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HomeMy WebLinkAbout5025; HYDROELECTRIC FACILITY MAERKLE RESERVOIR; GEOTECHNICAL EVALUATION; 2011-03-08v w - GEOTECHNICAL EVALUATION MAERKLE RESERVOIR PRESSURE CONTROL HYDROELECTRIC FACILITY CARLSBAD, CALIFORNIA PREPARED FOR: Carollo Engineers 9115 HarrisComers Parkway, Suite 440 Charlotte, North Carolina 28269 PREPARED BY: Ninyo&Moore - Geotechnical and Environmental Sciences Consultants 5710 Ruffm Road San Diego, California 92123 March 8,2011 Project No. 107028001 5710.%f~nRoad San Diego, California 92123 Phone (858) 576-1000 Fax(858)576-9600 'e March 8, 2011 Project No. 107028001 Mr. Christopher Crotwell, RE. Carol lo Engineers 9115 Harris Corners Parkway, Suite 440 Charlotte, North Carolina 28269 Subject: Geotechnical Evaluation Maerkle Reservoir Pressure Control Hydroelectric Facility Carlsbad, California Dear Mr. Crotwell: In accordance with your request and authorization, we have performed a geotechnical evaluation for the proposed Pressure Control Hydroelectric Facility located at the Maerkle Reservoir in Carlsbad, California. This report presents our geotechnical findings, 'conclusions, and recom- mendations regarding the proposed project. Our report was prepared in accordance with our proposal dated July 13, 2009. * We appreciate the opportunity to be of service on this project. Sincerely, NINYO & MOORE Emil Rudolph, GE. Senior Engineer -t Francis 0. Moreland, C.E.G. Senior Geologist eegoory 1Farrand, C.E.G. Principal Geologist ER/FOM/GTF/SG/gg Distribution: (2) Addressee 5710 Rufftn Road • San Diego, California 92123 • Phone (858) 576-1000 Fax (858)576-9600 i FRWII OMOREND\Q\ no CERTiR NEEPING 25 S~n Diego lrvin~6- Los Angeles • Rancho Cucmongà Oakland SanFrantho .; SacramentD Las Vegas Phoenix Tucson '• Prescott VaD Denver '• B Paso • Houston Maerkle Reservoir Pressure Control Hydroelectric Facility March 8, 2011 Carlsbad, California Project No. 107028001 TABLE OF CONTENTS Page 1. INTRODUCTION ....... ............................................................................................................. 1 2. SCOPE OF SERVICES............................................................................................................1 3. SITE AND PROJECT DESCRIPTION ............ . ....................................................................... 1 4. SUBSURFACE EXPLORATION AND LABORATORY TESTING....................................2 5. GEOLOGY AND SUBSURFACE CONDITIONS.................................................................2 5.1. Regional Geologic Setting ................................................................ ............................ 2 5.2. Site Geology .................................................................................................................3 5.2.1. Fill ....................................................................................................................... 3 5.2.2. Granitic Rock......................................................................................................3 5.3. Groundwater.................................................................................................................4 5.4. Faulting and Seismicity ................................................................................................4 5.4.1. Strong Ground Motion and Ground Surface Rupture.........................................4 5.4.2. Ground Rupture...................................................................................................5 5.4.3. Liquefaction and Seismically Induced Settlement..............................................5 5.4.4. Tsunamis.............................................................................................................5 5.5. Landsliding ..................................... ............................................................................... 5 6. CONCLUSIONS ...................................................................................................................... 7. RECOMMENDATIONS..........................................................................................................6 7.1. Earthwork .....................................................................................................................6 7.1.1. Site Preparation ............................................................................................ . ...... 7 7.1.2. Excavation Characteristics..................................................................................7 7.1.3. Remedial Grading...............................................................................................7 7.1.4. Temporary Excavations, Braced Excavations, and Shoring...............................7 7.1.5. Materials for Fill .................................................................................................8 7.1.6. Compacted Fill....................................................................................................9 7.1.7. Drainage............................................................................................................10 7.1.8. Seismic Design Parameters...............................................................................10 7.2. Foundations ........................................................................................... ......................11 7.2.1. Shallow Footings ............................................................................................... .11 7.2.2. Lateral Resistance ............. . ............................................................ ...................11 7.2.3. Static Settlement ...............................................................................................12 7.3. Slabs-on-Grade ........................................................................................................... 12 7.4. Concrete Flatwork ......................................................................................................12 7.5. Corrosion....................................................................................................................13 7.6. Concrete......................................................................................................................13 7.7. Pre-Construction Conference......................................................................................14 7.8. Plan Review and Construction Observation ................. ............................................... 