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HomeMy WebLinkAbout5003; El Camino Real Water System Project; Geotechnical Evaluation; 2006-04-24Geotechnical and Environmental Sciences Consultants GEOTECHNICAL EVALUATION EL CAMINO REAL WATER SYSTEM PROJECT CARLSBAD, CALIFORNIA PREPARED FOR: Daniel Boyle Engineering 5650 El Camino Real, Suite 155 Carlsbad, California 92008 PREPARED BY: Ninyo & Moore Geotechnical and Environmental Sciences Consultants 5710RuffinRoad San Diego, California 92123 April 24, 2006 Project No. 105761001 5710 Puffin Road - San Diego, California 92123 - Phone (858j 576-1000 • Fax (858) 576-9600 San Diego • Irvine • Ontario • Los Angeles - Oakland • Las Vegas - Salt Lake City • Phoenix Environmental Sciences Consultants April 24, 2006 Project No. 105761001 Mr. Dan Smith Daniel Boyle Engineering 5650 El Camino Real, Suite 155 Carlsbad, California 92008 Subject: Geotechnical Evaluation El Camino Real Water System Project Carlsbad, California Dear Mr. Smith: In accordance with your authorization, we have performed a geotechnical evaluation for the pro- posed El Camino Real Water System project in Carlsbad, California. This report presents our geotechnical findings, conclusions, and recommendations regarding the proposed project. We appreciate the opportunity to be of service. Please contact our project engineer (Dr. Qiu) with questions. Respectfully submitted, NINYO & MOORE Tong Qiu, Ph. Project Engineer Erik Olsen, GE. Chief Geotechnical Engineer TQ/JG/EO/gg Distribution: (4) Addressee (A& 3u— nathan Goodmacher, C.E.G incipal Geologist 5710 Ruffin Road • San Diego, California 92123 - Phone (858) 576-1000 • Fax (858) 576-9600 San Diego • Irvine • Ontario - Los Angeles • Oakland • Las Vegas • Salt Lake City • Phoenix Ei Camino Real Water System Project April 24, 2006 Carlsbad, California Project No. 105761001 TABLE OF CONTENTS Page 1. INTRODUCTION 1 2. SCOPE OF SERVICES 1 3. PROJECT DESCRIPTION 1 4. SITE DESCRIPTION 2 5. FIELD EXPLORATION AND LABORATORY TESTING 2 6. GEOLOGY AND SUBSURFACE CONDITIONS 3 6.1. Regional Geologic Setting 3 6.2. Site Geology 3 6.2.1. Alluvium 4 6.2.2. Terrace Deposits 4 6.2.3. Santiago Formation 4 6.3. Groundwater 4 7. GEOLOGIC HAZARDS 5 7.1. Faulting and Seismicity 5 7.1.1. Strong Ground Motion 5 7.1.2. Ground Surface Rupture 6 7.2. Liquefaction 6 7.3. Landsliding 6 8. CONCLUSIONS 6 9. RECOMMENDATIONS 7 9.1. Earthwork 7 9.1.1. Site Preparation 7 9.1.2. Excavation Characteristics 7 9.1.3. Materials for Fill 8 9.1.4. Compacted Fill 8 9.1.5. Temporary Slope Stability 9 9.1.6. Drainage 11 9.2. Pipe Bedding and Modulus of Soil Reaction (£") 11 9.3. CBC Seismic Design Parameters 12 9.4. Jack-and-Bore 13 9.5. Foundations 13 9.5.1. Shallow Foundations 13 9.5.2. Mat Foundations 14 9.5.3. Foundation Lateral Resistance 14 9.5.4. Static Settlement 15 9.6. Thrust Blocks 15 9.7. Corrosion 15 9.8. Construction Dewatering 16 Ninuo^105761001RHCaminoRcal.doc j *J 3 El Camino Real Water System Project April 24, 2006 Carlsbad, California Project No. 105761001 9.9. Pre-Construction Conference 16 9.10. Construction Observation 16 10. LIMITATIONS 17 11. SELECTED REFERENCES 19 Tables Table 1 - Pipe Bedding/Backfill Gradation Limits 12 Table2-CBC Seismic Design Parameters 12 Figures Figure 1 - Site Location Map Figures 2 through 4 - Boring Location Maps Figure 5 - Fault Location Map Figure 6 - Lateral Earth Pressures for Braced Excavation (Granular Soil) Figure 7 - Thrust Block Lateral Earth Pressure Diagram Appendices Appendix A - Boring Logs Appendix B - Laboratory Testing Appendix C - Typical Earthwork Guidelines 105761001 R El Camino Real .doc tylnyo El Camino Real Water System Project February 21,2005 Carlsbad, California Project No. 105761001 1. INTRODUCTION In accordance with your request, we have performed a geotechnical evaluation for the design of the proposed El Camino Real Water System project in Carlsbad, California (see Figure 1). This report presents the results of our field exploration and laboratory testing, our conclusions regard- ing the geotechnical conditions at the subject site, and our recommendations for the design and earthwork construction of this project. 2. SCOPE OF SERVICES The scope of services for this study included the following: • Reviewing readily available published and in-house geotechnical literature, stereoscopic ae- rial photographs, and topographic, geologic, and fault maps. • Performing a field reconnaissance to observe site conditions and to locate and mark pro- posed exploratory excavations. • Obtaining encroachment and traffic control permits from the City of Carlsbad. • Coordinating and mobilizing for the subsurface exploration. Underground Service Alert (USA) was notified to mark underground utilities at the proposed boring locations. • Coordinating traffic control services performed by an outside contractor • Performing a subsurface evaluation consisting of the excavating, logging, and sampling of five exploratory borings with a truck mounted hollow-stem auger drill rig. Relatively undis- turbed and bulk samples were obtained at selected intervals from the borings. • Obtaining a boring permit from County of San Diego Department of Environmental Health (DEH). • Performing geotechnical laboratory testing on selected samples. • Preparing this report presenting our findings, conclusions, and recommendations regarding the geotechnical design and construction aspects of the project. 3. PROJECT DESCRIPTION We understand the project involves five separate capital improvements to the Carlsbad Municipal Water District (CMWD), a subsidiary district of the City of Carlsbad. The project improvements 105649001 R Washington Ave.doc El Camino Real Water System Project April 24, 2006 Carlsbad, California Project No. 105761001 include approximately 4,300 linear feet (LF) of new 12-inch PVC pipeline, 2,200 LF of new 10-inch PVC pipeline, and replacement of an existing pressure reducing station. The new pipeline will consist of four sections. A 12-inch, approximately 4,000 foot long section of pipeline will be located within Jackspar Drive beginning at Longfellow Road proceeding north to El Camino Real, then east within El Camino Real to College Boulevard, then north within College Boulevard to Badger Lane. A 12-inch, approximately 300 foot long section of pipeline will be located within the El Camino Real and Kelly Drive intersection. A new 10-inch, approximately 200 foot long section of pipeline will cross El Camino Real at Carlsbad Vil- lage Drive. A 10-inch, approximately 2,000 foot long section of pipeline will be located within El Camino Real from Lisa Street west to Kelly Drive. A new pressure reducing station will be constructed at the southeast corner of El Camino Real and Carlsbad Village Drive to replace the existing one. We anticipate the proposed pipeline will be constructed at depths on average of 5 feet. Details of the pressure reducing station construction are not known, however foundation loads are expected to be typical of such a relatively light structure. 4. SITE DESCRIPTION The subject project site is located in Carlsbad, California. The proposed pipeline alignments are along existing asphalt-concrete paved roads. The site for the proposed pressure reducing station is undeveloped. The elevation of the project areas ranges from approximately 60 feet to 135 feet above Mean Sea Level (MSL). 5. FIELD EXPLORATION AND LABORATORY TESTING Our subsurface exploration was conducted on February 9 and 10, 2006, and consisted of drilling, logging, and sampling of five small-diameter exploratory borings. The borings were drilled to depths of up to approximately 16.5 feet below the existing ground surface, with a truck-mounted, hollow-stem auger drill rig. Drive and bulk soil samples were obtained from the borings. The 105761001 REICaminoREal.doc El Camino Real Water System Project April 24, 2006 Carlsbad, California Project No. 105761001 samples were then transported to our geotechnical laboratory for testing. The excavations were backfilled with bentonite grout in general accordance with current county standards. The ap- proximate locations of the exploratory borings are shown on Figures 2 to 4. Logs of the borings are included in Appendix A. Laboratory testing of representative soil samples included in-situ moisture content and dry den- sity, gradation analysis, Atterberg limits, shear strength, and corrosivity. The results of the in-situ moisture content and dry density tests are shown at the corresponding sample depth on the bor- ing logs in Appendix A. The results of the other laboratory tests performed are presented in Appendix B. 6. GEOLOGY AND SUBSURFACE CONDITIONS Our findings regarding regional and site geology and groundwater conditions at the subject site are provided in the following sections. 6.1. Regional Geologic Setting The project area is situated in the San Diego County coastal section of the 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 California (Norris and Webb, 1990). The province varies in width from approxi- mately 30 to 100 miles. In general, the province consists of rugged mountains underlain by Jurassic metavolcanic and metasedimentary rocks, and Cretaceous igneous rocks of the south- ern California batholith. The portion of the province in San Diego County that includes the project area consists generally of materials of Tertiary-age Santiago Formation. 6.2. Site Geology Geologic units encountered during our field reconnaissance and subsurface evaluation in- cluded alluvium, terrace deposits, and materials of the Santiago Formation. Generalized descriptions of the earth units encountered during our field reconnaissance and subsurface ex- 105761001 RElCaminoReal.doc El Camino Real Water System Project April 24, 2006 Carlsbad, California Project No. 105761001 ploration are provided in the subsequent sections. More detailed descriptions are provided on the boring logs in Appendix A. 6.2.1. Alluvium Alluvium is mapped in the project areas and was encountered in exploratory borings B-l, B-2, and B-4 from the bottom of pavement to total depth explored. As encountered, the materials generally consisted of brown to light brown, damp to moist, loose to me- dium dense, silty to clayey sand or firm to very stiff, sandy silty clay. 6.2.2. Terrace Deposits Terrace deposits are mapped in the project areas and were encountered in exploratory bor- ings B-3 and B-5 from the bottom of pavement to total depth explored and a depth of approximately 8 feet, respectively. As encountered, the materials generally consisted of light brown to brown, damp, dense to very dense, silty clayey fine sand and clayed sand. 6.2.3. Santiago Formation Materials of the Santiago Formation are mapped in the project areas and were encoun- tered in exploratory boring B-5 underlying the terrace deposits to the total depth explored. As encountered, the materials generally consisted of white and olive, damp to moist, medium dense, clayey sandstone. 6.3. Groundwater Groundwater was encountered in boring B-4 at a depth of approximately 7 feet below the ground surface. Groundwater was not encountered at the time of our explorations in the other borings (which were backfilled immediately upon completion). However, it should be noted that groundwater levels may fluctuate due to seasonal variations, irrigation, and other factors. 105761001REI CaminoReaJ doe El Camino Real Water System Project April 24, 2006 Carlsbad, California Project No. 105761001 7. GEOLOGIC HAZARDS In general, hazards associated with seismic activity include strong ground motion, ground sur- face rupture, and liquefaction. These considerations and other geologic hazards such as landsliding are discussed in the following sections. 