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3811; El Camino Real Widening Sprague Property; El Camino Real Widening Sprague Property; 2009-12-31
pi m Geotechnical and Environmental Sdences Consultants m m PI m m GEOTECHNICAL EVALUATION EL CAMINO REAL WIDENING, SPRAGUE PROPERTY CARLSBAD, CALIFORNIA PREPARED FOR: City of Carlsbad 1635 Faraday Avenue Carlsbad, California 92008 PREPARED BY: Ninyo & Moore Geotechnical and Environmental Sciences Consultants 5710RufFin Road San Diego, Califomia 92123 Ml p December 31,2009 Project No. 106641002 P 5710 Ruffin Road - San Diego, Califomia 92123 - Phone [858) 576-1000 - Fax [858) 576-9600 Ojqlcljsnrl Phnpnix npnvpr Tijr<;nn Geotechnical and Environmental Sciences Consultants December 31, 2009 Project No. 106641002 m P pi b r II Ms. Eva Plajzer City of Carlsbad 163 5 Faraday Avenue Carlsbad, Califomia 92008 Subject: Geotechnical Evaluation El Camino Real Widening, Sprague Property Carlsbad, Califomia Dear Ms. Plajzer: In accordance with your authorization, we have performed a geotechnical evaluation for the pro- posed Sprague property cut and fill slopes, which will be constructed as part of the El Camino Real widening project in Carlsbad, Califomia. This report presents our geotechnical findings, conclu- sions, and recommendations regarding the proposed project. Our report was prepared in accordance with our proposal dated October 5, 2009. We appreciate the opportunity to be of ser- vice on this project. Sincerely, NINYO & MOORE Gregory T. Farrand, C.E.G. Principal Geologist ER/FOM/GTF/gg Distribution: (5) Addressee Francis O. Moreland, CE' Senior Geologist I. L 57 1 0 Ruffin Road • San Diego, California 92 1 23 • Pfione (858) 576-1 000 • Fax (858) 576-9600 San Dieao • Irvine • Rancho Cucamonaa • Los Anaeles • Oakland • Las Veaas • Phoenix • Denver • El Paso • Tucson El Camino Real Widening, Sprague Property December 31, 2009 Carlsbad, Califomia Project No. 106641002 TABLE OF CONTENTS PI Page PI 1. INTRODUCTION 1 ^ 2. SCOPE OF SERVICES 1 PI 3. SITE AND PROJECT DESCRIPTION 2 ^ 4. SUBSURFACE EVALUATION AND LABORATORY TESTING 2 5. GEOLOGY AND SUBSURFACE CONDITIONS 2 5.1. Regional and Geologic Setting 3 ^ 5.2. Site Geology 3 m 5.2.1. Fill ^*'ZZ^IZ!Z^Z""'"'3 5.2.2. Very Old Paralic Deposits 3 5.2.3. Santiago Formation 4 5.3. Groundwater 4 6. GEOLOGIC HAZARDS 4 6.1. Faulting and Seismicity 4 6.1.1. Strong Ground Motion 5 ^ 6.1.2. Ground Surface Rupture 5 ^ 6.1.3. Liquefaction and Seismically Induced Settlement 6 6.2. Landsiiding 5 7. SLOPE STABILITY 6 " 8. CONCLUSIONS AND RECOMMENDATIONS 7 ^ 8.1. Earthwork ^ ^ 8.1.1. Site Preparation g 8.1.2. Treatment of Proposed Cut Slopes 9 ^ 8.1.3. Excavation Characteristics 9 ^ 8.1.4. Materials for Fill 9 :i 8.1.5. Compacted Fill 10 'im 8.1.6. Slopes 11 8.1.7. SiteRunoff ^^'"""n 8.2. Pre-Construction Conference 12 8.3. Plan Review and Construction Observation 12 9. LIMITATIONS 12 10. REFERENCES 14 Figures Figure 1 - Site Location Map Figure 2 - Test Pit Location Map Figure 3 - Cross Section A-A' Figure 4 - Cross Section B-B' Figure 5 - Fault Location Map P l06641002 Rdoc El Camino Real Widening, Sprague Property December 31, 2009 Carlsbad, Califomia Project No. 106641002 Appendices Appendix A - Test Pit Logs Appendix B - Laboratory Testing m m k m m L l0664ia02Rdoc il p ib m h IP P El Camino Real Widening, Sprague Property December 31, 2009 Carlsbad, Califomia Project No. 106641002 1. INTRODUCTION In accordance with your request and our proposal dated October 5, 2009, we have performed a geotechnical evaluation for the proposed cut and fill slopes on the Sprague property, which will be constmcted as part of the El Camino Real widening project located in Carlsbad, Califomia (Fig- ure 1). The purpose of this study was to evaluate the subsurface conditions at the project site and to provide design recommendations for the construction of the proposed slopes. This report pre- sents our findings, conclusions, and recommendations regarding the subject project. ^ 2. SCOPE OF SERVICES f» Ninyo & Moore's scope of services for this project included review of pertinent background data, performance of a geologic reconnaissance and subsurface evaluation, and engineering analysis with regard to the proposed project. Specifically, we performed the following tasks: Reviewing background data listed in the References section of this report. The data reviewed included geotechnical literature, topographic maps, geologic data, fault maps, and a site plan for the project showing exisfing and proposed grades. Performing a geologic reconnaissance of the proposed slope site including the observation and mapping of geologic conditions and the evaluation of possible geologic hazards which may impact the proposed project. Marking proposed test pit locations prior to contacting Underground Service Alert (USA) for underground utility clearance at the project site. Performing a subsurface evaluation consisting of excavafing six test pits to evaluate the sub- surface conditions. Performing geotechnical laboratory testing on selected soil samples to evaluate design pa- rameters. Compiling and analyzing the data obtained from our background research, subsurface evaluation, and laboratory testing. Preparing this report presenting our findings, conclusions, and recommendations regarding the geotechnical design and construction of the project. 106641002R doc 'li El Camino Real Widening, Sprague Property December 31, 2009 Carlsbad, Califomia Project No. 106641002 3. SITE AND PROJECT DESCRIPTION The proposed cut and fill slopes are located along the east side of El Camino Real at approximate Stations 529+50 to 536+00, south of Chestnut Avenue in Carlsbad, Califomia (Figure 2). The prop- erty east of El Camino Real consists of ascending slopes rising fi-om the roadway to a relatively flat property above. The northem portion of the existing slope is near vertical and the southem portion is moderately sloped. An asphalt concrete driveway extends fi'om the roadway to the property above. The parcel is cuirentiy vacant, however, remnants of a previous stmcture remain. Elevations range from a low of approximately 230 feet above mean sea level (MSL) along El Camino Real at the south end ofthe site to a high of approximately 290 feet MSL at the top ofthe exisfing slope. Vegeta- tion generally consists of a sparse to moderate growth of grass, weeds, brush, and trees. 