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HomeMy WebLinkAboutCDP 13-23; Burchfield Deck Addition; Coastal Development Permit (CDP) (2)UPDATED GEOTECHNICAL INVESTIGATION AND COASTAL DESIGN CRITERIA Proposed Patio 2627 Ocean Street Carlsbad, Califomia HETHERINGTON ENGINEERING, INC. HETHERIIMGTOIM ElMGINEERilVIG, IIMC. SOIL & FOUNDATION ENGINEERING • ENGINEERING GEOLOGY • HYDROGEOLOGY December 27, 2013 ProjectNo. 7227.1 Log No. 16417 Ms. Nancy Burchfield 2880 North Larkin Avenue Fresno, Califomia 93727 Subject: UPDATED GEOTECHNICAL INVESTIGATION AND COASTAL DESIGN CRITERIA Proposed Patio 2627 Ocean Street Carlsbad, Califomia References: Attached Dear Ms. Burchfield: In accordance with your request, we have performed an updated geotechnical investigation and are providing coastal design criteria for a proposed patio at the rear of the existing single-family residence at the subject site. Our work was performed in November and December 2013. The purpose of our work was to update the previous geotechnical work performed by Hetherington Engineering, Inc. (References 2 and 3) and provide coastal design criteria for the subject property. We have been provided with architectural plans for the proposed patio (Reference 5). This report includes coastal design criteria, seismic design criteria in accordance with the 2010 Califomia Building Code, and grading/foundation recommendations for the proposed construction. Our scope of work included the following: • Research and review of available plans and geologic literature pertinent to the site (see References). • Research and review of available reports and plans pertinent to coastal processes along the north San Diego County shoreline. • Site reconnaissance. • Engineering and geologic analysis. • Preparation of this report providing our findings, and our conclusions and recommendations relative to the proposed patio. 5365 Avenida Encinas, Suite A • Carlsbad, CA 92008-4369 • (760) 931-1917 • Fax (760) 931-0545 327 Third Street • Laguna Beach, CA 92651-2306 • (949) 715-5440 • Fax (949) 715-5442 www.hetheringtonengineering.com UPDATED GEOTECHNICAL INVESTIGATION AND COASTAL DESIGN CRITERIA ProjectNo. 7227.1 Log No. 16417 December 27, 2013 Page 2 SITE DESCRIPTION The subject property is located at 2627 Ocean Street, Carlsbad, Califomia and is also identified as Assessor's Parcel No. 203-140-07-00 (see Location Map, Figure 1). The site consists of a rectangular-shaped lot situated on a gently sloping beach-bluff that presently supports a two-story, wood-frame single-family residence with attached garage. Rock riprap, which we tmderstand was placed in early 1983, is present at the base of the bluff Overall relief across the property between street grade and the base of the bluff is approximately 30- feet. The subject site is bordered to the north and south by adjacent single-family residential lots of approximately the same elevation, to the east by Ocean Street and to the west by the Pacific Ocean. PROPOSED DEVELOPMENT It is our imderstanding that proposed development consists of a new patio with a finished fioor elevation of approximately 25-feet (msl). The plans indicate that the patio structure will be raised-wood and masonry. A non-habitable space beneath the deck is proposed. Building loads are expected to be typical for this type of relatively light constmction. Grading is anticipated to be minor. SUBSURFACE EXPLORATION Subsurface conditions were previously explored by excavating two small-diameter borings vsdth a tripod-mounted auger drill rig to maximimi depths of approximately 13.5 and 29-feet below site grades and a test pit was hand-excavated to a depth of