7.1. Faulting and Seismicity The project area is considered to be seismically active. Based on our review of the refer- enced geologic maps and stereoscopic aerial photographs, as well as on our geologic field reconnaissance, the subject site is not underlain by known active or potentially active faults (i.e., faults that exhibit evidence of ground displacement in the last 11,000 years and 2,000,000 years, respectively). Major known active faults in the region consist generally of en-echelon, northwest-striking, right-lateral, strike-slip faults. These include the Rose Can- yon, San Clemente, Agua Blanca-Coronado Bank, located west of the site, and the Whittier-Elsinore, San Jacinto, and San Andreas faults, located east of the site. The locations of these faults are shown on Figure 5. The closest known active fault is the Rose Canyon Fault, which can generate an earthquake magnitude of up to 6.9 (California Geological Survey [CGS], 1998). It is located approxi- mately 6 miles west of the project site. 7.1.1. Strong Ground Motion Based on a Probabilistic Seismic Hazard Assessment for California, issued by the United States Geological Survey/California Geological Survey (2003), the project is lo- cated in a zone where the horizontal peak ground acceleration having a 10 percent probability of exceedance in 50 years is 0.33g (33 percent of the acceleration of grav- ity). The requirements of the governing jurisdictions and the 2001 California Building Code (CBC) should be considered in the project design. 105761001 R El Camino Real .doc El Camino Real Water System Project April 24, 2006 Carlsbad, California Project No. 105761001 7.1.2. Ground Surface Rupture 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 rupture due to faulting at the site is considered very low. However, lurching or cracking of the ground surface as a result of nearby seismic events is possible. 7.2. Liquefaction Liquefaction of cohesionless soils can be caused by strong vibratory motion due to earth- quakes. 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 loose granular alluvial materials encountered during our subsurface evaluation and groundwater expected in drainage crossings, it is our opinion that liquefaction and dynamic set- tlement of up to approximately 1 inch is possible in the event of a major local earthquake. It is our opinion that this settlement is unlikely to damage the proposed PVC pipeline. 7.3. Landsliding Based on our review of published geologic literature and aerial photographs, and our geo- logic reconnaissance, no landslides or related features are been identified as underlying the proposed pipeline alignment. However, landslides have been mapped in the vicinity of Carlsbad Village Drive and El Camino Real (CGS, 1995). 8. CONCLUSIONS It is our opinion that there are no known geotechnical constraints that would preclude construc- tion of the planned project development provided consideration is given to the recommendations presented in this report and appropriate construction practices are followed. Geotechnical con- siderations include the following: • Due to the potential for liquefaction at drainage crossings, dynamic settlement up to ap- proximately 1 inch may occur in the event of a major local earthquake. The settlement is unlikely to damage the proposed PVC pipeline. 105761001 R El Camino Real .doc tyinyo El Camino Real Water System Project April 24, 2006 Carlsbad, California Project No. 105761001 • Shallow groundwater was encountered in our subsurface exploration, and may be present elsewhere along the alignment. Due to the anticipated depth of groundwater and the pro- posed pipeline depth, construction dewatering should be anticipated. • No active faults, landslides, or other geologic hazards are known or reported to be underly- ing the proposed pipeline alignment. 9. RECOMMENDATIONS Based on our understanding of the project, the following recommendations are provided for the design and construction of the proposed project. 9.1. 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. In addition, Typical Earthwork Guidelines for the project are included as Appendix C. In the event of a conflict in recommendations, the recommendations presented in the text of this report supersede those in Appendix C. 9.1.1. Site Preparation The project site should be cleared and grubbed prior to grading. Clearing and grubbing should consist of the removal of pavements and other deleterious materials, such as trash and debris, from the areas to be graded. Clearing and grubbing should extend to the outside of the proposed excavation and fill areas. The debris generated during clear- ing and grubbing should be removed from areas to be graded and disposed of off site at a legal dumpsite. 9.1.2. Excavation Characteristics The results of our subsurface exploration indicate that as presently proposed, the project site is underlain primarily by alluvium, terrace deposits, and materials of the Santiago Formation. Based on our subsurface exploration and experience with similar materials, 10576100! RElCaminoReal.doc El Camino Real Water System Project April 24, 2006 Carlsbad, California Project No. 105761001 the on-site soils should generally be excavatable by heavy-duty excavator and trackhoe type earthnioving equipment in good working condition. 9.1.3. Materials for Fill On-site soils with an organic content of less than 3 percent by volume (or 1 percent by weight) are suitable for use as fill. Fill material should not contain rocks or lumps over 6 inches in largest dimension, and not more than 40 percent larger than 3/4 inch. Utility trench backfill material should not contain rocks or lumps over 3 inches in largest dimen- sion. Soils classified as silts or clays should not be used for backfill material in the pipe zone. Larger chunks, if generated during excavation, may be broken into acceptably sized pieces or disposed of off site. Any imported fill material should be a low or very low ex- pansion potential (CBC Expansion Index of 50 or less) granular soil with a plasticity index of 12 or less. Import material should also have low corrosion potential (chloride content less than 500 parts per million [ppm], soluble sulfate content of less than 0.1 per- cent, and pH of 5.5 or more). Import material for bedding and the pipe zone should also meet the gradations indicated in Section 9.2. Materials for use as fill should be evaluated by Ninyo & Moore prior to filling or importing. 9.1.4. 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 ex- posed ground surface should then be scarified to a depth of approximately 8 inches and watered or dried, as needed, to achieve generally consistent moisture contents at or near the optimum moisture content. The scarified materials should then be compacted to 90 percent relative density in accordance with the latest American Society for Testing and Materials (ASTM) Test Method D 1557. The evaluation of compaction by Ninyo & Moore should not be considered to preclude any requirements for observation or ap- proval by governing agencies. It is the contractor's responsibility to notify Ninyo & Moore and the appropriate governing agency when project areas are ready for observa- tion, and to provide reasonable time for that review. 105761001 REICaminoRcal.doc tylnyo El Camino Real Water System Project April 24, 2006 Carlsbad, California Project No. 105761001 Fill materials should be moisture conditioned to near optimum 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 material following a delay in the grading operations, the exposed surface of previously compacted fill should be prepared to re- ceive fill. Preparation may include scarification, moisture conditioning, and recomp action. 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 near optimum moisture condition, 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 approximately 90 percent as evaluated by ASTM D 1557. Successive lifts should be treated in a like manner until the desired finished grades are achieved. In the trench zone defined as 1 foot or more above the top of the pipe, subgrade, aggregate base, and asphalt concrete should be compacted to 95 percent relative compaction. The thicknesses of asphalt concrete and aggregate base should be 6 inches and 20 inches, respectively, or match with the existing pavement sec- tions, whichever are greater. Special case should be exercised to avoid damaging the pipes during compaction of the backfill. 9.1.5. Temporary Slope Stability We recommend that trenches and excavations be designed and constructed in accor- dance with Occupational Health and Safety Administration (OSHA) regulations. These regulations provide trench sloping and shoring design parameters for trenches up to 20 feet deep based on a description of the soil types encountered. Trenches over 20 feet deep should be designed by the Contractor's engineer based on site-specific geotechni- cal analyses. For planning purposes, we recommend that the following OSHA soil classification be used: 105761001 R El Camino Real .doc El Camino Real Water System Project April 24, 2006 Carlsbad, California Project No. 105761001 Alluvium/Terrace Deposits Type C Santiago Formation Type B Upon making the excavations, the soil/rock classifications and excavation performance should be evaluated in the field by Ninyo & Moore in accordance with OSHA regulations. Temporary excavations should be constructed in accordance with OSHA recommenda- tions. For trench or other excavations, OSHA requirements regarding personnel safety should be met by laying back the slopes no steeper than 1.5:1 (horizontal:vertical) for alluvium and terrace deposits, and 1:1 for materials of the Santiago Formation. Tempo- rary excavations that encounter seepage may need shoring or may be stabilized by placing sandbags or gravel along the base of the seepage zone. Excavations encounter- ing seepage should be evaluated on a case-by-case basis. As an alternative to laying back the side walls, the excavations may be shored or braced. Temporary earth retaining systems will be subjected to lateral loads resulting from earth pressures. Shoring sys- tems for excavations may be designed using the lateral earth pressure parameters indicated on Figure 6. The design of the earth pressure diagram assumes that spoils from the excavation or other surcharge loads will not be placed above the excavation within a 1:1 plane extending up and back from the excavation. If spoil piles are placed closer than this to the braced exca- vation, the resulting surcharge loads should be considered in the bracing design. We recommend that an experienced structural engineer design the shoring systems. The shor- ing parameters presented in this report should be considered as guidelines. As discussed in the Section 7.3, landslides have been mapped in the vicinity of Carlsbad Village Drive and El Camino Real. Zones of weak, sheared earth materials may be pre- sent within landslide deposits and may be problematic if exposed in open excavations. Excavations should be evaluated by Ninyo & Moore to check if additional stabilization measures are needed. 105761001 RE1 Camino Real doc 10 El Camino Real Water System Project April 24, 2006 Carlsbad, California Project No. 105761001 9.1.6. Drainage Slope drainage should be diverted away from slopes and structures including temporary slopes during construction and the proposed pressure reducing station to suitable dis- charge areas by nonerodible devices (e.g., gutters, downspouts, concrete swales, etc.). Positive drainage adjacent to structures should be established and maintained. Surface drainage on the site should be provided so that water is not permitted to pond. A gradient of 2 percent or steeper should be maintained over wall backfill adjacent to the pressure reducing station and drainage patterns should be established to divert and re- move water from the site to appropriate outlets. Care should be taken by the contractor during grading to preserve any berms, drainage terraces, interceptor swales or other drainage devices on or adjacent to the property. Drainage patterns established at the time of grading should be maintained for the life of the project. The property operators should be made very clearly aware that altering drainage patterns during construction of the pipeline and pressure reducing station might be detrimental to adjacent slope stability and foundation performance. 