4. SUBSURFACE EVALUATION AND LABORATORY TESTING Our subsurface evaluafion was conducted on November 5, 2009 and consisted of excavafing six exploratory test pits with a backhoe to depths of up to approximately 17 feet. The test pit loca- tions were selected based on the results of our background review, field reconnaissance, and the anticipated grading at the site. Prior to commencing the subsurface evaluation, USA was notified for mark-out ofthe existing utilities. The approximate locations of the test pits are presented on Figure 2. The test pit logs are presented in Appendix A. Laboratory testing of representative soil samples included an evaluation of in-place moisture and density, grain size analysis, and shear strength. The results of the in-situ dry density and moisture content tests are presented on the test pit logs in Appendix A. The results of the other laboratory tests performed are presented in Appendix B. 5. GEOLOGY AND SUBSURFACE CONDITIONS Our findings regarding regional and site geology and groundwater conditions at the subject site are provided in the following sections. 1066'! 1002 R.doc El Camino Real Widening, Sprague Property December 31, 2009 Carlsbad, Califomia Project No. 106641002 mt m to* m P 5.L Regional and Geologic Setting The project area is situated in the San Diego County coastal section ofthe Peninsular Ranges Geomorphic Province. This geomorphic province encompasses an area that extends approxi- mately 900 miles from the Transverse Ranges and the Los Angeles Basin south to the southern tip of Baja Califomia (Norris and Webb, 1990). The province varies in width from approxi- mately 30 to 100 miles. In general, the province consists of mgged mountains underlain by Jurassic metavolcanic and metasedimentary rocks, and Cretaceous igneous rocks ofthe south- em Califomia batholith. The portion of the province in San Diego County that includes the project area consists generally of Quatemary and Tertiary sedimentary rock. 5.2. Site Geology Geologic units encountered during our reconnaissance and subsurface evaluation included fill, very old paralic deposits, and materials of the Santiago Formation. Generalized descriptions of the units encountered are provided in the subsequent sections. More detailed descriptions are provided on the test pit logs in Appendix A. 5.2.L Fill Fill was encountered in our test pits from approximately 1 foot to depths of up to 15 feet. As observed and encountered, the materials generally consisted of light brown, dry to moist, loose, silty fine to medium sand. Scattered to abundant constmction debris is present within the fill including concrete, asphalt concrete, steel, rebar, glass, and wood. 5.2.2. Very Old Paralic Deposits Very old paralic deposits were encountered from the surface in test phs TP-1 to a depth of approximately 8.5 feet and beneath the fill in test pits TP-2 and TP-3 to depths of ap- proximately 6.5 and 12.4 feet, respectively As encountered, the materials generally y consisted of light reddish brown, damp, moderately cemented, silty fine- to coarse- |pi grained sandstone with scattered layers of gravel and cobbles. 1^ P 106641002 Rdoc El Camino Real Widening, Sprague Property December 31, 2009 Carisbad, Califomia Project No. 106641002 IMI y m m m P h m m m 3 ii 5.2.3. Santiago Formation Materials of the Santiago Formation were encountered in test pits TP-1 through TP-3 under- lying the very old paralic deposits and in TP-6 underlying the fill to the depths explored. As encountered, the materials generally consisted of light brown, damp to moist, weakly ce- mented, silty fine- to medium-grained sandstone. Mudstone beds are commonly encountered within the sandier portions of the Santiago Formation. Previous consultants (Geosoils, Inc. 1989) mapped such a mudstone bed at the toe ofthe existing cut slope north of the entrance driveway This bed is currently covered by erosional debris and we could not confimi its presence. Materials of the Santiago Formation were also observed in the ex- isting cut slope along El Camino Real beneath the very old paralic deposits and fill. 5.3. Groundwater Groundwater was not encountered in our test pits during the time of our exploration. Based on our background review of the site, regional groundwater is estimated to be located at a depth in excess of 20 feet below the ground surface. Evidence of seepage was noted at the toe ofthe slope just north of the site. Fluctuations in the groundwater level may occur due to variations in ground surface topography, subsurface geologic conditions and stmcture, rain- fail, irrigation, and other factors. Seepage, particularly at geologic contacts, should be anticipated based on site geology and topography. 6. GEOLOGIC HAZARDS In general, hazards associated with seismic activity include ground surface rupture, strong ground motion, tsunamis, and liquefaction. These considerations and other geologic hazards such as landsiiding are discussed in the following sections. 