbad, California 92018 PRELIMINARYGEOTECHNICAL 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 anatyses 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. A~7}AMJ7^ Dennis Middleton CEG #980 DM/jt TABLE OF CONTENTS PAGE NO. I. INTRODUCTION 1 IL SITE DESCRIPTION 1 III. 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 SoilType 3 Grain Size Analysis 4 TABLE OF CONTENTS (continued) Liquid Limit, Plastic 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 15 Grain Size Analysis 16-17 Consolidation Tests 18-19 Typical Stabilization Fill 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 Ei 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 of this investigation was to detennine 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 mari^s 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 residentiat developments along the southerly and easteriy site margins. The anomalous hill rises neariy 30 feet above sun-ounding areas with slope gradients that generally approach 2:1 (horizontal to vertical) maximum. The large graded slopes that mark the southerly and easteriy 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 Survey 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 by 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 northwesteriy 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. ViNiH & MiDDLKTON ENGINEERING, INC, " 2450 Vineyard Avenue • Escondido, Califorma 92029-1229 • Phone (760) 743-1214 PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 2 26-LOT SUBDIVISION, CAMINO HILLS DRIVE, CARLSBAD JUNE 23, 2006 Site drainage sheetlfows in a northeasteriy 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 demolition 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 of the 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. 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 (#LMON 103949 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 VINJE & MIDDLETON ENGINEERING. INC. • 2450 Vineyard Avenue • Escondido, California 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 of the off-site development above. Consequently, the project 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 fomiational rock units are present at shalbw 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 dari<-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. Fill - 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. VINJE & MIDDLETON ENGINEERING, INC. • 2450 Vineyard Avenue • Escondido, Cahfornia 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 overly 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 easteriy 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 easteriy 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. Alternatively, a retaining wall may be constructed at the base ofthe 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. VINIE & MIDDLETON ENGINEERING, INC. • 2450 Vineyard Avenue " Escondido, California 92029-1229 • Phone (760) 743-1214 PRELIMINARY GEOTECHNICAL INVESTIGATION 26-LQT 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 of the 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 California 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 to 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 ofthe study site occurred 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 esfimated 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 accelerafion data compiled from Digitized California Faults (Computer Program EQFAULT VERSION 3.00 updated) typically associated with tiie fault is also tabulated: TABLE 1 Rose Canyon 6.6 miles 0.210g Newport-lnglewood 8.2 miles 0.182g Coronado Bank 22.6 miles 0.175g Elslnore-Jullan 22.6 miles 0.150g 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. VINJE & MIDDLETON ENGINEERING, INC. * 2450 Vineyard Avenue • Escondido, California 92029-1229 • Phone (760) 743-1214 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 coastal areas with moderate to locally heavy ground shaking resulfing in $700,000 in damages, one death, and injuries to 30 people. The quake occurred along an offshore fault located nearly 30 miles southwest of 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 of the 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 atthe 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 tifefime of the project. The faults are periodically active and capable of generating moderate to locally high levels of ground shaking at the site. Ground separafion 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: ViNiH & MIDDLETON ENGINHLRINI;!, INC. • 2450 Vineyard Avenue • Escondido, California 92029-1229 • Phone (760) 743-1214 PRELIMINARY GEOTECHNICAL INVESTIGATION 26-LOT SUBDIVISION, CAMINO HILLS DRIVE, CARLSBAD PAGE 7 JUNE 23, 2006 TABLE 2 Selipiic factor Seismic Seisinic Re^mte Coeffii^^ls Selipiic factor Seismic Nv 09 ^ Is TO SD 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 California Buildinq 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 relafionship, a 10 percent probability of exceedance in 50 years was estimated to produce a site specific peak ground accelerafion 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 shallow 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 Testing / 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 performing penetration tests (SPT), field exposures and site soils have been grouped into the following soil types: TABLE 3 OescritiUoii 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 (Flll/Topsoil/Alluvium) 4 grey silty clay / siltstone/ claystone (Topsoil/Formational Rock 6 grey / yellow-tan fine sand wl trace clay (Topsoil/Formational Rock/Ten-ace) VINJE & MIDDLETON ENGINEERING, INC:. • 2450 Vineyard Avenue • Kscondido, California 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 Test: Standard penetration tests (SPT) were peri'ormed 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 the Boring Logs. 2. Grain Size Analysis: Grain size analyses were performed on representafive samples of Soil Types 1, 2, 4, and 5. The test results are presented in Table 4 and graphically presented on the enclosed Plates 16 and 17. TABLE 4 Sieve Size 72" :i4: .1 #10 %7^^'t #40 7^Ji Location Soil Type Percent Passing T-1 @r 1 100 99 97 , m ^ 89 m T-1 @ 4' 2 100 97 76 T-3 @ 3' 4 100 'VM7-H 100 W'7M7"-^-% 98 T-2 @ 5' 5 100 ^.7rm: 99 97 86 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 T-1 @r 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 VINJE & MIDDLETON ENGINEERING, INC. • 2450 Vineyard Avenue • Escondido, California 92029-1229 • Phone (760) 743-1214 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 detennined in accordance with ASTM D-1557. The test results are presented in Table 6. TABLE 6 tM7 lUMmumiliv 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 Ring Samples): In-place dry density and moisture contents of representative soil deposits beneath the site were detennined from relatively undisturiDed 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 Sample Soli mm Field Moisture Ckmtent Field Dvy Density (Yd-pcf) Max. Diy penalty (Ym-pcf) R»tl0 Of In-Placo Dry Denistty To Max. Dry DensHy* (Yd/Ym X 100) 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 @ 5' 5 23.6 89.8 119.5 75.1 T-2 @ 8* 5 18.8 107.8 119.5 90.2 VlN|E &i MIDDLETON ENGINEERING, INC. • 2450 Vineyard Avenue • Escondido, Cahfornia 92029-1229 • Phone (760) 743-1214 PRELIMINARY GEOTECHNICAL INVESTIGATION 26-LOT 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 @ T 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-5 @ 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 16.0 102.5 119.5 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@ ir 2 12.2 104.1 129.6 80.3 T-8 ©12/2' 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 97.3 110.5 88.1 VINJE & MionLirroN ENGINEERING, INC. • 2450 Vineyard Avenue • Escondido, Cahfomia 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 othenwise 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 T-1 @1' 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. 