approximately 7-feet below site grades. The approximate locations of the borings and test pit are shown on the attached Plot Plan, Figtore 2. The subsurface exploration was supervised by a geologist from this office, who visually classified the soil materials, and obtained bulk and relatively undisturbed samples for laboratory testing. The soils were visually classified according to the Unified Soil Classification System. Soil classifications are shown on the attached Boring and Test Pit Logs, Figures 4 through 6. LABORATORY TESTING Laboratory testing was previously performed on samples obtained during the subsurface exploration. Tests performed consisted of the following: • Dry Density and Moisture Content (ASTM: D 2216) HETHERINGTON ENGINEERING, INC. ADAPTED FROM: The Thomas Guide, San Diego County, 2004 Edition I N I SCALE: 1"-2000' (1 Grid = 0.5 x 0.5 miles) LOCATION MAP HETHERINGTON ENGINEERING, INC. GEOTECHNICAL CONSULTANTS 2627 Ocean Street j Carlsbad, California HETHERINGTON ENGINEERING, INC. GEOTECHNICAL CONSULTANTS PROJECTNO. 7227.1 FIGURE NO. 1 UPDATED GEOTECHNICAL INVESTIGATION AND COASTAL DESIGN CRITERIA ProjectNo. 7227.1 Log No. 16417 December 27,2013 Page 3 • Sulfate Content (EPA 903 8) • Direct Shear (ASTM: D 3080) • Expansion (ASTM: D 4829) • Atterberg Limits (ASTM: D 4318) • Maximum Dry Density/Optimum Moisture Content (ASTM: D 1557) Results of the dry density and moisture content determinations are presented on the Boring Logs and the remaining laboratory test results are presented on the Laboratory Test Results, Figtires 7 and 8. SOIL AND GEOLOGIC CONDITIONS 1. Geologic Setting The subject site is located within the coastal plain region of northwestem San Diego County, Califomia and is situated within the west central portion of the USGS San Luis Rey 7-1/2 minute quadrangle. The coastal plain region of San Diego Coimty is underlain largely by middle and upper Eocene marine and non-marine sedimentary units of the "San Diego Embayment". These units have been modified by wave-cut action during Pleistocene sea-level changes. The modification has resulted in marine abrasion platforms characterized by "stair-step" morphology. Sediments of marine and non-marine origin mantle the wave-cut terraces and increase in age and elevation fi"om west to east. Based on the results of our investigation, the subject site is imderlain by fill. Pleistocene terrace deposits and sedimentary bedrock ofthe Santiago Formation. No known or reported deep-seated landsliding is known to exist on the site. No knovm or reported active or potentially active faults exist within the site. 2. Geologic Units a. Fill - A relatively thin veneer of fill was encountered in boring B-2. The fill is comprised of damp, loose, silty fine to medium sand. HETHERINGTON ENGINEERING, INC. UPDATED GEOTECHNICAL INVESTIGATION AND COASTAL DESIGN CRITERIA ProjectNo. 7227.1 Log No. 16417 December 27, 2013 Page 4 b. Terrace Deposits - Terrace deposits encountered in the exploratory borings and test pit consisted generally of damp to wet, dense to very dense, light red brown to orange brown, silty fine to coarse-grained sand. c. Bedrock (Santiago Formation) - Bedrock encountered in the exploratory borings consisted generally of damp, dense to very dense, light olive to yellow green, silty to clayey fine sandstone. 