6.L Faulting and Seismicity The project area is considered to be seismically active. Based on our review ofthe referenced geologic maps and stereoscopic aerial photographs, as well as our geologic field reconnais- sance, the subject site is not underlain by known active or potentially active faults (i.e., faults IO664i002 Rdoc m m m p El Camino Real Widening, Sprague Property December 31, 2009 Carisbad, Califomia Project No. 106641002 that exhibit evidence of ground displacement in the last 11,000 years and 2,000,000 years, re- spectively). Major known active faults in the region consist generally of en-echelon, northwest-striking, right-lateral, strike-slip faults. These include the San Clemente, Agua Blanca-Coronado Bank, Newport-Inglewood, and Rose Canyon faults, located to the west of the site, and the Whittier-Elsinore, San Jacinto, and San Andreas faults, located to the east of the site. The locations of these faults are shown on Figure 3. The nearest known active fauh is the Rose Canyon fault system, located approximately 6 miles west ofthe site, which can generate an earthquake magnitude of up to 7.2 (Cao, et al., 2003). ^ 6.1.L Strong Ground Motion lg The 2007 Califomia Building Code (CBC) recommends that the design of stmctures be based on the peak horizontal ground acceleration (PGA) having a 2 percent probability of p il exceedance in 50 years, which is defined as the Maximum Considered Earth- ^ quake (MCE). The statistical retum period for PGAMCE is approximately 2,475 years. The ^ Design Earthquake (PGADE) corresponds to two-thirds of the PGAMCE, and this value is ^ typically used for residential and commercial stmctures. Based on our review of subsur- «• face data, the project site corresponds to a Site Class C. The site modified PGAMCE and p, PGADE were estimated to be 0.49g and 0.33g, respectively using tiie United States Geo- !• logical Survey (USGS) (USGS, 2009) ground motion calculator (web-based). These p, estimates of ground motion do not include near-source factors that may be applicable to P the design of stmctures on site. p li 6.L2. Ground Surface Rupture E Based on our review of the referenced literature and our site reconnaissance, no active faults are known to cross the project site. Therefore, the potential for ground mpture due to faulting at the site is unlikely. However, lurching or cracking of the ground surface as a result of nearby seismic events is possible. 106641002 R doc m El Camino Real Widening, Sprague Property December 31, 2009 Carlsbad, Califomia Project No. 106641002 6.L3. Liquefaction and Seismically Induced Settlement Liquefaction of cohesionless soils can be caused by strong vibratory motion due to m earthquakes. Research and historical data indicate that loose granular soils and non- plastic silts that are saturated by a relatively shallow groundwater table are susceptible to liquefaction. Based on the dense nature of the formational materials underiying the site and the estimated depth to groundwater, the potential for liquefaction or seismically P induced settlement is not a design consideration. p ii p p p p L 6.2. Landsiiding Based on our review of published geologic literature and aerial photographs, and our geo- logic reconnaissance, landslides or related features have not been recognized as underiying the project site. 7. SLOPE STABILITY Both surficial and global stability analyses were performed for die existing and proposed slope con- figuration. The intent of the stability analysis was to evaluate the potential for deep seated failures of the slope. Global stability analyses for the proposed slope configurations were performed using the surface and subsurface profile of geologic units based on the preliminary project plans and the results • of our field exploration. Global stability analysis was performed on cross sections A-A' and B-B'a p representative section where the 1.5:1 (horizontal:vertical) cut slope is about 14 feet high, and a pro- ^ posed fill slope is planned at an inclination of 1.5:1 up to about 50 feet high. Il The intent ofthe global stability analysis was to evaluate the potential for deep-seated, rotational (Simplified Janbu type) or bedding plane failures through Santiago Formation or fill materials. A two-dimensional stability analysis program, GSTABL7, was used for this purpose. The design factors of safety under static and pseudo-static loading conditions were 1.5 and 1.1, respectively, Il following accepted geotechnical practices and agency guidelines. A horizontal acceleration coef- ^ ficient of 0.15g was used to evaluate the pseudo-static stability The bedrock layers were 106641002 R doc p p p p li p p p p m P m h P El Camino Real Widening, Sprague Property December 31, 2009 Carisbad, Califomia Project No. 106641002 assigned homogeneous, isotropic strength properties derived from laboratory direct shear tests performed during this evaluation. Ijg Our global stability analyses indicate that the proposed cut and fill slopes up to 1.5:1 inclination ^ have adequate factors of safety under static and pseudo-static loading conditions provided the 1^ recommendations presented in this report are implemented into project design and construction. 8. CONCLUSIONS AND RECOMMENDATIONS Based on our review of the referenced background data, geologic field reconnaissance, and sub- surface exploration, it is our opinion that construction of the proposed project is feasible from a geotechnical standpoint. Geotechnical considerations include the following: • Although the current cut slope has performed adequately in its near vertical state, the pro- posed cut slope will expose adversely dipping bedding within the Santiago Formation, particularly a reported mudstone depositional bed which possesses poor strength parameters. Additionally, erosion which has affected the current steepened slope will continue to affect the proposed 1.5:1 cut slope as vegetation will be very difficult to establish in sandstone. • In order to mitigate the marginal stability and erosion potential of the proposed 1.5:1 cut slope, we recommend that the cut slope be overcut and replaced as a geogrid reinforced fill slope planted appropriately in accordance with the recommendations of the landscape archi- tect. However, steepened slopes will need increased maintenance and will be difficult on which to establish vegetation. • The proposed fill slope on the southem portion of the site will overiie existing dumped fill mate- rials. Our slope stability analysis indicates that these dumped fill materials should be removed as indicated on Figure 3 to provide a fill