14 8. LIMITATIONS ....................................................................................................................... is 9. REFERENCES ................................................................. . ....................................................... 17 107028001 R Geo.doc Maerkle Reservoir Pressure Control Hydroelectric Facility Carlsbad, California Table Table I - Seismic Design Factors Figures Figure 1 - Site Location Figure 2 - Site Plan Figure 3 - Fault Locations Appendices - Appendix A - Boring Log Appendix B - Laboratory Testing - 4 . March 8,2011 Project No. 107028001 10. 107028001 R Gm. d= - - ii I .- jYngI1io4jow Maerkle Reservoir Pressure Control Hydroelectric Facility March 8, 2011 Carlsbad, California Project No. 107028001 INTRODUCTION In accordance with your request, we have performed a limited geotechnical evaluation at the Pressure Control Hydroelectric Facility located at Maerkle Reservoir in Carlsbad, California (Figure 1). This report presents the results of our field exploration and laboratory testing, our conclusions regarding the geotechnical conditions at the subject site, and our recommendations for the design and earthwork construction of this project SCOPE OF SERVICES The scope of services for this study included the following Reviewing background data listed in the References section of this report. The data reviewed included topographic maps, geologic data, stereoscopic aerial photographs, fault maps, and a site plan. Performance of a field reconnaissance by our engineering geologist to observe site condi- tions and to locate and mark the proposed exploratory boring. Coordinating and mobilizing for the subsurface exploration that included locating the exist- ing underground utilities. The existing underground utilities were located through Underground Service Alert (USA). Performing a subsurface evaluation consisting of the drilling, logging, and sampling of one exploratory boring with truck-mounted drill equipment. Relatively undisturbed and bulk samples were obtained at selected intervals from the borings. Performing geotechnical laboratory testing on selected soil samples obtained from our boring. Compiling and analyzing the engineering data obtained from our background, laboratory, and field evaluations. Preparing this report presenting our findings, conclusions, and recommendations regarding the geotechnical design and construction of the project. 3. SITE AND PROJECT DESCRIPTION The site is located southwest of the buried 10 million gallon (MG) Maerkle Reservoir and the existing pressure reducing station, north of Sunny Creek Road and northwest of the 200 MG Maerkle Dam Reservoir. The site is relatively flat and is adjacent to the asphalt concrete paved 107028001 RGeo.do 1 Maerkle Reservoir Pressure Control Hydroelectric Facility March 8, 2011 Carlsbad, California Project No. 107028001 access road for the existing pressure reducing station (Figure 2). A small descending fill slope is present approximately 20 feet southwest of the site. The elevation on the site is approximately 488 feet above mean sea level (MSL). There is sparce vegetation on the site. The proposed pres- sure control hydroelectric facility building will be approximately 18400t by 18-foot in dimension with a slab-on-grade floor and masonry walls. Excavations for associated pipeline trenches are anticipated to be up to 10 feet in depth. SUBSURFACE EXPLORATION AND LABORATORY TESTING Our subsurface exploration was conducted on February 18, 2011 and consisted of drilling, log- ging, and sampling one small-diameter exploratory boring. The boring was drilled to a depth of approximately .14 feet below existing grade with a truck-mounted hollow-stem auger drill rig. Drive and bulk soil samples were obtained from the boring. The samples were then transported to our in-house geotechnical laboratory for testing. The approximate location of the exploratory, boring is shown on Figure 2. The log of the boring is included in Appendix A. Laboratory testing of representative soil samples included in-situ dry density and moisture con- tent, gradation, shear strength, and soil corrosivity. The results of the in-situ dry density and moisture content tests are presented on the boring log in Appendix A. The results of the other laboratory tests are presented in Appendix B. GEOLOGY AND SUBSURFACE CONDITIONS Our findings regarding regional and nearby geology, including faulting and seismicity, land- slides, rippability (excavatability), and groundwater conditions at the subject site are provided in the following sections. 5.1. Regional Geologic Setting The project area is situated in the coastal foothill section of the Peninsular Ranges Geomor- phic Province. This geomorphic province encompasses an area that extends approximately 900 miles from the Transverse Ranges and the Los Angeles Basin south to the southern tip of Baja California (Norris and Webb, 1990; Harden, 1998). The province varies in width 107028001 ROeo.doc 2 Maerkle Reservoir Pressure Control Hydroelectric Facility March 8, 2011 Carlsbad, California Project No. 107028001 from approximately 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 southern California batholith. in the portion of the province in San Diego County that includes the project area, granitic basement rocks are present at the surface. The Peninsular Ranges Province is traversed by a group of sub-parallel faults and fault zones trending roughly northwest. Several of these faults, which are shown on Figure 3, are considered active faults. The Elsinore, San Jacinto, and San Andreas faults are active fault systems located northeast of the project area and the Rose Canyon, Agua Blanca-Coronado Bank, and San Clemente faults are active faults located west of the project area. The Rose Canyon Fault Zone, the nearest active fault system, has been mapped approximately 8 miles west of the project site (Figure 3). Major tectonic activity associated with these and other faults within this regional tectonic framework consists primarily of right-lateral, strike-slip movement. Further discussion of faulting relative to the site is provided in the Faulting and Seismicity section of this report. 