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HomeMy WebLinkAbout3537; Vista/Carlsbad Interceptor Sewer; North Agua Hedionda Interceptor Microtunneling Access Shafts; 2007-07-09SUPPLEMENTAL GEOTECHNICAL INVESTIGATION MICROTUNNELING ACCESS SHAFTS NORTH AGUA HEDIONDA INTERCEPTOR CARLSBAD, CALIFORNIA Prepared for DUDEK & ASSOCIATES, INC. Encinitas, California Prepared by TERRACOSTA CONSULTING GROUP, INC. San Diego, California Project No. 2181-3 July 9, 2007 Geotechnical Engineering Coastal Engineering Maritime Engineering Project No. 2181 July 9, 2007 Mr. Russ Bergholz DUDEK & ASSOCIATES, INC. 605 Third Street Encinitas, California 92024 SUPPLEMENTAL GEOTECHNICAL INVESTIGATION MICROTUNNELING ACCESS SHAFTS NORTH AGUA HEDIONDA INTERCEPTOR CARLSBAD, CALIFORNIA Dear Mr. Bergholz: In accordance with your request, TerraCosta Consulting Group, Inc. (TCG) has performed additional subsurface investigative work for the proposed microtunneling access shafts for the City of Carlsbad's North Agua Hedionda Interceptor project located near the northern shore of North Agua Hedionda lagoon in the City of Carlsbad, California. The accompanying report presents the results of our supplemental geotechnical investigation and our recommendations for the microtunneling operations for new sewer lines to be constructed as part of the project. We appreciate the opportunity to be of service and trust this information meets your needs. If you have any questions or require additional information, please give us a call. Very truly yours, TERRACOSTA CONSULTING GROUP, INC. tert, Ph.D., Dir. of Engineering R.C.E. 45171, R.G.E. 2316 MWE/BRS/jg Attachments (6) Addressee £.Graven R. Smillie, Princi C.E.G. 207, P.G. 402 4455 Murphy Canyon Road, Suite 100 2601 Ocean Park Blvd, Suite 110 San Diego, California 92123-4379 Santa Monica, California 90405 www.terracosta. com (858) 573-6900 (310)399-8190 (858)573-8900 (310)399-8195 DUDEK & ASSOCIATES Project No. 2181-3 July 9, 2007 TABLE OF CONTENTS 1 INTRODUCTION ....1 2 PURPOSE AND SCOPE OF INVESTIGATION 1 3 FIELD INVESTIGATION AND LABORATORY TESTING 2 3.1 Field Investigation 2 3.2 Laboratory Testing 3 4 SITE CONDITIONS AND GEOLOGY 3 4.1 Subsurface Soils 3 4.2 Groundwater Conditions 4 5 DISCUSSION AND CONCLUSIONS 5 5.1 General 5 5.2 Microtunneling Operations 6 5.2.1 Anticipated Subsurface Conditions along Proposed Microtunneling Segment... 6 5.3 Microtunneling 9 6 RECOMMENDATIONS 10 6.1 Site Preparation and Earthwork Operations 10 6.2 Excavations and Shoring Requirements 10 6.3 Microtunneling 11 7 LIMITATIONS 13 FIGURE 1 FIGURE 2 FIGURES 3a - 3c APPENDIX A APPENDIX B GEOLOGY AND VICINITY MAPS BORING LOCATION MAP GEOLOGIC PROFILES LOGS OF EXPLORATORY BORINGS LABORATORY TEST RESULTS TerniCostn N:\21\2181V2181-3 R01 Suppl Oeotech Invest.doc DUDEK & ASSOCIATES Project No. 2181-3 July 9,2007 Page 1 SUPPLEMENTAL GEOTECHNICAL INVESTIGATION MICROTUNNELING ACCESS SHAFTS NORTH AGUA HEDIONDA INTERCEPTOR CARLSBAD, CALIFORNIA 1 INTRODUCTION This report presents the results of our supplemental geotechnical investigation for the proposed microtunneling access shafts (i.e., jacking and receiving shafts) to be used for construction of the proposed sewer pipeline improvements for the North Agua Hedionda Interceptor. The project site is located near the northeastern shore of Agua Hedionda Lagoon in the City of Carlsbad, California (Figure 1). Due to environmental issues associated with the project, the portion of the proposed interceptor that was originally planned along the shoreline has been relocated landward. The new alignment of this segment of the pipeline is shown on Figure 2. In addition, access limitations along this portion of the interceptor require that the installation of the interceptor be performed using trenchless methods. We understand that the micro- tunneling method has been selected, and that three access shafts are planned to facilitate the microtunneling efforts. The approximate locations of these access shafts are also shown on Figure 2. The profile of this segment of the interceptor is shown on Figures 3a through 3c. 2 PURPOSE AND SCOPE OF INVESTIGATION Our understanding of the project stems from discussions with Mr. Russ Bergholz of Dudek & Associates, Inc. The purposes of this study were: • To assess general subsurface conditions at the access pit locations; • To perform laboratory tests on samples collected from the borings to aid in characterizing subsurface conditions at the access pit sites; • To evaluate subsurface data in order to develop recommendations for the grading and proposed microtunneling operations; and N:\21\2181V2181-3 R01 Suppl Geotech Invest.doc DUDEK & ASSOCIATES Project No. 2181-3 July 9,2007 Page 2 • To provide a report summarizing our findings and recommendations regarding the proposed microtunneling operations. In order to accomplish these purposes, TCG performed the following tasks: • Advanced a test boring at, or near, each of the three proposed access pit locations; • Conducted limited laboratory testing, consisting of grain-size determination and unconfined compressive strength tests on selected samples; • Performed various analyses to characterize subsurface conditions as they relate to microtunneling, site preparation, and earthwork operations; and • Prepared this report, which summarizes our findings and presents our recommendations. 3 FIELD INVESTIGATION AND LABORATORY TESTING 3.1 Field Investigation Our field investigation, conducted March 5, 2007, consisted of drilling, sampling and logging three exploratory test borings (one at each of three proposed shaft sites) ranging from 25 to 50 feet in depth. The borings were advanced using a truck-mounted Versa Drill-VI00 drill rig equipped with 101 mm core barrel continuous-core samplers to obtain soil samples. The continuous-core sampler is a 5-foot-long, thin-walled sampler designed for use in soft rock applications. The sampler is pushed into the soil ahead of the drill string as the bore hole is advanced. With this technique, continuous relatively undisturbed core samples of soft rock, up to 5 feet in length, are obtainable. In soil deposits, the quality of sample is related to the amount of fines (material passing a No. 200 sieve). Those portions of core runs encountering fairly clean sands are generally very disturbed. The core run number, box number, percent recovered, and RQD were reported for each run of the sampler. The locations of the borings are shown on Figures 2 and 3 a through 3c. A geologist from our firm logged the borings and obtained representative soil samples for visual classification and evaluation of geotechnical characteristics. A Key to Excavation Logs is presented in Appendix A as Figure A-l. Final logs of the borings are presented as Figures A-2 through N:\21\2181\2181-3 ROl Suppl Geotech Invest.doc DUDEK & ASSOCIATES Project No. 2181-3 July 9,2007 Page 3 A-4. The descriptions on the logs are based on our field logs and on subsequent sample inspections. 3.2 Laboratory Testing We performed both grain size distribution and unconfined compression strength tests on selected soft rock samples at, or near, the proposed invert elevation of the pipe. A summary of the laboratory tests results is presented in Appendix B of this report. 