slope condition with an appropriate factor of safety. • The proposed earthwork should be feasible with earthmoving equipment in good working order. However, strongly cemented zones within the very old paralic deposits or materials of the Santiago Formation may be encountered which would entail the use of heavy ripping or rock breakers. • Although groundwater was not encountered during our subsurface evaluation, evidence of seepage was observed north of the site and should be anticipated, particularly at geologic contacts, during grading. l066'll002 Rdoc El Camino Real Widening, Sprague Property December 31, 2009 Carisbad, Califomia Project No. 106641002 b P P p P P P P p P • The existing materials derived from the very old paralic deposits and Santiago Formation are H generally considered suitable for reuse as engineered fill provided that they are processed and prepared in accordance with the following recommendations. n • The on-site fill materials are generally not considered suitable for reuse as engineered fill unless processed to remove the abundant asphalt, concrete, metal, and wood debris within the fill. in li • Our analysis indicates that the factor of safety against surficial instability is marginal (not more than 1.5) for the proposed slope inclination of 1.5:1. Therefore, recommendations are m provided herein for geogrid reinforced slopes. • The site is subject to strong ground motion in the event of a nearby major earthquake. Hi • Earthquake induced liquefaction is not considered a design consideration due to the density and consistency of soils encountered during our subsurface exploration and the depth to the P groundwater table. P • The potential for landsiiding or an earthquake induced landslide is considered low. p b Based on the results of our subsurface evaluation and our understanding of the proposed grading, f» we present the following geotechnical recommendations relative to the design and construction ^ of the proposed slopes. The proposed grading should also be performed in accordance with the ^ requirements of applicable goveming agencies. 8.1. Earthwork In general, earthwork should be performed in accordance with the recommendations pre- sented in this report. Ninyo & Moore should be contacted for questions regarding the recommendations or guidelines presented herein. 8.1.1. Site Preparation Prior to excavation, the project site should be cleared of surface obstmctions, existing pave- ment sections, and stripped of mbble, debris, vegetation, any loose, wet, or otherwise unstable soils, as well as surface soils containing organic material. Existing utilities withm the project limits should be abandoned, rerouted, or protected from damage by constmction activities. Obstmctions that extend below finish grade, if any, should be removed and the resulting holes 106641002 R.doc El Camino Real Widening, Sprague Property December 31, 2009 Carlsbad, Califomia Project No. 106641002 * filled with compacted soils. Materials generated from the clearing operations should be re- * moved from the site and disposed of at a legal dumpsite away from die project area. m 8.1.2. Treatment of Proposed Cut Slopes m We recommend that the proposed 1.5:1 cut slope be overcut and replaced as a geogrid re- * inforced stability fill slope. The stability fill should be constmcted as recommended in p the Slopes section of this report. P P 8.1.3. Excavation Characteristics We anticipate that excavation of the site materials can generally be accomplished with m heavy constmction equipment in good operating condition. Strongly cemented zones • within the very old paralic deposits and Santiago Formation (concretions) may be encoun- p tered at the site and will be difficult to rip. The use of heavy ripping and/or rock breaking p " equipment should be anticipated. As a result, oversize materia! may be generated, p *i 8.1.4. Materials for Fill PI On-site soils relatively free of organics are suitable for reuse as fill. Fill materia! should ^ generally not contain rocks or lumps over approximately 3 inches, and generally not P more than approximately 30 percent larger than 3/4 inch. Utility trench backfill material should not contain rocks or lumps over approximately 3 inches in general. Soils classi- fied as silts or clays should not be used. Larger chunks, if generated during excavation, may be broken into acceptably sized pieces or disposed of off site. Imported fill material, if needed for the project, should generally be granular soils with a very low to low expansion potential (i.e., an EI of 50 or less as evaluated by the il American Society for Testing and Materials lASTM] D 4829). Import material should also be non-corrosive in accordance with the Caltrans (2003) corrosion guidelines. Ma- terials for use as fill should be evaluated by Ninyo & Moore's representative prior to filling or importing. p p IP p 106641002 R doc p p p p p p p p p p p p El Camino Real Widening, Sprague Property December 31, 2009 Carlsbad, Cahfomia Project No. 106641002 8.1.5. Compacted Fill Prior to placement of compacted fill, the contractor should request an evaluation of the exposed ground surface by Ninyo & Moore. Unless otherwise recommended, the exposed ground surface should then be scarified to a depth of approximately 8 inches and watered or dried, as needed, to achieve moisture contents generally above the op- timum moisture content. The scarified materials should then be compacted to a relative compaction of 90 percent as evaluated in accordance with ASTM D 1557. The evaluation of compaction by the geotechnical consultant should not be considered to preclude any requirements for observation or approval by governing agencies. It is the contractor's responsibility to notify the geotechnical consultant and the appropriate governing agency when the project area is ready for observation, and to provide rea- sonable time for that review. Fill materials should be moisture conditioned to generally above the laboratory opti- mum