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; Poinsettia Park Sewer Geotechnical Investigation; Poinsettia Park Sewer Geotechnical Investigation; 1995-12-14
I I LEIGHTON AND ASSOCIATES, INC Geotechnical and Environmental Engineering Consultants F M GEOTECHNICAL INVESTIGATION, PROPOSED POINSETTIA PARK SEWER, CARLSBAD MUNICIPAL WATER DISTRICT, CMWD PROJECT NO. 94-403 December 14,1995 Project No. 4950368-001 m m m m P M m M p m m » Prepared For: CARLSBAD MUNICIPAL WATER DISTRICT 5950 El Camino Real Carlsbad, California 92008 JJUH IE DEC I 81995 iIII 3934 MURPHY CANYON ROAD, SUITE B205, SAN DIEGO, CALIFORNIA 92123 (619) 292-8030 • (800) 447-2626 FAX (619) 292-0771 m * UIGHTON AND ASSOCIATES, INC Geotechnical and Environmental Engineering Consultants December 14,1995 Project No. 4950368-001 To: Carlsbad Municipal Water District 5950 El Camino Real Carlsbad, California 92008 Attention: Mr. William E. Plummer, P.E., District Engineer Subject: Geotechnical Investigation, Proposed Poinsettia Park Sewer, Carlsbad Municipal Water District, CMWD Project No. 94-403 In accordance with your request, Leighton and Associates (Leighton) has performed a geotechnical investigation at the subject site. The purpose of our investigation was to evaluate the existing subsurface profile and provide the contractor with the pertinent geotechnical information required to construct the Poinsettia Sewer improvements. The accompanying report presents a summary of our investigation and provides conclusions and recommendations relative to the proposed site construction. Based on the results of our investigation and review of the current preliminary plan provided by Carlsbad Municipal Water District, the proposed improvement is considered feasible from a geotechnical standpoint provided the recommendations outlined in this report are implemented during site grading and utility construction. If you have any questions regarding our report, please contact this office. We appreciate this opportunity to be of service to Carlsbad Municipal Water District Respectfully submitted, LEIGHTON AND ASSOCIATES, INC. Scott Burns Staff Engineer Michael R. Stewart, Director of Geology 1349 (Exp. 12/31/95) G. Franzone, RCE 39552 rotor of Engineering SCB/MRS/JGF/kam Distribution: (4) Addressee 3934 MURPHY CANYON ROAD, SUITE B205, SAN DIEGO, CALIFORNIA 92123 (619) 292-8030 • (800) 447-2626 FAX (619) 292-0771 m m 4950368-001 TABLE OF CONTENTS Section Page 1.0 INTRODUCTION 1 1.1 Purpose and Scope 1 1.2 Site Location and Proposed Development 1 2.0 SUBSURFACE EXPLORATION AND LABORATORY TESTING 4 2.1 Subsurface Exploration 4 2.2 Laboratory Testing 4 2.3 Geologic Units 4 2.4 Ground Water 6 2.5 Faulting and Seismicity 6 2.6 Seismic Considerations 7 2.6.1 Ground Shaking 7 2.6.2 Liquefaction/Dynamic Settlement 7 2.7 Sulfate Content, Minimum Resistivity and pH 8 3.0 CONCLUSIONS 9 4.0 RECOMMENDATIONS 10 Figures Figure 1 - Site Location Map 2 Figure 2 - Boring and Trench Location Map Rear of Text Figure 3 - Geologic Profile Rear of Text Appendices Appendix A - References Appendix B - Boring and Trench Logs Appendix C - Laboratory Testing Procedures and Test Results Appendix D - General Earthwork and Grading Specifications for Rough Grading -1 - LEIGHTOH AM ASSOCIATES, IHC. 4950368-001 1.0 INTRODUCTION 1.1 Purpose and Scope This report presents the results of our geotechnical investigation at the subject site. The m purposes of our investigation was to provide the contractor constructing the Poinsettia Sewer •i improvement with pertinent geotechnical information and provide conclusions and recommendations relative to the proposed improvements. Our scope of services included: M • Review of available geotechnical reports and geologic maps (Appendix A). «• • Excavation of three exploratory borings with a hollow-stem truck-mounted auger near M.H. — Numbers 3, 6, and 8 and three trenches with a backhoe between M.H. Number 1 and M.H. Number 3 of the proposed sewer improvement to identify the subsurface soils and m obtain representative samples for laboratory testing. All borings and trenches were logged by our field personnel and backfilled