7. Direct Shear Test: Three direct shear tests were peri'ormed 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. ViNiE & MlDPLlTON ENCilNEERiNG, ING. * 2450 Vineyard Avenue • Escondido, Cahfornia 92029-1229 • Phone (760) 743-1214 PRELIMINARY GEOTECHNICAL INVESTIGATION 26-LOT SUBDIVISION, CAMINO HILLS DRIVE. CARLSBAD PAGE 12 JUNE 23, 2006 TABLE 9 wet T-1 @ 4' 2 remolded to 90% of Ym @ % cjopt 127.8 32 75 T-3 @ 3' 4 remolded to 90% of Ym @ % toopt 117.9 23 280 T-2 @ 5' 5 remolded to 90% of Ym @ % coopt 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 7:>;i^M. :..-7-:ji T-1 @1' 1 504 6.2 1 T-3 m 3' 4 381 6.5 1 9. Sulfate Test: Sulfate tests were perfonned on representative samples of Soil Types 1 and 4 in accordance with the Califomia Test Method (CTM) 417. The test results are presented in Table 11. TABLE 11 T-1 @r 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. VINJE &L MIDDLETON ENGINEERING, INC. • 2450 Vineyard Avenue • Escondido, Cahfornia 92029-1229 • Phone (760) 743-1214 PRELIMINARY GEOTECHNICAL INVESTIGATION 26-LOT SUBDIVISION, CAMINO HILLS DRIVE. CARLSBAD PAGE 13 JUNE 23, 2006 TABLE 12 Soli Type Amount of Water Soluble Gfiloride (Ct) lnSolU%%Weiaht) T-1 @ r 1 0.007 T-3 @ 3' 4 0.006 11. Consolidation Tests: Consolidation tests were perfonned 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 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 ofthe following conditions exists: * Sulfate concentration is greater than or equal to 2000 ppm (0.2% 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 resisfivity 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 quantifies 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 ofthe 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 quantities of soluble salts. However, test results further indicated pH is greater than VINJE. & Minni.inON HN(;INHHR[NG, INC. • 2450 Vineyard Avenue • Escondido, California 92029-1229 " Phone (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 earthwori^s and grading operafions to further verify site corrosion conditions. The project site is not located within 1000 feet of salt or brackish water. Based upon the result ofthe 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-Resistivity test result: TABLE 14 BUS «:! 1 Years lo Perforation of Steel Culverts 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 investigafion, development of the study site into an 26-lot residentiai 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 properiy is chiefly a graded site developed to Its exisfing lines and grades for agricultural purposes in the late 1960's. Grading documents including engineering obsen/ations 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-Qai" on Plate 2). These soils occur in a loose to soft condition partlculariy 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 ViN|E & MIDDLETON ENGINEERING. INC. • 2450 Vineyard Avenue " Escondido, 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 construcfion settlement of site fills/alluvium after development is not expected to exceed approximately 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 anficipated to exceed ^/4-inch between similar elements, in a 20-foot span. Remaining areas of the site are mostly underiain by formational rocks or Terrace Deposit units (see mapped areas "Ts" and "Qt" on Plate 2). These are suitably dense units and will provide adequate support for the planned new fills, structures and improvements. Perimeter embankments at the project property are predominantly compacted fill slopes (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 vegetafion, and have performed well since their construcfion with no evidence of gross instability. Some additional 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 secfion 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 site Terrace Deposits underiaying the northwestem hill are expected to generate better quality low expansive sandy soils. Site marginal quality plastic clayey soils should be buried within 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 conditioning 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 secfions 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 ViNIE & MIDDLI:TON ENGINEI:RING, INC. • 2450 Vineyard Avenue • Escondido, California 92029-1229 • Phone (760) 743-1214 PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 16 26-LOT SUBDIVISION, CAMINO HILLS DRIVE. CARLSBAD JUNE 23, 2006 slab-on-ground foundafions 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 convenfional 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 silty sand (SC/CL) with 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 characterisfic ofthe 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. Foundafion bearing and subgrade soils at finish pad grades should be additionally tested at the completion of rough grading to evaluate actual expansion characteristic of final soil mixture and confirm foundafions and slab designs. Uniform bearing condifions 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 conditions are constructed throughout the buildings and improvement surfaces. Groundwater was encountered at the depth of 33 feet below the planned Lot 24 and 33 feet within the alluvial soils (B-3) feet along the easternmost portions of the site 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 conditions 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 recommendafions are incorporated into the final designs and implemented during the construction phase. Appropriate setbacks shall be maintained, and temporary excavation slope constructions completed as recommended below. Added field recommendations, however, may also be VINIE & MIDDLI-;TON ENGINEERING, INC. • 2450 Vineyard Avenue • Escondido, California 92029-1229 ' Phone (760) 743-1214 PRELIMINARYGEOTECHNICAL INVESTIGATION PAGE 17 26-LOT SUBDIVISION, CAMINO HILLS DRIVE, CARLSBAD JUNE 23, 2006 necessary and should be given by the project geotechnical consultant for the protection of adjacent properties and should be anficipated. 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 stabilizafion techniques using earth reinforcement Geogrid, and removal and recompaction of foundafion 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. VIM. RECOMMENDATIONS The following recommendations are consistent with the indicated geotechnical conditions at the project site and should be reflected in final plans and implemented during the construcfion 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 earthwori<s should be completed in accordance with the Appendix Chapter 33 ofthe California Building Code, City of Carlsbad Grading Ordinances, the Standard Specifications for Public Works Construction and the requirements ofthe following secfions: VINJE & MIDDLETON ENGINEERING, INC. * 2450 Vineyard Avenue • Escondido, California 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 unsuitable 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 properiy disposed of Construcfion 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 utilities in the construcfion areas should also be pot-holed, identified and mari<ed prior to the actual wori<. Abandoned in'igation lines should be properiy capped and sealed off to prevent any future water infiltrafions into the foundation bearing and subgrade soils. Voids created by the removals of the abandoned underground pipes, tanks and structures should be properiy backfilled with compacted fills in accordance with the requirements of this report. The prepared ground should be inspected and approved by the project geotechnical engineer or his designated field representative priorto remedial grading work. 2. Removals and Over-excavations - Uniform and stable bearing soils conditions should be constructed under the planned new buildings and site improvements and limit potential fill soil settlements within tolerable limits as specified. For this purpose, removal and recompaction of the upper fills/alluvium to fimri native ground or competent formation units where these deposits occur at shallower depths and removal and recompaction with ground stabilization techniques using earth reinforcement Geogrid placed at the bottom of over-excavations, should be considered. Approximate removal depths in the