5.2. Site Geology Geologic units encountered during our subsurface evaluation include fill and granitic rock. Generalized descriptions of the earth units encountered are provided in the subsequent sec- tions. More detailed descriptions of the subsurface units are provided on the boring log in Appendix A. 5.2.1. Fill Fill was encountered in our boring from the surface to a depth of approximately Y2 foot. As encountered, the fill generally consisted of damp, medium dense, silty fine to coarse sand, with scattered gravel. 5.2.2. Granitic Rock Granitic rock was encountered in our boring below the fill to the depth explored. The granitic rock generally consisted of damp, weathered granitic rock. 107028001 RGco.doc 3 Maerkle Reservoir Pressure Control Hydroelectric Facility March 8, 2011 Carlsbad, California Project No. 107028001 5.3. Groundwater Groundwater was not encountered in our exploratory boring. Fluctuations in the groundwater level and perched conditions may occur due to variations in ground surface 'topography, sub- surface geologic conditions and structure, rainfall, irrigation, and other factors. 5.4. 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 mapping, 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). However, the site is located in a seismically active area and the potential for strong ground motion is considered significant during the design life of the proposed structure. As noted earlier, the active fault is the Rose Canyon fault is located ap- proximately 8 miles west of the site. In general, hazards associated with seismic activity include strong ground motion, ground surface rupture, liquefaction, seismically induced settlement, and tsunamis. These hazards are discussed in the following sections. 5.4.1. Strong Ground Motion and Ground Surface Rupture The 2010 'California Building Code (CBC) recommends that the design of structures be based on the horizontal peak ground acceleration (PGA) having a 2 percent probability of exceedance in 50 years, which is defined as the Maximum Considered Earth- quake (MCE). The statistical return period for PGAMCE is approximately 2,475 years. Based on our review of subsurface data, the project site corresponds to a Site Class B. The site modified PGAMCE was estimated to be 0.44g using the United States Geologi- cal Survey (USGS) (USGS, 2010) ground motion calculator (web-based). The site modified design PGA was estimated to be 0.29g. I0702800IRQeo.doc 4 ' Maerkle Reservoir Pressure Control Hydroelectric Facility March 8, 2011 Carlsbad, California Project No. 107028001 5.4.2. Ground Rupture I Based on our review of the referenced literature and our site reconnaissance, no active faults are known to cross the project vicinity. Therefore, the potential for ground rupture due to faulting at the site is considered low. However, lurching or cracking of the ground surface as a result of nearby seismic events is possible. 5.4.3. Liquefaction and Seismically Induced Settlement Liquefaction of cohesionless soils can be caused by strong vibratory motion due to earthquakes Research and historical data indicate that loose granular soils and non- plastic silts that are saturated by a relatively shallow groundwater table are susceptible to liquefaction. Based on the relatively dense nature of the underlying granitic rock and lack of shallow groundwater, it is our opinion that the potential for liquefaction and seismically induced settlement to occur at the site is not a design consideration. 5.4.4. Tsunamis Tsunamis are long wavelength seismic sea waves (long compared to the ocean depth) generated by sudden movements Of the ocean bottom during submarine earthquakes, landslides, or volcanic activity. Based on the inland location and elevation of the site, the potential for a tsunami to affect the site is not a design consideration 55. Landsliding Based on our review of the original geotechnical evaluation for the site, other published geo- logic literature, and aerial photographs and our subsurface evaluation, no landslides or related features underlie or are adjacent to the subject site. 6. CONCLUSIONS Based on our review of the referenced baokground data, subsurface evaluation, and laboratory testing, it is our opinion that construction of the project is feasible from a geotechnical standpoint provided the recommendations presented in this report are incorporated into the design and con- struction of the project. In general, the following conclusions were made: 107028001 R0odoc 5 Maerkle Reservoir Pressure Control Hydroelecfric Facility March 8, 2011 Carlsbad, California Project No. 107028001 The project site is underlain by a thin layer of fill soils, which is in turn underlain by granitic rock. Although only encountered to a depth of 6 inches in our boring, deeper fill may be pre- sent closer to the existing fill slope southwest of the site. The fill is considered potentially compressible and not suitable for structural support. The granitic rock is considered suitable for support of structural fill or structural improvements. The fill should be removed and re- placed as compacted fill as recommended herein. The granitic rock underlying the site will be excavatable to relatively shallow depths with heavy-dirty earth moving equipment. The use of rock breakers or heavy ripping should be anticipated in deeper excavations at the site. Groundwater was not encountered at the site. Groundwater is not anticipated to be a design consideration, although seepage at shallow depths may be encountered in some areas. The active Rose Canyon fault zone is located approximately 8 miles west of the site. Ac- cordingly, the potential for relatively strong seismic ground motions should be considered in the project design. We estimated a PGAMCE of 0.44g at the subject site that has a 2 percent probability of ex- ceedance in 50 years. The design PGAwas estimated to be 0.29g. Based on the subgrade soils anticipated to be exposed during earthwork, a soil erodibility factor (K-value) of 0.1 can be used in evaluating the sediment risk factor by the project civil engineer. Based on the results of our limited soil corrosivity tests during this study and Caltrans corro- sion guidelines (2003), the site would not be classified as a corrosive site. We recommend soil corrosion at the project area be further evaluated by the corrosion engineer. 