9.2. Pipe Bedding and Modulus of Soil Reaction It is our recommendation that the new pipeline (pipe), where constructed in open excava- tions, be supported on 6 inches of granular bedding material. Granular pipe bedding should be provided to distribute vertical loads around the pipe. Bedding material and compaction re- quirements should be in accordance with this report, and the Carlsbad Municipal Water District Standard Specifications. The trench excavation should provide 6 to 8 inches of lateral clearance between the trench wall and the side of the pipe. Pipe bedding typically consists of graded aggregate. The pipe bedding and pipe zone backfill should conform to the following gradation limits: l05761001RE1CaminoRea1.doc 11 i^i fj El Camino Real Water System Project Carlsbad, California April 24, 2006 Project No. 105761001 Table 1 - Pipe Bedding/Backfill Gradation Limits Sieve Sizes 1" 3/4" No. 4 No. 30 No. 200 Percentage Passing Sieves 100% 90-100% 50-95% 25-45% 3-9% Pipe bedding and pipe zone backfill should have a Sand Equivalent (SE) of 30 or more, and be placed around the sides and top of the pipe. In addition, the pipe zone backfill should ex- tend 1 foot above the top of the pipe. The modulus of soil reaction (E) is used to characterize the stiffness of soil backfill placed at the sides of buried flexible pipes for the purpose of evaluating deflection caused by the weight of the backfill over the pipe. A soil reaction modulus of 1,800 pounds per square inch (psi) may be used for a 5- to 10-foot deep excavation backfilled with granular soil com- pacted to 90 percent based on ASTM D 1557. A soil reaction modulus of 2,100 psi may be used for trenches up to 15 feet deep. 9.3. CBC Seismic Design Parameters According to the 2001 CBC, the proposed project alignments are in Seismic Zone 4 and are within a Near Source Zone. Table 2 includes the seismic design parameters for the site as de- fined in, and for use with, the 2001 edition of the CBC. Table 2 - CBC Seismic Design Parameters Parameter Seismic Zone Factor, Z Soil Profile Type Seismic Coefficient, Ca Seismic Coefficient, Cv Near-Source Factor, N0 Near-Source Factor, Nv Seismic Source Type Value 0.40 Sz, 0.44 0.64 1.0 1.0 B 2001 CBC Reference Table 16A-I Table 16A-J Table 16A-Q Table 16A-R Table 16A-S Table 16A-T Table 16A-U 105761001 R El Camino Real .doc 12 Ei Camino Real Water System Project April 24, 2006 Carlsbad, California Project No. 105761001 9.4. Jack-and-Bore Design of shaft shapes, dimensions, and ground support systems for jack-and-bore excava- tions will be at the contractor's option in order to be compatible with his construction equipment and methods. Soldier piles with lagging or shored excavations may serve as a suitable support system for rectangular shafts, while circular steel ribs in conjunction with timber lagging or liner plates may be suitable for circular shafts. Jacking reaction force is developed by the action of the jack-and-bore operation against the surface of the opposite wall of the jacking pit. The jacking force is resisted by the bearing of the wall. The allowable jacking force may be calculated using the lateral earth pressures shown on Figure 7. Caving of the pipe shaft may occur. For stability and safety purposes, and to reduce ground movements, a full perimeter shaft support system should be installed as the excavation progresses. 9.5. Foundations Details of the future construction on the site are unknown at this time. Based on our under- standing that the proposed new pressure reducing station will be a relatively small, prefabricated structure, we are providing the following preliminary foundation recommenda- tions. Additional geotechnical evaluation studies may be needed once details of construction are known. 9.5.1. Shallow Foundations Continuous and/or spread footings should be founded in compacted fill or competent native material. Footings founded as recommended may be designed using an allowable bearing capacity of 2,500 pounds per square foot (psf). The allowable bearing pressures may be increased by one-third when considering loading of short duration such as wind or seismic forces. Recommendations for lateral resistance for footings are presented in the following section. 1057el001REICaminoRea] doc 13 • N'"jt" El Camino Real Water System Project April 24, 2006 Carlsbad, California Project No. 105761001 Foundations should have an embedment depth of 12 inches below the adjacent grade. Continuous footings should be 12 inches wide. Spread foundations should be 24 inches wide. Footings should be reinforced in accordance with the structural engineer's rec- ommendations. From a geotechnical standpoint, we recommend that footings founded in non-expansive granular materials be reinforced with four No. 4 or larger reinforcing bars, two placed near the top and two near the bottom of the footings. 9.5.2. Mat Foundations The proposed structures may be founded on a mat foundation supported on compacted fill or competent native material, using an allowable bearing capacity of 2,500 pounds psf. This allowable bearing capacity may be increased by one-third when considering loads of a short duration such as wind or seismic forces. Thickness and reinforcement of the mat foundation should be in accordance with the recommendations of a structural engineer. Mat foundations typically experience some deflection due to loads placed on the mat and the reaction of the soils underlying the mat. A design coefficient of subgrade reac- tion, Kyi, of 100 pounds per cubic inch (pci) may be used for evaluating such deflections at the building site. This value is based on a unit square foot area and should be adjusted for the planned mat size. The coefficient of subgrade reaction Kb for a mat of a specific width, may be evaluated using the following equation: Kb = Kvl[(b+l)/2b]2 where b is the width of the foundation. 9.5.3. Foundation Lateral Resistance For resistance of foundations to lateral loads, we recommend an allowable passive pres- sure exerted by an equivalent fluid weight of 300 pounds per cubic foot (pcf) be used with a value of up to 3,000 psf. This value assumes that the ground is horizontal for a distance of 10 feet or more, or three times the height generating the passive pressure, whichever is more. We recommend that the upper 1 foot of soil not protected by pave- ment or a concrete slab be neglected when calculating passive resistance. 105761001 REICammoReal.doc 14 ff/nyo El Camino Real Water System Project April 24, 2006 Carlsbad, California Project No. 105761001 For frictional resistance to lateral loads, we recommend a coefficient of friction of 0.35 be used between soil and concrete. The allowable lateral resistance can be taken as the sum of the frictional resistance and passive resistance provided the passive resistance does not exceed one-half of the total allowable resistance. The passive resistance values may be increased by one-third when considering loads of short duration such as wind or seismic forces. 9.5.4. Static Settlement We estimate that the proposed structures, designed and constructed as recommended herein, will undergo total settlements of less than approximately 1/2-inch. Differential settlements are typically less than about one-half of the total settlement. 9.6. Thrust Blocks Thrust blocks should be designed for the support of pipelines in accordance with the pres- sure diagram on Figure 7. Thrust block excavations should be backfilled with compacted granular material. 9.7. Corrosion Laboratory testing was performed on samples of the on-site soils to evaluate pH and electri- cal resistivity, as well as chloride and sulfate contents. The pH and electrical resistivity tests were performed in accordance with California Test 643 and the sulfate and chloride tests were performed in accordance with California Tests 417 and 422, respectively. These labora- tory test results are presented in Appendix B. The results of the corrosivity testing indicated electrical resistivity values of the samples tested of 2,350 and 5,630 ohm-cm. The soil pH values of the samples were 7.3 and 8.7. The test indi- cated chloride contents of 25 and 50. The sulfate content of the samples was 0.01%. Based on Caltrans criteria, the on-site soils would not be classified as corrosive, which is defined as soil with more than 500 ppm chlorides, more than 0.2 percent sulfates, or a pH less than 5.5. 105761001 R El Camino Real doc 15 El Camino Real Water System Project April 24, 2006 Carlsbad, California Project No. 105761001 Concrete in contact with soil or water that contains high concentrations of soluble sulfates can be subject to chemical deterioration. Laboratory testing indicated a sulfate content of the sample tested of less than 0.1 percent, which is considered negligible for sulfate attack (CBC, 2001). We recommend that 3 inches of concrete cover be provided over reinforcing steel for cast-in-place structures in contact with the soil. Although the results of the sulfate tests were not significantly high, due to the variability in the on-site soils along the pipeline alignment, we recommend that Type V cement be used for concrete structures in contact with soil. In addition, we recommend a water to cement ratio of no more than 0.45. 9.8. Construction Dewatering As discussed, groundwater was encountered in boring B-4 during our subsurface explora- tion. Accordingly, construction dewatering should be anticipated, particularly near Kelly Drive and El Camino Real where ground elevation is relatively low. Groundwater levels can fluctuate due to seasonal precipitation, irrigation, groundwater withdrawal or injection, and other factors. Discharge of water from excavations may require securing a National Pollution Discharge Elimination System (NPDES) permit. Compliance with the permit requirements may require testing and treatment of the water prior to discharge to storm drains. 9.9. Pre-Construction Conference We recommend that a pre-construction conference be held. Owner representatives, the civil engineer, Ninyo & Moore, and contractor should be in attendance to discuss the plans and the project. 9.10. Construction Observation The conclusions and recommendations presented in this report are based on analysis of ob- served conditions encountered in our exploratory borings. If conditions are found to vary from those described in this report, Ninyo & Moore should be notified, and additional rec- 105761001 R El Camino Real doc 16 El Camino Real Water System Project April 24, 2006 Carlsbad, California Project No. 105761001 ommendations will be provided upon request. Ninyo & Moore should review the project drawings and specifications prior to the commencement of construction. Ninyo & Moore should perform the needed observation and testing services during construction operations. The recommendations provided in this report are based on the assumption that Ninyo & Moore will provide geotechnical observation and testing services during construction. In the event that it is decided not to utilize the services of Ninyo & Moore during construction, we request that the selected consultant provide the client with a letter (with a copy to Ninyo & Moore) indicating that they fully understand Ninyo & Moore's recommendations, and that they are in full agreement with the design parameters and recommendations contained in this report. Construction of proposed improvements should be performed by qualified subcon- tractors utilizing appropriate techniques and construction materials. 