vicinity of individual exploratory excavations are summarized in Table 15 and depicted on the enclosed Plate 2 based upon site soil condifions and proposed grades. The tabulated values are typical and subject to field changes by the project geotechnical consultant based on actual field exposures. Locally deeper removals may be necessary and should be anficipated. VINJE & MIDDLETON ENGINEERING, INC. * 2450 Vineyard Avenue • Escondido, California 92029-1229 • Phone (760) 743-1214 PRELIMINARY GEOTECHNICAL INVESTIGATION 26-LOT SUBDIVISION, CAMINO HILLS DRIVE, CARLSBAD PAGE 19 JUNE 23, 2006 TABLE 15 ' ^m00 l^ttsms^d •'.illMhoval. ^Conioidint^- T-1 16^2' not encountered 9' Lot 13 - private street improvement areas. T-2 WW not encountered 7' Lot 8 areas. Depth of undercut may govem. T-3 9' not encountered 8' Lot 5 areas. Depth of undercut may govem. Reconstruct toe slope as a stability fill. T-4 10/2' not encountered 6' Lot 2 areas. Depth of undercut may govern. T-5 16/2' not encountered 9' Lot 25 areas. Depth of undercut may govem. T-6 8" not encountered 3' Lot 22 areas. Depth of undercut may govem. Stockpile better quality sandy soils from Ten-ace Deposit excavations for capping the pads. T-7 14%' not encountered 7' Fill slope/private street improvement areas. Toe keyway shoutd 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 specified herein UOA. T-9 15/2' not encountered 7" Private street rmprovement areas. T-10 15' not encountered 4%' Private street Improvement areas. Depth of undercut may govem. Stockpile better quality sandy soils from Terrace Deposit excavations for capping the pads. B-1 not encountered 5" Lot 11 areas. Depth of undercut may govem. B-2 40%' 33' 10" Lot 24 areas. Place Tensar Geognd 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. B-4 20' not encountered 8' Lot 26 areas. Private street improvements. ViN|E & MIDDLETON ENGINEERING, INC. " 2450 Vineyard Avenue • Escondido, California 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 Othenvise 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 backfilled with loose and uncompacted deposits. The toose/uncompacted backfill soils within these 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 ptaced 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 limit potential fill soil settlements within 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 lifts 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 with 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 anficipated. 5. Cut-Fill Transitions and Undercuts - Ground transition 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 VINIE & MiDiJLhi ON ENGINEERINC;, INC. • 2450 Vineyard Avenue • 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, paridng and on-grade slabs/improvement transition 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 otherwise specified) and reconstructed to design grades with compacted fills as specified herein. 6. Temporary Construction Slopes - Excavations and removals adjacent to existing improvements and graded embankments should be performed 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 othenvise specified or approved. Temporary slopes greater than 12 feet and less than 20 feet high maximum may be constructed at 1:1 within the lower 7 feet and laid back at 1%:1 gradient within the upper portions. The remaining wedge of soil should then be properiy benched out and new fills/backfills fightly keyed-in as the backfilling progresses. Temporary trench and construction slopes greaterthan 3 feet maximum constructed at near vertical gradients will require shoring/trench shield support unless otherwise approved. All temporary construction slopes require continuous geotechnical inspections during the grading operations. Addttional 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 permits, 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 HNGINHHRING, INC. • 2450 Vineyard Avenue • Escondido, Cahfomia 92029-1229 • Phone (760) 743-1214 PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 22 26-LOT SUBDIVISION, CAMINO HILLS DRIVE, CARLSBAD JUNE 23. 2006 7. Soil Properties and Select Grading - Soils generated from the excavations of site existing fills, alluvium and formational rock units (map symbols af-Qal and Ts) wili consist of marginal quality plastic silty to clayey deposits with high expansion potenfial which can be detrimental to stmctures and improvements, if they occur at or near finish grades. Plastic silty to clayey soils also required added processing, mixing and moisture conditioning 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 mitigated 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 within the fill mass. Better quality sandy soils available from the site Terrace Deposit excavations should to stockpiled and selecfively used within the upper pad grades and outer fill embankment slope surfaces. Improvement areas should be provided with 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) with 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 with the requirements of this report. Project fill soils should be clean deposits free of roots, stumps, vegetation, deleterious matter, trash, demolition debris, and unsuitable materiais 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^ operafions. Site soils should be adequately processed, thoroughly mixed, moisture condifioned to slightly above VINIE & MIDDLETON ENGINEERING, INC. • 2450 Vineyard Avenue • Escondido, Cahfornia 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) unifonn 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 density within the upper 3 feet of final grades per ASTM D-1557, unless othenwise specified. 10. Permanent Graded Slopes - Project graded slopes are programmed for 2:1 or fiatter gradients maximum. Engineered graded slopes constructed at 2:1 or flatter gradients will be grossly stable with 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 connecfion with the private street improvements along the eastern margins. The planned fill slopes should be provided with a lower keyway. The keyway should maintain a minimum depth of 3 feet below the adjacent ground surface at the toe into with 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 anficipated. Loose to soft soils may be anticipated at the bottom of keyway excavations requiring mitigation 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. Inifial fill lifts should then be carefully placed over the Geogrid and compacted followed with subsequent lifts. All keyways should be heeled back a minimum of 2% into the hillside and inspected and approved by the project geotechnical engineer. Additional 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 otherwise 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 compacfion levels within the fill slope face. VINJE & MIDDLETON ENGINEERINC;, INC. • 2450 Vineyard Avenue • 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 witl 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 with a minimum bottom equipment-width of 15 feet extended at least 2 feet into the underiying competent formational rock as approved in the field. Temporary construction slopes for the stabilization fill should be no steeper than y^.^. The stabitity fitl should then be reconstructed 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 shoutd 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 anficipated. 