moisture content prior to placement. The optimum moisture content will vary with material type and other factors. Moisture conditioning of fill soils should be generally consistent within the soil mass. Prior to placement of additional compacted fill materia! following a delay in the grading operations, the exposed surface of previously compacted fill should be prepared to receive fill. Preparation may include scarification, moisture conditioning, and recompaction. Compacted fill should be placed in horizontal lifts of approximately 8 inches in loose thickness. Prior to compaction, each lift should be watered or dried as needed to achieve a moisture content generally above the laboratory optimum, mixed, and then compacted by mechanical methods, using sheepsfoot rollers, multiple-wheel pneumatic-tired rollers or other appropriate compacting rollers, to a relative compaction of 90 percent as evalu- ated by ASTM D 1557. Successive lifts should be treated in a like manner until the desired finished grades are achieved. 106641002 R doc 10 p p II AH p ii p k El Camino Real Widening, Sprague Property December 31, 2009 Carlsbad, California Project No. 106641002 8.1.6. Slopes Cut and fill slopes should not be steeper than 2:1, unless otherwise recommended by Ninyo & Moore and approved by the regulating agencies. Steepened slopes may be con- stmcted up to an inclination of 1.5:1 if reinforced with geogrid. Steepened slopes should be constmcted upon a key excavated to a width of 30 feet and a depth of 1 foot into competent formational materials. The back cut should be benched. We recommend that a geogrid such as Tensar LH800 or equivalent be incorporated into the slope at 2-foot vertical increments and extend into the fill 8 feet from the slope face. The fill should be granular material, com- pacted as recommended in the Compacted Fill section of this report, and planted. Compaction ofthe face of slopes should be performed by overbuilding and cutting back the slope face. Alternatively, the slope face may be compacted by backrolling at inter- im vals of 4 feet or less in vertical slope height, or as dictated by the capability of the available equipment, whichever is less. Fill slopes should be backroiled utilizing a con- «• ventional sheepsfoot-type roller. Care should be taken to maintain the desired moisture conditions and/or reestablish them, as needed, prior to backrolling. b 8.1,7. Site Runoff p, Site runoff should not be permitted to flow over the tops of slopes. Positive drainage ii should be established away from the top of slopes. This may be accomplished by utiliz- pi ing brow ditches placed at the top of slopes to divert surface runoff away from the slope ^ face where drainage devices are not otherwise available, p The on-site soils will be highly susceptible to erosion. Therefore, the project plans and specifications should contain design features and constmction requirements to mitigate lg erosion of on-site soils during and after constmction. Slopes and other exposed ground surfaces should be appropriately planted with protective ground cover consisting of a 1^ combination of shallow and deep rooted vegetation in accordance with the landscape architect's recommendations. The erosion potential of the slope face may be improved P p by considering the use of an intermediate geogrid or geotextile. P k IU664I002 R.doc | | b 1^ El Camino Real Widening, Sprague Property December 31,2009 Carlsbad, California Project No. 106641002 p P P P P li p b p ii p b m 8,2. Pre-Construction Conference We recommend that a pre-constmction meeting be held prior to commencement of construc- tion activities. The owner or his representative, the agency representatives, the architect, the civil engineer, Ninyo & Moore, and the contractor should be in attendance to discuss the P plans, the project, and the proposed constmction schedule. P 8,3. Plan Review and Construction Observation The conclusions and recommendations presented in this report are based on analysis of ob- served conditions in widely spaced exploratory excavations. If conditions are found to vary from those described in this report, Ninyo & Moore should be notified, and additional recom- mendations will be provided upon request. Ninyo & Moore should review the final project drawings and specifications prior to the commencement of constmction. Ninyo & Moore should perform the needed observation and testing services during constmction operations. The recommendations provided in this report are based on the assumption that Ninyo & Moore will provide geotechnical observation and testing services during constmction. In the event that it is decided not to utilize the services of Ninyo & Moore during constmction, we request that the selected consultant provide the client with a letter (with a copy to Ninyo & Moore) indicating that they frilly understand Ninyo & Moore's recommendations, and that they are in full agreement with the design parameters and recommendations contained in this report. Constmction of proposed improvements should be performed by qualified subcon- tractors utilizing appropriate techniques and construction materials. _ 9. LIMITATIONS Il The field evaluation, laboratory testing, and geotechnical analyses presented in this geotechnical report ^ have been conducted in general accordance with current practice and die standard of care exercised by li geotechnical consultants performing similar tasks in the project area. No warranty, expressed or im- plied, is made regardmg the conclusions, recommendations, and opinions presented in this report. Li There is no evaluation detailed enough to reveal every subsurface condition. Variations may exist and r L ^ io664ioo2Rdoc j2 ^mffo&^mn p p P b p p p ii p El Camino Real Widening, Sprague Property December 31, 2009 Carlsbad, Califomia Project No. 106641002 p conditions not observed or described in this report may be encountered during constmction. Uncertain- ties relative to subsurface conditions can be