10. LIMITATIONS The field evaluation, laboratory testing, and geotechnical analyses presented in this geotechnical report have been conducted in general accordance with current practice and the standard of care exercised by geotechnical consultants performing similar tasks in the project area. No warranty, expressed or implied, is made regarding the conclusions, recommendations, and opinions pre- sented in this report. There is no evaluation detailed enough to reveal every subsurface condition. Variations may exist and conditions not observed or described in this report may be encountered during construction. Uncertainties relative to subsurface conditions can be reduced through addi- tional subsurface exploration. Additional subsurface evaluation will be performed upon request. Please also note that our evaluation was limited to assessment of the geotechnical aspects of the project, and did not include evaluation of structural issues, environmental concerns, or the pres- ence of hazardous materials. This document is intended to be used only in its entirety. No portion of the 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 content, interpretations presented, or completeness of this document. 105761001 R El Camino Real .doc 17 El Camino Real Water System Project April 24, 2006 Carlsbad, California Project No. 105761001 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 that the conditions of a site could change with time as a result of natural processes or the activities of man at the subject site or nearby sites. In addition, changes to the applicable laws, regulations, codes, and standards of practice may occur due to government 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 control. This report is intended exclusively for use by the client. Any use or reuse of the findings, conclu- sions, and/or recommendations of this report by parties other than the client is undertaken at said parties' sole risk. 105761001 R El Camino Real .doc 18 El Camino Real Water System Project April 24, 2006 Carlsbad, California Project No. 105761001 11. SELECTED REFERENCES California Building Standards Commission, 2001, California Building Code, Title 24, Part 2, Volumes 1 and 2. California Department of Conservation, Division of Mines and Geology, 1996, Geologic Maps of the Encinitas and Rancho Santa Fe 7.5' Quadrangles: Scale 1:24,000. California Geological Survey (CGS), 1995, Landslide Hazards in the Northern Part of the San Diego Metropolitan Area, San Diego County, California: Open File Report 95-04. California Geological Survey (CGS), 1996, Geologic Maps of the Northwestern Part of San Diego County, California: Open File Report 96-02. California Geological Survey (CGS), 1998, Maps of Known Active Fault Near-Source Zones in Cali- fornia and Adjacent Portions of Nevada: International Conference of Building Officials. County of San Diego, 1975, Orthotopographic Survey Map, Sheet 354-1683, Scale 1:2400. County of San Diego, 1975, Orthotopographic Survey Map, Sheet 358-1677, Scale 1:2400. County of San Diego, 1975, Orthotopographic Survey Map, Sheet 3584671, Scale 1:2400. County of San Diego, 1975, Orthotopographic Survey Map, Sheet 366-1671, Scale 1:2400. Jennings, C.W., 1994, Fault Activity Map of California and Adjacent Areas: California Division of Mines and Geology (CDMG), California Geologic Data Map No. 6, scale 1:750,000. Norris, R.M., and Webb, R.W., 1990, Geology of California: John Wiley & Sons, Inc. United States Department of the Interior, Bureau of Reclamation, 1989, Earth Manual. 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/California Geological Survey, 2003, Probabilistic Seismic Haz- ards Assessment Model for California. AERIAL PHOTOGRAPHS Source Date Flight Numbers Scale United States Department of Agriculture 4-11-53 AXN-8M 102 & 103 1:20,000 105761001 RElCaminoRcal.doc 19 tyinyo « • jr JfVJJjri ^*f> '& ti&>- i W ««t» i r^w^ / x<^ < * «A fe, '-Ja• '• , { r ^% ,$|?g* REFERENCE; 2005 THOMAS GUIDE FOR SAN DtEGO COUNTY, STREET GUIDE AND DIRECTORY APPROXIMATE SCALE IN FEET NOTE: ALL DIMENSIONS. DIRECTIONS AND LOCATIONS ARE APPROXI MATE SITE LOCATION MAP EL CAMINO REAL WATER SYSTEM PROJECT CARLSBAD, CALIFORNIA itrasm c».t*rett*tto. aw APPROXIMATE SCALE Z 30 60 MILES After Norris and Webb, 1990. PROJECT NO. 105761001 DATE 4/06 FAULT LOCATION MAP FIGURE EL CAMINO REAL WATER SYSTEM PROJECT CARLSBAD, CALIFORNIA GROUND SURFACE• £±£ITt=l 11_ 12 INCHES OR MORE £. H 12 INCHES OR MORE D NOTES: APPARENT LATERAL EARTH PRESSURE, Pg Pa - 27H psf CONSTRUCTION TRAFFIC INDUCED SURCHARGE PRESSURE, Ps F| = 120 psf PASSIVE LATERAL EARTH PRESSURE. P Pp - 300D psf ASSUMES GROUNDWATER NOT PRESENT SURCHARGES FROM EXCAVATED SOIL OR CONSTRUCTION MATERIALS ARE NOT INCLUDED H AND D ARE IN FEET NOT TO SCALE /y//gr**yyVonre PROJECT NO. 105761001 DATE 4/06 LATERAL EARTH PRESSURES FOR BRACED EXCAVATION (GRANULAR SOIL) EL CAMINO REAL WATER SYSTEM PROJECT CARLSBAD, CALIFORNIA FIGURE 6 GROUND SURFACE d (VARIES) THRUST BLOCK Vt d \_ P D (VARIES) NOTES: GROUNDWATER BELOW BLOCK X (D2-d2) = 150(D2-d2) Ib/ft d AND D ARE IN FEET ASSUMES BACKFILL IS GRANULAR MATERIAL ASSUMES THRUST BLOCK IS ADJACENT TO COMPETENT MATERIAL NOT TO SCALE yy//gr0*yyioorB PROJECT NO. 105761001 DATE 4/06 THRUST BLOCK LATERAL EARTH PRESSURE DIAGRAM EL CAMINO REAL WATER SYSTEM PROJECT CARLSBAD, CALIFORNIA FIGURE 7 El Camino Real Water System Project April 24, 2006 Carlsbad, California Project No. 105761001 APPENDIX A BORING 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 excava- tions. 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 140-pound hammer, in general accordance with ASTM D 3550-84. The driving weight was permitted to fall freely. The approximate length of the fall, the weight of the hammer, and the number of blows per foot of driving are presented on the boring logs as an index to the relative resistance of the materials sampled. The samples were removed from the sample barrel in the brass rings, sealed, and transported to the labo- ratory for testing. 105761001 RElCaminoReal.doc i o 0 SAMPLES 1Jgl£ : I 1 [\ 0 h- o m xx/xx MOISTURE (%)9 •¥•DRY DENSITY (PCF)SYMBOL1 F1CATION.C.S.1O SM BORING LOG EXPLANATION SHEET Bulk sample. Modified split-barrel drive sampler. No recovery with modified split-barrel drive sampler. Sample retained by others. Standard Penetration Test (SPT). No recovery with a SPT. Shelby tube sample. Distance pushed in inches/length of sample recovered in inches. No recovery with Shelby tube sampler. Continuous Push Sample. Seepage. Groundwater encountered during drilling. Groundwater measured after drilling. ALLUVIUM: Solid line denotes unit change. Dashed line 3enotes materiarcEange. Attitudes: 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 boring. bottom of the M-M&L^ AM BORING LOG ,jnm6^ff:^^nKi^O^^ EXPLANATION OF BORING LOG SYMBOLS f H f PROJECT NO. DARev.TE FIGURE 31/03 U.S.C.S. METHOD OF SOIL CLASSIFICATION MAJOR DIVISIONS SYMBOL TYPICAL NAMES COARSE-GRAINED SOILS(More than 1/2 of soil>No. 200 sieve size)VJ _. o 'I i« *S '" R £3 >w ^ £ g g 'S3 <! § °2 £ o 9 g 6 £ 1 SZ g, VE 1 GRAVELS * •(More than 1/2 of coarse •/ fraction ' •» i.> No. 4 sieve size) ./ • •-.- i SANDS [1 : (More than 1/2 of coarse 1 fraction I <No. 4 sieve size) |! SILTS & CLAYS Liquid Limit <50 SILTS & CLAYS j-^x Liquid Limit >50 K$ EH JJ ^E 2•S 2Kg gj HIGHLY ORGANIC SOILS uw fflali_ —:/ GP '• GM• :"/ GC j ! ;: i SW Mi SP : SM ^ sc ML CL • OL MHn™ m Si sl OH Pt Well graded gravels or gravel-sand mixtures, Poorly graded gravels or gravel-sand mixtures, little or no fines Silty gravels, gravel-sand-silt mixtures Clayey gravels, gravel-sand-clay mixtures Well graded sands or gravelly sands, little or no fines Poorly graded sands or gravelly sands, little or no fines Silty sands, sand-silt mixtures Clayey sands, sand-clay mixtures Inorganic silts and very fine sands, rock flour, silty or clayey fine sands or clayey silts with Inorganic clays of low to medium plasticity, gravelly clays, sandy clays, silty clays, lean Organic silts and organic silty clays of low plasticity Inorganic silts, micaceous or diatomaceous fine sandy or silty soils, elastic silts Inorganic clays of high plasticity, fat clays Organic clays of medium to high plasticity, organic silty clays, organic silts Peat and other highly organic soils GRAIN SIZE CHART CLASSIFICATION BOULDERS COBBLES GRAVEL Coarse Fine SAND Coarse Medium Fine SILT & CLAY RANGE OF GRAIN SIZE U.S. Standard Sieve Size Above 12" 12" to 3" 3" to No. 4 y to 3/4" 3/4" to No. 4 No. 4 to No. 200 No. 4 to No. 10 No. 10 to No. 40 No. 40 to No. 200 Below No. 200 Grain Size in Millimeters Above 305 305 to 76.2 76.2 to 4.76 76.2 to 19.1 19.1 to 4.76 4.76 to 0.075 4.76 to 2.00 2.00 to 0.420 0.420 to 0.075 Below 0.075 PLASTICITY CHART Zj/t / CL-M / L / / CL / ML / X 1OL / / / CH X // MH / OH / 0 10 20 30 40 50 6O 70 BO 90 100 LIQUID LIMTT(LL), % U.S.C.S. METHOD OF SOIL CLASSIFICATION USCS Soil Classification Updated Nov. 2004 "S&I Q.IllQ 0 \ 5- 10~ 70 0u <c ^3 _ 11 " 9LJJ • 0 (U Q. 1 - i oOu_co5o CD 10 » A *31MT £ W£D CO O 18.0 7JS«/ oo^ fw LUQ>-fcO 98.8 w oCD ? W 5i% *t zo1- .< w 9d"- co«-lw ^5o CL-ML SM M AMuF DATE DRILLED 02/09/06 BORING NO. B-l GROUND ELEVATION 60'+/-MSL SHEET 1 OF 1 METHOD OF DRILLING 8" Diameter Hollow Stem Auger CME 75 DRIVE WEIGHT 140 Ibs. Spooling Cable DROP 30" SAMPLED BY RUB LOGGED BY RUB REVIEWED BY JG/RI DESCRIPTION/INTERPRETATION 6" Asphalt concrete. ALLUVIUM: Light brown, moist, firm, silty CLAY to clayey SILT; with some fine sand; micaceous. Gray, moist, medium dense, silty fine SAND; micaceous. Total Depth- 11.5'. No groundwater encountered. Backfilled with bentonite on 02/09/06. Capped top 1 foot with concrete. BORING LOG • ••^^^ft El Camino Real Water System Project !%•• ^5 Carlsbad, California PROJECT NO. DATE FIGURE 105761001 04/06 A-l "ffi£ I Q.litQ 0 • 10- 15- 70 Vu ^tf<u ^ D _ 1 •• ^ 1 1 ; 3JJ • 3 <L D f- .1 • ' i 1 J OOLL. CO5o 20 21 27 M *Jm" g_ HIo:31 COo 17.2 ^ •J OQ-^ c CO LUQ >-o:a 103.3 fO oCOF CO • b\ ^ zot~ .< CO96"-coto-SCO 35o SM CL « ^MaF DATE DRILLED 02/09/06 BORING NO. B-2 GROUND ELEVATION 75'+/-MSL SHEET 1 OF 1 METHOD OF DRILLING 8" Diameter Hollow Stem Auger CME 75 DRIVE WEIGHT 140 Ibs. Spooling Cable DROP 30" SAMPLED BY RUB LOGGED BY RUB REVIEWED BY JG/RI DESCRIPTION/INTERPRETATION 6" Asphalt concrete. ALLUVIUM: Brown, damp, loose, silty SAND. Moist; micaceous. Brown, moist to wet, very stiff, fine san3y CLAY. Grayish brown. Total Depth- 16.51. No groundwater encountered. Backfilled with bentonite on 02/09/06. Capped top 1 foot with concrete. BORING LOG •••• ^k E1 Camino Real w^ter System Project I%M ^5 Carlsbad, California PROJECT NO. DATE FIGURE 105761001 04/06 A-2 "<£ X D_ Q 0 10- 30 yu • « 0 3 _ 1 - - 3JJ 3 c0 Q — F - ,- j OOu.w O 50/6" 50/5" A *JMiF jo^sD (0 O 13-6 7£ •/ OD^ ^CO LUQ >-o:Q 109.1 fO OCQ?>-w 1™ ^****** ^ zO h- .< COyd"- coCOl^CO ^5O SC SM • •IMQF DATE DRILLED 02/10/06 BORING NO. B-3 GROUND ELEVATION 90'+/-MSL SHEET 1 OF I METHOD OF DRILLING 8" Diameter Hollow Stem Auger CME 75 DRIVE WEIGHT 140 Ibs. Spooling Cable DROP 30" SAMPLED BY RUB LOGGED BY RUB REVIEWED BY JG/RI DESCRIPTION/INTERPRETATION 8" Asphalt concrete. TERRACE DEPOSITS: Light brown, damp, very dense, clayey fine SAND. Light brown and tan, damp, very dense, silty fine SAND. Total Depth =10.5'. No groundwater encountered. Backfilled with bentonite on 02/10/06. Capped top 1 foot with concrete. BORING LOG vmWB^h El Camino Real Water System Project i%*M iB Carlsbad, California PROJECT NO. DATE FIGURE 105761001 04/06 A-3 I Q.LUO 0 5* 10- 70 II (Ju m <V "5 .1 1 ; — >jj 5 ca Q I 1 X j h-OOLL CO O 18 46 jv/7 q- LUcc3 to o 27.4 .SZ. fILU o0-£ CO 01o Eo 89.6 f0 Om? CO • i^ I 1!i 1 &J zo < CO 96 "- coCO _;CO D 3O SC M _MUT DATE DRILLED 02/10/06 BORING NO. B-4 GROUND ELEVATION 52'+/-MSL SHEET I OF \ METHOD OF DRILLING 8" Diameter Hollow Stem Auger CME 75 DRIVE WEIGHT 140 Ibs. Spooling Cable DROP 30" SAMPLED BY RUB LOGGED BY RUB REVIEWED BY JG/RI DESCRIPTION/INTERPRETATION 5" asphalt concrete. 