7.' RECOMMENDATIONS Based on our understanding of the project, the following recommendations are provided for the design and construction of the project. The proposed site improvements should be constructed in accordance with the requirements of the applicable governing agencies. 7.1. Earthwork In general, earthwork should be performed in accordance with the recommendatiOns pre- sented in this report. The geotechnical consultant should be contacted for questions regarding the recommendations or guidelines presented herein. 107028001 RGo.doc - 6 Maerkle Reservoir Pressure Control Hydroelectric Facility March 8, 2011 Carlsbad, California Project No. 107028001 7.1.1. Site Preparation Site preparation should begin with the removal of vegetation, utility lines, asphalt, con- crete, and other deleterious debris from areas to be graded. Tree stumps and roots should be removed to such a depth that organic material is generally not present. Clearing and grubbing should extend to the outside of the proposed excavation and fill areas. The de- bris and unsuitable material generated during clearing and grubbing should be removed from areas to be graded and disposed of at a legal dumpsite away from the project area. 7.1.2. Excavation Characteristics The results of our field exploration program indicate that the project site, as presently proposed, is underlain by fill soils and granitic rock. The fill materials should be gener- ally excavatable with standard earth moving equipment. The granitic rock is excavatable to relatively shallow depths with standard earth moving equipment and the use of rock breakers or heavy ripping should be anticipated. 7.1.3. Remedial Grading To create uniform bearing conditions for the building's slab-on-grade, we recommend that the proposed building pad consist of 6 inches or more of compacted fill with a very low to low expansion potential. We anticipate that footing excavations will expose granitic rock or, the excavations below the bottom of the footings will be deepened to granitic rock. The overexcavation should extend laterally outward from the building footprint for a dis- tance of 3 feet The extent and depths of removals should be evaluated by Ninyo & Moore's representative in the field based on the materials exposed. The excavated soils may be replaced as compacted fill provided they meet the recommendations for fill mate- rials described below. 7.1.4. Temporary Excavations, Braced Excavations, and Shoring For temporary excavations, we recommend that the following Occupational Safety and Health Administration (OSHA) soil classifications be used: 107028001 R Gco.doc 7 Maerkle Reservoir Pressure Control Hydroelectric Facility March 8, 2011 Carlsbad, California Project No. 107028001 Fill Type C Granitic Rock Type B Upon making the excavations, the soil classifications and excavation performance should be evaluated in the field by a competent person in accordance with the OSHA regulations. Temporary excavations should be constructed in accordance with OSHA recommendations. For trench or other excavations, OSHA requirements regarding per- sonnel safety should be met using appropriate shoring (including trench boxes) or by laying back the slopes to no steeper than 1.5:1 (horizontal to vertical) in fill and 1:1 in granitic rock. Temporary excavations that encounter seepage may be shored or stabi- lized by placing sandbags or gravel along the base of the seepage zone. Excavations encountering seepage should be evaluated on a case-by-case basis. On-site safety of personnel is the responsibility of the contractor. 7.1.5. Materials for Fill On-site soils with an organic content of less than approximately 3 percent by volume (or 1 percent by weight) are suitable for use as fill. In general, fill material should be granu- lar (not clayey), not contain rocks or lumps over approximately 3 inches in diameter, and not more than approximately 30 percent larger than % inch. The on-site materials may generate numerous cobbles larger than 3 inches in dimension. Oversize materials should be separated from material to be used for fill and removed from the site. Utility trench backfill material should not contain rocks or lumps over approximately 3 inches in general. Soils classified as silts or clays should not be used for backfill in the pipe zone. Larger chunks, if generated during excavation, may be broken into accepta- bly sized pieces or disposed of offsite. Imported fill material, if needed for the project, should generally be granular soils with a very low expansion potential (i.e., an expansion index [El] of 20 or less as evaluated by the American Society for Testing and Materials [ASTM] D 4829). Import material should also be non-corrosive in accordance with the Caltrans (2003) corrosion guide- lines and not contain soluble sulfate contents more than 1,000 parts per million (ppm). 107028001 R Geo.doc 8 Maerkle Reservoir Pressure Control Hydroelectric Facility March 8, 2011 Carlsbad, California Project No. 107028001 Materials for use as fill should be evaluated by Ninyo & Moore's representative prior to filling or importing. 