on completion. m • Laboratory testing of soil samples to determine their pertinent engineering properties. m • Evaluation of the subsurface soil profile in the alignment of the proposed sewer. • Preparation of backfill requirements and required relative compaction for various backfill *• materials over the proposed sewer. ~" • Analyses of maximum slope for laying back trench side walls. • Determination of ground-water levels at the time of drilling between M.H. Numbers 1 and 2 "" and recommendations for special construction methods, if required. • Recommendations of whether the backfill must be "benched" or "stepped" between proposed *~ M.H. Numbers 2 and 3 to prevent creation of a slip plane. Recommendations regarding the «. use and spacing of concrete slope anchors as identified in the San Diego Regional Standard Drawing S-9, to mitigate slip potential without benching. M • Recommendations regarding open-cut construction as compared to pulling a shoring shield to reduce the horizontal excavation width. — • Preparation of this report. 1.2 Site Location and Proposed Development m The location of the future sewer improvement will be located south of Palomar Airport Road , west of the future Hidden Valley Road and east of the Price Club (see Figure 1 - Site Location Map). The proposed sewer line (Figure 2) will consist of approximately 3,600 lineal feet of 8-inch, I.D. PVC with 12 associated manholes (M.H.). Sewer flowline depths will range from approximately 4 to 29 feet below proposed finished grade. -1- LtlGHTOHAm ASSOCIATES, OK. Oil olHw» % _, Mairrtentnoi Stltion .•'' \' PROJECT \ V M SITE \ v -N- Base Map: Aerial Foto-Map Book, San Diego County, 1986-87, Aerial Graphics, Page 8D 2000i£E? Approximate Scale 4000 feet CMWD Poinsettia Park Sewer Carlsbad, California SITE LOCATION MAP Project No. 950368-001 Date 12-12-95 LflJ 1042889 Figure No. 1 4950368-001 Vegetation consists of dense weeds and pampas grass between M.H. Numbers 1 through 3 and agricultural land between M.H. Numbers 3 through 12. At the time of our investigation, the agricultural land was vegetated with tomato plants. m m -3- Lfteimii Am ASSOCIATES, UK. 4950368-001 m, 2.0 SUBSURFACE EXPLORATION AND LABORATORY TESTINGH 2.1 Subsurface Explorationm Our subsurface exploration consisted of the excavation of three 8-inch diameter hollow-stem *V auger borings to a maximum depth of 30 feet below the existing ground surface adjacent to Hi proposed M.H. Numbers 3, 6, and 8 and the excavation of three trenches by a John Deere 310 backhoe to a maximum depth of 12 feet below existing grade between M.H. Numbers 1 and 3. 1 The purpose of these excavations was to evaluate the engineering characteristics of the onsite «f soils relative to the proposed development Prior to boring excavation, Underground Service Alert (USA) was contacted to coordinate location and identification of nearby underground 4| utilities. 4 The borings and trenches were logged by a representative from our firm. Representative «t relatively undisturbed and bulk samples were collected during the field work for laboratory — testing. The approximate locations of the borings and trenches are shown on Figure 2. Logs of borings and trenches are presented in Appendix B. **Subsequent to logging, the borings and trenches were backfilled. Some settlement of the boringm and trench backfill soils should be expected with time. <«• m 2.2 Laboratory Testing Representative samples were tested for the following parameters: in-situ moisture content and <"• density, soluble sulfate content, pH and maximum resistivity, maximum dry density, and shear strength. The results of our laboratory testing, along with a summary of the testing procedures """ are presented in Appendk C. In-situ moisture and density test results are presented on the <•» boring and trench logs (Appendk B). *. 