reduced through additional subsurface exploration. P Additional subsurface evaluation will be performed upon request. Please also note that our evaluation p was limited to assessment of the geotechnical aspects of die project, and did not include evaluation of p stmctural issues, environmental concems, or the presence of hazardous materials. This document is intended to be used only in its entirety. No portion ofthe document, by itself, is designed to completely represent any aspect of the project described herein. Ninyo & Moore should be contacted if the reader requires additional information or has questions regarding the ii content, interpretations presented, or completeness of this document. This report is intended for design purposes only It does not provide sufficient data to prepare an accurate bid by contractors. It is suggested that the bidders and their geotechnical consultant per- form an independent evaluation of the subsurface conditions in the project areas. The independent evaluations may include, but not be limited to, review of other geotechnical reports prepared for the adjacent areas, site reconnaissance, and additional exploration and laboratory testing. Our conclusions, recommendations, and opinions are based on an analysis of the observed site conditions. If geotechnical conditions different from those described in this report are encountered, our office should be notified, and additional recommendations, if warranted, will be provided upon request. It should be understood tiiat the conditions of a site could change with time as a result of natural processes or the activities of man at tiie subject site or nearby sites. In addition, changes to the applicable laws, regulations, codes, and standards of practice may occur due to govemment ac- tion or the broadening of knowledge. The findings of this report may, therefore, be invalidated over time, in part or in whole, by changes over which Ninyo & Moore has no controls. This report is intended exclusively for use by the client. Any use or reuse ofthe findings, conclu- sions, and/or recommendations of tiiis report by parties other than the client is undertaken at said b parties' sole risk. 0664,002 R doc ,3 /^itiffO^^^W^ p ^ El Camino Real Widening, Sprague Property December 31,2009 Carlsbad, Califomia Project No. 106641002 p P li b p k m p p 10. REFERENCES California Building Standards Commission (CBSC), 2007, Califomia Building Code (CBC), Ti- m tie 24, Part 2, Volumes 1 and 2. Califomia Department of Conservation Division of Mines and Geology (CDMG), 1998, Maps of Known Active Fault Near-Source Zones in Califomia and Adjacent Portions of Nevada: dated February. Cao, T., Bryant, W.A., Rowshandel, B., Branum, D., and Wills, C.J., California Geological Sur- vey (CGS), 2003, The Revised 2002 Califomia Probabilistic Seismic Hazard Maps. County of San Diego, 1963, Topographic Survey Sheet 362-1671, Scale 1" -200'. P |g County of San Diego, 1975, Orthotopographic Survey, Sheet 362-1671, Scale 1" = 200'. Geosoils, Inc., 1989, Preliminary Geotechnical Study, El Camino Real Near Chestnut, Carisbad, P California: dated September 11. Jennings, CW, 1994, Fault Activity Map of Califomia and Adjacent Areas: Califomia Division of Mines and Geology California Geologic Data Map Series, Map No. 6, Scale 1:750,000. Kennedy, M.P and Tan, S.S., 2005, Geologic Map of the Oceanside 30 x 60 Quadrangle, Cali- fomia, Scale 1:100,000. Norris, R. M. and Webb, R. W, 1990, Geology of California, Second Edition: John Wiley & Sons, hic. Public Works Standards, Inc., 2006, "Greenbook," Standard Specifications for Public Works Con- • stmction. p Tan, S.S., and Giffen, D.G., 1995, Landslide Hazards in the Northem Part of the San Diego Metro- il politan Area, San Diego County, Califomia, Oceanside and San Luis Rey Quadrangle: Scale 1:24,000. P |j Testing Engineers, 2006, Geotechnical Engineering Investigation Report, El Camino Real Wid- ening: dated May 31. Thielen, D.L., and Collin, J.G, 1993, Geogrid Reinforcement for Surficial Stability of Slopes, Proceedings of GeoSynthetics '93, Vancouver, BC, Canada. ^ United States Department of the Interior, Bureau of Reclamation, 1998, Engineering Geology b Field Manual. p United States Geological Survey, 1968 (photo-revised 1975), San Luis Rey Quadrangle, Califor- ^ nia, San Diego County, 7.5-Minute Series (Topographic): Scale 1:24,000. ^ United States Geological Survey, 2009 Ground Motion Parameter Calculator v 5.0.9a, Worid Wide Web, http://earthquake.usgs.gov/research/hazmaps/design/. 10664l002Rdoc 14 m HI Camino Real Widening, Sprague Property Carlsbad, Califomia December 31, 2009 Project No. 106641002 p Source AERIAL PHOTOGRAPHS Date Flight Numbers Scale p United States Department of Agriculture April 11, 1953 AXN-8M 102 and 103 1:20,000 p p p p p b p m p P 106641002 R doc 15 I Vi*^ L ^B-^o\ # REFERENCE: 2005 THOMAS GUIDE FOR SAN DIEGO COUNTY, STREET GUIDE AND DIRECTORY, APPROXIMATE SCALE 2400 4800 FEET N A NOTE: ALL DIMENSIONS. DIRECTIONS AND LOCATIONS ARE APPROXIMATE Map©Rand McNally. R.L.07-S-129 SITE LOCATION MAP FIGURE 1 PROJECT NO. DATE EL CAMINO REAL WIDENING, SPRAGUE PROPERTY CARLSBAD, CALIFORNIA FIGURE 1 106641002 12/09 EL CAMINO REAL WIDENING, SPRAGUE PROPERTY CARLSBAD, CALIFORNIA FIGURE 1 APPROXIMATE SCALE 80 160 FEET -fji- TP-6 APPROXIMATE LOCATION OF TD=i7.0' EXPLORATORY TEST PIT TD=T0TAL DEPTH IN FEET B B' I I CROSS SECTION TEST PIT LOCATION MAP FIGURE 2 PROJECT NO. DATE EL CAMINO REAL WIDENING, SPRAGUE PROPERTY CARLSBAD, CALIFORNIA FIGURE 2 106641002 12/09 EL CAMINO REAL WIDENING, SPRAGUE PROPERTY CARLSBAD, CALIFORNIA FIGURE 2 A 320-, 290- Q 260- 230- 200- A' r 320 UNDOCUMENTED FILL TO BE REMOVED 8' REINFORCED ZONE EXISTING GRADE PROPOSED GRADE - 290 KEY BACK CUT TO BE BENCHED LEGEND TP-4 APPROXIMATE LOCATION OF 1 EXPLORATORY TEST PIT i TD=9.5' TD=T0TAL DEPTH IN FEET i TD=9.5' Qaf FILL Tsa SANTIAGO FORMATION 3° BEDDING MUDSTONE LAYER POSSIBLE m 260 Q I-< > LU —I LU - 230 - 200 APPROXIMATE SCALE 30 60 