3. Groimdwater Groundwater was encountered in boring B-2 at approximately 10-feet below the groimd surface. It should be noted, however, that fluctuations in the amount and level of groundwater may occur due to variations in rainfall, irrigation, tidal fluctuation and other factors that may not have been evident at the time of our field investigation. SEISMICITY The site is located within the seismically active southem Califomia region. There are, however, no known active or potentially active faults presently mapped that pass through the site. Active fault zones within the general site region include the Rose Canyon/Newport-Inglewood, Coronado Bank/Palos Verdes Hills, and Elsinore. Strong ground motion could also be expected fi-om earthquakes occurring along the San Jacinto and San Andreas fault zones, which lie northeast of the site at greater distances, as well as a number of other offshore faults. The following table lists the known active faults that would have the most significant impact on the site: Fault Maximum Probable Earthquake (Moment Magnitude) Slip Rate (mm/year) Fault Type Rose Canyon (6.0-kilometers/3.7-miles SW) 6.9 1.5 B Coronado Bank/Palos Verdes Hills (38-kilometers/23.4-miles SW) 7.6 3 B Elsinore (Julian Segment) (38-kilometers/23.4-miles NE) 7.3 5 A HETHERINGTON ENGINEERING, INC. UPDATED GEOTECHNICAL INVESTIGATION AND COASTAL DESIGN CRITERL\ ProjectNo. 7227.1 Log No. 16417 December 27, 2013 Page 5 SEISMIC EFFECTS 1. Ground Accelerations The most significant probable earthquake to effect the property would be a 6.9 magnitude earthquake on the Rose Canyon fault zone. Based on Section 1803.5.12 of the 2010 Califomia Building Code, peak ground accelerations of 0.36g are possible for the design earthquake. 2. Ground Cracks The risk of fault surface mpture due to active faulting is considered low due to the absence of an active fault within the site. Ground cracks due to shaking from seismic events in the region are possible, as with all of southem Califomia. 3. Landsliding The risk of seismically induced landsliding effecting the site is considered negligible due to the gently sloping topography of the property. 4. Liquefaction The risk of liquefaction is considered low due to the dense underlying earth materials. 5. Tsunamis The "Tsunami Inundation Map..." (Reference 1), indicates that the tsunamis inundation area extends to about elevation 25-feet (msl) in the site vicinity. 6. Coastal Design Criteria The following coastal design criteria are based on data taken from the available referenced oceanographic reports/literature that are considered appropriate for the subject location (References 6, 7, 8 and 10). Calculations have been performed in accordance with the guidelines presented in "Coastal Flood Plain Development, Orange County Coastline..." (Reference 6) and "Shore Protection Manual..." (Reference 10). We have ignored the presence of the riprap revetment in our coastal design criteria as required by the city of Carlsbad. HETHERINGTON ENGINEERING. INC. UPDATED GEOTECHNICAL INVESTIGATION AND COASTAL DESIGN CRITERIA ProjectNo. 7227.1 Log No. 16417 December 27, 2013 Page 6 The highest observed water level used in the calculations (-1-7.4 ft. NGVD) is from the La Jolla Station (Reference 8). The anticipated rise in sea level over the next 75-years (Reference 7), estimated to be 2.0-feet, was then added to the highest observed water level to obtain the design still water level. We have conservatively used a scour elevation of 0.0-feet (NGVD) in the analysis. The following is a summary of the oceanographic parameters used in the wave runup analysis. Still Water Elevation (Hw) = +7.4-feet (NGVD) Scour Elevation (Hsc) = 0.0-feet (NGVD) Water Depth (ds) = +7.4-feet (NGVD) Design Wave Period for elevation of breaking wave (T) = 22 sec. Elevation of Breaking Wave (Hb) = +14.8-feet (NGVD) Run-up Elevation (HR) = +19.4-feet (NGVD) for riprap inclined at 1.5:1 (H:V) CONCLUSIONS AND RECOMMENDATIONS 1. General The proposed patio