6irsandy~gravel. ALLUVIUM: Brown, damp, loose, clayey SAND. Dark brown and gray; moist to wet; micaceous. Saturated. Medium dense; no recovery. Total Depth =16.5'. Groundwater encountered at 7.0'. Backfilled with bentonite on 02/10/06. Capped top 3 foot with concrete. BORING LOG VVVH^^B El Camino Real Water System Project |%BM ^S Carlsbad, California PROJECT NO. DATE FIGURE 105761001 04/06 A-4 c- X Q.01O ° 5- 10- ?n ifLL «= < U - .1 : - )I ) a O 1 j K OOLL. 1g 67 m * Jv/ F 5^ LUm D COo 9.0 10.8 ma oa. f CO LU D o: Q 100.6 108.8 P'r OCD ? (O •*; | *£$ yyfyry*}*}lrrr\^y' %il zo < (O"d "- w8" O SC SC MpF DATE DRILLED 02/10/06 BORING NO. B-5 GROUND ELEVATION 135'+/-MSL SHEET 1 OF 1 METHOD OF DRILLING 8" Diameter Hollow Stem Auger CME 75 DRIVE WEIGHT 140 Ibs. Spooling Cable DROP 30" SAMPLED BY RUB LOGGED BY RUB REVIEWED BY JG/RI DESCRIPTION/INTERPRETATION 4.5" asphalt concrete. 6" sandy~gravel; brown; damp to moist. TERRACE DEPOSITS: Brown and gray, damp, dense, clayey SAND; micaceous. SANTIAGO FORMATION: White and olive, damp to moist, weakly cemented, clayey SANDSTONE. Total Depth = 11.5'. No groundwater encountered. Backfilled with bentonite on 02/1 0/06. Capped top 1 foot with concrete. BORING LOG , VmMB ^m HI Cairano Real Water System Project \ wMk ^B Carlsbad, California PROJECT NO. DATE FIGURE 105761001 04/06 A-5 El Camino Real Water System Project April 24, 2006 Carlsbad, California Project No. 105761001 APPENDIX B LABORATORY TESTING Classification Soils were visually and texturally classified in accordance with the Unified Soil Classification System (USCS) in general accordance with ASTM D 2488-00. Soil classifications are indicated on the logs of the exploratory excavations in Appendix A. ID-Place Moisture and Density Tests The moisture content and dry density of relatively undisturbed samples obtained from the ex- ploratory excavations were evaluated in general accordance with ASTM D 2937-00. The test results are presented on the logs of the exploratory excavations in Appendix A. Gradation Analysis A test was performed on a selected representative soil sample in general accordance with ASTM D 422-63. The grain-size distribution curve is shown on Figures B-l. The test results were utilized in evaluating the soil classifications in accordance with the Unified Soil Classification System. Atterberg Limits A Test was performed on a selected representative fine-grained soil sample to evaluate the liquid limit, plastic limit, and plasticity index in general accordance with ASTM D 4318-00. These test results were utilized to evaluate the soil classification in accordance with the Unified Soil Classi- fication System. The test results and classifications are shown on Figure B-2. Shear Strength Test A shear test was performed on an undisturbed sample in general accordance with ASTM D 3080-98 to evaluate the shear strength characteristics of selected materials. The sample was inundated during shearing to represent adverse field conditions. The results are shown on Fig- ure B-3. Soil Corrosivity Tests Soil pH, and electrical resistivity tests were performed on representative samples in general ac- cordance with California Test (CT) 643. The chloride content of the selected sample was evaluated in general accordance with CT 422. The sulfate content of the selected sample was evaluated in general accordance with CT 417. The test results are presented on Figure B-4. 105761001REICaminoReal.doc GFiAVEL Coarse Fine SAND Coarse j Medium Fine U.S. STANDARD SIEVE NUMBERS 3" 2"1-1/2" 1-3/4" 3/8' 4 10 16 30 50 1- 5 LU * •z. LL. ID IDQ. I T 1 100 10 c>ymbol • Sample Location B-4 k^"^ ; vN s i ^,s\1 FINES SILT CLAY HYDROMETER 100 200 \ \ i Ss • i 1 0.1 0.01 0.001 0.0001 GRAIN SIZE IN MILLIMETERS Depth (ft) 1 0-5.0 Liquid Limit - Plastic Limit - Plasticity Index - DID - DM D60 - c. - cc - Passing No. 200 33 U.S.C.S SC PERFORMED IN GENERAL ACCORDANCE WITH ASTM D 422-63 (02) ty/nyO&tyfSWT* GRADATION TEST RESULTS PROJECT NO. 105761001 DATE 4/06 El Camino Real Water System Project Carlsbad, California FIGURE B-1 105761001 SIEVE B-4 @ 1.0-5.0.ilS SYMBOL • LOCATION B-1 DEPTH (FT) 0.5-5.0 LIQUID LIMIT, LL (%) 21 PLASTIC LIMIT, PL (%) 17 PLASTICITY INDEX, PI (%) 4 uses CLASSIFICATION (Fraction Finer Than No. 40 Sieve) CL-ML uses (Entire Sample) CL-ML NP - Indicates Non-Plastic 60 50 40 _ 30 20 10 CL-ML • CLorOL- MLorOL CHorOH • MHorOH. 0 10 20 30 40 50 60 70 80 90 100 LL (%) PERFORMED IN GENERAL ACCORDANCE WITH ASTM D 4318-00 PROJECT 105761001 DATE 4/06 ATTERBERG LIMITS TEST RESULTS El Camino Real Water System Project Carlsbad, California FIGURE B-2 10S7B1001 ATTERBERG.xls 2000 1500 u_ COCO LU LU Xco 1000 500 500 1000 1500 NORMAL STRESS (PSF) . 2000 Description Clayey SAND Clayey SAND Symbol - -X - • Sample Location B-5 B-5 Depth (ft) 5.0-6.5 5.0-6.5 Shear Strength Peak Ultimate Cohesion, c (psf) 80 60 Friction Angle, 4> (degrees) 33 33 Soil Type SC SC PERFORMED IN GENERAL ACCORDANCE WITH ASTM D 3080-03 PROJECT 105761001 DATE 4/06 DIRECT SHEAR TEST RESULTS El Camino Real Water System Project Carlsbad, California FIGURE B-3 105761001 SHEAR B-5 @ 5,0 -6.5.xls SAMPLE LOCATION B-1 B-5 SAMPLE DEPTH (FT) 0.5-5.0 1.0-5.0 PH1 7.3 8.7 RESISTIVITY ' (Ohm-cm) 5,630 2,350 SULFATE CONTENT 2 0.01 0.01 CHLORIDE CONTENT 3 (ppm) 25 50 PERFORMED IN GENERAL ACCORDANCE WITH CALIFORNIA TEST METHOD 643 PERFORMED IN GENERAL ACCORDANCE WITH CALIFORNIA TEST METHOD 417 PERFORMED IN GENERAL ACCORDANCE WITH CALIFORNIA TEST METHOD 422 PROJECT 105761001 DATE 4/06 CORROSIVITY TEST RESULTS El Camino Real Water System Project Carlsbad, California FIGURE B-4 105781001 CORROSlVITY.xls El Camino Real Water System Project April 24, 2006 Carlsbad, California Project No. 105761001 APPENDIX C TYPICAL EARTHWORK GUIDELINES El Camino Real Water System Project April 24, 2006 Carlsbad, California Project No. 105761001 TABLE OF CONTENTS Page 1. GENERAL 1 2. OBLIGATIONS OF PARTIES 2 3. SITE PREPARATION 3 4. REMOVALS AND EXCAVATIONS 4 5. COMPACTED FILL 4 6. OVERSIZED MATERIAL 7 7. SLOPES 8 8. TRENCH BACKFILL 10 9. DRAINAGE 12 10. SITE PROTECTION 12 11. DEFINITIONS OF TERMS 15 10576100] Earthwork.doc ; ftev 12/05 El Camino Real Water System Project April 24, 2006 Carlsbad, California Project No. 105761001 TYPICAL EARTHWORK GUIDELINES GENERAL These guidelines and the standard details attached hereto are presented as general procedures for earthwork construction for sites having slopes less than 10 feet high. They are to be utilized in conjunction with the project grading plans. These guidelines are considered a part of the geo- technical report, but are superseded by recommendations in the geotechnical report in the case of conflict. Evaluations performed by the consultant during the course of grading may result in new recommendations which could supersede these specifications and/or the recommendations of the geotechnical report. It is the responsibility of the contractor to read and understand these guide- lines as well as the geotechnical report and project grading plans. The contractor shall not vary from these guidelines without prior recommendations by the geotechnical consultant and the approval of the client or the client's authorized rep- resentative. Recommendations by the geotechnical consultant and/or client shall not be considered to preclude requirements for approval by the jurisdictional agency prior to the execution of any changes. The contractor shall perform the grading operations in accordance with these specifications, and shall be responsible for the quality of the finished product notwithstanding the fact that grading work will be observed and tested by the geotechnical consultant. It is the responsibility of the grading contractor to notify the geotechnical consultant and the jurisdictional agencies, as needed, prior to the start of work at the site and at any time that grading resumes after interruption. Each step of the grading operations shall be observed and documented by the geotechnical consultant and, where needed, reviewed by the appropriate jurisdictional agency prior to proceeding with subsequent work. If, during the grading operations, geotechnical conditions are encountered which were not anticipated or described in the geotechnical report, the geotechnical consultant shall be notified immediately and additional recommendations, if applicable, may be provided. An as-graded report shall be prepared by the geotechnical consultant and signed by a regis- tered engineer and registered engineering geologist. The report documents the geotechnical consultants' observations, and field and laboratory test results, and provides conclusions regarding whether or not earthwork construction was per- 105761001 Earthwork-doc 1 Rev. 12/05 El Camino Real Water System Project April 24, 2006 Carlsbad, California Project No. 105761001 formed in accordance with the geotechnical recommendations and the grading plans. Recommendations for foundation design, pavement design, subgrade treat- ment, etc., may also be included in the as-graded report. For the purpose of evaluating quantities of materials excavated during grading and/or locat- ing the limits of excavations, a licensed land surveyor or civil engineer shall be retained. Definitions of terms utilized in the remainder of these specifications have been provided in Section 11. OBLIGATIONS OF PARTIES The parties involved in the projects earthwork activities shall be responsible as outlined in the following sections. The client is ultimately responsible for each of the aspects of the project. The client or the client's authorized representative has a responsibility to review the findings and recommendations of the geotechnical consultant. The client shall authorize the con- tractor and/or other consultants to perform work and/or provide services. During grading the client or the client's authorized representative shall remain on site or remain reasonably accessible to the concerned parties to make the decisions that may be needed to maintain the flow of the project. The contractor is responsible for the safety of the project and satisfactory completion of grading and other associated operations, including, but not limited to, earthwork in accordance with the project plans, specifications, and jurisdictional agency re- quirements. During grading, the contractor or the contractor's authorized representative shall remain on site. The contractor shall further remain accessible during non-working hours, including at night and during days off. The geotechnical consultant shall provide observation and testing services and shall make evaluations to advise the client on geotechnical matters. The geotechnical consult- ant shall report findings and recommendations to the client or the client's authorized representative. Prior to proceeding with any grading operations, the geotechnical consultant shall be noti- fied two working days in advance to schedule the needed observation and testing services. Prior to any significant expansion or reduction in the grading operation, the geotechni- cal consultant shall be provided with two working days notice to make appropriate adjustments in scheduling of on-site personnel. 