11. Surface Drainage and Flood / Erosion Control - A critical element to the continued stability ofthe graded building pads is adequate surface drainage and flood control. This can most effectively be achieved by installafion of appropriate fiood 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 underiying bearing soils. Storm water and surface run-off shall be diverted from entering the site. The finished slope should be planted soon after complefion of grading. Unprotected slope faces will be subject to severe erosion and should not be allowed. Over-watering ofthe slope faces should also not be allowed. Only the amount of water to sustain vegetation should be provided. Temporary erosion control facilities and silt fences should be installed during the construction phase periods and until landscaping is established as indicated and specified on the approved project erosion plans. ViNil-, & MlDDl.Ei ON ENGINEERING, INC. • 2450 Vineyard Avenue • Escondido, 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 - Alt grading operafions including removals, suitability 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 shoutd also be confirmed in the final compacfion report at the complefion of grading. Geotechnical engineering inspections shall include but not limited 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. * Excavafion 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. * Foundafion 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 conform to the project material specifications and approved by the project soils engineer. ViN|E & MIDDLETON ENGINEERING, INC. * 2450 Vineyard Avenue * Escondido, California 92029-1229 • Phone (760) 743-1214 PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 26 26-LOT SUBDIVISION, CAMINO HILLS DRIVE, CARLSBAD JUNE 23, 2006 * Underground utility/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 inspecfion - After the backfill placement is started above the pipe zone but before the vertical height of backfill exceeds 2 feet. Testing ofthe backfill within the pipe zone may also be required by the governing agencies. Pipe bedding and backfill materials shall conform to the requirements of governing agencies and project soils report if applicable. Alt trench backfills shall be mechanically compacted to the minimum specified compaction levels per ASTM D-1557, unless othen/vise superseded. Plumbing trenches over 12 inches deep maximum under the interior fioor slabs should also be mechanically compacted and tested for the minimum specified compaction levels. Flooding or jetting techniques as a means of compaction method shali 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 foofings and slab- on-grade floor type foundations. The following recommendations and geotechnical mitigation are consistent with silty sandy clay to clayey silty sand (SC/CL) foundation bearing and subgrade soils with 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 foundafions and fioor slab recommendafions should also be further confirmed and / or revised as necessary at the completion of rough grading based on the actual expansion characterisfics ofthe foundation bearing and subgrade soils: 1. Perimeter and interior continuous strip foundafions 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 with 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 fioor slabs. VlN|E & MlDDl.l-TON ENGINEERING, INC. • 2450 Vineyard Avenue • Escondido, Cahfornia 92029-1229 • Phone (760) 743-1214 PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 27 26-LOT SUBDIVISION, CAMINO HILLS DRIVE, CARLSBAD JUNE 23, 2006 Exterior confinuous footings shoutd enclose the enfire building perimeter. Flagpole footings also need to be tied together if the footing depth is less than 4 feet below rough finish grade. 2. Continuous interior and exterior foundafions should be reinforced with 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 betow the top of the footing. Tie beams should also be reinforced with 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 prior to pouring the concrete, as additional ground preparations, moisture re- conditioning and presaturation witl be necessary as directed in the field. The required moisture content of the 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 ofthe subgrade and bearing soils. 4. In the case of presaturafion ofthe stab subgrade and/or non-monolithic 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 shoutd be placed mid-height in the stab. Alternate the dowels each way for atl 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 forthe footings has cured and underground utilities tested, place 4 inches of %-inch rock over the stab subgrade. Flood with water to the top of the 3/8-inch rock, and allow the slab subgrade to soak until moisture testing indicates thatthe required moisture content is present. After the slab subgrade soils have soaked, notify this office and schedule for appropriate moisture testing. 8. When the required moisture content has been achieved, place a well- performing 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 & MIDDLE.TON ENGINEERING, INC. • 2450 Vineyard Avenue • Escondido, California 92029-1229 • Phone (760) 743-1214 PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 28 26-LOT SUBDIVISION, CAMINO HILLS DRIVE, CARLSBAD JUNE 23, 2006 If sufficient moisture is present, flooding/presaturation will not be required. The dowels may be deleted, slab underiayment may consist of 2 inches of clean sand over a well performing moisture barrier/vapor retardant (minimum 15-mil plastic) over 2 inches of clean sand, and the footings and slab may be poured monolithically. This office shoutd be notifled to inspect the sand, slab thickness, and reinforcing prior to concrete pour. 9. Alt interior slabs should be a minimum of 5 inches in thickness reinforced with #4 reinforcing bars spaced 18 inches on center each way placed 1% inches below the top of slab. 10. Interior slabs shoutd be provided with "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 within 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 with 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. Foundafion 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 unifonn slab thickness foundation, the design shall satisfy all requirements ofthe design procedure for ribbed foundation. The fully VINJE & MIDDLI;TON ENGINEERING, INC. • 2450 Vineyard Avenue • Escondido, California 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 ofthe California Building Code (CBC), specifications ofthe Posttensioning Institute (PTI), local standards, and the specifications given in this report. 3. Foundation bearing soils should 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 structural slab-on- ground foundafions should be constructed as detailed on the structural/construction drawings. 6. Based upon our experience on similar projects, available laboratory tesfing and analysis of the test results, the following soil design parameters are appropriate: * Design predominant clay mineral type MontmoriUonite. * 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 fiow 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 condition (Ym) 1.095 inches. * Design differential swell occurring at the perimeter of slab for center lift condifion (Ym) 5.677 inches. * Design soit subgrade modulus (k) 100 pci. * Design net allowable bearing pressure for Post-tensioned or structural slab-on-ground foundations 1000 psf VINJE & MIDDLETON ENGINEERING. INC. • 2450 Vineyard Avenue • Escondido, 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 may 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 shoutd enclose the enfire building circumference and reinforced with at teast 1-#5 continuous bar near the bottom. Provide adequate interior stiffening ribs as necessary. 8. Posttension slab should be a minimum of 5% inches thick. Use minimum f0=3000 psi concrete. We recommend to consider pre-tensioning in order to preclude eariy concrete shrinkage cracking. D. Exterior Concrete Slabs / Flatworks 1. Atl 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 Vz 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 without disturbing the final finish which is normally 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 %-inch but should not exceed 1-inch deep maximum. In case of softcut joints, anfi-ravel skid plates should be used and replaced with each blade to avoid spalling and raveling. Avoid wheeled equipments across cuts for at least 24 hours. 3. In order to enhance perfomiance of exterior slabs and fiatworks 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 confinned in the final as-graded compaction report. 