4 SITE CONDITIONS AND GEOLOGY The existing North Agua Hedionda sewer interceptor alignment is located along the northerly shoreline of Agua Hedionda Lagoon. Elevations along the project alignment range from approximately 0 to 10 feet, Mean Sea Level (MSL) datum. The existing 1,800 lineal feet of subject sewer easement traverses a low coastal bluff and undeveloped hillside. The general site topography and general geologic profile along the project alignment are shown on Figures 3a through 3c. 4.1 Subsurface Soils The existing sewer alignment and easement are underlain by artificial fill soils, geologically recent alluvial and colluvial soils, and Tertiary sedimentary deposits. The specific soil units, in order of increasing age, are described below, along with comments on geotechnical characteristics pertinent to construction. Fill Soils - Locally derived fill soils cover much of the alignment. These soils, which consist predominantly of silty to clayey sands, are relatively shallow and appear to have been generated from grading during construction of the original sewer line. These soils have similar behavior as the alluvium/colluvium soils. Alluvium/Colluvium - Alluvial and colluvial soils (derived from Santiago Formation) are present along the entire alignment. These soils generally consist of silty sand, clayey sand, and sandy clay, with thin lenses of gravel and cobble. It should be noted that when wetted, such as by perched groundwater or high tides, these soils may N :\21 \2181 \2181 -3 ROI Suppl Geotech Invest.doc DUDEK & ASSOCIATES July 9, 2007 Project No. 2181 -3 Page 4 become locally unstable and "flow" into trenches or steep-walled excavations. When dry, layers or lenses of "clean" friable sands may tend to be unstable as well. As such, the cleaner sands will be potentially running when dry and flowing when wet. I Santiago Formation - Typically, the Santiago Formation consists of a very dense, gray-brown, interbedded, well-indurated, silty to clayey sand and very stiff to very hard clay. Within the Santiago Formation, there are carbonate-cemented zones that are similar to a soil-cement and/or a two-sack sand slurry (100 to 500 psi). In isolated areas, the unconfined compressive strength of these cemented sands may approach that of plain concrete (approximately 3000 psi or less). Typically, the cemented zones are on the order of a few feet to 10 feet in thickness. In addition, lenses and zones of gravel should be expected, as evidenced by several lenses encountered during the drilling of our test borings. In our opinion, the occurrence of cobbles in the Santiago Formation should be considered to be rare (<5%), and the occurrence of boulders should be considered to be very rare (<1%). It should be noted that the Santiago Formation locally contains concentrations of abrasive silica sand (as contrasted with feldspar sands and/or clays, which are less damaging to excavation equipment). Prediction of the relative percentages of these constituents, without resorting to an extensive drilling and testing program (or actual microtunneling) is outside the scope of this project. Based on a review of the boring information collected for this project, Standard Penetration Resistances (SPT) within the clay zones vary from 11 to 50, while in the dense to very dense silty to clayey sands and sands, the SPTs are typically 50 plus blows for 6 inches. Unconfined compressive strengths in the silty sands and clayey sands in the Santiago Formation are generally on the order of 2,000 psf (14 psi) or less, and one pocket penetrometer test in a clayey zone indicated an undrained compressive strength of 2.75 tons/square foot (tsf), or 5,500 psf or 38 psi. Within the Santiago Formation, lenses of cleaner may be encountered, which may be considered potentially "running" when dry and "flowing" when wet. 4.2 Groundwater Conditions Groundwater was encountered in each of the borings we drilled for this supplemental 1 investigation. These conditions are summarized below: N:\2I\2181\2181-3R01 Suppl Geotech Invesl.doc DUDEK & ASSOCIATES July 9,2007 Project No. 2181-3 Page 5 Groundwater was encountered in Boring B-l (ground surface elevation +18 feet, MSL) at an approximate depth of 12 feet, or approximate elevation +6 feet, MSL. The invert of the interceptor near Boring B-l is at approximate elevation -4 feet, MSL, or approximately 10 feet below the groundwater table. Groundwater was encountered in Boring B-2 (ground surface elevation +34 feet, MSL) at an approximate depth of 33 feet, or approximate elevation +1 foot, MSL. The invert of the interceptor near Boring B-2 is at approximate elevation -3 feet, MSL, or approximately 4 feet below the groundwater table. Groundwater was not encountered in Boring B-3 (ground surface elevation +8 feet). However, as the boring is located near the lagoon, we anticipate that groundwater will be encountered near Mean Sea Level. The invert of the interceptor near Boring B-3 is at approximate elevation -2 feet, MSL, or approximately 2 feet below the anticipated groundwater table. 5 DISCUSSION AND CONCLUSIONS 5.1 General Proposed earthwork operations for construction of the new interceptor pipeline will likely consist of: • Cut and cover operations from Station 0+00 (Manhole No. 1) to Station 1+37 (Manhole No. 2) and from Station 19+20.97 to Station 19+43.66 (Manhole No. 6); • Excavation and construction of three microtunneling pits near Stations 1+37.12 (Manhole No. 2), 11+41.53 (Manhole No. 4), and 19+20.97 (Manhole No. 5); • Microtunneling operations between the three microtunneling pits; and • Limited grading to prepare construction access roads and work areas. Based on the results of our field investigation and analyses, it is our opinion that there are no significantly adverse conditions or geologic hazards along the proposed microtunneling segment. However, due to the anticipated invert elevations of the interceptor, we expect that groundwater will be encountered within the pipe zone area. As such, dewatering of the N:\21\2181V2l81-3 RO] Suppl Oeotech Invest.doc DUDEK & ASSOCIATES Project No. 2181-3 July 9, 2007 Page 6 excavations may be needed, depending upon the construction methods selected for this project. 5.2 Microtunneling Operations 5.2.1 Anticipated Subsurface Conditions along Proposed Microtunneling Segment The selection and type of microtunneling operation, including the selection of the machine, is greatly influenced by the subsurface conditions encountered. A discussion and description of anticipated subsurface conditions for the microtunneling pits and segments are presented below: • Microtunnel Pit near Station 1+37 (Manhole No. 2): The subsurface conditions anticipated for this microtunneling pit are based on the conditions encountered in Boring B-l. The subsurface conditions, from the ground surface (approximate elevation +18 feet, MSL) down to the approximate bottom of the pit (elevation -7 feet, MSL), are anticipated to be colluvial soils (Qcol) generally comprised of medium dense, silty sands. Santiago Formation soils (Tsa) are estimated to be approximately 27 feet below existing grade. Groundwater is anticipated to be encountered approximately 12 feet below the existing ground surface. The excavation for the pit will need to be shored in some manner. Depending upon microtunneling