105761001 Eanhwork.doc El Camino Real Water System Project April 24, 2006 Carlsbad, California Project No. 105761001 Between phases of grading operations, the geotechnical consultant shall be provided with two working days notice in advance of commencement of additional grading operations. SITE PREPARATION Site preparation shall be performed in accordance with the recommendations presented in the following sections. The client, prior to any site preparation or grading, shall arrange and attend a pre-grading meeting between the grading contractor, the design engineer, the geotechnical con- sultant, and representatives of appropriate governing authorities, as well as any other involved parties. The parties shall be given two working days notice. Clearing and grubbing shall consist of the substantial removal of vegetation, brush, grass, wood, stumps, trees, tree roots greater than 1/2-inch in diameter, and other deleteri- ous materials from the areas to be graded. Clearing and grubbing shall extend to the outside of the proposed excavation and fill areas. Demolition in the areas to be graded shall include removal of building structures, founda- tions, reservoirs, utilities (including underground pipelines, septic tanks, leach fields, seepage pits, cisterns, etc.), and other manmade surface and subsurface im- provements, and the backfilling of mining shafts, tunnels and surface depressions. Demolition of utilities shall include capping or rerouting of pipelines at the project perimeter, and abandonment of wells in accordance with the requirements of the governing authorities and the recommendations of the geotechnical consultant at the time of demolition. The debris generated during clearing, grubbing and/or demolition operations shall be re- moved from areas to be graded and disposed of off site at a legal dump site. Clearing, grubbing, and demolition operations shall be performed under the obser- vation of the geotechnical consultant. The ground surface beneath proposed fill areas shall be stripped of loose or unsuitable soil. These soils may be used as compacted fill provided they are generally free of or- ganic or other deleterious materials and evaluated for use by the geotechnical consultant. The resulting surface shall be evaluated by the geotechnical consultant prior to proceeding. The cleared, natural ground surface shall be scarified to a depth of approximately 8 inches, moisture conditioned, and compacted in accordance with the specifications presented in Section 5 of these guidelines. 10576100! Earthworkdoc El Camino Real Water System Project April 24, 2006 Carlsbad, California Project No. 105761001 REMOVALS AND EXCAVATIONS Removals and excavations shall be performed as recommended in the following sections. Removals Materials which are considered unsuitable shall be excavated under the observation of the geotechnical consultant in accordance with the recommendations con- tained herein. Unsuitable materials include, but may not be limited to, dry, loose, soft, wet, organic, compressible natural soils, fractured, weathered, soft bedrock, and undocumented or otherwise deleterious fill materials. Materials deemed by the geotechnical consultant to be unsatisfactory due to moisture conditions shall be excavated in accordance with the recommendations of the geotechnical consultant, watered or dried as needed, and mixed to a generally uniform moisture content in accordance with the specifications presented in Section 5 of this document. Excavations Temporary excavations no deeper than 5 feet in firm fill or natural materials may be made with vertical side slopes. To satisfy California Occupational Safety and Health Administration (CAL OSHA) requirements, any excavation deeper than 5 feet shall be shored or laid back at a 1:1 inclination or flatter, depend- ing on material type, if construction workers are to enter the excavation. COMPACTED FILL Fill shall be constructed as specified below or by other methods recommended by the geotechni- cal consultant. Unless otherwise specified, fill soils shall be compacted to 90 percent relative compaction, as evaluated in accordance with ASTM Test Method D 1557. Prior to placement of compacted fill, the contractor shall request an evaluation of the ex- posed ground surface by the geotechnical consultant. Unless otherwise recommended, the exposed ground surface shall then be scarified to a depth of ap- proximately 8 inches and watered or dried, as needed, to achieve a generally uniform moisture content at or near the optimum moisture content. The scarified materials shall then be compacted to 90 percent relative compaction. The evalua- tion of compaction by the geotechnical consultant shall 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 appro- priate governing agency when project areas are ready for observation, and to provide reasonable time for that review. 105761001 Earthwork.doc El Camino Real Water System Project April 24, 2006 Carlsbad, California Project No. 105761001 Excavated on-site materials which are in general compliance with the recommendations of the geotechnical consultant may be utilized as compacted fill provided they are generally free of organic or other deleterious materials and do not contain rock fragments greater than 6 inches in dimension. During grading, the contractor may encounter soil types other than those analyzed during the preliminary geotechnical study. The geotechnical consultant shall be consulted to evaluate the suitability of any such soils for use as compacted fill. Where imported materials are to be used on site, the geotechnical consultant shall be notified three working days in advance of importation in order that it may sample and test the materials from the proposed borrow sites. No imported materials shall be deliv- ered for use on site without prior sampling, testing, and evaluation by the geotechnical consultant. Soils imported for on-site use shall preferably have very low to low expansion potential (based on UBC Standard 18-2 test procedures). Lots on which expansive soils may be exposed at grade shall be undercut 3 feet or more and capped with very low to low expansion potential fill. Details of the undercutting are provided in the Transi- tion and Undercut Lot Details, Figure B of these guidelines. In the event expansive soils are present near the ground surface, special design and construction considera- tions shall be utilized in general accordance with the recommendations of the geotechnical consultant. Fill materials shall be moisture conditioned to near optimum moisture content prior to placement. The optimum moisture content will vary with material type and other factors. Moisture conditioning of fill soils shall be generally uniform in the soil mass. Prior to placement of additional compacted fill material following a delay in the grading op- erations, the exposed surface of previously compacted fill shall be prepared to receive fill. Preparation may include scarification, moisture conditioning, and re- compaction. Compacted fill shall be placed in horizontal lifts of approximately 8 inches in loose thick- ness. Prior to compaction, each lift shall be watered or dried as needed to achieve near optimum moisture condition, mixed, and then compacted by mechanical methods, using sheepsfoot rollers, multiple-wheel pneumatic-tired rollers, or other appropriate compacting rollers, to the specified relative compaction. Successive lifts shall be treated in a like manner until the desired finished grades are achieved. Fill shall be tested in the field by the geotechnical consultant for evaluation of general com- pliance with the recommended relative compaction and moisture conditions. Field density testing shall conform to ASTM D 1556-00 (Sand Cone method), D 2937-00 (Drive-Cylinder method), and/or D 2922-96 and D 3017-96 (Nuclear Gauge method). Generally, one test shall be provided for approximately every 2 vertical 105761001 Earthwork doc El Camino Real Water System Project April 24, 2006 Carlsbad, California Project No. 105761001 feet of fill placed, or for approximately every 1000 cubic yards of fill placed. In ad- dition, on slope faces one or more tests shall be taken for approximately every 10,000 square feet of slope face and/or approximately every 10 vertical feet of slope height. Actual test intervals may vary as field conditions dictate. Fill found to be out of conformance with the grading recommendations shall be removed, mois- ture conditioned, and compacted or otherwise handled to accomplish general compliance with the grading recommendations. The contractor shall assist the geotechnical consultant by excavating suitable test pits for removal evaluation and/or for testing of compacted fill. At the request of the geotechnical consultant, the contractor shall "shut down" or restrict grading equipment from operating in the area being tested to provide adequate test- ing time and safety for the field technician. The geotechnical consultant shall maintain a map with the approximate locations of field density tests. Unless the client provides for surveying of the test locations, the loca- tions shown by the geotechnical consultant will be estimated. The geotechnical consultant shall not be held responsible for the accuracy of the horizontal or verti- cal locations or elevations. Grading operations shall be performed under the observation of the geotechnical consultant. Testing and evaluation by the geotechnical consultant does not preclude the need for approval by or other requirements of the jurisdictional agencies. Fill materials shall not be placed, spread or compacted during unfavorable weather condi- tions. When work is interrupted by heavy rains, the filling operation shall not be resumed until tests indicate that moisture content and density of the fill meet the project specifications. Regrading of the near-surface soil may be needed to achieve the specified moisture content and density. Upon completion of grading and termination of observation by the geotechnical consultant, no further filling or excavating, including that planned for footings, foundations, re- taining walls or other features, shall be performed without the involvement of the geotechnical consultant. Fill placed in areas not previously viewed and evaluated by the geotechnical consultant may have to be removed and recompacted at the contractor's expense. The depth and ex- tent of removal of the unobserved and undocumented fill will be decided based upon review of the field conditions by the geotechnical consultant. Off-site fill shall be treated in the same manner as recommended in these specifications for on-site fills. Off-site fill subdrains temporarily terminated (up gradient) shall be surveyed for future locating and connection. 105761001 Earthwork doc El Camino Real Water System Project April 24, 2006 Carlsbad, California Project No. 105761001 OVERSIZED MATERIAL Oversized material shall be placed in accordance with the following recommendations. During the course of grading operations, rocks or similar irreducible materials greater than 6 inches in dimension (oversized material) may be generated. These materials shall not be placed within the compacted fill unless placed in general accordance with the recommendations of the geotechnical consultant. "Where oversized rock (greater than 6 inches in dimension) or similar irreducible material is generated during grading, it is recommended, where practical, to waste such mate- rial off site, or on site in areas designated as "nonstructural rock disposal areas." Rock designated for disposal areas shall be placed with sufficient sandy soil to gen- erally fill voids. The disposal area shall be capped with a 5-foot thickness of fill which is generally free of oversized material. Rocks 6 inches in dimension and smaller may be utilized within the compacted fill, provided they are placed in such a manner that nesting of rock is not permitted. Fill shall be placed and compacted over and around the rock. The amount of rock greater than 3/4-inch in dimension shall generally not exceed 40 percent of the total dry weight of the fill mass, unless the fill is specially designed and constructed as a "rock fill." Rocks or similar irreducible materials greater than 6 inches but less than 4 feet in dimension generated during grading may be placed in windrows and capped with finer materi- als in accordance with the recommendations of the geotechnical consultant, the approval of the governing agencies, and the Oversized Rock Placement Detail, Fig- ure D, of these guidelines. Selected native or imported granular soil (Sand Equivalent of 30 or higher) shall be placed and flooded over and around the wind- rowed rock such that voids are filled. Windrows of oversized materials shall be staggered so that successive windrows of oversized materials are not in the same vertical plane. Rocks greater than 4 feet in dimension shall be broken down to 4 feet or smaller before