2.3 Geologic Units "~ The results of our subsurface exploration program and review of available geologic literature «. (Appendk A) indicate the pipeline alignment will encounter several different geologic units. In general, the alignment may be separated into these three areas: ^ • Station 10+00 to 13+50 «• In the lower elevations of the site, the site topography consists of a relatively broad alluvial m valley. From M.H. 1 to near M.H. 2 the proposed alignment is underlain by alluvial soils. The alluvium is predominately recent alluvial silty sand with older alluvial sandy clay „ encountered near the base of the existing slope near Trench T-2. The soils as encountered j are medium dense with ground water at approximately 10 feet below existing site grades at the time of our investigation. This ground water depth will most likely vary seasonally. m 4 m m -4- LflBHTOH AM ASSOCIATES, UK. 4950368-001 • Station 13+50 to Station 17+90 Due to limited access to the slope area between Station Nos. 13+50 and 17+90, the subsurface conditions below the proposed alignment could not be observed. However, given the profile observed in Boring B-3, Trenches T-2 and T-3, and our experience with similar sites in the area, we anticipate the slope profile to consist of surficial deposits of topsoil and slopewash underlain by the Santiago Formation. • Station 17+90 to Station 45+20 Between Station 17+90 and Station 45+20, the materials encountered will consist of a thin veneer of topsoil and some disced soil due to farming with an average depth of 1 to 2 feet Below this surficial soil, the Terrace deposits and underlying Santiago Formation will be encountered. The materials encountered in these three areas are described below: • Topsoil Topsoil was encountered in all areas of our subsurface exploration. As observed, this material was composed of reddish-brown, damp, loose to medium dense silty sand. This material had a maximum thickness of 6 feet between M.H. Numbers 3 and 4. • Fill Soils Fill soils were to a maximum thickness of 4 feet was encountered in the vicinity of Boring B-3. This material was described as medium dense, silty sand. • Slopewash (Recent) Below an elevation of ±120 feet mean sea level (msl), the gently sloping terrain is overlain by surficial deposits as observed in Trenches T-2 and T-3, at the toe area of the slope. This material, as encountered to a maximum depth of 2.5 feet below existing grade, consisted of red-brown, loose, wet, fine silty sand. This material appears to be derived from the Quaternary-aged terrace deposits located in the upper elevation of the site. This material is underlain by dense bedrock of the Santiago Formation. • Quaternary Terrace Deposits The Quaternary-aged terrace deposits were encountered between proposed M.H. Numbers 12 and 3 above an elevation of 120 to 130 feet. As encountered, this material consisted of red-brown, moist, dense to very dense, silty sand. This material was encountered to a maximum depth of 29 feet below existing grade in Boring B-2. This is the predominate material anticipated to be encountered between M.H. 3 and M.H. 12. -5- LEI6HTM AMD ASSOCIATES, OK. 4950368-001 Santiago Formation The bedrock unit below an elevation of ±120 to 130 feet is the Santiago Formation. This unit consists of pale gray very dense silty sand with interbedded siltstone and claystone. This unit is anticipated to be encountered in the trench excavation between Stations 14+00 and 18+00 and at the bottom of the excavation between Stations 18+00 to 45+20. 2.4 Ground Water Ground water was encountered in both the upper mesa and low-lying alluvial areas during our subsurface investigation. In the upper mesa area, perched ground water was encountered in Boring B-2 at a depth of 21 feet below existing ground surface. However, ground water was not encountered in Borings B-l or B-3. In the slope area, perched ground water was encountered from 2.5 to 1.5 feet below existing grade in T-2 and T-3, respectively. In the low-lying alluvial area, ground water was encountered at a depth of 10 feet below existing grade at Trench T-l. It should be noted that fluctuations in the level of ground water may occur due to the amount of irrigation and/or rainfall Given the time of year that our investigation was performed, the depths to ground water can be considered a relative maximum. Recommendations regarding special water control techniques during construction are addressed in the recommendations portion of this report. In addition, due to the permeability differences between the Terrace Deposits and the underlying Santiago Formation, seepage may be anticipated at contacts between these materials. 