operations, dewatering may be needed. However, we understand that the planned microtunneling operations are remotely controlled and able to operate below water. Zones of encountered cleaner sands may be considered "running" when dry and "flowing" when wet. • Microtunneling Segment between Station 1+37 (Manhole No. 2) and Station 11+42 (Manhole No. 4): Starting at Station 1+37 and moving upstation, we anticipate that microtunneling operations will be below the groundwater table and will be excavating medium dense to dense, silty sands and sands with gravels. As the operation approaches Station 2+40 to 3+00, we anticipate that the excavation will begin to encounter the Santiago Formation (Tsa). From Station 3+00 to 11+41, we anticipate that the microtunneling will be within the Santiago Formation (Tsa). Typically, the Santiago Formation consists of a very dense, gray-brown, interbedded, well-indurated, silty to clayey sand and very stiff to very hard clay. Within the Santiago Formation, there are carbonate-cemented zones that are similar to a soil- N:\21\2181\2181-3 R01 Suppl Geotech lnvest.doc DUDEK & ASSOCIATES Project No. 2181-3 July 9,2007 Page? TerrnCosta cement and/or two-sack sand slurry. In isolated areas, the unconfined compressive strength may approach that of plain concrete. Typically, the cemented strata are on the order of a few feet to 10 feet in thickness. In addition, lenses and zones of gravel should be expected, as evidenced by several lenses encountered during drilling of our test borings. The occurrence of cobbles is considered rare (<5%), and the occurrence of boulders is considered very rare (<1%). From a review of the boring information collected for this project, Standard Penetration Resistances (SPT) within the clay zones vary from 11 to 50, while in the dense to very dense, silty to clayey sands and sands, the SPTs are typically 50 plus blows for 6 inches. Unconfined compressive strengths in the silty sands and clayey sands in the Santiago Formation are generally on the order of 2,000 psf (14 psi) or less, and one pocket penetrometer test in a clayey zone indicated an unconfined compressive strength of 2.75 tsf (or 5,500 psf or 38 psi). Zones of encountered cleaner sands may be considered "running" when dry and "flowing" when wet. Microtunnel Pit near Station 11+42 (Manhole No. 4): The subsurface conditions anticipated for this microtunneling pit are based on the conditions encountered in Boring B-2. We anticipate that the bottom of the pit will be near elevation -6 feet, MSL. The subsurface conditions, from the ground surface (approximate elevation 34 feet, MSL) down to approximate elevation 25 feet, MSL, are anticipated to be colluvial soils generally comprised of medium dense, silty sands. We anticipate that Santiago Formation soils will be encountered from elevation 25 feet, MSL, to the bottom of the pit at approximate elevation -6 feet, MSL. Groundwater is anticipated to be encountered at a depth of approximately 33 feet (approximate elevation +1 foot (MSL) below the existing ground surface. The excavation for the pit will need to be shored in some manner. Depending upon microtunneling operations, dewatering may be needed. However, we understand that the planned microtunneling operations are remotely controlled and able to operate below water. Zones of encountered cleaner sands may be considered "running" when dry and "flowing" when wet. Microtunneling Segment between Station 11+42 (Manhole No. 4) and Station 19+21 (Manhole No. 5): Starting at Station 11+42 and moving upstation, we anticipate that microtunneling operations will be below the groundwater table, and will be excavated within the Santiago Formation. As the operation approaches N:\21\2I81\2181-3 R01 Suppl Geotech lnvesl.doc DUDEK & ASSOCIATES Project No. 2181-3 July 9, 2007 PageS Station 12+90 to 13+40, we anticipate that the tunneling operations may encounter saturated colluvial and alluvial soils. From Station 13+40 to 19+21, we anticipate that the microtunneling will be within the Santiago Formation. Typically, the Santiago Formation consists of a very dense, gray-brown, interbedded, well- indurated, silty to clayey sand and very stiff to very hard clay. Within the Santiago Formation, there are carbonate-cemented zones that are similar to a soil-cement and/or two-sack sand slurry. In isolated areas, the unconfined compressive strength may approach that of plain concrete. Typically, the cemented zones are on the order of a few feet to 10 feet in thickness. In addition, lenses and zones of gravel should be expected, as evidenced by several lenses encountered during the drilling of our test borings. The occurrence of cobbles is considered rare (<5%), and the occurrence of boulders is considered very rare (<1%). From a review of the boring information collected for this project, Standard Penetration Resistances (SPT) within the clay zones vary from 11 to 50, while in the dense to very dense, silty to clayey sands and sands, the SPTs are typically 50 plus blows for 6 inches. Unconfined compressive strengths in the silty sands and clayey sands are on the order of 2,000 psf (14 psi) or less, and one pocket penetrometer test in a clayey zone indicated an unconfined compressive strength of 2.75 tsf (or 5,500 psf or 38 psi). Zones of encountered cleaner sands may be considered "running" when dry and "flowing" when wet. Microtunnel Pit near Station 19+21 (Manhole No. 5): The subsurface conditions anticipated for this microtunneling pit are based on the conditions encountered in Boring B-3. We anticipate that the bottom of the pit will be near elevation -5 feet, MSL. The subsurface conditions, from the ground surface (approximate elevation +8 feet, MSL) down to approximate elevation +5 feet (MSL), are anticipated to be colluvial soils generally comprised of medium dense, silty sands. Forrnational soils are anticipated to be encountered from a depth of 3 feet (elevation +5 feet, MSL) to the bottom of the pit at approximate elevation -5 feet, MSL. Groundwater is anticipated to be encountered at a depth of approximately 8 feet (approximate elevation 0 feet, MSL). However, we anticipate a lag in time in this behavior. In addition, we anticipate that the water table will vary with the tide. The excavation for the pit will need to be shored in some manner. Depending upon microtunneling operations, dewatering may be needed. However, we understand that the planned microtunneling operations are remotely controlled and able to operate below water. N:\21\2181\2181-3 ROI SupplGeotech InvesLdoc DUDEK & ASSOCIATES Project No. 2181-3 July 9,2007 Page 9 5.3 Microtunneling We understand that two segments of the proposed pipeline will be installed using the trenchless technology of microtunneling. Microtunneling operations, by their nature, are greatly influenced by many geotechnical factors. Several important geotechnical issues include soil/rock types and distribution, groundwater, soil/groundwater contamination, settlement/heave damage potential, ground stability and pipe-face stability, the need for ground stabilization/improvement, obstructions, soil properties, pipe friction, shaft and portal construction, shaft shoring requirements, portal stability, thrust block resistance, preparation of subgrade conditions for the alignment