5. Subgrade soiis shoutd be tested for proper moisture and specified compaction levels and approved by the project geotechnical consultant prior to the placement of concrete. VINJE & MIDDLETON ENGINEERING, INC. • 2450 Vineyard Avenue • Escondido, California 92029-1229 • Phone (760) 743-1214 PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 31 26-LOT SUBDIVISION, CAMINO HILLS DRIVE, CARLSBAD JUNE 23, 2006 E. Soil Desiqn 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 ofthe 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 waits. * 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 soil 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 developed, a minimum safety factor of 2 may be considered for sliding stability partlculariy where sensitive 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 detennined based on a minimum 15 inches wide by 24 inches deep footing and may be increased by 20% for each additional foot of depth and 10% for each ViNji-: & MIDDLETON ENGINEERING, INC. • 2450 Vineyard Avenue ' Escondido, Califomia 92029-1229 • Phone (760) 743-1214 PRELIMINARY GEOTECHNICAL INVESTIGATION 26-LOT SUBDIVISION, CAMINO HILLS DRIVE, CARLSBAD PAGE 32 JUNE 23, 2006 additional 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 forwind and seismic loading. * The lateral bearing earth pressures may be increased by the amount of designated value for each additional foot of depth to a maximum of 1500 pounds per square foot. F. Asphalt and PCC Pavement Design 1. Asphalt Paving: A new private street improvement is planned, and widening of Camino Hills Drive is proposed in connecfion with the site development. All roadway improvements and paving constructions shali be completed in accordance with the City of Carisbad ordinances. The following asphalt 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 initial planning phase cost estimating purposes. A minimum section of 3 inches asphalt (AC) over 6 inches of Class 2 aggregate base (AB) or the minimum structural section required by City of Carisbad, whichever is more, will be required and shall govern when a lesser pavement section is indicated by design caicuiations: TABLE 16 • , . • J 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 current 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 confinned and/or revised as necessary at the completion of rough pavement subgrade preparations. Revised pavement secfions should be anticipated. Base materials should be compacted to a minimum 95% ofthe 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 ViNjl-: & MIDDLETON ENGINE.I.RING, INC. • 2450 Vineyard Avenue • Escondido, Cahfornia 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 consultant prior to the placement of the base or asphalt layers. 2. PCC Paving: PCC driveways and parking supported on expansive subgrade soils should be a minimum of 5S4 inches in thickness, 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 within the upper 6 inches, unless othen/vise 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 with a minimum 1-#4 confinuous bar placed near the bottom is recommended 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 without disturbing the final finish which is normally 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 1%-inches deep maximum. In case of softcut joints, anti- ravel skid plates should be used and replaced with each blade to avoid spalling and raveling. Avoid wheeled equipments across cuts for at teast 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 with a 95% compacted Class 2 base section per the structural secfion 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 shoutd 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 othen/vise specified. Specific recommendations should be given in the final as-graded compaction report. VINJE & MIDDLETON ENGINEERINC;, INC. • 2450 \'ineyard Avenue • Escondido, California 92029-1229 * Phone (760) 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 ofthe base or asphalt/PCC finish surface. G. General Recommendations 1. The minimum foundafion 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 properiy 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 services. Inadequate staking and/or lack of grading control may result 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 of the 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 structures including fences, posts, pools, spas, etc. Concrete and AC improvements should be provided with a thickened edge to satisfy this requirement. 4. Open or backfilled trenches parallel with a footing shall not be below a projected plane having a downward slope of 1-unit vertical to 2 units horizontal (50%) from a tine 9 inches above the bottom edge ofthe 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 of the ground slopes more than 1-unit vertical in 10 units horizontal (10% slope) shali 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-unit vertical to 2 units horizontal (50%) unless otherwise 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 foundafions as appropriate and applicable. VINIE & MIDDLETON ENGINEERING, INC. • 2450 Vineyard Avenue • Escondido, 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% ofthe maximum dry density ofthe soil unless othen/vise specified. Care should be taken not to crush the utilities or pipes during the compaction of the soil. Non-expansive, granular backfill soils should be used. Trench backfill materials and compaction beneath pavements within the public right-of-way shall conform to the City of Carisbad 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 peri'ormance of the 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 recommendafions provided bythe project geotechnical consultant. Planfing large trees near the building foundations should be avoided. 10. Site drainage over the finished pad surfaces shoutd 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 patterns. Roof lines ofthe buildings shoutd be provided with roof gutters. Roof water should be collected and directed away from the buildings and structures to a suitable locafion. 11. Final plans should reflect preliminary recommendations given in this report. Final foundations and grading plans may also be reviewed by the project geotechnical consultant for conformance with the requirements of the geotechnical investigation report outlined herein. More specific recommendafions may be necessary and should be given when final grading and architectural/structural drawings are available. 12. All foundafion 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 & MIDDLETON ENGINEERING, INC. • 2450 Vineyard Avenue * Escondido, 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 %-inch maximum size aggregate usually requires about 40-lbs. more (nearly 5-gaL) water per cubic yard than concrete with 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 of this 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 with 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 with 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 ofthe 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. It 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 additional recommendations issued ifrequired. VINJE, & MIDDLE.TON ENGINEERING, INC. * 2450 Vineyard Avenue • Escondido, 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 ofthe 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 addition 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 atl concrete surfaces such as fioor slabs and exterior stucco are associated with normal concrete shrinkage during the curing process. These features depend chiefiy upon the condition of concrete and weather conditions at the time of construction and do not refiect detrimental ground movement. Hairiine stucco cracks will often develop at window/door corners, and fioor surface cracks up to Vs-inch wide in 20 feet may develop as a result of nonnal concrete shrinkage (according to the American Concrete Institute). This report shoutd be considered valid for a period of one year and is subject to review by our firm following that time. If significant modificafions are made to your tentative development plan, especially with 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 with 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 recommendafions 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 with the usual thoroughness and competence of the engineering profession. No other warranty or representafion, either expressed or implied, is included or intended. ViNjE & MIDDLETON ENGINEERING, INC. • 2450 Vineyard Avenue " Escondido, California 92029-1229 • Phone (760) 743-1214 PRELIMINARY GEOTECHNICAL INVESTIGATION 26-LOT SUBDIVISION, CAMINO HILLS DRIVE, CARLSBAD PAGE 38 JUNE 23, 2006 Once again, shoutd any questions arise concerning this report, please do not hesitate to contact this office. Reference to our Job #06-210-P witl help to expedite our response to your inquiries. We appreciate this opportunity to be of service to you. VINJE & MIDDLETON ENGINEERING, INC. Steven J. Melzer CEG #2362 DM/SMSS/SJM/jt Distribution: Addressee (5) c:/jt/myfiles/prelilms.06/06-210-P VINIE & MIDDLETON ENGINEERING, INC. • 2450 Vineyard Avenue • Escondido, Cahfomia 92029-1229 • Phone (760) 743-1214 ^IIIT GEORC-E CT CHANCERY CT Calav6ia847 Dam AUBURN AVE <SV , PLATE 1 Cetro d«la REGIONAL INDEX MAP '-co V&M JOB #06-210-P S;;B AEERCeEN CT 'Cr J GATESHEAD RO ATHOSWAV S m T't-OS WAY Los Monos Canyon SV-EETBRIARCIR ^.