2.5 Faulting and Seismicitv Our discussion of the faults on the site is prefaced with a discussion of California legislation and state policies concerning the classification and land-use criteria associated with faults. By definition of the California Mining and Geology Board, an active fault is a fault which has had surface displacement within Holocene time (about the last 11,000 years). The State Geologist has defined a potentially active fault as any fault considered to have been active during Quaternary time (last 1,600,000 years). This definition is used in delineating Earthquake Fault Zones as mandated by the Alquist-Priolo Earthquake Faulting Zone Act of 1972 and as subsequently revised in 1974,1975,1976,1979,1990,1991,1992 and 1993. The intent of this act is to assure that unwise urban development does not occur across the traces of active faults. The subject site is not located within any earthquake fault zones as created by the Alquist-Priolo Act (Hart, 1992). Our review of available geologic literature indicated that there are no known active or potentially active faults that transect the site. The location of the proposed development can be considered to lie within a seismically active region, as can all of southern California. The Rose Canyon Fault Zone, which is located approximately 3.5 miles to the west of the site is considered to have the most significant seismic effect at the site from a design standpoint A maximum probable earthquake of moment magnitude 6.25 on the fault could produce a peak horizontal ground acceleration of -6- LEI6HTOHAHD ASSOCIATES, IHC. 4950368-001 approximately 0.30g at the site. For design purposes, an effective ground acceleration of 0.40g based on the Uniform Building Code criteria (ICBO, 1991) may be assumed. 2.6 Seismic Considerations The principal seismic considerations for most structures in southern California are surface rupturing of fault traces, damage caused by ground shaking and/or seismically induced liquefaction or dynamic settlement. The probability of damage due to ground rupture is considered minimal since active faults are not known to cross the site. Ground lurching due to shaking from distant seismic events is not considered a significant hazard, although it is a possibility throughout the southern California region. 2.6.1 Ground Shaking The seismic hazard most likely to impact the site is ground shaking resulting from an earthquake on one of the major regional faults. As discussed above, a maximum credible event on the Rose Canyon Fault Zone (considered the design earthquake for this site) could produce a peak horizontal bedrock acceleration at the site of 0.30g and an effective ground acceleration of 0.40g. 2.6.2 Liquefaction/Dynamic Settlement Liquefaction of cohesionless soils can be caused by strong vibratory motion due to earthquakes. Research and historical data indicate that loose granular soils underlain by a near-surface ground water table are most susceptible to liquefaction, while the stability of most silty clays and clays is not adversely affected by vibratory motion. Due to the relatively dense nature of the onsite Terrace Deposits and Santiago Formation, the potential for liquefaction in the upper mesa area due to the design earthquake is anticipated to be very low. However, due to the presence of perched ground water conditions within the loose and potentially compressible alluvium and colluvium in the area between Station Nos. 10+00 and 14+00, liquefaction and dynamic settlement of these soils may occur as a result of the design earthquake. Dynamic settlement is estimated at a differential settlement of 1/2 to 1 inch in a horizontal distance of 50 to 100 feet The potential for large-scale liquefaction of the alluvial soils is low to moderate. This type of liquefaction will result in the soils over and under the pipe to behave as a liquid. The most