and steering equipment, shaft backfilling (if required), and instrumentation and monitoring systems. The microtunneling operations proposed for this project will likely be conducted primarily within the Santiago Formation. Typically, the Santiago Formation consists of a gray-brown, interbedded, well-indurated, very dense, silty to clayey sand and very stiff to very hard clay. Within the Santiago Formation, there are carbonate-cemented zones that are similar to a soil- cement and/or two-sack sand slurry. In isolated areas, the unconfined compressive strength may approach that of plain concrete. Typically, the cemented strata are on the order of a few feet to 10 feet in thickness. In addition, lenses and zones of gravel should be expected, as evidenced by several lenses encountered during drilling of our test borings. The occurrence of cobbles is considered rare (<5%), and the occurrence of boulders is considered very rare (<1%). From a review of the boring information collected for this project, Standard Penetration Resistances (SPT) within the clay zones vary from 11 to 50, while in the dense to very dense, silty to clayey sands and sands, the SPTs are typically 50 plus blows for 6 inches. Unconfined compressive strengths in the silty sands and clayey sands are on the order of 2,000 psf (14 psi) or less, and one pocket penetrometer test in a clayey zone indicated an undrained compressive strength of 2.75 tsf (or 5,500 psf or 38 psi). Zones of encountered cleaner sands may be considered "running" when dry and "flowing" when wet. In addition, microtunneling operations are generally conducted in enclosed areas. Hence, ventilation is a critical safety element. According to the Caltrans "Highway Design Manual of Instructions," Tunnel Safety Order Section 8422 requires the Department of Transportation to request the Division of Industrial Safety to review and classify tunnel projects relative to flammable gas and vapors prior to bidding. In general, the California N:\21\2181\2181-3 R01 Suppl Oeotech Invest.doc DUDEK & ASSOCIATES Project No. 2181-3 July 9, 2007 Page 10 Department of Occupational Safety and Health (CALOSHA) is to be contacted prior to the initiation of the operations. The mailing address for the Department of Occupational Safety and Health is: California Department of Occupational Safety and Health 1367 E. Lassen Avenue, Suite B-4 Chico, California 95973 Telephone: (530) 895-6738 TerraL'osta 6 RECOMMENDATIONS 6.1 Site Preparation and Earthwork Operations All grading and site preparation should be performed under the observation of the geotechnical engineer, and in accordance with the 1994 Edition of The Standard Specifications for Public Works Construction (SSPWC) and the 1994 City of San Diego and County of San Diego Regional Supplement Amendments. All vegetation, debris, and other deleterious materials should be removed from the areas to receive fill prior to site grading. All structural fill soils should be compacted to a minimum 90 percent of the maximum dry density as determined by ASTM Test Method D1557-91. Moisture content in the fill should be maintained between the optimum moisture content and 2 percent over optimum. The geotechnical engineer should review the plans to evaluate whether the intent of the recommendations presented herein has been properly interpreted and incorporated into the contract documents. 6.2 Excavations and Shoring Requirements We recommend that all trenches and excavations be designed and constructed in accordance with OSHA and CALOSHA regulations. For preliminary planning purposes, we recommend using an OSHA soil classification of Type C for excavations within fill soils, and Type B for excavations in formational soils. In all instances, soil and trench conditions should be assessed by a competent person in accordance with 29CFR Part 1926, Occupational Safety N:\21\2181\2l81-3 ROl Suppl Geotech Invest.doc DUDEK & ASSOCIATES Project No. 2181-3 July 9, 2007 Page 11 and Health Standards - Excavations. For excavations and trenches in excess of 20 feet, shoring selection shall be designed and approved by a registered professional engineer per 29CFR Part 1926.652, Requirements for Protective Systems. The proposed excavations for the microtunneling pits will encounter groundwater. As such, the excavation operations and plans should take this into consideration. Also, zones of "clean" saturated sands may be encountered within the proposed pits and along the microtunneling alignment. 6.3 Microtunneling For preliminary design purposes, we recommend the following geotechnical parameters to assist the design of the microtunneling operations: • For assessing face stability of the excavated annulus within the Santiago Formation, we recommend modeling the Santiago Formation using both a cohesionless and cohesive material condition. • For the cohesionless model, we recommend assuming that the Santiago Formation has a friction angle of 34 degrees and a total unit weight of 135 pcf. • For the cohesive model, we recommend modeling the Santiago Formation as having a typical equivalent undrained shear strength of 2,000 psf (14 psi) and a total unit weight of 130 pcf. In addition, we recommend that the tunneling operations consider the possibility of encountering zones of cementation with unconfined compressive strengths on the order of 3,000 psi or less. These potential zones, if they occur, are anticipated to be less than 10 feet in thickness. Recall that harder zones are possible, but not anticipated. • For assessing face stability of the excavated annulus within the colluvial and alluvial soils, we recommend modeling these materials as being cohesionless. As such, we recommend assuming that the Santiago Formation has a friction angle of 30 degrees and a total unit weight of 125 pcf. • We recommend assuming that the groundwater table will be encountered at elevation +6 feet, MSL. N:\21\2181\2181-3 R01 Suppl Geotech Invest.doc DUDEK & ASSOCIATES July 9,2007 Project No. 2181 -3 Page 12 For estimating the likely ground deformation resulting from the proposed pipejacking/microtunneling operations, we recommend the following equations: maX~ Vs where: dmax is the maximum ground settlement; i is equal to K times the depth to the center of the pipe; and Vs is the volume loss due to the excavation per foot of pipe. For this equation, we recommend using a K ranging from 0.25 to 0.5 and a Vs equal to 1 percent of the excavated face. In order to estimate the shape of ground settlement manifested at the surface, we recommend using the following equation: 2 — JC TerraCosta where: x is the distance from the centerline of the pipe in feet; i is defined as Kz, where z is the depth to the center of the pipe; d is the ground displacement at x; and dmax is the maximum ground displacement as calculated above. • For estimating the jacking force required to push the pipe casing, we recommend using a coefficient of friction equal to 0.6 for steel casing against soil and a coefficient of friction of 0.9 for concrete against soil. Furthermore, we recommend using a total unit weight of 135 pcf for calculating the normal pressure acting on the pipeline that is being jacked. For designing the reaction wall for jacking, we recommend using an allowable passive pressure, expressed as an equivalent fluid pressure, of 350 psf. For design of shoring systems for the microtunneling access shafts, we recommend using an active earth pressure coefficient of 0.3 and an equivalent total unit weight of soil of 125 pcf. In addition, we recommend that in areas where water is encountered, the shoring should be N:\21 \2181 \2181 -3 RO1 Suppl Geotech Invest.doc DUDEK & ASSOCIATES Project No. 2181-3 July 9,2007 Page 13 designed to accommodate hydrostatic pressures. Lastly, the shoring for the access shafts should be designed to accommodate any surface surcharge loads associated with construction equipment and/or stockpiled construction materials. 