placement, or they shall be disposed of off site. 105761001 Earthwork.doc El Camino Real Water System Project April 24, 2006 Carlsbad, California Project No. 105761001 SLOPES The following sections provide recommendations for cut and fill slopes. Cut Slopes The geotechnical consultant shall observe cut slopes during excavation. The geotechni- cal consultant shall be notified by the contractor prior to beginning slope excavations. If, during the course of grading, adverse or potentially adverse geotechnical conditions are encountered in the slope which were not anticipated in the preliminary evaluation report, the geotechnical consultant shall evaluate the conditions and provide appropriate recommendations. Fill Slopes When placing fill on slopes steeper than 5:1 (horizontal:vertical), topsoil, slope wash, colluvium, and other materials deemed unsuitable shall be removed. Near- horizontal keys and near-vertical benches shall be excavated into sound bed- rock or firm fill material, in accordance with the recommendation of the geotechnical consultant. Keying and benching shall be accomplished. Com- pacted fill shall not be placed in an area subsequent to keying and benching until the area has been observed by the geotechnical consultant. Where the natural gradient of a slope is less than 5:1, benching is generally not recom- mended. However, fill shall not be placed on compressible or otherwise unsuitable materials left on the slope face. Within a single fill area where grading procedures dictate two or more separate fills, temporary slopes (false slopes) may be created. When placing fill adjacent to a temporary slope, benching shall be conducted in the manner described in Section 7.2.1. A 3-foot or higher near-vertical bench shall be excavated into the documented fill prior to placement of additional fill. Unless otherwise recommended by the geotechnical consultant and accepted by the Building Official, permanent fill slopes shall not be steeper than 2:1 (horizon- tal:vertical). The height of a fill slope shall be evaluated by the geotechnical consultant. Unless specifically recommended otherwise, compacted fill slopes shall be overbuilt and cut back to grade, exposing firm compacted fill. The actual amount of overbuilding may vary as field conditions dictate. If the desired results are not achieved, the existing slopes shall be overexcavated and reconstructed in ac- cordance with the recommendations of the geotechnical consultant. The 105761001 Eaithwortt doc El Camino Real Water System Project April 24, 2006 Carlsbad, California Project No. 105761001 degree of overbuilding may be increased until the desired compacted slope face condition is achieved. Care shall be taken by the contractor to provide mechanical compaction as close to the outer edge of the overbuilt slope sur- face as practical. If access restrictions, property line location, or other constraints limit overbuilding and cutting back of the slope face, an alternative method for compaction of the slope face may be attempted by conventional construction procedures including backrolling at intervals of 4 feet or less in vertical slope height, or as dictated by the capability of the available equipment, whichever is less. Fill slopes shall be backrolled utilizing a conventional sheeps foot-type roller. Care shall be taken to maintain the specified moisture conditions and/or reestablish the same, as needed, prior to backrolling. The placement, moisture conditioning and compaction of fill slope materials shall be done in accordance with the recommendations presented in Section 5 of these guidelines. The contractor shall be ultimately responsible for placing and compacting the soil out to the slope face to obtain a relative compaction of 90 percent as evaluated by ASTM D 1557 and a moisture content in accordance with Sections. The geotechnical consultant shall perform field moisture and density tests at intervals of one test for approximately every 10,000 square feet of slope. Backdrains shall be provided in fill as recommended by the geotechnical consultant. Top-of-Slope Drainage For pad areas above slopes, positive drainage shall be established away from the top of slope. This may be accomplished utilizing a berm and pad gradient of 2 per- cent or steeper at the top-of-slope areas. Site runoff shall not be permitted to flow over the tops of slopes. Gunite-lined brow ditches shall be placed at the top of cut slopes to redirect surface runoff away from the slope face where drainage devices are not otherwise provided. Slope Maintenance In order to enhance surficial slope stability, slope planting shall be accomplished at the completion of grading. Slope plants shall consist of deep-rooting, variable root depth, drought-tolerant vegetation. Native vegetation is generally desir- able. Plants native to semiarid and arid areas may also be appropriate. Large- leafed ice plant should not be used on slopes. A landscape architect shall be 105761001 Earthwork doc El Camino Real Water System Project April 24, 2006 Carlsbad, California Project No. 105761001 consulted regarding the actual types of plants and planting configuration to be used. Irrigation pipes shall be anchored to slope faces and not placed in trenches excavated into slope faces. Slope irrigation shall be maintained at a level just sufficient to support plant growth. Property owners shall be made aware that over wa- tering of slopes is detrimental to slope stability. Slopes shall be monitored regularly and broken sprinkler heads and/or pipes shall be repaired immedi- ately. Periodic observation of landscaped slope areas shall be planned and appropriate meas- ures taken to enhance growth of landscape plants. Graded swales at the top of slopes and terrace drains shall be installed and the property owners notified that the drains shall be periodically checked so that they may be kept clear. Damage to drainage improvements shall be repaired immedi- ately. To reduce siltation, terrace drains shall be constructed at a gradient of 3 percent or steeper, in accordance with the recommendations of the project civil engineer. If slope failures occur, the geotechnical consultant shall be contacted immediately for field review of site conditions and development of recommendations for evaluation and repair. TRENCH BACKFILL The following sections provide recommendations for backfilling of trenches. Trench backfill shall consist of granular soils (bedding) extending from the trench bottom to 1 foot or more above the pipe. On-site or imported fill which has been evaluated by the geotechnical consultant may be used above the granular backfill. The cover soils directly in contact with the pipe shall be classified as having a very low ex- pansion potential, in accordance with UBC Standard 18-2, and shall contain no rocks or chunks of hard soil larger than 3/4-inch in diameter. Trench backfill shall, unless otherwise recommended, be compacted by mechanical means to 90 percent relative compaction as evaluated by ASTM D 1557. Backfill soils shall be placed in loose lifts 8-inches thick or thinner, moisture conditioned, and compacted in accordance with the recommendations of Section 5. of these guide- lines. The backfill shall be tested by the geotechnical consultant at vertical intervals of approximately 2 feet of backfill placed and at spacings along the trench of ap- proximately 100 feet in the same lift. 105761001 Earthwork doc El Camino Real Water System Project April 24, 2006 Carlsbad, California Project No. 105761001 Jetting of trench backfill materials is generally not a recommended method of densification, unless the on-site soils are sufficiently free-draining and provisions have been made for adequate dissipation of the water utilized in the jetting process. If it is decided that jetting may be utilized, granular material with a sand equivalent greater than 30 shall be used for backfilling in the areas to be jetted. Jetting shall generally be considered for trenches 2 feet or narrower in width and 4 feet or shallower in depth. Following jetting operations, trench backfill shall be mechanically com- pacted to the specified compaction to finish grade. Trench backfill which underlies the zone of influence of foundations shall be mechanically compacted to 90 percent or greater relative compaction, as evaluated by ASTM D 1557-02. The zone of influence of the foundations is generally defined as the roughly triangular area within the limits of a 1:1 (horizontal:vertical) projection from the inner and outer edges of the foundation, projected down and out from both edges. Trench backfill within slab areas shall be compacted by mechanical means to a relative compaction of 90 percent, as evaluated by ASTM D 1557. For minor interior trenches, density testing may be omitted or spot testing may be performed, as deemed appropriate by the geotechnical consultant. When compacting soil in close proximity to utilities, care shall be taken by the grading con- tractor so that mechanical methods used to compact the soils do not damage the utilities. If the utility contractors indicate that it is undesirable to use compaction equipment in close proximity to a buried conduit, then the grading contractor may elect to use light mechanical compaction equipment or, with the approval of the geotechnical consultant, cover the conduit with clean granular material. These granular materials shall be jetted in place to the top of the conduit in accordance with the recommendations of Section 8.4 prior to initiating mechanical compaction procedures. Other methods of utility trench compaction may also be appropriate, upon review by the geotechnical consultant and the utility contractor, at the time of construction. Clean granular backfill and/or bedding materials are not recommended for use in slope areas unless provisions are made for a drainage system to mitigate the potential for buildup of seepage forces or piping of backfill materials. The contractor shall exercise the specified safety precautions, in accordance with OSHA Trench Safety Regulations, while conducting trenching operations. Such precau- tions include shoring or laying back trench excavations at 1:1 or flatter, depending on material type, for trenches in excess of 5 feet in depth. The geotechnical con- sultant is not responsible for the safety of trench operations or stability of the trenches. 105761001 Earthwori:.doc El Camino Real Water System Project April 24, 2006 Carlsbad, California Project No. 105761001 DRAINAGE The following sections provide recommendations pertaining to site drainage. Roof, pad, and slope drainage shall be such that it is away from slopes and structures to suit- able discharge areas by nonerodible devices (e.g., gutters, downspouts, concrete swales, etc.). Positive drainage adjacent to structures shall be established and maintained. Positive drain- age may be accomplished by providing drainage away from the foundations of the structure at a gradient of 2 percent or steeper for a distance of 5 feet or more out- side the building perimeter, further maintained by a graded swale leading to an appropriate outlet, in accordance with the recommendations of the project civil en- gineer and/or landscape architect. Surface drainage on the site shall be provided so that water is not permitted to pond. A gra- dient of 2 percent or steeper shall be maintained over the pad area and drainage patterns shall be established to remove water from the site to an appropriate outlet. Care shall be taken by the contractor during grading to preserve any berms, drainage ter- races, interceptor swales or other drainage devices of a permanent nature on or adjacent to the property. Drainage patterns established at the time of finish grading shall be maintained for the life of the project. Property owners shall be made very clearly aware that altering drainage patterns may be detrimental to slope stability and foundation performance. SITE PROTECTION The site shall be protected as outlined in the following sections. Protection of the site during the period of grading shall be the responsibility of the contractor unless other provisions are made in writing and agreed upon among the concerned parties. Completion of a portion of the project shall not be considered to preclude that portion or adjacent areas from the need for site protection, until such time as the project is finished as agreed upon by the geotechnical consultant, the client, and the regulatory agency. The contractor is responsible for the stability of temporary excavations. Recommendations by the geotechnical consultant pertaining to temporary excavations are made in consideration of stability of the finished project and, therefore, shall not be consid- ered to preclude the responsibilities of the contractor. Recommendations by the geotechnical consultant shall also not be considered to preclude more restrictive re- quirements by the applicable regulatory agencies. 