is considered feasible from a geotechnical standpoint. Grading and foundation plans should consider the appropriate geotechnical features of the site. Provided that the recommendations presented in this report and good constmction practices are utilized during the design and constmction, the proposed constmction is not anticipated to adversely impact the adjacent properties from a geotechnical standpoint. Due to coastal design considerations, the proposed patio should be supported by drilled piers founded in the underlying bedrock and designed for wave forces as well as stmctural loads. Since the area below the patio is intended to be enclosed non- habitable space, provisions should be made to withstand uplift pressures and for venting the pressure from water and trapped air. Consideration can be given to making the non-habitable space walls breakaway elements as the costs to design the walls for wave impact forces may be cost prohibitive. HETHERINGTON ENGINEERING, INC. UPDATED GEOTECHNICAL INVESTIGATION AND COASTAL DESIGN CRITERIA ProjectNo. 7227.1 Log No. 16417 December 27, 2013 Page 7 2. Seismic Parameters for Stmctural Design Seismic considerations that may be used for stmctural design at the site include the following: a. Ground Motion - The proposed patio should be designed and constmcted to resist the effects of seismic ground motions as provided in Section 1613 of the 2010 Califomia Building Code. Site Address: 2627 Ocean Sfreet, Carlsbad, Califomia Latitude: 33.161° Longitude:-117.3559° b. Spectral Response Accelerations - Using the location of the property and data obtained from the U.S.G.S. Java Ground Motion Calculator Program, short period Spectral Response Accelerations Ss (0.2 second period) and Si (1.0 second period) are: Ss= 1.355 Si = 0.511 c. Site Class - In accordance with Table 1613.5.2, and the underlying geologic conditions, a Site Class D is considered appropriate for the subject property. d. Site Coefficients Fg and Fy - In accordance with Table 1613.5.3 and considering the values of Ss and Si, Site Coefficients for a Class D site are: Fa =1.0 Fv= 1.5 e. Spectral Response Acceleration Parameters Sm, and Sm^ - In accordance with Section 1613.5.3 and considering the values of Ss and Si, and Fa and Fv, Spectral Response Acceleration Parameters for Maximum Considered Earthquake are: Sms ^ (Fa)(Ss) = (1.00) (1.355) =1.355 Smi (Fv)(Si) = (1.5) (0.511) = 0.766 HETHERINGTON ENGINEERING, INC. UPDATED GEOTECHNICAL INVESTIGATION AND COASTAL DESIGN CRITERIA ProjectNo. 7227.1 Log No. 16417 December 27,2013 Page 8 f Design Spectral Response Acceleration Parameters Sd, and Sd^ - In accordance with Section 1613.5.4 and considering the values of Sms and Smi, Design Spectral Response Acceleration Parameters for Maximum Considered Earthquake are: Sds = 2/3 Sms = 2/3 (1.355) = 0.903 Sdi = 2/3 Smi = 2/3 (0.766) = 0.511 g. Long Period Transition Period - A Long Period Transition Period of TL = 8 seconds is provided for use in San Diego County. h. Seismic Design Category - In accordance with Tables 1613.5.6(1) and 1613.5.6(2), and ASCE 7-05, an Occupancy Category II and a Seismic Design Category D are considered appropriate for the subject property. 