7.1.6. Compacted Fill Prior to placement of compacted fill; the contractor sh6u1d 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 moisture conditioned by wetting or aeration to generally above the optimum moisture content. The scarified materials should then be compacted to 90 percent of their Proctor density as evaluated by ASTM D 1557. The evaluation of compaction by the geotechni- cal consultant should not be considered to preclude any requirements for observation or approval by governing agencies. It is the contractor's responsibility to notify this office and the appropriate governing agency when project areas are ready for observation, and to provide reasonable time for that review. Fill materials should be moisture conditioned to generally above the laboratory opti- mum moisture content prior to placement. The optimum moisture content will vary with material type and other factors. Moisture conditioning of fill soils should be generally consistent within the soil mass. Prior to placement of additional compacted fill material following a delay in the grading operations, .the exposed surface of previously compacted fill should be prepared to receive fill. Preparation may include scarification, moisture conditioning, and recompaction. Compacted fill should be placed in horizontal lifts of approximately 8 inches in loose thickness Prior to compaction, each lift should be moisture conditioned to generally above the laboratory optimum, mixed, and then compacted by mechanical methods, using sheepsfoot rollers, multiple-wheel pneumatic-tired rollers or other appropriate compacting rollers, to 90 percent of its Proctor density as evaluated by ASTM D 1557. Successive lifts should be treated in a like manner until the desired finished grades are achieved. 107028001 RGeo.doc 9 Maerkle Reservoir Pressure Control Hydroelectric Facility March 8, 2011 Carlsbad, California Project No. 107028001 7.1.7. Drainage Roof, pad, and slope drainage should be diverted such that runoff water is conveyed away from slopes and structures to suitable discharge areas by nonerodible devices (e.g., gutters, downspouts, concrete swales, etc.). Positive drainage adjacent to struc- tures should be established and maintained. Positive drainage maybe 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 outside the building perimeter, and further maintained by a graded swale leading to an appropriate outlet, in accordance with the recommendations of the project civil engineer and/or landscape architect. 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 the pad area and drainage pat- terns should be established to divert and remove water from the site to appropriate outlets. Care should be taken by the contractor during final grading to preserve any berm, drainage terraces, interceptor swales or othôr drainage devices of a permanent nature on or adjacent to the property. Drainage patterns established at the time of final grading should be maintained for the life of the project. The property owner and the maintenance personnel should be made aware that altering drainage patterns might be detrimental to foundation performance. 7.1.8. Seismic Design Parameters Design of the proposed improvements should be in accordance with the requirements of governing jurisdictions and applicable building codes. Table 1 presents the seismic de- sign parameters for the site in accordance with CBC (20 10) guidelines and mapped spectral acceleration parameters (USGS, 2011). Table 1 —Seismic Design Factors Factors .. Values Site Class • B Site Coefficient, Pa 1.00 Site Coefficient, F . 1.00 Mapped Short Period Spectral Acceleration, Ss 1.10 g Mapped One-Second Period Spectral Acceleration, S1 0.42 g 10702900I ROcodoc 10 Maerkle Reservoir Pressure Control Hydroelectric Facility March 8, 2011 Carlsbad, California Project No. 107028001 Table I Seismic Design Factors Factors Values Short Period Spectral Acceleration Adjusted For Site Class, SMS 1.10 g One-Second Period Spectral Acceleration Adjusted For Site Class, SM! 0.42 g Design Short Period Spectral Acceleration, SDS 0.73 g Design One-Second Period Spectral Acceleration, S1), 0.28 g 7.2. Foundations .. The proposed hydroelectric facility building may be supported on shallow, spread footings bearing on granitic rock. Where fill materials are encountered below excavations for foot- ings, the excavations should be deepened to competent granitic rock. The deepened excavation can be backfihled with lean concrete. Foundations should be designed in accor- dance with structural considerations and the following recommendations. In addition, requirements of the appropriate governing jurisdictions and applicable building codes should be considered in the design of the structures. 7.2.1. Shallow Footings Shallow, spread or continuous footings, may be designed using an allowable bearing capacity of 4,000 pounds per square foot (ps. This allowable bearing capacity may be increased by one-third when considering loads of short duration such as wind or seismic forces. Spread footings should be founded 12 inches below the adjacent grade. Continu- ous and, isolated footings should have a width of 18 inches or more. The spread footings should be reinforced in accordance with the recommendations of the project structural engineer. 7.2.2. 'Lateral Resistance ' For resistance of footings to lateral loads, we recommend an allowable passive pressure of 350 psf of depth be used with a value of up to 3,500 psf. This value assumes that the ground is horizontal for a distance of 10 feet, or three times the height generating the passive pres- sure, whichever is greater. We recommend that the upper 1 foot of soil not protected by pavement or a concrete slab be neglected when calculating passive resistance. J0702800I RGeo.doc 11 .. - F'I!'gotftursry .Maerkle Reservoir Pressure Control Hydroelectric Facility March 8, 2011 Carlsbad, California Project No. 107028001 For frictional resistance to lateral loads, we recommend that a coefficient of friction of 0.40 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 re- sistance 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 dura- tion such as wind or seismic forces. 7.2.3. Static Settlement We estimate that the proposed structure, designed and constructed as recommended herein, will undergo total settlement on the order of ½ inch. Differential settlement on the order of ¼ inch over a horizontal span of 40 feet should be expected. 7.3. Slabs-on-Grade We recommend that conventional,, slab-on-grade floors, underlain by compacted fill materi- als of generally very low to low expansion potential, be 4 inches or more in thickness and be reinforced with No. 4 reinforcing bars spaced 24 inches on center each way. The reinforcing bars should be placed near the middle of the slab. The slab reinforcement and expansion joint spacing should be designed by the project structural engineer. If moisture sensitive floor coverings are to be used, we recommend that slabs be underlain by a vapor retarder and capillary break system consisting of a 10-mu-thick polyethylene (or equivalent) membrane placed over 4 inches of medium to coarse, clean sand or pea gravel and overlain by an additional 2 inches of sand to help protect the membrane from puncture during placement and to aid in concrete curing. The exposed subgrade should be moistened just prior to the placement of concrete. 