FEET NOTE: ALL DIMENSIONS. DIRECTIONS AND LOCATIONS ARE APPROXIMATE PROJECT NO. 106641002 DATE 12/09 CROSS SECTION A-A' EL CAMINO REAL WIDENING, SPRAGUE PROPERTY CARLSBAD, CALIFORNIA FIGURE I m -I UJ 240- 220- LEGEND TP-2 APPROXIMATE LOCATION OF j EXPLORATORY TEST PIT ^pi^^, TD=TOTAL DEPTH IN FEET QVOP VERY OLD PARALIC DEPOSITS Tsa SANTIAGO FORMATION NOTE: ALL DIMENSIONS, DIRECTIONS AND LOCATIONS ARE APPROXIMATE APPROXIMATE SCALE 20 40 FEET 3° BEDDING MUDSTONE LAYER POSSIBLE - 280 - 240 - 220 - 260 O < > UJ -J UJ CROSS SECTION B-B' FIGURE 4 PROJECT NO. DATE EL CAMINO REAL WIDENING, SPRAGUE PROPERTY CARLSBAD, CALIFORNIA FIGURE 4 106641002 12/09 EL CAMINO REAL WIDENING, SPRAGUE PROPERTY CARLSBAD, CALIFORNIA FIGURE 4 SAN \ CAYETANO \ ^^^^^ ^^^^^ yGaks ^''-vi^'*l-IBU COAST Kern County Los Angeles County Palmdale untv vf^^N \.'::-: Arrowhead ^i^'Q^'-C'ty 1 v h \\ \x M^ICA ^iTos Angeles ^~^\ • An-owhead ^^'9 "^^^ar i.Ky. ^ ^ - \ ^ ^ v^^ \ Ariahei.m Long'Beach 'vV ^'^ Sa\Bernardtno Cbu^nt/^ Riverside Count/^,:^ ynine Palms • ' - ounryi'^x esert.Center vA,^ Island \ o?^ ^ xplemente / ^' " San DiegsTCounty ] Imperial County San Clemente Island PACIFIC OCEAN USA MEXICO LEGEND CALIFORNIA FAULT ACTIVITY HISTORICALLY ACTIVE HOLOCENE ACTIVE LATE QUATERNARY (POTENTIALLY ACTIVE) QUATERNARY (POTENTIALLY ACTIVE) — STATE/COUNTY BOUNDARY SOURCE FAULTS - CA DEPT OF CONSERVATION 2000: BASE - ESRI. 2008 N A NOTES: ALL DIRECTIONS, DIMENSIONS AND LOCATIONS ARE APPROXIMATE APPROXIMATE SCALE 25 50 MILES FAULT LOCATION MAP FIGURE 5 PROJECT NO. DATE EL CAMINO REAL WIDENING, SPRAGUE PROPERTY CARLSBAD, CALIFORNIA FIGURE 5 106641002 12/09 EL CAMINO REAL WIDENING, SPRAGUE PROPERTY CARLSBAD, CALIFORNIA FIGURE 5 El Camino Real Widening, Sprague Property December 31, 2009 Carlsbad, Califomia Project No. 106641002 APPENDIX A TEST PIT LOGS Field Procedure for the Collection of Disturbed Samples Disturbed soil samples were obtained in the field using the following methods. Bulk Samples Bulk samples of representative earth materials were obtained from the exploratory borings. The samples were bagged and transported to the laboratory for testing. Field Procedure for the Collection of Relatively Undisturbed Samples Relatively undisturbed soil samples were obtained in the field using the following method. The Modified Split-Barrel Drive Sampler The sampler, with an external diameter of 3.0 inches, was lined with 1-inch long, thin brass rings with inside diameters of approximately 2.4 inches. The sample barrel was driven into the ground with the weight of a hammer. The driving weight was permitted to fall freely. The samples were removed from the sample barrel in the brass rings, sealed, and transported to the laboratory for testing. 106MI002 R-doc f 1 r Explanation of Test Pit, Core. Trench and Hand Auger Log Symbols PROJECT NO. 3 o c m DATE riiiiiiiriiiii EXCAVATION LOG EXPLANATION SHEET FILL Bulk sample. Dashed line denotes material change. Drive sample. Sand cone performed. Seepage Groundwater encountered during excavation. No recovery with drive sampler. Groundwater encountered after excavation. Sample retained by others. Shelby tube sample. Distance pushed in inches/length of sample recovered in inches No recovery with Shelby tube sampler. ALLUVIUM- Solid line denotes unit change. Attitude: Strike/Dip b; Bedding c: Contact j: Joint f Fracture F: Fault cs: Clay Seam s; Shear bss: Basal Slide Surface sf: Shear Fracture sz: Shear Zone sbs: Sheared Bedding Surface The total depth line is a solid line that is drawn at the bottom of the excavation log. SCALE: 1 inch = 1 foot Testpil explanaljon.xls r I i I r 1 n ri ri ri ri ri ii ri ri m § ri m M BI II ti ri TEST PIT LOG EL CAMINO REAL ROAD WIDENING, SPRAGUE PROPERTY CARLSBAD, CALIFORNIA PROJECT NO. DATE 106641002 12/09 LU LU Q_ UJ Q CO LU < LU Q: I- O o a. w LU Q >- a: z o H . < U) yd o DATE EXCAVATED 11/5/09 TEST PIT NO. TP-1 GROUND ELEVATION 290'± (MSL) LOGGED BY RTW METHOD OF EXCAVATION BACKHOE WITH 24" BUCKET LOCATION SEE SITE PLAN DESCRIPTION -2 -4 - 10 Al SM FILL: Light brown, dry to damp, loose, silty fine to medium SAND. VERY OLD PARALIC DEPOSITS: Light reddish brown, damp, moderately cemented, silty fme- to coarse-grained SANDSTONE. 6' to 6.5': Layer of gravel and cobbles. 8.5': Sharp contact with underlying. SANTIAGO FORMATION: Light brown, moist, weakly cemented, silty fine-grained SANDSTONE. Total Depth = 9.6 feet. No groundwater encountered. No caving. Backfilled on 11/5/09. SCALE = 1 in./2fl r I • 1 r I r 1 r^ n r i r i r i ri ri ii ri ci KI RI RI ii RI TEST PIT LOG EL CAMINO REAL ROAD WIDENING, SPRAGUE PROPERTY CARLSBAD, CALIFORNIA PROJECT NO. DATE 106641002 12/09 LU LU D. LU Q to LU < CO LU OH 13 H CO o LL. o Q_ CO LU Q > CC Q < CO yd y=co o DATE EXCAVATED 11/5/09 TEST PIT NO. TP-2 GROUND ELEVATION 290'± (MSL) LOGGED BY RTW METHOD OF EXCAVATION BACKHOE WITH 24" BUCKET LOCATION SEE SITE PLAN DESCRIPTION o c X m > -2 -4 -6 - 10 Al 9.9 SM FILL: 111.9 Brown to light brown, damp, loose, silty fine SAND; scattered roots. VERY OLD PARALIC DEPOSITS: Light reddish brown, damp, moderately cemented, silty fme- to coarse-grained SANDSTONE. 