105761001 Earthwoik.doc El Camino Real Water System Project April 24, 2006 Carlsbad, California Project No. 105761001 Precautions shall be taken during the performance of site clearing, excavation, and grading to protect the site from flooding, ponding, or inundation by surface runoff. Tempo- rary provisions shall be made during the rainy season so that surface runoff is away from and off the working site. Where low areas cannot be avoided, pumps shall be provided to remove water as needed during periods of rainfall. During periods of rainfall, plastic sheeting shall be used as needed to reduce the potential for unprotected slopes to become saturated. Where needed, the contractor shall install check dams, desilting basins, riprap, sandbags or other appropriate devices or methods to reduce erosion and provide recommended conditions during inclement weather. During periods of rainfall, the geotechnical consultant shall be kept informed by the contrac- tor of the nature of remedial or precautionary work being performed on site (e.g., pumping, placement of sandbags or plastic sheeting, other labor, dozing, etc.). Following periods of rainfall, the contractor shall contact the geotechnical consultant and ar- range a walk-over of the site in order to visually assess rain-related damage. The geotechnical consultant may also recommend excavation and testing in order to aid in the evaluation. At the request of the geotechnical consultant, the contractor shall make excavations in order to aid in evaluation of the extent of rain-related damage. Rain- or irrigation-related damage shall be considered to include, but may not be limited to, erosion, silting, saturation, swelling, structural distress, and other adverse condi- tions noted by the geotechnical consultant. Soil adversely affected shall be classified as "Unsuitable Material" and shall be subject to overexcavation and re- placement with compacted fill or to other remedial grading as recommended by the geotechnical consultant. Relatively level areas where saturated soils and/or erosion gullies exist to depths greater than 1 foot shall be overexcavated to competent materials as evaluated by the geotechni- cal consultant. Where adverse conditions extend to less than 1 foot in ucpth, saturated and/or eroded materials may be processed in-place. Overexcavated or in-place processed materials shall be moisture conditioned and compacted in accor- dance with the recommendations provided in Section 5. If the desired results are not achieved, the affected materials shall be overexcavated, moisture conditioned, and compacted until the specifications are met. Slope areas where saturated soil and/or erosion gullies exist to depths greater than 1 foot shall be overexcavated and replaced as compacted fill in accordance with the appli- cable specifications. Where adversely affected materials exist to depths of 1 foot or less below proposed finished grade, remedial grading by moisture conditioning in-place and compaction in accordance with the appropriate specifications may be attempted. If the desired results are not achieved, the affected materials shall be overexcavated, moisture conditioned, and compacted until the specifications are met. As conditions dictate, other slope repair procedures may also be recommended by the geotechnical consultant. During construction, the contractor shall grade the site to provide positive drainage away from structures and to keep water from ponding adjacent to structures. Water shall 10576100) Eanhwork.doc El Camino Real Water System Project April 24, 2006 Carlsbad, California . Project No. 105761001 not be allowed to damage adjacent properties. Positive drainage shall be maintained by the contractor until permanent drainage and erosion reducing devices are in- stalled in accordance with project plans. 105761001 Eanhwortc.doc El Camino Real Water System Project Carlsbad, California April 24, 2006 Project No. 105761001 DEFINITIONS OF TERMS ALLUVIUM: AS-GRADED (AS-BUILT): BACKCUT: BACKDRAIN: BEDROCK: BENCH: BORROW (IMPORT): BUTTRESS FILL: CIVIL ENGINEER: CLIENT: COLLUVIUM: COMPACTION: Unconsolidated detrital deposits deposited by flowing water; includes sediments deposited in river beds, canyons, flood plains, lakes, fans at the foot of slopes, and in estuaries. The site conditions upon completion of grading. A temporary construction slope at the rear of earth-retaining structures such as buttresses, shear keys, stabilization fills, or retaining walls. Generally a pipe-and-gravel or similar drainage system placed behind earth-retaining structures such as buttresses, stabilization fills, and retaining walls. Relatively undisturbed in-place rock, either at the surface or beneath surficial deposits of soil. A relatively level step and near-vertical riser excavated into sloping ground on which fill is to be placed. Any fill material hauled to the project site from off-site areas. A fill mass, the configuration of which is designed by engi- neering calculations, to retain slopes containing adverse geologic features. A buttress is generally specified by a key width and depth and by a backcut angle. A buttress normally contains a back drainage system. The Registered Civil Engineer or consulting firm responsible for preparation of the grading plans and surveying, and evaluating as-graded topographic conditions. The developer or a project-responsible authorized represen- tative. The client has the responsibility of reviewing the findings and recommendations made by the geotechnical consultant and authorizing the contractor and/or other con- sultants to perform work and/or provide services. Generally loose deposits, usually found on the face or near the base of slopes and brought there chiefly by gravity through slow continuous downhill creep (see also Slope Wash). The densification of a fill by mechanical means. 105761001 Earthwork.doc El Camino Real Water System Project Carlsbad, California April 24, 2006 Project No. 105761001 CONTRACTOR: DEBRIS: ENGINEERED FILL: ENGINEERING GEOLOGIST: EROSION: EXCAVATION: EXISTING GRADE: FILL: FINISH GRADE: GEOFABRIC: GEOTECHNICAL CONSULTANT: A person or company under contract or otherwise retained by the client to perform demolition, grading, and other site improvements. The products of clearing, grubbing, and/or demolition, or contaminated soil material unsuitable for reuse as compacted fill, and/or any other material so designated by the geotech- nical consultant. A fill which the geotechnical consultant or the consultant's representative has observed and/or tested during placement, enabling the consultant to conclude that the fill has been placed in substantial compliance with the recommendations of the geotechnical consultant and the governing agency re- quirements, A geologist registered by the state licensing agency who ap- plies geologic knowledge and principles to the exploration and evaluation of naturally occurring rock and soil, as re- lated to the design of civil works. The wearing away of the ground surface as a result of the movement of wind, water, and/or ice. The mechanical removal of earth materials. The ground surface configuration prior to grading; original grade. Any deposit of soil, rock, soil-rock blends, or other similar materials placed by man. The as-graded ground surface elevation that conforms to the grading plan. An engineering textile utilized in geotechnical applications such as subgrade stabilization and filtering. The geotechnical engineering and engineering geology con- sulting firm retained to provide technical services for the project. For the purpose of these specifications, observations by the geotechnical consultant include observations by the geotechnical engineer, engineering geologist and other per- sons employed by and responsible to the geotechnical consultant. 105761001 Earthwoik.doc El Camino Real Water System Project Carlsbad, California April 24, 2006 Project No. 105761001 GEOTECHNICAL ENGINEER: GRADING: LANDSLIDE DEPOSITS: OPTIMUM MOISTURE: RELATIVE COMPACTION: ROUGH GRADE: SHEAR KEY: SITE: SLOPE: SLOPE WASH: SLOUGH: A licensed civil engineer and geotechnical engineer, regis- tered by the state licensing agency, who applies scientific methods, engineering principles, and professional experience to the acquisition, interpretation, and use of knowledge of materials of the earth's crust to the resolution of engineering problems. Geotechnical engineering encompasses many of the engineering aspects of soil mechanics, rock mechanics, geology, geophysics, hydrology, and related sciences. Any operation consisting of excavation, filling, or combina- tions thereof and associated operations. Material, often porous and of low density, produced from instability of natural or manmade slopes. The moisture content that is considered optimum relative to correction operations obtained from ASTM test method D 1557. The degree of compaction (expressed as a percentage) of a material as compared to the dry density obtained from ASTM test method D 1557. The ground surface configuration at which time the surface elevations approximately conform to the project plan. Similar to a subsurface buttress; however, it is generally con- structed by excavating a slot within a natural slope in order to stabilize the upper portion of the slope without enc '.ach- ing into the lower portion of the slope. The particular parcel of land where grading is being per- formed. An inclined ground surface, the steepness of which is gener- ally specified as a ratio of horizontal units to vertical units. Soil and/or rock material that has been transported down a slope by gravity assisted by the action of water not confined to channels (see also Colluvium). Loose, uncompacted fill material generated during grading operations. 105761001 Eartliworlc.doc El Camino Real Water System Project Carlsbad, California April 24, 2006 Project No. 105761001 SOIL: STABILIZATION FILL: SUBDRAIN: TAILINGS: TERRACE: TOPSOIL: WINDROW: Naturally occurring deposits of sand, silt, clay, etc., or com- binations thereof. A fill mass, the configuration of which is typically related to slope height and is specified by the standards of practice for enhancing the stability of locally adverse conditions. A stabi- lization fill is normally specified by a key width and depth and by a backcut angle. A stabilization fill may or may not have a back drainage system specified. Generally a pipe-and-gravel or similar drainage system placed beneath a fill along the alignment of buried canyons or former drainage channels. Non-engineered fill which accumulates on or adjacent to equipment haul roads. A relatively level bench constructed on the face of a graded slope surface for drainage and maintenance purposes. The upper zone of soil or bedrock materials, which is usually dark in color, loose, and contains organic materials. A row of large rocks buried within engineered fill in accor- dance with guidelines set forth by the geotechnical consultant. 105761001 Eaithwork.doc