7 LIMITATIONS This report should be considered as documentation of a preliminary investigation, and is intended to aid and assist the client in their evaluation of potential constructability problems and their planning needs. The data and conclusions provided in this report are based on limited field data collected for this investigation (only three points were explored over an approximately 1,800-foot-long project alignment) and on our review of available data. We have assumed that the soil and rock conditions do not deviate appreciably from those disclosed in our field and laboratory investigations, and in our review of available literature regarding the site area. This firm does not practice or consult in the field of safety engineering. We do not direct the contractor's operations and we cannot be responsible for the safety of other than our own personnel on site. Therefore, the safety of others is the responsibility of the contractor. The contractor should notify the owner if he considers any of the recommended actions presented herein to be unsafe. N:\21 \2181 \2181 -3 RO1 Suppl Geotech lnvest.doc ::> VX ^SP\J\_ CARLSBAD "i >•' B"^' aic.TyjBi "•<*Jtsrij•; • .423S&&,.---"•"-- TSlSiJr BASE MAP CONSISTS OF THE FOLLOWING U.S.G.S ACCOMPANYING INDEX MAP: B - BONSALL, 1968 0 - OCEAHSIDE, 1968 (PHOTOREVISED, 1975); S (PHOTOREVISED, 1975); SM - SAN MARCOS (196f). REFERENCE: GEOLOGIC MAP OF NORTH-CENTRAL COASTAL AREA OF SAN DIEGO COUNTY, CALIFORNIA, 1982, BY F. HAROLD WEBER, JR. LEGEND: LID lflcl*! rill iinniviMci) . - MQ!™»t« fill; PeildtntUI Irar.t) (an I <M?y I L^H I Obp I 1000 3000 5000 7000 (FEET) 117° 21,000' W 117°20,000' W 117°19,000' W WGS84117°18,QOO' W 117°21.000' W 117°20.000' W 117°19,000' Wt Mi WGS34 117°1S,000' W 1000 FEET Q_500 1000 METEflS Printed from TOPO! ©2000 National Geographic Holdings (www.topo.com) TERRACOSTA CONSULTING GROUP ENGINEERS AND GEOLOGISTS 1455 MURPHY CANYON ROAD. SUITE 100 DIEGO. CA 92123 (858) 573-6900 NAME NORTH AQUA HEDIONDA INTERCEPTOR FIGURE NUMBER PROJECT NUMBER 2181-3 GEOLOGY AND VICINITY MAPS SB(Ea 1+37.1 (MAIN) 1+00 (BRANCH)CONSTRUCT 5' DIA ACCESS HOLE PER CMWD STD DWG S-1 AND DETAIL r 3 V 1CONSTRUCT 5 DIA ACCESS HOLE PER CMWD STD DWG S-1 AND DETAIL 2 N= 8230954.51 E-1999086.46 N=623091+.83 £=1999101.37 TEMPORARY / MICROTUNNELJNG PIT I PROPOSED TEMPORARY CONSTRUCTION EASEMENT PER DOC, TE:CONSTRUCT 5 DIA ACCESS HOLE PER CMWD STD DWG S-1 AND DETAIL f 1 V 1 EX 15' EASEMENT^ 206-200-03 INSTALL LATERAL f 1 (SEE TABLE— PROPOSED 2ff SEWtR EASEMENT DOC. NO. DATE: 19+15 ± 10' LTHAVE STUB" TOR FUTURE SEWER LATERAL APN: 2O6-2OO-O4-OOINSTALL LATERAL (SEE TABtl 1) 18+50 7.5' LT \ "" \ CONTRACTOR SHALL PROTECT-^ IN PLACE ANY STRUCTURES EXISTING OR 0EING E«JILT DURING THE INSTALLATION OF NEW SEWER LINE LEAVE STUB FOR FUTURE SE»ER LATERAL CONSTRUCT 5 DIA ACCESS H PER CMWD STD DWG AND DETAIL N-19929Sh82 .£-8232125.54 19+43.66 MH NO. 6 CONSTRyCT 5' D»A ACCESS HOLE \ PER" CMWD STD DWG S-1 ' .AND DETAIL =1997944.17 -9232140.03 DOWNSTREAM SITE SCALE: r = 40' APN: 2O6-I72-O6-OO HINGE POINT UPSTREAM SITE- LOCATION MAP NOT TO SCALE 11+41.53 MH NO. 4 CONSTRUCT 5' DIA ACCESS PER CMWD STD DWG S-1 AND DETAIL N-1998215.76 E-6231388.70 APN: 2O6-t72-O6-OO CONTRACTOR SHALL PROTECT EXCAVATION AND MATERIAL FROM SLUFF1NG DOWN SLOPE OR DAMAGING ANY ENVIRONMENTALLY SENSITIVE AREAS EX AH NO. 13 HINGE POINT SITE SCALE: l" = 40f UPSTREAM SITE SCALE: l" = 40' LEGEND APPROXIMA TE LOCA TION OF SOIL BORING TERRACOSTA CONSULTING GROUP ENGINEERS AND GEOLOGISTS 4458 MURPHY CANYON ROAD, SUITE 100 SAN DIEGO. CA 92123 (898) 973-8000 PROJECT NAME NORTH AGUA HEDIONDA INTERCEPTOR FIGURE NUMBER PROJECT NUMBER 2181-3 BORING LOCATION MAP 40—1 3O- 2O- o- -w —' RANGE IN POTENTIALFOKMATIONAL CONTACT o+oo 1+OO 2+00 3+OO SEWER ALIGNMENTSTA TIONING 4+OO 5+OO 6+OO LEGEND Qcol Qal Tsa B-1 COLLUVIUM ALLUVIUM SANTIAGO FORMATION GEOLOGIC CONTACTS Queried where uncertain SOIL BORING B-1 GEOLOGIC PROFILE-STA 0+00 to 6+50 SCALE: l"=20' (VERT.) l"=50' (HORIZ.I TERRACOSTA CONSULTING GROUP ENGINEERS AND GEOLOGISTS 4496 MURPHY CANYON ROAD. SUITE 100 SAN DEQO. CA 92123 I8S8I 573-9000 PROJECT NAME NORTH AQUA HEWONDA INTERCEPTOR FIGURE NUMBER 3a PROJECT NUMBER 2181-3 GEOLOGIC PROFILE \AND FORMATIONAL 40-i 3O- 2O- w- o- -ro-> 11+41.53 MH NO. 4 CONSTRUCT 5' DIA AH PER CMWD STD DWO S~1 AND DETAIL / 1 - EXISTING GRADE INSTALLATION S STA 11+41.53 •£//- STEEL CASING 4" ID DRILL HOPE CARRIER PVC OPE=0.t47X GROUNDWATERATX/X// TIME OF DRILLING - POSSIBLE LOWER BOUND CONTACTBETH ANDFOMATION 7+OO 8+OO 9+OO -i | r- /o+oo SEWER ALIGNMENT STATIONING rr+oo 12+00 ts+oo LEGEND Qcol Qal Tsa B-2 COLLUVIUM ALLUVIUM SANTIAGO FORMATION GEOLOGIC CONTACTS Queried where uncertain SOIL BORING B-2 GEOLOGIC PROFILE-STA 6+50 to 13+50 SCALE: r=20' IVERT.I l"=50' (HORIZ.I 1ERRACOSTA CONSULTTNG GROUP ENGINEERS AND GEOLOGISTS 4495 MURPHY CANYON ROAD. SUITE 100 SAN DEQO. CA 92123 I88»l S73-8900 PROJECT NAME NORTH AQUA HEUONDA INI FIGURE NUMBER 3b 2181-3 GEOLOGIC PROFILE - EXISTING GRADE PROJECTED CONTACT BETWEEN AND FORMATION WIN 2X SLOPE * WIN 4' DEPTH MIN 2* SLOPE It WIN 4' DEPTHSTUB FOR FUTURE CONNECTION AT If 42" STEEL CASING 24" ID DRILL HOPE CARRIER PVC ASLOPE=0.147Jl 42" STEEL CASING 24" ID DRIU. HOPE C SLOPE-0.147X UKELY CONTACT BETWEEN^^f\ ANDFOMATION ANTICIPATED GROUNOWATE& (— 4O -3O -to '— O ~-ro 14+OO 15+OO /6+OO 17+OO SEWER ALIGNMENTSTA TIONING 1 18+OO 19+OO LEGEND Qcol Qat Tsa ——f— 8-3 COLLUVIUM ALLUVIUM SANTIAGO FORMATION GEOLOGIC CONTACTS Queried where uncertain SOIL BORING B-3 GEOLOGIC PROFILE-STA 13+50 to 19+43.66 SCALE: l"=20' [VERT.) l"=50' IHORIZ.) TERRACOSTA CONSULTING GROUP ENGINEERS AND GEOLOGISTS MURPHY CANYON ROAO. SUITE 100 SAN DEOO. CA 92123 I856) 573-8900 PROJECT NAME NORTH AQUA HEDKWDA INI FIGURE NUMBER 3c PROJECT NUMBER 2181-3 GEOLOGIC PROFILE APPENDIX A LOGS OF EXPLORATORY BORINGS LOG OF CORE BORING North Agua Hedionda Interceptor SITE LOCATION DATE(S) DRILLED Carlsbad, CA 3/5/2007 to 3/5/2007 PROJECT NUMBER 2181-3 LOGGED BY G. Spaulding DRILLING METHOD DRILL BIT SIZE/TYPE Rotary Core 6" /101mm DRILL RIG TYPE DRILLED BY Versa Drill - V1 00 Gregg Drilling APPARENT GROUNDWATER DEPTH (feet) 2 COMMENTS DEPTH (ft)- -5 - -10 - -15 -20 -ELEVATION (ft)ROCK CORE o z K. 6 XoCD RECOVERY, %OLUOLLLiu_ £ D 0 ai FRACTUREDRAWING/NUMBERLITHOLOGY1 CHECKED BY BORING LEGEND SHEET NO. 1 of 2 TOTAL DEPTH DRILLED (feet) 35 INCLINATION FROM VERTICAL/BEARING 0 APPROXIMATE SURFACE ELEVATION (feet) BOREHOLE BACKFILL Cement Grout MATERIAL DESCRIPTION KE Y TO EXCAVATION LOGS r Estimated water table measured at time of drilling ROCK CORE Run No.: Number of the individual starting at the top of bedrock. coring