immediate effect will be upward movement of the pipe due to the buoyant effect of the ground water table. The buoyant effect on the pipe, and thus the movement of the pipe due to liquefaction will be lessened if the pipe is at least 3/4 full at all time in the areas of the saturated alluvial soils. If this is not the case, concrete lugs may be constructed to counteract the buoyant forces. -7- LEKHTOH AM ASSOCIATES, UK. 4950368-001 2.7 Sulfate Content. Minimum Resistivity and pH The test results from the previous investigations performed for the Poinsettia Sewer project and adjacent tracts indicate the onsite soils possess a negligible to minor soluble sulfate content. Accordingly, ordinary Type I/II cement may be used for onsite uses. Our pH and minimum resistivity testing indicates that the on site soils have a heavy to severe potential for corrosion. Based on the above, if uncoated buried metal is planned, a corrosion engineer should be consulted. -8- 4950368-001 3.0 CONCLUSIONS Based on our geotechnical investigation, it is our opinion that the proposed sewer line construction is feasible from a geotechnical standpoint provided the following conclusions and recommendations are incorporated into the project plans and specifications. The following is a summary of the significant geotechnical conditions which may impact the proposed construction. • In general, soil materials encountered in the upper mesa area and lower stream channel area are anticipated to be reusable as backfill material. However, the colluvial/alluvial dark grey clay soils encountered in Trenches T-2 and T-3 are not suitable due to their high in-place moisture content and high plasticity index. • Excavation along the proposed sewer improvement is anticipated to be possible with conventional, heavy-duty trenching equipment, localized hard digging should be anticipated in the upper mesa area. However, due to the perched ground water conditions encountered in the lower elevations near Trenches T-2 and T-3, excavation may be difficult and require specialized equipment or techniques. • Ground water was encountered in the upper mesa area at a depth of 21 feet in Boring B-2. Ground water was not encountered in Boring B-l and B-3 in the upper mesa area. Therefore, area of localized perched ground water should be anticipated between the Terrace material and Santiago Formation in the upper mesa area especially near the contact between the two formations. This seepage may make unshored (and shored) excavations especially dangerous. Perched ground water was also observed in Trenches T-2 and T-3 at a depth of 2.5 and 1.5 feet, respectively, with caving of the overlying topsoil/slopewash. Ground water and caving were observed at a depth of 10 feet below ground surface in Trench T-l. • Since alluvial removals below the pipe invert are not proposed between Stations 10+00 to 13 +00, no additional fill loads should be placed above existing grades (above the proposed alignment) as additional fill loads may cause differential settlement of the underlying, relative loose alluvial soils impacting the proposed sewer line. -9- LflBHTOHAHD ASSOCIATES, UK. 4950368-001 4.0 RECOMMENDATIONS m Station Nos. 17+90 to 45+20 * As indicated in Borings B-l, B-2 and B-3, the soils encountered during construction will consist of " a red-brown, moist, dense, silty sand underlain by a pale grey, moist, very dense, silty sand to sandy dt silt. If a trench shield is not used, maximum layback of trench walls in this material shall be no greater than 1:1 (horizontal to vertical). As an alternate, the upper 10 to 15 feet may be sloped at « a 1:1 with the use of trench shield for the lower 15 feet. Backfill in the sewer trench shall be 4l compacted near optimum moisture content of a minimum of 90 percent of the maximum dry density as determined by ASTM Test Method D1557-91. As previously stated, perched ground water may m be encountered at the contact between, at or above the Terrace material and Santiago Formation. ^ Therefore, dewatering of the trench in localized areas may be necessary. Ground water may make unshored excavations particularly