^ ^^IDELGRME Seal* 1 : 26,0OO 1 •• • 2080 ft © 2002 DeLorm*. Topo USA ®. Data copyright of oontant owner. www.delorme.com mi 1200 LAT: 33.1452 LONG: 117.2880 PRIMARY DIVISIONS GROUP SYMBOL SECONDARY DIVISIONS < _i ERI o o \-CJ O < CJ CO 2 O o u. z lU LU O z N "Z. LL < to < _J X LU cc < 1-LU o X cc LU LU z LU CO CO < CD CO CC X cc < \-< O lORE _l o lORE GRAVELS IVIORE THAN HALF OF COARSE FRACTION IS LARGER THAN NO. 4 SIEVE SANDS MORE THAN HALF OF COARSE FRACTION IS SIVIALLER THAN NO. 4 SIEVE CLEAN GRAVELS (LESS THAN 5% FINES) GRAVEL WITH FINES CLEAN SANDS {LESS THAN 5% FINES) SANDS WITH FINES GW Well graded gravels, gravel-sand mixtures, little or no fines. GP Poorly graded gravels or gravel-sand mixtures, little or no fines. GM Silty gravels, gravel-sand-silt mixtures, non-plastic fines. GC Clayey gravels, gravel-sand-clay mixtures, plastic fines. SW Well graded sands, gravelly sands, little or no fines. SP Poorly graded sands or gravelly sands, little or no fines. SIVI Silty sands, sand-silt mixtures, non-plastic fines. SC Clayey sands, sand-clay mixtures, plastic fines. CO _j O CO o LU z < GC CD lU LU CC N lU CO diu < > CO CO <^ GC LU O 2 Z < X ML SILTS AND CLAYS LIQUID LIMIT IS LESS THAN 50% Inorganic silts and very fine sands, rock flour, silty or clayey fine sands or clayey silts with slight plasticity. CL Inorganic clays of low to medium plasticity, gravelly clays, sandy clays, silty clays, lean clays. OL Organic stits and organic silty clays of low plasticity. SILTS AND CLAYS LIQUID LIMIT IS GREATER THAN 50% MH Inorganic silts, micaceous or diatomaceous fine sandy or silty soils, elastic silts. CH Inorganic clays of high plasticity, fat clays. OH Organic clays of medium to high plasticity, organic silts. HIGHLY ORGANIC SOILS PT Peat and 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 FINE MEDIUIVI COARSE GRAVEL FINE COARSE COBBLES BOULDERS RELATIVE DENSITY CONSISTENCY SANDS, GRAVELS AND NON-PLASTIC SILTS BLOWS/FOOT VERY LOOSE 0 - 4 LOOSE 4 - 10 MEDIUtUI 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 2 - 4 FIRt^ Vs - 1 4 - 8 STIFF 1 - 2 8 - 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 •o -r * M .> . I ^'*6 = Standard Penetration Test (SPT) (ASTM D-1586) Sancj Cone Test • Bulk Sample | ^ith blow counts per 6 inches n Chunl< Sample O Driven Rings II = California Sampler with blow counts per 6 inches VINJE & MIDDLETON ENGINEERING, INC. 2450 Vineyard Ave., #102 Escondido. CA 92029-1229 KEY TO EXPLORATORY BORING LOGS Unified Soil Classification Systeni (ASTM D-2487) PROJECT NO. KEY I Date: 4-11-06 Logged by: SJM DER™ (ft) SAMPLE T-1 uses SYMBOL FIELD MOISTURE (%) FIELD DRY DENSITY (pcf) RELATIVE COMPACTION {%) DER™ (ft) SAMPLE DESCRIPTION uses SYMBOL FIELD MOISTURE (%) FIELD DRY DENSITY (pcf) RELATIVE COMPACTION {%) - 0 - • • FILL: Sandy clay. Pale brown color. Moist to very moist. Soft. Plastic. ST-1 CUCH 18.5 100.8 - 5 -• • • TERRACE DEPOSIT (Q* V 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 -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- • • 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- • • 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 I6V2' - extent of backhoe. No caving. No groundwater. Date: 4-11 -06 Logged by: SJM DEPTH (ft) SAMPLE T-2 USCS SYMBOL FIELD MOISTURE (%) FIELD DRY DENSITY (pcf) RELATIVE COMPACTION (%) DEPTH (ft) SAMPLE DESCRIPTION USCS SYMBOL FIELD MOISTURE (%) FIELD DRY DENSITY (pcf) RELATIVE COMPACTION (%) - 0 -FILL / TOPSOIL: Sandy clay. Pale brown color. Moist. Soft. Plastic. ST-1 CL - FILL / TOPSOIL: Sandy clay. Pale brown color. Moist. Soft. Plastic. ST-1 CL - 5 - -10- • • • • FORMATIONAL ROCK (Tst: Claystone. Grey color. Weathered. "Popcorn" texture. ST^ CL/CH 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- • • • • Silty sandstone. Fine grained. Trace of clay. Tan with rust-colored staining. Includes 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. Fine grained. Trace of clay. Tan with rust-colored staining. Includes clasts of claystone. Weathered. Friable. Moderately to poorly cemented. No discernable structure. ST-5 SM/SC i -15- - 20- End Test Trench at lOVS. 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 CAMINO HILLS DRIVE, CARLSBAD PROJECT NO. 06-210-P PLATE 3 i 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 (pcf) RELATIVE COMPACTION (%) DEPTH (ft) SAMPLE DESCRIPTION uses SYMBOL FIELD MOISTURE (%) FIELD DRY DENSITY (pcf) RELATIVE COMPACTION (%) - 0 -FILL/ALLUVIUM faf-QalV. Sandy clay. Pale brown color. Moist. Soft. ST-1 CUCH / - 5 - • • • FILL/ALLUVIUM faf-QalV. Sandy clay. Pale brown color. Moist. Soft. ST-1 CUCH / 28.6 27.8 88.0 88.8 796 80.4 - 5 - • • • Silty clay. Dark grey color. Moist. Soft to stiff. Plastic. ST-4 CL/CH 28.6 27.8 88.0 88.8 796 80.4 -• Fine sand. Trace of clay. Off-white to grey color. Somewhat hlrt/-ky Mpriiiim Hpnsft ST-5 SC 18.4 10.6 84.2 FORMATIONAL ROCK {JsV. Fine sandy siltstone/clayslone. Grey color. Weathered. Fractured. Blocky. ST-4 MH/CH -10- -20- FORMATIONAL ROCK {JsV. Fine sandy siltstone/clayslone. Grey color. Weathered. Fractured. Blocky. ST-4 MH/CH -10- -20- End Test Trench at 9. No caving. No groundwater. Date: 4-11-06 Logged by: SJM T-4 uses FIELD FIELD DRY RELATIVE DEPTH (ft) SAMPLE DESCRIPTION SYMBOL MOISTURE (%) DENSITY (pcf) COMPACTION (%) - 0 -FILL fafl: Sandy clay. Brown color. Moist. Soft. ST-1 CL • k FILL fafl: Sandy clay. Brown color. Moist. Soft. ST-1 CL -FORMATIONAL ROCK (Ts): Fine sandy siltstone. Grey color. Deeply weathered. Soft. ST-4 MH / - 5 - • \ FORMATIONAL ROCK (Ts): Fine sandy siltstone. Grey color. Deeply weathered. Soft. ST-4 MH / 22.0 106.0 95.5 -10- • \ Pinch-out lens of medium sand. Trace of clay. Red-brown color. Friable. Some gravel and small rock. ST-3 SC/GC / 22.4 108.0 97.7 -10-• Fine sandy siltstone / claystone. Grey color. Maroon colored staining. Polished surfaces. Fractured. Grades blocky at 9'. ST-4 MH/CH 1 21.2 106.9 96.7 - Fine sandy siltstone / claystone. Grey color. Maroon colored staining. Polished surfaces. Fractured. Grades blocky at 9'. ST-4 MH/CH 1 -15- End Test Trench at lOVS. No caving. No groundwater. - 20- I I VINJE & MIDDLETON ENGINEERING, INC 2450 Vineyard Avenue, Suite 102 Escondido, California 92029-1229 Office 760-743-1214 Fax 760-739-0343 CAMiNO HILLS DRIVE, CARLSBAD PROJECT NO. 06-210-P PLATE 4 • Sand Cone Test Bulk Sample • Chunk Sample Q Driven Rings Date: 4-11-06 Logged by: SJM DEPTH (ft) SAMPLE T-5 uses SVWBOL FIELD MOlSnJRE (%) FIELD DRY DENSITY (pcf) RELATIVE COMPACTION (%) DEPTH (ft) SAMPLE DESCRIPTION uses SVWBOL FIELD MOlSnJRE (%) FIELD DRY DENSITY (pcf) RELATIVE COMPACTION (%) - 0 - • FILL - ALLUVIUM faf-Qaih 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 1 SC - 5 -• • • Clayey sand. Fine grained. Dark brown color. Moist. Loose to medium dense. ST-2 1 SC 11.9 13.1 109.0 110.8 84.1 85.5 - 5 -• • • TEpRACE DEPOSIT (Qt): Clayey sand. Red-brown color. Moist. Medium dense. White carbonate stringers and 3"-6" diameter sub-angular rock below 11'. ST-2 sc 11.9 13.1 109.0 110.8 84.1 85.5 -10- -15- • TEpRACE DEPOSIT (Qt): Clayey sand. Red-brown color. Moist. Medium dense. White carbonate stringers and 3"-6" diameter sub-angular rock below 11'. ST-2 sc 13.9 13.4 106.8 108.5 82.4 83.7 -10- -15- • FORMATIONAL ROCK tJs): 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 -n FORMATIONAL ROCK tJs): 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 tJs): Clayey sandstone. Fine grained. Off-white color. Moderately cemented. Somewhat blocky. No apparent structure. ST-2 SC -20- End Test Trench at 16Vi' - extent of backhoe. No caving. No groundwater. Date: 4-11-06 Logged by: SJM DEPTH (ft) SAMPLE T-6 USCS SYMBOL FIELD MOISTURE (%) FIELD DRY DENSrrY (pcf) RELATIVE COMPACTION (%) DEPTH (ft) SAMPLE DESCRIPTION USCS SYMBOL FIELD MOISTURE (%) FIELD DRY DENSrrY (pcf) RELATIVE COMPACTION (%) - 0 -FILUUf): Clayey sand. Tan color. Moist. Loose. ST-2 SC - 5 - • TERRACE DEPOSIT fO.