7.4. Concrete Flatwork Exterior concrete flatwork should be 4 inches in thickness and underlain by 2 inches of sand. No vapor retarder is needed for exterior flatwork. To reduce the potential manifestation of distress to exterior concrete flatwork due to movement of the underlying soil, we recom- I07028001RGco.doc . .. 12 4f/I?5O44tUOTe Maerkle Reservoir Pressure Control Hydroelectric Facility March 8, 2011 Carlsbad, California Project No. 107028001 mend that such flatwork be installed with crack-control joints at appropriate spacing as de- signed by the structural engineer. The subgrade soils should be scarified to a depth of 12 inches, moisture conditioned to generally above the laboratory optimum moisture con- tent, and compacted to 90 percent of its Proctor density as evaluated by ASTM D 1557. Positive drainage should be established and maintained adjacent to flatwork. 7.5. Corrosion Laboratory testing was performed on a representative sample of the on-Site earth materials to evaluate pH and electrical resistivity, as well as chloride and sulfate contents. The pH and electrical resistivity tests were performed in accordance with the California Test (CT) 643 and the sulfate and chloride content tests were performed in accordance with CT 417 and CT 422, respectively. These laboratory test results are presented in Appendix B. The results of the corrosivity testing indicated an electrical resistivity of 3,350 ohm-cm, a soil pH of 6.8, a chloride content of 265 ppm and a sulfate content of 0.023 percent (i.e., 230 ppm). Based on the Calirans corrosion (2003) criteria, the on-site soils would not be classified as corrosive, which is defined as soils with more than 500 ppm chlorides, more than 0.2 percent sulfates, or a pH less than 5.5. 7.6. Concrete Concrete in contact with soil or water that contains high concentrations of water-soluble sul- fates can be subject to premature chemical and/or physical deterioration. The soil sample tested in this evaluation indicated a water-soluble sulfate content of 0.023 percent by weight (i.e., about 230 ppm). According to the American Concrete Institute (ACT) 318-08 building code, the potential for sulfate attack is negligible for water-soluble sulfate contents in soils ranging from about 0.00 to 0.10 percent by weight. Therefore, the site soils may be consid- ered to have a negligible potential for sulfate attack. However, due to the variability of site soils and potential for reclaimed irrigation, consideration should be given to using Type V cement and concrete with a water-cement ratio no higher than 0.45 by weight for normal 107028001 R Geodoc 13 .Maerkle Reservoir Pressure Control Hydroelectric Facility March 8, 2011 Carlsbad, California Project No. 107028001 weight aggregate concrete and a 28-day compressive strength of 4,500 pounds per square inch (psi) or more for the project. In order to reduce the potential for shrinkage cracks in the concrete during curing, we rec- ommend that for slabs-on-grade, the concrete be placed with a slump in accordance with Table'5.2.1 of Section 302.IR of The Manual of Concrete Practice, "Floor and Slab Con- struction," or Table 2.2 of Section 332R in The Manual of Concrete Practice, "Guide to Residential Cast-in-Place Concrete Construction." If a higher slump is needed for screening and leveling, a super plasticizer is recommended to achieve the higher slump without chang- ing the required water-to-cement ratio. The slump should be checked periodically at the site prior to concrete placement. We also recommend that crack control joints be provided in slabs in accordance with the recommendations of the structural engineer to reduce the poten- tial for distress due to minor soil movement and concrete shrinkage. The structural engineer should be consulted for additional concrete -specifications. 7.7. Pre-Construction Conference We recommend that a pre-construction' meeting be held prior to commencement of grading. The owner or his representative, the agency representatives, the architect, the civil engineer, Ninyo & Moore, and the contractor should attend to discuss the plans, the project, and the proposed construction schedule. 7.8. Plan Review and Construction Observation The conclusions and recommendations presented in this report are based on analysis of ob- served conditions in one exploratory boring. If conditions are found to vary from those described in this report, Ninyo & Moore should be notified, and additional recommendations will be provided upon request. Ninyo &Moore should review the final 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 I07028001RGeodoc 14 Maerkle Reservoir Pressure Control Hydroelectric Facility March 8, 2011 Carlsbad, California Project No. 107028001 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. 8. LIMITATIONS The field evaluation, laboratory testing, and geotechnical analyses presented in this 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, ex- pressed or implied, is made regarding the conclusions, recommendations, and opinions presented in this report. There is no evaluation detailed enough to reveal every subsurface con- dition. Variations may exist and conditions not observed or described in this report may be encountered during construction. Uncertainties relative to subsurface conditions can be re- duced through additional 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, envi- ronmental concerns, or the presence 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. 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. 