3. Site Grading Prior to any grading, the site should be cleared of any existing debris and vegetation. Materials generated during clearing should be properly disposed of at an approved location off-site. Holes resulting from the removal of buried obstmctions that may be encountered during grading should be removed and replaced with compacted fill. In areas where any new on-grade improvements are plaimed (including hardscape) existing fill should be removed and replaced as compacted fill. Removal depths on the order of approximately 2 to 3-feet below existing site grades are anticipated. The removals should extend to at least 3-feet beyond the limits of the proposed improvements where possible. Final removal depths should be determined in the field during grading by the Geotechnical Consultant. Followdng removals, the exposed subgrade should be scarified, moisture conditioned to about optimum moisture content, and compacted to a minimum of 90-percent relative compaction based upon ASTM: D-1557. Fill should be compacted by mechanical means in uniform horizontal lifts of 6 to 8- inches in thickness. All fill should be compacted to a minimum relative compaction of 90-percent based upon ASTM: D 1557. The on-site materials are suitable for use as compacted fill provided all vegetation and debris are removed. Rock fragments over 6-inches in maximum dimension and other perishable or unsuitable materials should be excluded from the fill. All grading should be observed and tested as necessary by the Geotechnical Consultant. HETHERINGTON ENGINEERING, INC. UPDATED GEOTECHNICAL INVESTIGATION AND COASTAL DESIGN CRITERIA ProjectNo. 7227.1 Log No. 16417 December 27, 2013 Page 9 4. Foundations Due to the anticipated bluff retreat, the proposed patio should be supported by drilled piers founded in approved bedrock. The drilled piers should be designed to resist wave forces as well as the stmctural loads. Constmction difficulties due to caving sands and the presence of groundwater should be anticipated by the contractor. Drilled piers should extend at least 5-feet into approved bedrock and should have a minimum diameter of 24-inches. Drilled piers founded as recommended may be designed for a dead plus live load end bearing capacity of 4000-pounds-per-square- foot. This value may be increased by one-third for wind and seismic forces. A skin friction value of 200-pounds-per-square-foot may be assumed in bedrock. Piers may resist lateral loads by a passive pressure of 250-pounds-per-square-foot per foot of depth into bedrock to a maximum value of 4000-pounds-per-square-foot. The passive resistance may be calculated over two pier diameters. Total and differential settlement of the proposed new constmction due to foundation loads is considered to be less than 1/2 and 1/4 inch, respectively, for drilled piers founded as recommended. 5. Retaining Walls Retaining wall foundations should be designed in accordance with the previous building foundation recommendations. Retaining walls free to rotate (cantilevered walls) should be designed for an active pressure of 35-pounds-per-cubic-foot (equivalent fluid pressure) assuming level backfill consisting of the granular on-site soils. Any additional surcharge pressure behind the walls should be added to this value. Retaining walls should be provided with adequate drainage to prevent buildup of hydrostatic pressure and should be adequately waterproofed. The subdrain system behind retaining walls should consist of at least 4-inch diameter Schedule 40 (or equivalent) perforated (perforations down) PVC pipe embedded in at least 1 cubic foot of 3/4-inch crushed rock per lineal foot of pipe all wrapped in approved filter fabric. Recommendations for wall waterproofing should be provided by the project Architect and/or Stmctural Engineer. HETHERINGTON ENGINEERING, INC. UPDATED GEOTECHNICAL INVESTIGATION AND COASTAL DESIGN CRITERIA ProjectNo. 7227.1 Log No. 16417 December 27,2013 Page 10 6. Temporary Slopes Temporary slopes should be inclined at a slope ratio no steeper that 1:1 (horizontal to vertical) or shored. Field observations by the Engineering Geologist during grading of temporary slopes is recommended and considered necessary to confirm anticipated conditions and to provide revised recommendations if warranted. 