interval, Box No.: Number of the core box that contains core from the corresponding run. Recovery, %: Amount (in percent) of core recovered from the cor ng interval; calculated as the length of core recovered divided by the length of the run. R.Q.D., % (Rock Quality Designation) Amount (in percent) of intact core (pieces of sound core greater than 4 inches in length) in each coring interval; calculated as the sum of the lengths of intact core divided by the length of the core run. SAMPLES Sample Type: Continuous-Core Sampler - A continuous thin-v\ sampler. The sampler, designed for use in soft i applications, is pushed into the soil ahead of the as the bore hole is advanced. Continuous, relat undisturbed samples up to 5 feet in length are ol /ailed ock drill string vely Gained. NOTES ON FIELD INVESTIGATION Borings were advanced using a truck-mounted Versa Drill-V100 drill rig with a 101mm core barrel. Continuous-Core Samplers were used to obtain soil samples. When the samplers were withdrawn from the boring, the samples were removed, visually classified, and taken to the laboratory for detailed inspection. TerraCosta Consulting Group, Inc. Murphy Canyon Road, Suite 100 mmSm San Diego, California 92123 SAMPLE TYPEn THIS SUMMARY APPLIES ONLY AT THE LOCATION OF THIS BORING AND AT THE TIME OF DRILLING. SUBSURFACE CONDITIONS MAY DIFFER AT OTHER LOCATIONS AND MAY CHANGE AT THIS LOCATION WITH THE PASSAGE OF TIME. THE DATA PRESENTED IS A SIMPLIFICATION OF THE ACTUAL CONDITIONS ENCOUNTERED.SAMPLE NO.1 PENETRATION RESISTANCE(BLOWS/fl)DRY DENSITY(pcf)MOISTURE(%)CE</> UJI-ICO &r FIGURE A-1 a LOG OF CORE BORING North Agua Hedionda Interceptor SITE LOCATION DATE(S) DRILLED Carlsbad, CA 3/5/2007 to 3/5/2007 PROJECT NUMBER 2181-3 LOGGED BY G. Spaulding DRILLING METHOD DRILL BIT SIZE/TYPE Rotary Core 6" /101mm DRILL RIG TYPE DRILLED BY Versa Drill -V100 Gregg Drilling APPARENT GROUNDWATER DEPTH (feet) 2 COMMENTS Ii-Q. UJ Q -25 — - ^30 ^35 -45 ELEVATION (ft)S ROCK CORE dzz BOX NO.RECOVERY, %FRAC. FREQ.Qcio:FRACTUREDRAWING/NUMBERLITHOLOGYCHECKED BY BORING LEGEND SHEET NO. 2 of 2 TOTAL DEPTH DRILLED <feet> 35 INCLINATION FROM VERTICAL/BEARING 0 APPROXIMATE SURFACE ELEVATION (feet) BOREHOLE BACKFILL Cement Grout MATERIAL DESCRIPTION NOTES ON FIELD INVESTIGATION (Continued) Free groundwater was encountered shown on the logs. in the borings as Classifications are based upon the Unified Soil Classification System and include color, moisture, and consistency. Field descriptions have been modified to reflect results of laboratory inspection where deemed appropriate. TerraCosta Consulting Group, Inc. 4455 Murphy Canyon Road, Suite 100 San Diego, California 92123 SAMPLE TYPETHIS SUMMARY APPLIES ONLY AT THE LOCATION OF THIS BORING AND AT THE TIME OF DRILLING. SUBSURFACE CONDITIONS MAY DIFFER AT OTHER LOCATIONS AND MAY CHANGE AT THIS LOCATION WITH THE PASSAGE OF TIME. THE DATA PRESENTED IS A SIMPLIFICATION OF THE ACTUAL CONDITIONS ENCOUNTERED.SAMPLE NO.PENETRATION RESISTANCE(BLOWSffl)DRY DENSITY(pcf)MOISTURE(%)LUH I-LUOl- FIGURE A-1 b LOG OF CORE BORING SITE LOCATION Carlsbad, CA DRILLING METHOD Rotary Core DRILL RIG TYPE Versa Drill -V1 00 PROJECT NAME North Agua Hedionda Interceptor DATE(S) DRILLED 3/5/2007 to 3/5/2007 PROJECT NUMBER BORING 2181-3 B-1 LOGGED BY SHEET NO. G. Spaulding 1 of 2 DRILL BIT SIZE/TYPE 6"/ 101mm DRILLED BY Gregg Drilling APPARENT GROUNDWATER DEPTH (feet) 12 COMMENTS g Xi- 0. LLJ D -5 -10 -15 -20 -ELEVATION (ft)-15 -10 -5 -0 5 ROCK CORE 6 z <r 1 2 3 4 5 6 BOX NO.1 1 1 2 2 2 RECOVERY, %60 40 20 25 100 60 OUJ<£.u_ d 2u_ ^ d ci CL 0 0 0 0 0 0 FRACTUREDRAWING/NUMBERLITHOLOGY:i CHECKED BY TOTAL DEPTH DRILLED (feet) 3g INCLINATION FROM VERTICAL/BEARING 0 APPROXIMATE SURFACE ELEVATION (feet) 18 BOREHOLE BACKFILL 8 Cubic Feet Cement Grout MATERIAL DESCRIPTION COLLUVIUM Silty SAND (SM) medium dense, red-brown to dark brown, dry to damp r TerraCosta Consulting Group, Inc. f 4455 Murphy Canyon Road, Suite 100 ftlplfm San Diego, California 92123 SAMPLE TYPETHIS SUMMARY APPLIES ONLY AT THE LOCATION OF THIS BORING AND AT THE TIME OF DRILLING. SUBSURFACE CONDITIONS MAY DIFFER AT OTHER LOCATIONS AND MAY CHANGE AT THIS LOCATION WITH THE PASSAGE OF TIME. THE DATA PRESENTED IS A SIMPLIFICATION OF THE ACTUAL CONDITIONS ENCOUNTERED.SAMPLE NO.UJOZ<\-w V) £•£| §3 fUJzUJQ. >-DRY DENSH(pcf)MOISTURE(%)ttwUJI-IWI-UJ OH FIGURE A-2 a LOG OF CORE BORING SITE LOCATION Carlsbad, CA DRILLING METHOD Rotary Core DRILL RIG TYPE Versa Drill -V1 00 1 PROJECT NAME North Agua Hedionda Interceptor DATE(S) DRILLED 3/5/2007 to 3/5/2007 PROJECT NUMBER BORING 2181-3 B-1 LOGGED BY SHEET NO. G. Spaulding 2 of 2 DRILL BIT SIZE/TYPE 6"/ 101mm DRILLED BY Gregg Drilling APPARENT GROUNDWATER DEPTH (feet) 12 COMMENTS g £LUQ -25 - -30 - -35 - -40 -45 ELEVATION (ft)— 10 — —15 - —20 —25 —30 g ROCK CORE d z cr t 8 9 10 11 12 BOX NO.6 3 3 4 5 5 RECOVERY, %bU 20 80 80 0 0 aLUo:u. %U_ £ D dcd 0 0 0 0 0 0 FRACTUREDRAWING/NUMBERLITHOLOGYCHECKED BY TOTAL DEPTH DRILLED (feet) 39 INCLINATION FROM VERTICAL/BEARING 0 APPROXIMATE SURFACE ELEVATION (feet) 18 BOREHOLE BACKFILL 8 Cubic Feet Cement Grout MATERIAL DESCRIPTION - Estimated up to 10% gravels SANTIAGO FORMATION Silty to Clayey SAND (SM/SC,) medium dense, interbedded olive-gray to gray, wet, highly weathered, with estimated up to 1 0% gravels in the upper 2 feet of the boundary Boring terminated at depth of 39 feet. Groundwater encountered at depth of 12 feet at time of excavation. TerraCosta Consulting Group, Inc. 4455 Murphy Canyon Road, Suite 100 San Diego, California 92123 SAMPLE TYPETHIS SUMMARY APPLIES ONLY AT THE LOCATION OF THIS BORING AND AT THE TIME OF DRILLING. SUBSURFACE CONDITIONS MAY DIFFER AT OTHER LOCATIONS AND MAY CHANGE AT THIS LOCATION WITH THE PASSAGE OF TIME. THE DATA PRESENTED IS A SIMPLIFICATION OF THE ACTUAL CONDITIONS ENCOUNTERED.SAMPLE NO.PENETRATION RESISTANCE(BLOWS/ft)DRY DENSITY(PCf)MOISTURE(%)Kw LUI-IC/3I-LUOl- FIGURE A-2 b LOG OF CORE BORING SITE LOCATION Carlsbad, CA DRILLING METHOD Rotary Core DRILL RIG TYPE Versa Drill -V1 00 PROJECT NAME North Agua Hedionda Interceptor DATE(S) DRILLED 3/5/2007 to 3/5/2007 PROJECT NUMBER 2181-3 LOGGED BY G. Spaulding DRILL BIT SIZE/TYPE 6"/ 101mm DRILLED BY Gregg Drilling APPARENT GROUNDWATER DEPTH (feet) 33 COMMENTS g ii-D_UJD -5 - -10 15 -20 - s ELEVATION-30 25 -20 - -15 -10 ROCK CORE d zna: 1 2 3 4 5 6 BOX NO.1 1 2 2 2 3 3 3 RECOVERY, %100 100 90 90 50 80 d UJtrLL d $U- ^ DdaL 0 0 0 0 0 0 FRACTUREDRAWING/NUMBERLITHOLOGY: CHECKED BY BORING B-2 SHEET NO. 1 of 3 TOTAL DEPTH DRILLED <feet> 50 INCLINATION FROM VERTICAL/BEARING 0 APPROXIMATE SURFACE ELEVATION (feet) 34 BOREHOLE BACKFILL 10 Cubic Feet Cement Grout MATERIAL DESCRIPTION COLLUVIUM / TERRACE DEPOSITS Silty to Clayey SAND (SM/SC,)medium dense, mottled brown / red-brown / olive-grown, damp SANTIAGO FORMATION Silty SAND (SM) dense, olive-gray, damp - Occasional iron oxide staining - Estimated 15 - 20% gravels and cobbles to 6", of rhyolitic to dacitic volcanic clasts - Rotary through gravels aTerraCosta Consulting Group, Inc. 4455 Murphy Canyon Road, Suite 100 San Diego, California 92123 consisting SAMPLE TYPETHIS SUMMARY APPLIES ONLY AT THE LOCATION OF THIS BORING AND AT THE TIME OF DRILLING. SUBSURFACE CONDITIONS MAY DIFFER AT OTHER LOCATIONS AND MAY CHANGE AT THIS LOCATION