*^ 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- - 20- End Test Trench at 8'. 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 VINJE & MIDDLETON ENGINEERING, INC 2450 Vineyard Avenue, Suite 102 Escondido, California 92029-1229 Office 760-743-1214 Fax 760-739-0343 CAMiNO HiLLS DRIVE, CARLSBAD VINJE & MIDDLETON ENGINEERING, INC 2450 Vineyard Avenue, Suite 102 Escondido, California 92029-1229 Office 760-743-1214 Fax 760-739-0343 PROJECT NO. 06-210-P PLATE 5 T Sand Cone Test • 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 (pcf) RELATIVE COMPACTION (%) DEPTH (ft) SAMPLE DESCRIPTION uses SYMBOL FIELD MOISTURE (%) FIELD DRY DENSITY (pcf) RELATIVE COMPACTION (%) - 0 - n 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 fQtl: Fine sand. Trace of clay. Tan color. Somewhat blocky. Loose to medium dense. Local clean sand lenses. ST-5 SM/SC 18.9 25.2 99.3 92.8 83.1 77.6 -• • 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 14Vi'. No caving. No groundwater. Date: 4-11-06 Logged by: SJM DEPTH (ft) SAMPLE T-8 uses SYMBOL FIELD MOISTURE (%) FIELD DRY DENSITY (pcf) RELATIVE COMPACTION (%) DEPTH (ft) SAMPLE DESCRIPTION uses SYMBOL FIELD MOISTURE (%) FIELD DRY DENSITY (pcf) RELATIVE COMPACTION (%) - 0 - - 5 -• FILL-ALLUVIUM (af-Qail: 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- • • FORMATIONAL ROCK (Ts): Sandstone. Fine grained. 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 ? 113.6 104.1 87.9 80.3 15 • FORMATIONAL ROCK (Ts): Sandstone. Fine grained. 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 - 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 VINJE & MIDDLETON ENGINEERING, INC 2450 Vineyard Avenue, Suite 102 Escondido, California 92029-1229 Office 760-743-1214 Fax 760-739-0343 CAMINO HILLS DRIVE, CARLSBAD VINJE & MIDDLETON ENGINEERING, INC 2450 Vineyard Avenue, Suite 102 Escondido, California 92029-1229 Office 760-743-1214 Fax 760-739-0343 PROJECT NO. 06-210-P PLATE 6 • Sand Cone Test • Bulk Sample • Chunk Sample O Driven Rings Date: 4-11-06 Logged by: SJM DEPTH (ft) SAMPLE T-9 uses SYMBOL FIELD MOISTURE (%) FIELD DRY DENSITY (pcf) RELATIVE COMPACTION (%) DEPTH (ft) SAMPLE DESCRIPTION uses SYMBOL FIELD MOISTURE (%) FIELD DRY DENSITY (pcf) RELATIVE COMPACTION (%) - 0 -FILL-ALLUVIUM (af-Qah: Sandy clay. Pale brown color. Moist Soft. ST-1 CL - FILL-ALLUVIUM (af-Qah: Sandy clay. Pale brown color. Moist Soft. ST-1 CL - Fine sandy silt. Grey color. Moist. Soft. ST-4 MH y - 5 - -10- \ • • • ° 1 Fine sandy silt. Grey color. Moist. Soft. ST-4 MH y 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- \ • • • ° 1 TERRACE DEPOSIT (Qt): 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- \ • • • ° 1 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 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 15^2'. No caving. No groundwater. Date: 4-11-06 Logged by: SJM DEPTH (ft) SAMPLE T-10 uses SYMBOL FIELD MOISTURE (%) FIELD DRY DENSITY (pcf) RELATIVE COMPACTION (%) DEPTH (ft) SAMPLE DESCRIPTION uses SYMBOL FIELD MOISTURE (%) FIELD DRY DENSITY (pcf) RELATIVE COMPACTION (%) FILLn-OPSOIL: Clayey sand. Red-brown color. Moist. Loose. ST-2 CL TERRACE DEPOSIT (Qt): Silty fine sand. Trace of day. Red-brown color. Locally blocky. Friable. Some rust-colored staining. ST-5 SM/SC -5- 1 TERRACE DEPOSIT (Qt): Silty fine sand. Trace of day. Red-brown color. Locally blocky. Friable. Some rust-colored staining. ST-5 SM/SC -5- 1 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 \ - Sandy clay- Dark grey color. Moist. Blocky. Moderately plastic. Polished surfaces. ST-4 CH \ -Clayey sand. Brown color. Rust-colored staining. Local polished surfaces. Blocky. Medium dense. ST-2 SC 1-15 Clayey sand. Brown color. Rust-colored staining. Local polished surfaces. Blocky. Medium dense. ST-2 SC 1-20- \ Fine sandy silt. Grey color. Blocky. Polished surfaces. Medium dense. ST-4 MH / 1-20- \ 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 CAMINO HILLS DRIVE, CARLSBAD PROJECT NO. 06-210-P PLATE 7 i • 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 (afl: Clayey sand. Brown color. Slightly moist. Loose. SC ST-2 1 17.4 113.8 87.8 -• 17.4 113.8 87.8 - 5 -o 12,20 • TERRACE DEPOSIT (Qt): Medium to coarse sand. Clay binder. Red-brown color. Moist. ST-3 sc -10-II 5,9,4 Sandy clay. Olive-brown color. Moist Stiff. Plastic. Local grey-colored staining. Weathered reflection of underlying siltstone. CL/CH -15- II 1 1 — ST-* -15-6,10,13 5,10.13^1 FORMATIONAL ROCK (Ts): Sandy siltstone. Pale grey color. Weathered. Friable. Firm. ST-4 MH -20- 6,10,13 5,10.13^1 -25-End Boring at 191/2'. No caving. No groundwater. -30- -35- -40- Proiect; CAMINO HILLS DRIVE. CARLSBAD Bulk Sample • Ring Sample O SPT Sample i Groundwater ^ PLATE 8 Proiect No: 06-210-P Date Drilled: 5-25-06 Loaaed Bv: SM Bulk Sample • Ring Sample O SPT Sample i Groundwater ^ PLATE 8 Truck-mounted rotary drill. 8" hollow-stem auger. Drill, Sample Method: 140-lb. Hammer, 30" hydraulic drop. 5' AW Rods. Bulk Sample • Ring Sample O SPT Sample i Groundwater ^ PLATE 8 VINJE & MIDDLETON ENGINEERING, INC. BORING LOG B.2 DEPTH FT SAMPLE Description USGS SYMBOL MOISTURE {%) DRY DENSITY (PCF) RELATIVE COMPACTION (%) - 0 -FILL-ALLUVIUM (af-Qal): Clayey sand / sandy clay. Brown color. Slightly moist Soft. ST-1 SC/CL - 5 - -10- II 3,2.2 II • 3,5,7 Clayey silt Grey color. Moist. Soft. ST-5 Sandy clay. Red-brown color. Moistto very moist Soft. Plastic. ST-1 MH CL/CH -15- -20- o 9,18 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 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 10,11,14 End Boring at 4072'. No caving. Groundwater encountered at 33'. 19,20,24 End Boring at 4072'. No caving. Groundwater encountered at 33'. Project Project Drill, Si CAMINO HILLS DRIVE. CARLSBAD Bulk Sarr iple • Project Project Drill, Si No: 06-210-P Date Drilled: 5-25-06 Loqqed By: SM SPT Sample i Groundwater 5- PLATE 9 Project Project Drill, Si Truck-mounted rotary drill. 8" hollow-stem auger, imple Method: 140-lb. Hammer, 30" hydraulic drop. 5' AW Rods. SPT Sample i Groundwater 5- PLATE 9 BORING LOG B-3 DEPTH FT SMNPLE Description USGS SYMBOL MOISTURE (%) DRY DENSITY (PCF) RELATIVE COMPACTION (%) - 0 -FILL-ALLUVIUM (af-Qal): Clayey sand. Brown color. Slightly moist. Loose. ST-2 SC - 5 -o 13,20 Medium to coarse sand. Clay binder. Red-brown SC 9.0 113.2 97.3 _ _ color. Friable. Medium dense. ST-3 -Silty fine sand. Tan color. Firm to medium dense. ST-5 SM -10-11,12,13 Silty fine sand. Tan color. Firm to medium dense. ST-5 - 11,12,13 Medium sand. Trace of clay. Red-brown color. Friable. Medium dense. ST-3 SC -O 1 Clayey fine sand. Red-brown to tan color. Medium SC ^15-— 18,20 dense. Local rust and grey colored staining. Massive. ST-5 9.7 113.8 87.8 -20- -25- 1 6,10,14 o 13,22 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 16.2 109.5 91.6 -30- 7,13,1*1 - O 12,35, 20.3 110.7 92.6 -35-O 12,35, End Boring at 39'. Caving 35'- 39'. Groundwater at 32'. -40- Prolect: CAMINO HILLS DRIVE. CARLSBAD Bulk Sample • Ring Sample O SPT Sample || Groundwater ^ PLATE 10 Proiect No: 06-210-P Date Drilled: 5-25-06 Loaaed Bv: SM Bulk Sample • Ring Sample O SPT Sample || Groundwater ^ PLATE 10 Truck-mounted rotary drill. 