7. Concrete Flatwork Concrete flatwork should be at least 4-inches thick (actual) and reinforced with No. 3 bars spaced at 18-inches on center (two directions) and placed on chairs so that the remforcement is in the center of the slab. The slab subgrade should be thoroughly moistened prior to placement of concrete. Contraction joints should be provided at 10-feet spacing (maximum). It should be noted that any flatwork not supported by the recommended drilled piers will be susceptible to bluff retreat and resulting damage. 8. Soluble Sulfate Representative samples of the on-site soils were previously submitted for sulfate analyses. The results ofthe soluble sulfate tests per EPA 9038 methods are presented in the attached Appendix A. The sulfate content of the on-site soils is consistent with a negligible sulfate exposure classification per Table 4.2.1 and 4.3.1 of the American Concrete Institute publication 318. However, due to the proximity of the proposed constmction to seawater, concrete should be designed for a severe sulfate exposure. Other corrosivity testing has not been performed, consequently, the on-site soils should be assumed to be severely corrosive to buried metals unless testing is performed to indicate otherwise. 9. Retaining Wall and Trench Backfill All retaining wall and trench backfill should be compacted to at least 90-percent relative compaction based upon ASTM: D1557 and the backfill should be observed and tested by the Geotechnical Consultant. HETHERINGTON ENGINEERING, INC. UPDATED GEOTECHNICAL INVESTIGATION AND COASTAL DESIGN CRITERIA ProjectNo. 7227.1 Log No. 16417 December 27, 2013 Page 11 10. Recommended Observation and Testing During Constmction The following tests and/or observations by the Geotechnical Consultant are recommended: a. Observation and testing during grading. b. Observation of drilled pier excavations prior to placement of forms and reinforcement. c. Retaining wall backdrains. d. Utility french and retaining wall backfill. 11. Grading and Foundation Plan Review Final grading and foundation plans should be reviewed by the Geotechnical Consultant to corifirm conformance with the recommendations presented herein or to modify the recommendations as necessary. LIMITATIONS The analyses, conclusions and recommendations contained in this report are based on site conditions, as they existed at the time of our investigation and further assume the excavations to be representative of the subsurface conditions throughout the site. If different subsurface conditions from those encountered during our exploration are observed or appear to be present in excavations, the Geotechnical Consultant should be promptly notified for review and reconsideration of recommendations. Our investigation was performed using the degree of care and skill ordinarily exercised, under similar circumstances, by reputable Geotechnical Consultants practicing in this or similar localities. No other warranty, express or implied, is made as to the conclusions and professional advice included in this report. HETHERINGTON ENGINEERING, INC. UPDATED GEOTECHNICAL INVESTIGATION AND COASTAL DESIGN CRITERIA ProjectNo. 