WITH THE PASSAGE OF TIME. THE DATA PRESENTED IS A SIMPLIFICATION OF THE ACTUAL CONDITIONS ENCOUNTERED.SAMPLE NO.PENETRATION RESISTANCE(BLOWS/ft)DRY DENSITY(pcf)MOISTURE(%)KcoUJH ICOI-UJOH FIGURE A-3 a LOG OF CORE BORING SITE LOCATION Carlsbad, CA DRILLING METHOD Rotary Core DRILL RIG TYPE Versa Drill -V1 00 PROJECT NAME North Agua Hedionda Interceptor DATE(S) DRILLED 3/5/2007 to 3/5/2007 PROJECT NUMBER BORING 2181-3 B_2 LOGGED BY SHEET NO. G. Spaulding 2 of 3 DRILL BIT SIZE/TYPE 6"/ 101mm DRILLED BY Gregg Drilling APPARENT GROUNDWATER DEPTH (feet) 33 COMMENTS ii-D_ HI Q -25 - -30 ^35 -40 -45 - £"ELEVATION- -5 -0 —5 - -10 - ROCK CORE d z a: 7 8 9 10 11 12 13 14 15 BOX NO.3 3 4 4 4 4 5 6 RECOVERY, %0 0 100 100 20 0 60 85 60 aHIa:U- d Ddcd 0 0 0 0 0 0 0 0 0 FRACTUREDRAWING/NUMBERLITHOLOGYi CHECKED BY TOTAL DEPTH DRILLED <feet> 50 INCLINATION FROM VERTICAL/BEARING 0 APPROXIMATE SURFACE ELEVATION (feet) 34 BOREHOLE BACKFILL 10 Cubic Feet Cement Grout MATERIAL DESCRIPTION - Clean sand and 10% gravels - Mottled olive-gray / red r - Harder dirlling TerraCosta Consulting Group, Inc. I 4455 Murphy Canyon Road, Suite 100 San Diego, California 92123 SAMPLE TYPETHIS SUMMARY APPLIES ONLY AT THE LOCATION OF THIS BORING AND AT THE TIME OF DRILLING. SUBSURFACE CONDITIONS MAY DIFFER AT OTHER LOCATIONS AND MAY CHANGE AT THIS LOCATION WITH THE PASSAGE OF TIME. THE DATA PRESENTED IS A SIMPLIFICATION OF THE ACTUAL CONDITIONS ENCOUNTERED.SAMPLE NO.PENETRATION RESISTANCE(BLOWS/fl)DRY DENSITY(pcf)MOISTURE(%)a: en UJI-ICfl h-UJOH FIGURE A-3 b LOG OF CORE BORING North Agua Hedionda Interceptor SITE LOCATION DATE(S) DRILLED Carlsbad, CA 3/5/2007 to 3/5/2007 PROJECT NUMBER BORING 2181-3 B_2 LOGGED BY SHEET NO. G. Spaulding 3 of 3 DRILLING METHOD DRILL BIT SIZE/TYPE Rotary Core 6" /101mm DRILL RIG TYPE DRILLED BY Versa Drill - V1 00 Gregg Drilling APPARENT GROUNDWATER DEPTH (feet) 33 COMMENTS DEPTH (ft)-50 : -55 - -60 - -65 - -70 ELEVATION (ft)— — 20 : —25 — —30 — —35 - ROCK CORE RUN NO.BOX NO.RECOVERY, %FRAC. FREQ.cici U.FRACTUREDRAWING/NUMBERLITHOLOGYCHECKED BY TOTAL DEPTH DRILLED <feet> 50 INCLINATION FROM VERTICAL/BEARING 0 APPROXIMATE SURFACE ELEVATION (feet) 34 BOREHOLE BACKFILL 10 Cubic Feet Cement Grout MATERIAL DESCRIPTION Boring terminated at depth of 50 feet. Groundwater encountered at depth of 33 feet at time of excavation. aTerraCosta Consulting Group, Inc. 4455 Murphy Canyon Road, Suite 100 San Diego, California 92123 SAMPLE TYPETHIS SUMMARY APPLIES ONLY AT THE LOCATION OF THIS BORING AND AT THE TIME OF DRILLING. SUBSURFACE CONDITIONS MAY DIFFER AT OTHER LOCATIONS AND MAY CHANGE AT THIS LOCATION WITH THE PASSAGE OF TIME. THE DATA PRESENTED IS A SIMPLIFICATION OF THE ACTUAL CONDITIONS ENCOUNTERED.SAMPLE NO.LU W £• ^ 2, •z.DRY DENSITY(pcf)MOISTURE(%)Q^ C/3111 h- FIGURE A-3c LOG OF CORE BORING SITE LOCATION Carlsbad, CA DRILLING METHOD Rotary Core DRILL RIG TYPE Versa Drill -V1 00 PROJECT NAME North Agua Hedionda Interceptor DATE(S) DRILLED 3/5/2007 to 3/5/2007 PROJECT NUMBER BORING 2181-3 B-3 LOGGED BY SHEET NO. G. Spaulding 1 of 2 DRILL BIT SIZE/TYPE 6"/ 101mm DRILLED BY Versa Drill APPARENT GROUNDWATER DEPTH (feet) COMMENTS DEPTH (ft)- -5 -10 -15 -20 ELEVATION (ft)—5 — -0 5 —15 a ROCK CORE d zID 1 2 3 4 5 6 O XoCD 1 1 2 2 3 3 4 RECOVERY, %100 100 100 100 20 100 OUJo:LL 6 LL ci da: 0 95 95 90 0 85 FRACTUREDRAWING/NUMBERLITHOLOGY'/ / ( , \ / \ / / / / / / / / / / / / / / / / / / CHECKED BY TOTAL DEPTH DRILLED (feet) 25 INCLINATION FROM VERTICAL/BEARING 0 APPROXIMATE SURFACE ELEVATION (feet) 8 BOREHOLE BACKFILL 5 Cubic Feet Cement Grout MATERIAL DESCRIPTION COLLUVIUM Silty SAND (SM) loose to medium dense, brown to red-brown, damp SANTIAGO FORMATION Interbedded Clayey SAND and Sandy CLAY (SC/CL) very dense, light olive-gray, damp Note: Groundwater not measured at time of drilling; however, due to proximity of the lagoon, groundwater should be anticipted at approximate mean sea level. - Clean sand lense from 17 to 21 feet TerraCosta Consulting Group, Inc. 4455 Murphy Canyon Road, Suite 100 San Diego, California 92123 SAMPLE TYPETHIS SUMMARY APPLIES ONLY AT THE LOCATION OF THIS BORING AND AT THE TIME OF DRILLING. SUBSURFACE CONDITIONS MAY DIFFER AT OTHER LOCATIONS AND MAY CHANGE AT THIS LOCATION WITH THE PASSAGE OF TIME. THE DATA PRESENTED IS A SIMPLIFICATION OF THE ACTUAL CONDITIONS ENCOUNTERED.SAMPLE NO.UJ PENETRATION RESI(BLOWS/ft)DRY DENSITY(pcf)MOISTURE(%)LJJI-ICfll-LilOK FIGURE A-4 a LOG OF CORE BORING North Agua Hedionda Interceptor SITE LOCATION DATE(S) DRILLED Carlsbad, CA 3/5/2007 to 3/5/2007 DRILLING METHOD DRILL BIT SIZE/TYPE Rotary Core 6" /101mm DRILL RIG TYPE DRILLED BY Versa Drill - V1 00 Versa Drill APPARENT GROUNDWATER DEPTH (feet) COMMENTS g ii-Q_ UJD -25 - ^30 - -35 - -40 - -ELEVATION (ft)— —20 - —25 - —30 - —35 —40 ROCK CORE d •z. a: 6 XoCO RECOVERY, %dUJo; d£ d dof FRACTUREDRAWING/NUMBERLITHOLOGY/ X / PROJECT NUMBER BORING 2181-3 B-3 LOGGED BY SHEET NO. G. Spaulding 2 of 2 CHECKED BY TOTAL DEPTH DRILLED (feet) 25 INCLINATION FROM VERTICAL/BEARING 0 APPROXIMATE SURFACE ELEVATION (feet) 8 BOREHOLE BACKFILL 5 Cubic Feet Cement Grout MATERIAL DESCRIPTION Boring terminated at fepth of 25 feet. No free groundwater encountered at time of excavation.SAMPLE TYPETHIS SUMMARY APPLIES ONLY AT THE LOCATIONaTerraCosta Consulting Group, Inc. SUBSURFACE CONDITIONS MAY DIFFER ATOTHER .Am, u ^ r-. -i o -i inn LOCATIONS AND MAY CHANGE AT THIS LOCATION4455 Murphy Canyon Road, Suite 1 00 WITH THE PASSAGE OF TIME. THE DATA o™ rv~™ r^rf^r,,-., 00-10-3 PRESENTED IS A SIMPLIFICATION OF THE ACTUALSan Diego, California 92123 CONDITIONS ENCOUNTERED.SAMPLE NO.UJO 1wco £• ii UJ UJQ.DRY DENSITY(pcf)MOISTURE(%)LUI- IC/)HLU FIGURE A-4 b APPENDIX B LABORATORY TEST RESULTS PERCENT FINER |100 go 80 70 60 50 40 30 20 10 0 Particle Size Distribution Report C Cc'^C^^m O OQ'OOO^fOco (o CN £ •«- S js 8 a % S 8 5 a ¥ * «I I i i 1 1 ! iI 1 i ! i 1 i I 1 ! t j ! 1 I i i I | I [ i 1 i i 1 I 1 1 i i 1 i i l i i ! i i 1 1 1 1 i i 1 i 1 i 1 1 ! | i | 1 | i | 1 j ! i !1 | 1 i 1 1 ! 1 I : I i 1 i 1 1 i I 1 i I i i : ! 1 1 i 1 | i i I 1 I I 1 TY r «s s\ 1 1I 1 y ! Vft! \V \ y s s,:x•o — c ^><* f b*0-<.>-.-•0 100 10 1 0.1 0.01 0.001 GRAIN SIZE - mm. %+3" 0.0 % Gravel Coarse 0.0 Fine 0.0 %Sand Coarse 0.7 SIEVE SIZE #4 #10 #20 #40 #100 #200 PERCENT FINER 100.0 99.3 96.3 85.4 41.4 27.3 SPEC.