8" hollow-stem auger. Drill, Sample 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 Description USGS SYMBOL MOISTURE (%) DRY DENSITY (PCF) RELATIVE COMPACTION (%) - 0 -FILL-ALLUVIUM (af-Qal): Clayey sand. Brown color. Slightly moist. Loose. ST-2 SC - 5 - 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 (Qt): Clayey sand. Includes gravel and pebbles. Red- brown color. Medium dense. ST-2 SC/GC -15-1 9,10,14 TERRACE DEPOSIT (Qt): Clayey sand. Includes gravel and pebbles. Red- brown color. Medium dense. ST-2 SC/GC —20 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 1 Groundwater g PLATE 11 Proiect No: 06-210-P Date Drilled: 5-25-06 Loaaed Bv: SM Bulk Sample • Ring Sample O SPT Sample 1 Groundwater g PLATE 11 Truck-mounted rotary drill. 8" hollow-stem auger. Drill, Sample Method: 140-lb. Hammer, 30" hydraulic drop. 5' AW Rods. Bulk Sample • Ring Sample O SPT Sample 1 Groundwater g PLATE 11 VINJE & MIDDLETON ENGINEERING, INC. PLATE 12 EXISTING STHVCTVRE TO BE DKUOLmifED 120- 100- 120- lOO- SO- 60 - B-4 Jproj.) -so -60 SCALE: 1"=30' V&M JOB #06-210-P PLATE 13 160 - 140- lao - 100- 120 -100 160- 140- 120- 100 - SCALE: 1"=30' V&M JOB #06-210-P Origiim] ground surface approximated from County of San Diego Topographic Survey Map No. 's 354-1677 Sf 354-1683, dated 1975. \IC CM©! PLATE 14 150- IOO. B-2 (proj.) ^ 100 TEMMAam DEFOmT: if ' t o 3 o - 50 FOEMATIOMML MOCK r • SCALE: 1"=50' >\ l_ oV v> ••7, \ 30 MILES FAUU - EPICENTER MAP SAN DEGO COUNTY REGION INDICATED EARTHQUAKE EVENTS THROUGH 75 YEAR PERIOD (1900-1974) Map data is compiied from various sources including California Division of Mines and Geology, Califomia 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." I I I I Earthquake Magnitude I . 4.0 TO 4.9 • O 5.0 TO 5.9 (D 6.0 TO 6.9 O 7.0 TO 7.9 I I Fault. PROJECT: PLATE: Job #06-21D-P CAMINO Hil^LS DRIVE. CARLSBAD 15 U. S. STANDARD SIEVE IN INCHES U. S. STANDARD SIEVE NUMBERS HYDROMETER 2 S ? i i 100 so 1 0.5 GRAIN SiZE MILUMETERS 0.1 0.0S 0.01 0.005 Cobbtes Gravei Sand SILT OR CLAY Coarse Fine COMM to medium Fine SILT OR CLAY SAMPLE* DEPTH (FEET) SYMBOL CLASSIFICATION NAT W% LL PL PI PROJECT: 06-210-P T-1 1 • CL/CH -45 24 23 ADDRESS: GAMING HILLS DRIVE T-1 4 SC/CL 12.9 32 16 16 CARLSBAD DATE: JUNE, 2006 PLATE 16 VINJE AND MIDDLETON ENGINEERING, INC. U. S. STANDARD SIEVE IN INCHES U. S. STANDARD SIEVE NUMBERS Q p 5 HYDROMETER 1 0.5 GRAIN SIZE MILUMETERS 0.01 0.005 Cobbtos Graval Sand SILT OR CLAY Coaru Fine CoaeM to medun Rne SILT OR CLAY SAMPLE* DEPTH (FEET) SYMBOL CLASSinCATION NAT W% LL PL PI PROJECT: 06-210-P T-2 5 • SC/SM 23.6 36 25 11 ADDRESS; GAMING HILLS DRIVE T-3 3 .CL/CH 28.6 49 27 22 CARLSBAD DATE: JUNE, 2006 PLATE 17 VINJE AND MIDDLETON ENGINEERING, INC. SAMPLE DEPTH (FEET) SYMBOL EXPLANATION T-1 4 • FIELD MOISTURE SAMPLE SATURATED REBOUND Sample condition j 1.070 L060 1.050 L040 1.030 1.020 1.010 1.000 0.990 0.980 0.970 0.960 0.950 0.940 0.930 s s ^ Pi NORMAL LOAD (PSF) 06-210-P LOAO CONSOLIDATION TEST PLATE PLATE 18 VINJE & MIDDLETON ENGINEERING, INC. SAMPLE T-3 DEPTH (FEET) SYMBOL EXPLANATION Sample condition 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 s ^ CM NORMAL LOAD (PSF) FIELD MOISTURE SAMPLE SATURATED REBOUND \ • \ \ ll \ \ \ . J OB#06-210-P LOAD CONSOLIDATION TEST PLATE PLATE 19 VINJE & MIDDLETON ENGINEERING, INC. It Remove andrecompact loose filf-ailuvium (see report) Existing grade Proposed grade - 5'mm. — 2' JL - Remove and recompact 2.% — 'Minimum equiptment width 15' min. Temporary backcut RETAINING WALL (See report for backcut specifications and beanng soil preparation, Wall drain —Bench as directed in the field TYFIOAL STABILmTirOM FILL ©M MSTAIMII EL CAMINO REAL AT CAMINO HILLS DRIVE, CARLSBAD CONSTRUCTION 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 CRACK RE-ENTRANT CORNER-—-* REINFORCEMENT NO. 4 BARS PLACED LS" BELOW TOP OF SLAB NOTES: 1. Isolation joints around the columns should t>e either circular as shown In (a) or diannond shaped as shown in (b). If no isolation joints are used around columns, or if the comers 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 comer reinforcement shown herein is provided as a general guideline only and is subject to verificatton and changes by the project architect and/or structural engineer based upon slab geometry, tocation, and other engineering and constructbn factors. VINJE & MIDDLETON ENGINEERING, INC. PLATE 21 RETAINING WALL DRAIN DETAIL Typical - no scale Granular, non-expansive backfill. Compacted. '7 Waterproofing Perforated drain pipe droingqe Filter Material. Crushed rock (wrapped in filter fabric) or Class 2 Permeable Material Csee specifications below) _ Competent, approved soils or bedrock CONSTRUCTION SPECIFICATIONS: SPECIFICATIONS FOR CALTRANS CLASS Z PERMEABLE MATERIAL U.S. STANDARD SIEVE SIZE % PASSING 1 No 4 No e No 3D No SO No 200 400 2S40 0-7 0-3 Sand Equivalent > 75 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 vi/all to prevent build-up of hydrostatic pressures. Use drainage openings along base of wall or back drain system as outiined below. 3. Backdrain should consist of 4" diameter PVC pipe (Schedule 40 or equivalent) vwth perforations down. Drain to suitable outlet at minimum 1 %. Provide %" -1V5" crushed gravel filter wrapped in filter fabric (Mirafi MON 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 avray from wall is recommended. * Use 1V5 cubic foot per foot vwth granular backfill soil and 4 cubic foot per foot if expansive backfill soil is used. VINJE & MIDDLETON ENGINEERING, INC. PLATE 22 REFERENCES Annual Book of ASTM Standards, Section 4 - Constnjction, Volume 04.08: Soil And Rock (I); D 420-0 5611,2005. Annual Book of ASTM Standards, Section 4 - Construction, Volume 04.09: Soil And Rock (II); D 5714 - Latest. 2005. Highway Design Manual, Caltrans. Fifth Edition. Corrosion Guidelines, Caltrans, Version 1.0, September 2003. Califomia Building Code, Volumes 1 & 2, Intemational Conference of Building Officials, 2001. "Green Book" Standard Specifications For Public Works Construction, Public Works Standards, Inc., BNi Building News, 2003 Edition. Califomia Department of Conservation, Division of Mines and Geology (California Geological Sun/ey), 1997, Guidelines for Evaluating and Mitigating Seismic Hazards in California, DMG Special Publication 117, 71 p. California Department of Consen/ation, Division of Mines and Geology (California Geological Survey), 1986 (revised), Guidelines for Preparing Engineering Geology Reports; DMG Note 44. Califomia Department of Conservation, Division of Mines and Geology (California Geological Survey), 1986 (revised), Guidelines to Geologic and Seismic Reports: DMG Note 42. EQFAULT, Ver. 3.00, 1997, Detemiinistic Estimation of Peak Acceleration from Digitized Faults, Computer Program, T. Blake Computer Services 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 Northwestem Part of San Diego County, Califomia, 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 Mitigation Liquefaction tn California," 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 Edition. "Foundation Analysis And Design," Joseph E. Bowels. Caterpillar Performance Handbook, Edition 29, 1998. Jennings, C.W., 1994, Fault Activity Map of California and Adjacent Areas, Califomia 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 Southem Riverside County, California, Special Report 131, Califomia 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, Califomia: Califomia 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 Diego Metropolitan Area, California, 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. Caterpillar Performance Handbook, Edition 29, 1998. Jennings, C.W., 1994, Fault Activity Map of Califomia and Adjacent Areas, California Division of Mines and Geotogy, Geologic Data Map Series, No. 6. Kennedy, M.P., 1977, Recency and Character of Faulting Along the Elsinore Fault Zone in Southern Riverside County, Califomia, Special Report 131, Califomia Division of Mines and Geology, Plate 1 (EastA/Vest), 12p. Kennedy, M.P. and Peterson, G.L., 1975, Geology ofthe 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, Southern San Diego Metropolitan Area, California, 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 Institute And State University, March 1987.