7227.1 Log No. 16417 December 27, 2013 Page 12 This opportunity to be of service is sincerely appreciated. If you have any questions, please call this office. Sincerely, Hetherington Engineering, Inc. *aul A Professional Geologist 3772 Certified Engineering Geolo Certified Hydrogeologist 59 ll (expires 3/31/14) Attachments: Location Map Plot Plan Geologic Cross-Section Boring and Test Pit Logs Laboratory Test Results Civil Enginedr 304^ Geotechnical (expires 3/31/ Figure 1 Figure 2 Figure 3 Figures 4 through 6 Figures 7 and 8 Distribution: 5-Addressee 1-via e-mail (nancv(2),spravforce.com) HETHERINGTON ENGINEERING, INC. REFERENCES 1) Califomia Geological Survey, "Tsunami Inundation Map for Planning, Oceanside Quadrangle, San Luis Rey Quadrangle," dated June 1,2009. 2) Hetherington Engineering, Inc., "Geotechnical Investigation, Proposed Single- Family Residence, 2627 Ocean Street, Carlsbad, Califomia, APN: 203-140-07- 01," dated November 30, 2005. 3) Hetherington Engineering, Inc., "Response to City of Carlsbad Review Letter, Amendment to Geotechnical Investigation, Proposed Single-Family Residence, 2627 Ocean Sfreet, Carlsbad, Califomia," dated September 12,2006. 4) ICBO, "Califomia Building Code," 2010 Edition. 5) J. Quan Design, Architectural Plans, "Burchfield Patio, 2625 Ocean Street, Carlsbad, CA 92008," dated October 9, 2012 (Sheets AO.O, Al.O, Al.l, A2.0, A2.1, AD.l andAD.2). 6) Moffatt and Nichol, Engineers, , "Coastal Flood Plan Development, Orange County Coastline," dated January 1985. 7) Moffatt & Nichol, et al., "San Diego Region Coastal, Sea Level Rise Analysis, Draft Report," dated Febmary 2013. 8) NOAA.gov, Station 9410230 (La Jolla, Califomia), oceanographic data. 9) Peterson, Mark P., et al, "Documentation for the 2008 Update ofthe United States National Seismic Hazards Maps," USGS Open File Report 2008-1128, dated 2008. 10) US Army Corps of Engineers, "Shore Protection Manual," dated 1984. 11) United States Geologic Survey, "Java Ground Motion Calculator," Version 5.1.0. 12) 2007 Working Group and Califomia Earthquake Probability, "The Uniform Califomia Earthquake Rupture Forecast, Version 2 (UCERF-2)," USGS Open File Report 2007-1437 and CGS Special Report 203, dated 2008. ProjectNo. 7227.1 Log No. 16417 HETHERINGTON ENGINEERING, INC. LEGEND A' 10 15 20 APPROXIMATE LOCATION OF BORING APPROXIMATE LOCATION OF TEST TRENCH APPROXIMATE LIMITS OF GEOLOGIC CROSS-SECTION PLOT PLAN HETHERINGTON ENGINEERING, INC. GEOTECHNICAL CONSULTANTS 2627 Ocean Street Carlsbad, Califomia HETHERINGTON ENGINEERING, INC. GEOTECHNICAL CONSULTANTS PROJECT NO. 7227.1 FIGURE NO. 2 PRESUMED BLUFF EDGE AT 75 YEARS (HEI 2006) EXISTING BLUFF EDGE —, 50 n 40- 30- SCALE: 1"= 10' 1 r50 -40 -30 -20 -10 10 15 20 GEOLOGIC CROSS-SECTION A - A' HETHERINGTON ENGINEERING, INC. GEOTECHNICAL CONSULTANTS 2627 Ocean Street Carlsbad, Califomia HETHERINGTON ENGINEERING, INC. GEOTECHNICAL CONSULTANTS PROJECT NO. 7227.1 FIGURE NO. 3 DRILLING COMPANY: Pacific Drilling RIG: Tri-pod DATE: 10/19/05 BORING DIAMETER: 6" DRIVE WEIGHT: 140 Ibs DROP: 30' ELEVATION: 39' + EH W DJ EH DJ W Q 0.0 EH O O tu \ OT B O m >H EH H OT 2 W Q >H a; Q o a cc; D EH OT M o s EH 2 M EH O U OT — OT <; OT o u OT H O D OT ~- BORING NO. B-1 SOIL DESCRIPTION 5.0- 10.0- 15.0- 20.0- 25.0- 30.0- 35.0- 18 22 23 25 34 35 60 65 55 119 116 111 107 101 103 51 100 102 118 6.9 7.3 6.8 6.0 4.0 98 4.2 4.5 4.2 20.5 13.4 TERRACE DEPOSITS: Dark orange brown silty fine to medium sand, damp, dense, non porous @ 7': Becomes light red brown silty fine to medium sand, damp, dense 10': Becomes medium to coarse grained @ 13': Light gray brown fine sand, little to no fines, damp, dense to very dense @ 16': Color becomes yellowish orange. Sand contains abundant mica flecks. Damp, friable, dense to very dense 19': Color becomes grey white to orange brown @ 22': Yellowish brown fine to coarse grained sand, damp, very dense @ 25': Gray white to orange brown fine to medium grained sand with few well rounded gravels to 2 inches in diameter, moist, dense @ 26': Gravel zone, well rounded gravels up to 2.5 inches in diameter in a matrix of coarse grained sand BEDROCK (Santiago Formation): Light olive to yellow green silty to clayey fine sandstone, moist, very dense Total depth 29 feet No caving No groundwater or seepage Boring backfilled with bentonite BORING LOG HETHERINGTON ENGINEERING, INC. GEOTECHNICAL CONSULTANTS 2627 Ocean Street Carlsbad, California HETHERINGTON ENGINEERING, INC. GEOTECHNICAL CONSULTANTS PROJECTNO. 