* PERCENT PASS? (X=NO) (no specification provided) ' Sample Number: Bl Depth: 22' MACTEC ENGINEERING AND AND CONSULTING, INC. San Diego, California Medium 13.9 Fine 58.1 % Fines Silt 17.6 Clay 9.7 Material Description Brown Silty Sand (Lab #1 8835) Atterberg Limits PL= LL= Pl= Coefficients D85= 0.4197 DRO= 0.2347 D50= 0.1884 D3Q= 0.0876 Di5= 0.0183 DIQ= 0.0056 Cu= 42.06 Cc= 5.85 Classificationuscs=AASHTO= Remarks Date: Client: TerraCosta Consulting, Inc. Project: North Agua Hedionda Interceptor Project No: 5014-04-0026.33 Figure GRAIN SIZE DISTRIBUTION TEST DATA 3/28/2007 Client: TerraCosta Consulting, Inc. Project: North Agua Hedionda Interceptor Project Number: 5014-04-0026.33 Depth: 22' Material Description: Brown Silty Sand (Lab #18835) Sample Number: Bl Sieve Opening Size #4 #10 #20 #40 #100 #200 Percent Finer 100.0 99.3 96.3 85.4 41.4 27.3 • 99.3 Hydrometer test uses material passing #10 Percent passing #10 based upon complete sample Weight of hydrometer sample =116.17 Hygroscopic moisture correction: Moist weight and tare = 31.49 Dry weight and tare = 31.40 Tare weight* 20.68 Hygroscopic moisture = 0.8% Table of composite correction values: Temp., deg. C: 18.0 20.6 Comp. corn: -8.0 -7.0 Meniscus correction only = 1.0 Specific gravity of solids = 2.65 Hydrometer type = 152H Hydrometer effective depth equation: L = 16.294964 - 0.164 x Rm 21.1 -7.0 21.6 -6.0 Elapsed Time (min.) 1.00 2.00 5.00 15.00 30.00 60.00 120.00 250.00 1440.00 Temp, (deg. C.) 22.0 22.0 22.0 22.0 22.0 22.0 22.0 23.0 20.0 Actual Reading 27.0 25.0 24.0 21.0 20.0 18.0 17.0 16.0 15.0 Corrected Reading 21.1 19.1 18.1 15.1 14.1 12.1 11.1 10.2 7.8 K 0.0133 0.0133 0.0133 0.0133 0.0133 0.0133 0.0133 0.0132 0.0136 Rm 28.0 26.0 25.0 22.0 21.0 19.0 18.0 17.0 16.0 27.7 -5.0 Eff. Depth 11.7 12.0 12.2 12.7 12.9 13.2 13.3 13.5 13.7 Diameter (mm.) 0.0455 0.0327 0.0208 0.0122 0.0087 0.0062 0.0044 0.0031 0.0013 Percent Finer 18.2 16.4 15.6 13.0 12.1 10.4 9.5 8.8 6.7 MACTEC Engineering and Consulting, Inc. Cobbles 0.0 Gravel Coarse 0.0 Fine 0.0 Total 0.0 Sand Coarse . 0.7 Medium 13.9 Fine 58.1 Total 72.7 Fines Silt 17.6 Clay 9.7 Total 27.3 D10 0.0056 D15 0.0183 °20 0.0518 DSO 0.0876 D50 0.1884 D60 0.2347 D80 0.3650 °85 0.4197 D90 0.5069 °95 0.7158 Fineness Modulus 0.97 cu 42.06 °c 5.85 MACTEC Engineering and Consulting, Inc. PERCENT FINER j100 90 80 70 60 SO 40 30 20 10 0 Particle Size Distribution Report . £ . c e •- .OOOS .E.Es;£~*oo - o SS2 S g5°<o co N £ »• S 5S ;§ 3 5 SS***S«r i i i ! 1 i ! i i i i 1 i !' 1 i i ! i I I 1 1 • 1 1 1 1 1 11 1 1 i 1 i1 1 i 1 1 ! : r ! i i 1 1 ! i i I 1 1 1 1 | I | i I i I 1 I 1 1 | | E ! 1 '. i I i 1 1 i i 1 1A i 1 1 i 1 [ ] 1 | 1 1 1 1 ! ! 1 1 X \••'!_ \ \ \ S \ \ \lS i 1i I \ i \\ 1 1 1 ! ! i 1 ! I N\i i 1 Ii II 1 S. Sh1 I1j+O -O 1 • 2 •*3<-— O 100 10 1 0.1 0.01 -0.001 GRAIN SIZE - mm. %+3" 0.0 % Gravel Coarse 0.0 Fine 1.7 % Sand Coarse 8.8 SIEVE SIZE .375" #4 #10 #20 #40 #100 #200 PERCENT FINER 100.0 98.3 89.5 71.5 49.4 22.2 14.0 SPEC.* PERCENT PASS? (X=NO) (no specification provided) Sample Number: B2 Depth: 37' MACTEC ENGINEERING AND AND CONSULTING, INC. San Diego, California Medium 40.1 Fine 35.4 % Fines Slit 8.8 Clay 5.2 Material Description Light Brown Silty Sand (Lab #18836) Atterberq Limits PL= LL= Pl= Coefficients D85= 1.5275 D60= 0.5859 D50= 0.4329 D30= 0.2186 DIR= 0.0826 D-\n= 0.0524 GU= 11.19 GC= 1.56 Classification USCS= AASHTO= Remarks Date: 3/20/07 Client: TerraCosta Consulting, Inc. Project: North Agua Hedionda Interceptor Project No: 5014-04-0026.33 Figure Tested By: NS Checked By: LC GRAIN SIZE DISTRIBUTION TEST DATA Client: TerraCosta Consulting, Inc. Project: North Agua Hedionda Interceptor Project Number: 5014-04-0026.33 Depth: 37' Sample Number: B2 Material Description: Light Brown Silty Sand (Lab #18836) Date: 3/20/07 Tested by: NS Checked by: LC 3/28/2007 Sieve Opening Size .375" #4 #10 #20 #40 #100 #200 Percent Finer 100.0 98.3 89.5 71.5 49.4 22.2 14.0 Hydrometer test uses material passing #10 Percent passing #10 based upon complete sample Weight of hydrometer sample =115.93 Hygroscopic moisture correction: Moist weight and tare = 33.07 Dry weight and tare = 32.93 Tare welght= 20.73 Hygroscopic moisture = 1.1% Table of composite correction values: Temp., deg. C: 18.0 20.6 Comp.corr.: -8.0 -7.0 Meniscus correction only =1.0 Specific gravity of solids = 2.65 Hydrometer type = 152H Hydrometer effective depth equation: L '89.5 21,1 -7.0 21.6 -6.0 Elapsed Time (mln.) 1.00 2.00 5.00 15.00 30.00 60.00 120.00 250.00 1440.00 Temp. (deg.C.) 21.0 21.0 21.0 22.0 22.0 22,0 22.0 23.0 20.0 Actual Reading 19.0 17.0. 16.0 15.0 14.0 14.0 12.0 11.0 11.0 > 16.294964- 0.164 xRm Corrected Reading 12.0 10.0 9.0 9.1 8.1 8.1 6.1 5.2 3.8 K 0.0135 0.0135 0.0135 0.0133 0.0133 0.0133 0.0133 0.0132 0.0136 Rm 20.0 18.0 17.0 16.0 15.0 15.0 13.0 12.0 •12.0 27.7 -5.0 Eff. Depth 13.0 13.3 13.5 13.7 13.8 13.8 14.2 14.3 14.3 Diameter (mm.) 0.0486 0.0348 0,0222 0.0127 0.0090 0.0064 0.0046 0.0031 0.0014 Percent Finer 9.4 7.8 7.0 7.1 6.3 6.3 4.7 4.1 2.9 MACTEC Engineering and Consulting, Inc. Cobbles 0.0 Gravel Coarse 0.0 Fine 1.7 Total 1.7 Sand Coarse 8.8 Medium 40.1 Fine 35.4 Total 84.3 Fines Silt 8.8 Clay 5.2 Total 14.0 DID 0.0524 D15 0.0826 D20 0.1294 °30 0.2186 DSO 0.4329 DBO 0.5859 D80 1.1932 D85 1.5275 D9& 2.0683 D95 3.0944 Fineness Modulus 2.09 Cu 11.19 cc 1.56 MACTEC Engineering and Consulting, Inc. PERCENT FINER ]100 90 80 70 60 50 40 30 20 10 0 Particle Size Distribution Report isslaliils i iiiilll i I i ! i ! 1 i i \ ! i i i i } i i ii ! i 1 ! 1 ! 1 i i I i 1 ! ! ! i 1 ! i i i i i i 1 i i i ! ! i 1 t i i j i : i i ! i t I ; I i ! 1 ! ! : ! | i "i 1 i t ! i ! 1 " "X,N \ 1 \\ .1 1 1 1 1 1 1 l 1 1 1 \ \i i ( 1! I i s. i i rN- 1 C"C ^ S^,^^^>,kt X t •*( ^^X) 100 10 1 0.1 0.01 0.001 GRAIN SIZE - mm. %+3" 0.0 % Gravel Coarse 0.0 Fine 0.0 % Sand Coarse 6.1 SIEVE SIZE #4 #10 #20 #40 #100 #200 PERCENT FINER 100.0 93.9 68.5 43.3 28.5 25.0 SPEC.* PERCENT PASS? (X-NO) (no specification provided) Sample Number: B3 Depth: 12' MACTEC ENGINEERING AND AND CONSULTING, INC. San Diego, California Medium 50.6 Fine 18.3 % Fines Silt 10.0 Clay 15.0 Material Description Light Brown SUty Sand (Lab #18837) Atterberg Limits PL= LL= Pl= Coefficients D85= 1.3751 D60= 0.6833 D50= 0.5235 D30= 0.1867 015=0.0050 DIO= 0.0016 C^= 420.94 Cc= 31.44 Classification USCS= AASHTO= Remarks Date: 3/20/07 Client: TerraCosta Consulting, Inc. Project: North Agua Hedionda Interceptor Project No: 5014-04-0026.33 ' Figure GRAIN SIZE DISTRIBUTION TEST DATA Client: TerraCosta Consulting, Inc. Project: North Agua Hedionda Interceptor Project Number: 5014-04-0026.33 Depth: 12* Sample Number: B3 Material Description: Light Brown Silty Sand (Lab #18837) Date: 3/20/07 3/28/2007 Sieve Opening Size #4 #10 #20 #40 •#100 #200 Percent Finer 100.0 93.9 68.5 43.3 28.5 25.0 Hydrometer test uses material passing #10 Percent passing #10 based upon complete sample = 93.9 Weight of hydrometer sample =115.67 Hygroscopic moisture correction: Moist weight and tare = 33.67 Dry weight and tare = 33.34 Tare welght= 20.63 Hygroscopic moisture = 2.6% Table of composite correction values: Temp.,deg.C: 18.0 20.6 Comp. corr.: -8.0 -7.0 Meniscus correction only =1.0 Specific gravity of solids = 2.65 Hydrometer type = 152H Hydrometer effective depth equation: L = 21.1 -7.0 21.6 -6.0 Elapsed Time (min.) 1.00 2.00 5.00 15.00 30.00 60.00 120.00 250.00 1440.00 Temp, (deg. C.) 22.0 22.0 22.0 22.0 22.0 22.0 22.0 23.0 20.0 ActualReading 34.0 33.0 . 31.0 29.0 27.0 25.0 23.0 21.0 18.0 »16.294964- 0.164 xRm Corrected Reading 28.1 27.1 25.1 23.1 21.1 19.1 17.1 15.2 10.8 K 0.0133 0.0133 0.0133 0.0133 0.0133 0.0133 0.0133 0.0132 0.0136 Rm 35.0 34.0 32.0 30.0 28.0 26.0 24.0 22.0 19.0 27.7 -5.0 Eff. Depth 10.6 10.7 11.0 11.4 11.7 12.0 12.4 12.7 13.2 Diameter (mm.) 0.0433 0.0308 0.0198 0.0116 0.0083 0.0060 0.0043 0.0030 0.0013 Percent Finer 23;4 22.5 20.9 19.2 17.5 15.9 14.2 12.7 9.0 MACTEC Engineering and Consulting, Inc. Cobbles 0.0 Gravel Coarse 0.0 Fine 0.0 Total 0.0 Sand Coarse 6.1 Medium 50.6 Fine 18.3 Total 75.0 Fines Silt 10.0 Clay 15.6 Total 25.0 DID 0.0016 °15 0.0050 D2Q 0.01.46 DSO 0.1867 D50 0.5235 D60 0.6833 DSO 1.1714 DBS 1.3751 Dgo 1.6587 °95 2.1388 Fineness Modulus 2.04 cu 420,94 cc 31.44 MACTEC Engineering and Consulting, Inc.