107028001k Geo doc is IyiI,9O 44(oIr Maerkle Reservoir Pressure Control Hydroelectric Facility March 8, 2011 Carlsbad, California Project No. 107028001 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. LI 10702800IROeo.doc 16 I!wu4iuw Maerkle Reservoir Pressure Control Hydroelectric Facility March 8, 2011 Carlsbad, California .. Project No.. 107028001 9 REFERENCES American Concrete institute, 1991 a, Guidelines for Concrete Floor and Slab Construction, (AC! 302.1 R). American Concrete Institute, .1991b, Guidelines for Residential Cast-in-Place Concrete Con- struction, (ACI 332R). American Concrete Institute (AC.I), 2008, ACI 318-08 Building Code Requirements for Struc- tural Concrete and Commentary. Anderson, J.G., Rockwell, T.K., and Agnew, D.C., 1989, Past and Possible Future Earthquakes of Significance to the San Diego Region: Earthquake Engineering Research Institute (EERI), Earthquake Spectra, Volume 5; No. 2. California Building Standards Commission (CBSC), 2010, California Building Code, Title 24, Part 2, Volumes I and 2. California Department of Transportation (Caltrans), 2003, Corrosion Guidelines (Version 1.0), Divi- sion of Engineering and Testing Services, Corrosion Technology Branch: dated September. California Geological Survey, 1998, Maps of Known Active Fault Near-Source Zones in Califor- nia and Adjacent Portions of Nevada dated February.. Cao, T., Bryant, W. A., Rowshandel, B., Branum, D., and Willis, C. J., 2003, The Revised 2002 California Probabilistic Seismic Hazards Maps: California Geological Survey: dated June. Harden, D.R., 1998, California Geology: Prentice Hall, Inc. Jennings, C.W. and Bryant, W. A., 2010, Fault Activity Map of California: California Geological Survey, Geologic Data Map No. 6. Kennedy, M.P., and Tan, 5 .S., 2005, Geologic Map of the Oceanside 30' X 60' Quadrangle, California, Regional Geologic Map Series, 1:100,000 Scale, Map No. 2, Sheet 1 of 2. Mualchin, L., 1996, California Seismic Hazard Map, Based on Maximum Credible Earthquakes (MCE): California Department of Transportation (Caltrans). Norris, R. M. and Webb, R. W.,'1990, Geology of California, Second Edition: John Wiley & - Sons, Inc. . United States Department of the Interior, Bureau of Reclamation, 1989, Engineering Geology Field Manual. United States Geological Survey, 1968 (photorevised 1975), San Luis Rey Quadrangle, Califor- nia, 7.5 Minute Series: Scale 1:24,000. United States Geological Survey, 2011, Ground Motion Parameter Calculator Y. 5.1 0,. World Wide Web, httt://earthcivake.usgs.ov/researchIhazmaps/designI. 107028001 RGeodoc 17 18 107028001 RGeo.doc Maeikle Reservoir Pressure Control Hydroelectric Facility March 8, 2011 Carlsbad, California Project No. 107028001 AERIAL PHOTOGRAPHS Source Date Flight Numbers Scale USDA I April 11, 1953 I AXN-8M 21 and 22 I 1:20,000 4 JLvj 15 f t $BRIDGEJ t RTL -- :' I 71 AN pe SL1 J 4 Y1 - - - /4- 1O8 gFW 47 1k A __ Eii - / ItI '1 17 P .,4e 2 \ cc 491 Its, Ir TA ZA FS 2tv''I I t Af ", Af", to All z 1 / r a - 0 SOURCE 2008 Thomas Gddo far San Diego county. Stmot Giddo and 0rroctary. Map Rand McNally. R.L07-S.129 a, 0 0 NOTE DIRECTIONS, DIMENSIONS AND LOCATIONS ARE APPROXIMATE 0 or 0 0 0 0 /01/IWO PROJECT NO. I DATE 107028001 3/11 SCALE IN FEET 0 1,000 2,000 4.000 SITE LOCATION MAERKLE RESERVOIR PRESSURE CONTROL HYDROELECTRIC FACILITY CARLSBAD, CALIFORNIA FIGURE I -- - S. N A - - - - - - /\ : , - - 5' - - - - - I - - N \ -14 4 t' - -- ~-' \~Tv' PROPOSED HYDROELECTR FACILITY (POWERHOUSE) LOCATION OF st 3 r Yi - : 17 - LEGEND . .- p - . . •5 - BORING S - , TD=14' TD=TOTAL DEPTH IN FEET - SOURCE: CAROIjO ENGINEERS, 2011 * * SCALE IN FEET 80 160 FEET - NOTE: DIMENSIONS, OtREC11ONSANb LOCATIONS ARE APPROXIMATE. JIII,i/o&4trIore SITE PLAN FIGURE PROJECT NO DATE MAERKLE RESERVOIR - - - PRESSURE CONTROL HYDROELECTRIC FACILITY 2 107028001 - 3/11 CARLSBAD, CALIFORNIA 1 N CALIFORNIA A _ denacnapi ; rKernunty . 4. b k Los Angeles County Palmdale lb NTh 4rightwood o%LaR \A \ - - s tf Beal vflc~c C, -çø swent ' ' or rdlo \ 1140 N4 dill an San • 4 44RWId9C unt çIemee - Imperial, 0. con Sa 0 MEXIC - LEGEND SOURCE: FaultAclivity Map of California, 2010, Jennings, C.W, and Bryant, WA., CALIFORNIA FAULT ACTIVITY California Geological Survey. HISTORICALLY ACTIVE . QUATERNARY (POTENTIALLY ACTIVE) SCALE IN MILES HOLOCENE ACTIVE ---- STATE/COUNTY BOUNDARY LATE QUATERNARY (POTENTIALLY ACTIVE) 0 30 60 NOTES: DIRECTIONS, DIMENSIONS AND LOCATIONS ARE APPROXIMATE 4III144o&/ftOWe FAULT LOCATIONS FIGURE PROJECT NO. DATE MAERKLE RESERVOIR PRESSURE CONTROL HYDROELECTRIC FACILITY 3 107028001 3/11 CARLSBAD, CALIFORNIA .Maerkle Reservoir Pressure Control Hydroelectric Facility March 8, 2011 Carlsbad, California Project No. 107028001 APPENDIX BORING LOG 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 boring. The samples were bagged and transported to the laboratory for testing. The Standard Penetration Test Sampler Disturbed drive samples of earth materials were obtained by means of a Standard Penetra- tion Test sampler. The sampler is composed of a split barrel with an external diameter of 2 inches and an unlined internal diameter of 1% inches. The sampler was driven into the ground 12 to. 18 inches with a 140-pound hammer falling freely from a height of 30 inches in general accordance with ASTM D 1586. The blow counts were recorded for every 6 inches of penetration; the blow counts reported on the logs are thosefor the last 12 inches of penetration. Soil samples were oberved and removed from the sampler, bagged, sealed 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 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. 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 sam- ples were removed from the sample barrel in the brass rings, sealed, and transported to the laboratory for testing. 107028001 R Geo.do a- W LI C,) 0 . 0 ZF ' ? 0 a_ . W a z U) C) . BORING LOG EXPLANATION SHEET . c a. C 0 - = _____ = _____ = Bulk sample. Modified split-barrel drive sampler. I. • - - No recovery with modified split-barrel drive sampler. Sample retained by others. . I Standard Penetration Test (SPT). 5- - - No recovery with a SPT. - xxixx - Shelby tube sample. Distance pushed in inches/length of sample recovered' in inches. c - - No recovery with Shelby tube sampler. • ' -' Continuous Push Sample. 