5298.1 FIGURE NO. 4 DRILLING COMPANY: Pacific Drilling RIG: Tri-pod DATE: 10/19/05 BORING DIAMETER: 6" DRIVE WEIGHT: 140 Ibs DROP: 30" ELEVATION: 21' + EH W M faj ffi EH Q 0.0 EH o o \ OT s o IJ m >H EH M OT z M Q >H B: Q M-l u EH OT H o s H 2 W EH 2 O u OT OT < OT BORING NO. B-2 SOIL DESCRIPTION 5.0- 10.0- 15.0- 20.0- 25.0- 30.0- 35.0- 28 28 32 SM FILL: Medium red brown silty fine to medium sand, damp, loose, contains brick fragments 106 103 5.2 9.0 101 22.3 TERRACE DEPOSITS: Dark red brown silty medium to coarse sand, damp, dense, friable 5': Color becomes light red brown to gray white @ 10': Gray brown fine to medium sand, abundant mica flecks, moist, dense @ 12': Gravel zone, well rounded gravels up to 2.5 inches in diameter in a matrix of coarse grained sand BEDROCK (Santiago Formation): Light olive to yellow green silty to clayey fine sandstone, damp, very dense Total depth 13.5 feet Groundwater at 10 feet Caving between 10 and 13.5 feet Boring backfilled with bentonite BORING LOG HETHERINGTON ENGINEERING, INC. GEOTECHNICAL CONSULTANTS 2627 Ocean Street Carlsbad, California HETHERINGTON ENGINEERING, INC. GEOTECHNICAL CONSULTANTS PROJECT NO. 5298.1 FIGURE NO. 5 BACKHOE COMPANY: Mansolf Excavation BUCKET SIZE: Hand Pit DATE: 07/14/06 ffi EH EH Cd Ol H Q 0.0 • CQ OT >H EH h-l OT MH ^1 2 O Ct; w Cb Q Q — OT —. OT • a: OT i-q • u o OT M O D OT "SM" SOIL DESCRIPTION TEST PIT NO. T-1 ELEVATION: ' 5.0— BEACH SANDS: White to gray, slightly silty fine to medium sand, dry, loose, friable Note: Depth to Terrace Deposits varies between 1.9 feet (east) and 7 feet (west) across the 27-foot-long trench TERRACE DEPOSITS: Light brown to gray silty fine to medium sand, moist, dense; massive and moderately oxide stained 10.0— Maximum depth 7 feet No groundwater Severe caving in beach sands 15.0- LOG OF TEST PITS HETHERINGTON ENGINEERING, INC. GEOTECHNICAL CONSULTANTS 2627 Ocean Street Carlsbad, California HETHERINGTON ENGINEERING, INC. GEOTECHNICAL CONSULTANTS PROJECTNO. 5298.1 j FIGURE NO. 6 LABORATORY TEST RESULTS DIRECT SHEAR (ASTM: D 3080) Sample Location Angle of Internal Friction (") Cohesion (psf) Remarks B-1 @ 10' 29 200 Remolded to 90% @ optimum, consolidated, saturated, drained B-1 @ 16' 41 150 Undisturbed, consolidated, saturated, drained B-l(%28' 32 275 Undisturbed, consolidated, saturated, drained SULFATE TEST RESULTS (EPA 9038) Sample Location Soluble Sulfate in Soil (%) B-1 (a), 13' -14' 0.0043 B-2 @ 5' - 6' 0.0093 EXPANSION INDEX (ASTMD: 4829) Sample Location Initial Compacted Final Expansion Expansion Moisture Dry Moisture Index Potential (%) Density B-1 13' -14' 7.0 114.7 13.5 0 Very low B-2 (S, 5' - 6' 12.0 101.7 21.2 0 Very low MAXIMUM DRY DENSITY/OPTIMUM MOISTURE CONTENT (ASTM: D 1557) Sample Location Description Maximum Dry Optimum Moisture Density (pcf) Content (%) B-1 @0 - 15' Red brown silty fine to medium sand 126.5 9.0 Figure 7 ProjectNo. 7227.1 Log No. 16417 LABORATORY TEST RESULTS ATTERBERG LIMITS (ASTM: D 4318) Sample Location Liquid Limit (%) Plastic Limit (%) Plasticity Index U.S.C.S. Class (%) B-1 13'-14' ~ — — NP B-1 @29'-30' 31 25 6 CL-ML B-2 (^,5'-6' — ~ NP Figure 8 ProjectNo. 7227.1 Log No. 16417