4': Layer of gravel and cobbles. SANTIAGO FORMATION: Light brown, moist, weakly cemented, silty fine-grained SANDSTONE; few clay. Total Depth = 7.5 feet. No groundwater encountered. No caving. Backfilled on 11/5/09. SCALE = 1 in./2ft. R 1 R 1 r 1 R1 t 1 ri tl ri ri ri ii ri ti Ri ti Ri Ri RI Ri TEST PIT LOG EL CAMINO REAL ROAD WIDENING, SPRAGUE PROPERTY CARLSBAD, CALIFORNIA PROJECT NO. DATE 106641002 12/09 I-LU LU Q. LU Q CO LU < CO LU I- CO o o CO z LU Q >-CC Q o h- . < to yd y=co (O to O DATE EXCAVATED 11/5/09 TEST PIT NO. TP-3 GROUND ELEVATION 289'± (MSL) LOGGED BY RTW METHOD OF EXCAVATION BACKHOE WITH 24" BUCKET LOCATION SEE SITE PLAN DESCRIPTION a 73 m ^> u -3 -6 -9 - 12 - 15 AK SM FILL: Brown, dry to damp, loose, silty fine SAND; scattered debris including broken concrete, rebar, etc. VERY OLD PARALIC DEPOSITS: Light reddish brown, damp, moderately cemented, silty fine- to medium- grained SANDSTONE. SANTIAGO FORMATION: Light brown, damp to moist, weakly cemented, silty fme-grained SANDSTONE. Total Depth = 12.8 feet. No groundwater encountered. No caving. Backfilled on 11/5/09. SCALE = 1 in./3 ft. f] fl ri tl tl ri ri ii ii ri ri ri ri ri ti ri ri TEST PIT LOG EL CAMINO REAL ROAD WIDENING, SPRAGUE PROPERTY CARLSBAD, CALIFORNIA PROJECT NO. DATE 106641002 12/09 UJ LU LI. CL LU a CO LU < CO LU QC Z) l_ to O o >- to z LU Q >-CC a o < to yd y=co to to ^ < —I o DATE EXCAVATED 11/5/09 TEST PIT NO. 1 R i TP-4 GROUND ELEVATION 286'± (MSL) LOGGED BY RTW METHOD OF EXCAVATION BACKHOE WITH 24" BUCKET LOCATION SEE SITE PLAN DESCRIPTION -2 I -4 - 10 _LZ SM FILL: Brown, damp to moist, loose, silty fine SAND; abundant broken concrete rubble, broken glass, pieces of pipe, rock and other debris. Scattered zones of light gray material. Total Depth = 9.5 feet. No groundwater encountered. Caving in rubble. Backfilled and tamped on 11/5/09. SCALE = 1 in./2 ft fl ti tl tl tl il 1! II 11 II fl II ti RI Ri Ri RI tl Ri TEST PIT LOG EL CAMINO REAL ROAD WIDENING, SPRAGUE PROPERTY CARLSBAD, CALIFORNL\ PROJECT NO. DATE 106641002 12/09 I- LU lU Q. UJ Q CO LU < to UJ cc H CO o o CL CO z LU Q >-CC Q Z o H . < CO yd y=co to to -J < o DATE EXCAVATED 11/5/09 TEST PIT NO. TP-5 GROUND ELEVATION 284'± (MSL) LOGGED BY RTW METHOD OF EXCAVATION BACKHOE WITH 24" BUCKET LOCATION SEE SITE PLAN DESCRIPTION -2 -4 -6 -10 Al SM FILL: Brown to light brown, damp to moist, loose, silty fme SAND; scattered debris including broken glass, concrete rubble, wood, cans, etc. Caving between 3 feet and 10 feet; abundant concrete (up to 24 inches wide), asphalt chunks and other debris. Total Depth = 10.5 feet No groimdwater encountered. Caving fi-om 3 feet to 10 feet. Backfilled and tamped on 11/5/09. SCALE = 1 in./2 fl fill t 1 ri r 1 r^i ri rt ri ri ri ii ri ri Rt Ri i R i R i TEST PIT LOG EL CAMINO REAL ROAD WIDENING, SPRAGUE PROPERTY CARLSBAD, CALIFORNIA PROJECT NO. DATE 106641002 12/09 LU UJ CL UJ Q to UJ < to UJ cc z> \-to o o CL to z LU Q > OC a O \- . < to yd 3 o DATE EXCAVATED 11/5/09 TEST PIT NO. TP-6 GROUND ELEVATION 289'± (MSL) LOGGED BY RTW METHOD OF EXCAVATION BACKHOE WITH 24" BUCKET LOCATION SEE SITE PLAN DESCRIPTION -3 l__ -6 -9 - 12 - 15 SM FILL: Dark brown, damp to moist, loose, silty fine SAND; few cobbles; scattered debris (broken glass, concrete, rubble, wood debris and brick). SANTIAGO FORMATION: Light brown, moist, weakly cemented, silty fine- to medium-grained SANDSTONE. Total Depth -= 17 feet No groundwater encountered. No caving. Bacfilled on 11/5/09. SCALE = 1 in./3 ft. Ml m El Camino Real Widening, Sprague Property December 31,2009 Carlsbad, CalifiDmia Project No. 106641002 il IP k m APPENDIX B LABORATORY TESTING Classification m Soils were visually and texturally classified in accordance with the Unified Soil Classification •I System in general accordance with ASTM D 2488-00. Soil classifications are indicated on the logs of the exploratory test pits in Appendix A. m In-Place Moisture and Densitv Tests m The moisture content and dry density of relatively undisturbed samples obtained from the ex- ^ ploratory borings were evaluated in general accordance with ASTM D 2937. The test results are presented on the logs of the exploratory test pits in Appendix A. Gradation Analvsis Gradation analysis tests were performed on selected representative soil samples in general accor- ^ dance with ASTM D 422. The grain-size distribution curves are shown on Figures B-1 and B-2. These test results were utilized in evaluating the soil classifications in accordance with the Uni- fied Soil Classification System (USCS). ^ Direct Shear Test A direct shear test was performed on a relatively undisturbed sample in general accordance witli ASTM D 3080 to evaluate the shear strength characteristics of selected material. The sample was ^ inundated during shearing to represent adverse field conditions. The results are shown on Figure B-3. 1066<11002 R doc GRAVEL SAND FINES Coarse Fine Coarse Medium Fine SILT CLAY U.S. STANDARD SIEVE NUMBERS 3- 2' VA" V V.' 4 8 16 30 50 100 ZOO HYDROMETER 80.0 50.0 GRAIN SIZE IN MILLIMETERS Symbol Sample Location Depth (ft) Liquid Limit Plastic Limit Plasticity Index D30 Deo Passing No. 200 (%) Equivalent USCS • TP-2 6.5-7.5 ~ ~ ~ -~ ~ -18 SM PERFORMED IN GENERAL ACCORDANCE WITH ASTM D 422 GRADATION TEST RESULTS FIGUHi£ B-1 PROJECT NO. DATE EL CAMINO REAL ROAD WIDENING, SPRAGUE PROPERTY CARLSBAD, CALIFORNIA FIGUHi£ B-1 106641002 12/09 EL CAMINO REAL ROAD WIDENING, SPRAGUE PROPERTY CARLSBAD, CALIFORNIA FIGUHi£ B-1 1M641002SIEVETP-; a6.5-75,xls GRAVEL SAND FINES Coarse Fine Coarse Medium Fine SILT CLAY U S, STANDARD SIEVE NUMBERS 3- 2 114' 1" y." 4 8 16 30 50 100 200 HYDROMETER 70.0 GRAIN SIZE IN MILLIMETERS PERFORMED IN GENERAL ACCORDANCE WITH ASTM D 422 Symbol Sample Location Deptii (ft) Liquid Limit Plastic Limit Plasticity Index D30 Deo Co Passing No. 200 {%) USCS • TP-6 2.0-3.0 ~ ------~ 30 SM GRADATION TEST RESULTS FIGURE B-2 PROJECT NO. DATE EL CAMINO REAL ROAD WIDENING, SPRAGUE PROPERTY CARLSBAD, CALIFORNIA FIGURE B-2 106641002 12/09 EL CAMINO REAL ROAD WIDENING, SPRAGUE PROPERTY CARLSBAD, CALIFORNIA FIGURE B-2 106641002 SIEVE TP-B Q 2.0-3,0 nit 5000 4000 9^ 3000 w (/> LU cc w cc 2 2000 X CO 1000 I 1 / .... ^ * / .... ^ * — — •* — — y \ y \ 1000 2000 3000 NORMAL STRESS (PSF) 4000 5000 Description Symbol Sample Location Depth (ft) Shear Strength Cohesion, c (psf) Friction Angle, ^ (degrees) Soil Type Silty SANDSTONE TP-2 6.5-7.5 Peak 420 37 Formation Silty SANDSTONE TP-2 6.5-7.5 Peak 420 37 Formation Silty SANDSTONE - -X - • TP-2 6.5-7.5 Ultimate 0 36 Formation PERFORMED IN GENERAL ACCORDANCE WITH ASTM D 3080 DIRECT SHEAR TEST RESULTS FIGURE B-3 PROJECT NO. DATE EL CAMINO REAL ROAD WIDENING, SPRAGUE PROPERTY CARLSBAD. CALIFORNIA FIGURE B-3 106641002 12/09 EL CAMINO REAL ROAD WIDENING, SPRAGUE PROPERTY CARLSBAD. CALIFORNIA FIGURE B-3 106641002 SHEAR TP-Z @ 6.5-7.5.xls