unsafe depending on the time of year of construction. «i Figure E-l in Appendix E should be referenced for general trench specifications. Station Nos. 13+50 (approximately) to 17+90 ... The material anticipated to be encountered from Station Nos. 13+50 to 17+90 will consist of a thin veneer of loose silty sand slopewash/topsoil, underlain by Terrace deposits, (at higher elevations only), *• in turn underlain by the Santiago Formation. Maximum layback of trench wall shall be no greater than 3/4:1 (horizontal to vertical) in competent Santiago Formation material and 1:1 in Terrace *" Deposits, with a 3-foot vertical cut at the bottom of the trench. Backfill shall be compacted near «• optimum moisture content to a minimum of 90 percent of the maximum dry density, as determined by ASTM Test Method D1557-91. Horizontal benches are not considered necessary unless needed """ to aid in compaction. The bottom of the sewer trench in this area should be in the Santiago •v Formation. However, this excavation should be observed by the geotechnical consultant prior to placement of the sewer to verify the competency of the underlying materials. mm «. Perched ground water may be encountered in this area between the overlying topsoil and Santiago Formation. Grading measures may be necessary adjacent to the top of the slope to keep water from — entering the excavation (i.e. swales or berms). Figure E-l in Appendix E should be'referenced for general trench specifications. In addition, the — construction of cut-off walls and slope anchors in this area will be necessary and will be addressed ^ later in this section. Station Nos. 13+50 to 12+00 „ The material anticipated to be encountered between Station Nos. 13+50 to 11 +00 should consist of a thin veneer of fine silty sand underlain by a wet, medium-stiff, silty, sandy clay. Trench walls in dry m areas can be laid back at a minimum of 1:1 (horizontal to vertical) with a 2-foot vertical cut at the bottom of the trench. Seepage conditions may necessitate 2:1 or gentler laybacks. However, due to -10- LCIBHTOH AMD ASSOCIATES, IHC. 4950368-001 the perched ground water conditions and resulting caving of the trench sidewalk (as encountered in Trenches T-2 and T-3) the use of trench shield and dewatering pumps may be prudent As previously stated, the dark grey clay soils in this area will not be suitable as backfill material. Soils derived from the upper mesa area can be used or similar import materials are acceptable. Station Nos. 10+00 to 12+00 The material encountered between Station Nos. 10+00 and 12+00 consisted of a tan, damp to wet, loose, fine, silty sand. Ground water was encountered a depth of 10 feet below existing grade at the time of our investigation. At this depth, the trench walls caved due to seepage of the ground water. If construction occurs after a rainy period, ground water levels can be expected to be somewhat higher. Trench excavation should be performed in accordance with OSHA requirements, and excavations deeper than 5 feet or within poorly consolidated soils should be shored and/or slopes laid back to 1:1 to 1-1/2:1 (horizontal to vertical) or flatter if workers are to enter the excavations. In areas where the ground water is near or above the bottom of the proposed excavation, the trench should be shored, evaluated during construction or a shield used during excavation. Special considerations should be taken during construction in this area. Due to the close proximity of the ground water table to the proposed sewer, the stabilization of the trench base may be necessary. A layer of pea gravel at least one foot thick may provide a stable base. If ground water levels rise prior to construction, localized dewatering may be necessary. Figure E-3 in Appendix E should be referenced to for general trench specifications. Cut-off Walls Cut-off walls are recommended from Station No. 13+30 to 17+75 and placed at 100 feet center-to- center intervals down the slope. Cut-off walls should conform to the modified San Diego Regional Drawing S-10 Type A or B (provided in Appendix E). Subdrains should be placed behind walls and exited to the