9 Seepage. Groundwater encountered during drilling. Groundwater measured after drilling. • - SM ALLUVIUM: Solid line denotes unit change. - - change- - ----- - ---- -- -- -- — — — — — — — — — — - 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 bottom of the boring. BORING LOG - . . PROJECT NO DATE Rev. 01/03 FIGURE iiuirii u.N.lrB,i. I i•iii iI!UP4iIUIU U.S.C.S. METHOD OF SOIL CLASSIFICATION MAJOR DIVISIONS SYMBOL TYPICAL NAMES (3W Well graded gravels or gravel-sand mixtures, little or no fines GRAVELS Poorly graded gravels or gravel-sand GP (More than 1/2 of coarse •: mixtures, little or no fines En N fraction GM Silty gravels, gravel-sand-silt mixtures I > No. 4 sieve Size) SANDS (More than 1/2 of coarse U fraction <No. 4 sieve size) SC ICIayey sands, sand-clay mixtures 11111111 ML Inorganic silts and very fine sands, rock flour, silty or clayey fine sands or clayey silts with Ln SILTS & CLAYS CL Inorganic clays of low to medium plasticity, , Liquid Limit <50 gravelly clays, sandy clays, silty clays, lean OL Organic silts and organic silty clays of low — plasticity MH Inorganic silts, micaceous or diatomaceous fine sandy or silty soils, elastic silts o SILTS & CLAYS Liquid Limit >50 CH Inorganic clays of high plasticity, fat clays OH Organic clays of medium to high plasticity, silty clays, organic silts GC Clayey gravels, gravel-sand-clay mixtures SW Well graded sands or gravelly sands, little or no fines SP Poorly graded sands or gravelly sands, little or no fines SM Silty sands, sand-silt mixtures HIGHLY ORGANIC SOILS GRAIN SIZE CHART RANGE OF GRAIN SIZE CLASSIFICATION U.S. Standard Grain Size in Sieve Size Millimeters BOULDERS Above 12' Above 305 COBBLES 12' to 3' 305 to 76.2 GRAVEL 3' to No. 4 76.2 to 4.76 Coarse 3'to3/4 76.2 to 19.1 Fine 3/4to No. 4 19.1 to 4.76 SAND No. 4 to No. 200 4.76 to 0.075 Coarse No. 4 to No. 10 4.76 to 2.00 Medium No. 10 to No. 40 2.00 to 0.420 Fine No. 40 to No. 200 0.420 to 0.075 SILT & CLAY Below No. 200 Below 0.075 Pt IPeat and other highly organic soils tf1#7h18&*1Q1Qr8 U.S.C.S. METHOD OF SOIL CLASSIFICATION USCS Soil Classification Updated Nov. 2004 (I) a.. DATE DRILLED 2/18/11 BORING NO. B-I u.. 0 Z GROUND ELEVATION 488'± (MSL) SHEET I OF 0 U- w Ix > I- M <Cl) -- FL METHOD OF DRILLING 6" Diameter Hollow Stem Auger (A-300) (Scotts Drilling) c .1 M a. W Fn C') W C') DRIVE WEIGHT 140 lbs. (Cathead) DROP 30" of 0 0 SAMPLED BY MJB LOGGED BY MJB REVIEWED BY GTF _____ ____ _______ DESCRIPTION/INTERPRETATION 0 - SM FILL: Brown to light brown, damp, medium dense to dense, silty fine to coarse SAND; - scattered fine to coarse gravel. - GRANITIC ROCK: : Light reddish brown to reddish brown, damp, weathered GRANITIC ROCK. - 5 - - 73 - 7.7 119.6 - - - - - - - 10- - I 50/5" Refusal. - - Total Depth = 14 feet. • Groundwater not encountered during drilling. 15- - - Backfilled with hydrated bentonite chips and soil shortly after drilling on 2/18/11. - - Groundwater, though not encountered at the time of drilling, may rise to a higher level due to seasonal variations in precipitation and several other factors as discussed in the report. AlJiiiii & BORING LOG MAERKLE RESERVOIR PRESSURE CONTROL ffYDROELECTRIC FACILITY CARLSBAD, CALIFORNIA PROJECT NO. DATE FIGURE 107028001 3/11 A-I Maerkle Reservoir Pressure Control Hydroelectric Facility March 8, 2011 Carlsbad, California Project No. 107028001 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. Soil classifications are indicated on the log of the exploratory boring in Appendix A. In-Place Moisture and Density Tests The moisture content and dry density of a relatively undisturbed sample obtained from the ex- ploratory boring was evaluated in general accordance with ASTM D 2937. The test results are presented on the log of the exploratory boring in Appendix A. Gradation Analysis A gradation analysis test was performed on a selected representative earth material in general accor- dance with ASTM D 422. The grain-size distribution curve is shown on Figure B-i. The test results were utilized in evaluating the equivalent soil classification in accordance with the USCS. Direct Shear Test A direct shear test was performed on a relatively undisturbed sample in general accordance with ASTM D 3080 to evaluate the shear strength characteristics of the selected material. The sample was inundated during shearing to represent adverse field conditions. The results are shown on Figure B-2. Soil Corrosivity Tests Soil p11, and resistivity tests were performed on a representative sample in general accordance with CT 643. The soluble sulfate and chloride content of the selected sample were evaluated in general accordance with CT 417 and CT 422, respectively. The test results are presented on Figure B-3. 107028001 R Gco.doc GRAVEL I SAND FINES L Coarse Fine Coarse Medium Fine SILT CLAY U.S. STANDARD SIEVE NUMBERS 100.0 90.0 80.0 70.0 0 60.0 50.0 z Ij I- 40.0 Ui 0 30.0 Ui a. 20.0 10.0 0.0 100 10 HYDROMETER 0.1 0.01 0.001 00001 GRAIN SIZE IN MILLIMETERS Symbol I Sample I Depth I Liquid I Plastic Plasticity I D10 I D I D I CuC C I Passing I USGS I I I Location () I Limit I Limit . Index No. (%) I • B1 117 (SM PERFORMED IN GENERAL ACCORDANCE WITH ASTM 0422 4tin4w&IpltuIw GRADATION TEST RESULTS FIGURE PROJECT NO. DATE MAERKLE RESERVOIR PRESSURE CONTROL HYDROELECTRIC FACILITY B-I 107028001 3/11 CARLSBAD CALIFORNIA 17020001 SIEVE BI 3000 LL Cl) 0 U) (I) w 2000 Cl) w Cl) 1000 0. 0 1000 2000 3000 NORMAL STRESS (PSF) 4000 4000 Description Symbol Sample Location Depth (ft) Shear Strength Cohesion, c (psf) Friction Angle, $ (degrees) Soil Type Silty SAND B-i 5.0-6.5 Peak 190 45 SM Silty SAND - - X .- B-i 5.0-6.5 Ultimate 0 44 SM PERFORMED IN GENERAL ACCORDANCE WITH ASTM 03080 Pf/n,qo&IftrMw DIRECT SHEAR TEST RESULTS FIGURE PROJECT NO. DATE MAERKLE RESERVOIR PRESSURE CONTROL HYDROELECTRIC FACILITY B-2 107028001 3/11 CARLSBAD. CALIFORNIA 107028001 SHEAR B-i @ 5.0-65.*Is SAMPLE LOCATION SAMPLE DEPTH (FT) pH RESISTIVITY' (Oh) SULFATE CONTENT CHLORIDE CONTENT (ppm) N B-1 0.5-5.0 6.8 3,350 230 0.023 265 PERFORMED IN GENERAL ACCORDANCE WITH CALIFORNIA TEST METHOD 643 2 PERFORMED IN GENERAL ACCORDANCE WITH CALIFORNIA TEST METHOD 417 PERFORMED IN GENERAL ACCORDANCE WITH CALIFORNIA TEST METHOD 422 flngO&I'ftwwe CORROSMTY TEST RESULTS FIGURE PROJECT NO.. DATE MAERKLE RESERVOIR PRESSURE CONTROL HYDROELECTRIC FACILITY B-3 107028001 3/11 . CARLSBAD. CALIFORNIA I0702001 CORROSIVITY PROc 1.I%