slope face. Subdrains should consist of Schedule 40, 4-inch perforated PVC pipe incased in 3 cubic feet of gravel per linear foot of drain line. Filter fabric should be used around the gravel as shown in Figure E-4. Water from the subdrain should be collected in a buried tightline to the toe-of-slope. -11- LCI6HTOHAHO ASSOCIATE, HK. 4950368-001 Lateral Earth Pressures The following earth pressures may be used in the design of the cut-off walls and shoring. Lateral Earth Pressures Condition Active (Rectangular Distribution) Passive (Triangular Distribution) Slope Wash/ Alluvial/ Fill Soils 40Hpsf 150 pcf Terrace Deposits and Santiago Formation 25Hpsf 300 pcf Soil resistance developed against lateral structural movement can be obtained from the passive pressure value provided above. Further, for sliding resistance, a friction coefficient of 0.35 may be used at the concrete and soil interface. The passive value may be increased by one-third when considering loads of short duration, including wind or seismic loads. The total lateral resistance may be taken as the sum of the factional and passive resistances provided that the passive portion does not exceed two-thirds of the total resistance. Ground water should be considered in all designs. Construction Observation The recommendations provided in this report are based on widely spaced borings and trenches. We recommend that all excavations be observed by a representative of our firm as conditions will likely vary across the site and the time of the year will have a significant impact on the ground water/seepage locations along the alignment Observation and testing should also be performed by this firm to ensure that compaction operations are performed in accordance with the recommendations of this report. -12- LEI6HTOHAHD ASSOCIATES, HK. io l"=400' EXISTING INTERCEPTOR SEWERS BRAMALEA PROPERTYSAMBI PROPERTY (FUTURE HIDDEN VALLEY ROAD) CITY OF/^CARLSBAp FUTURE7 POINSETTlA COMMUNITY HIDDEN VALLEY ESTATES REST-KOOM RESTROOM ABADA PROPERTY FUTURE. C08J.' n. DO SOL' -MH #6 ///. r,-- . • A. -p ,;. -\i/. s u . - -/i -\r- •. !• • .H •.-.- — McREYNOLDS PROPERTY .FUTURE MAR VISTA LEGEND B-3 PROPOSED PROPERTY\ APPROXMATE LOCATION OF GEOTEChNCAL BORMG APPROXMATE LOCATION OF EXPLORATORY TRENCH PROPOSED SERVICE AREA PROPOSED POINSETTIA PARK SEWER ALIGNMENT PROPOSED FLOW DIRECTION ALTERNATIVE FLOW DIRECTION SEWER ALIGNMENT IN PROPOSED DEVELOPMENTS PAMPAS GRASS <Q.PRICE CLUB Base ,Prelminary^undated BORING AND TRENCH LOCATION MAP CMWD/Poinseftia Park Sewer Carlsbad, California 4950368-001 r=400' Project No. Scale Engr./GeoL JGF/MRS Drafted By WJP Date 12-12-95 JL 1045 889 Figure No. 2 100940 PRELIMINARY PIPELINE PROFILE EXISTING GROUND LINE PROPOSED FINISHED SURFACE Qsw/top LEGEND SEWER FLOWLINE SM = sity sand CH = highly plastic day Qal r alluvium Qsw/tpp = slopewash/tppspi Qt = Terrace deposits fs = Santiago Formation -¥- = ground water etetation encountered during investigation forT-1 = TD for T-2 and T-3 = 10' PROFILE SCALES: HORIZONTAL 1"=300' VERTICAL r=30'... (SM) 3u. he, PrefcninaryDaniel Boyte Engineei 4950368-001Project No. Scale Engr./GeoL Drafted By Date GEOLOGIC PROFILE CMWD/Polnsettia Park Sewer Carlsbad, iCalifornia 1045 889 Figure No.-3 APPENDIX A 4950368-001 APPENDIX A REFERENCES California Division of Mines and Geology, 1983, Guidelines for Evaluating the Hazard of Surface Faulting Rupture: California Division of Mines and Geology, Note 49, 2p. -.# , 1991, Special Study Zones (Alquist-Priolo Special Studies Zones Act): Point Loma "* Quadrangle; California Division of Mines and Geology, Scale 1:24,000. -at Campbell, KW. (1987), Predicting Strong Ground Motion in Utah, in Gori, P.L., and Hays, W.W., '* ed., Assessment of Regional Earthquake Hazards and Risk Along the Wasatch Front, ,« Utah, U.S. Geological Survey, Open-File Report 87-585, Vol. II, Sect. K, p. 1-90. «• Heilman, J.A., Allen, C.R., and Nordquist, J.M., 1973, Seismicity of the Southern California Region, M 1 January 1932 to 31 December 1972; California Institute of Technology Seismological Laboratory, Pasadena, California. Ishihara, K., 1985, Stability of Natural Deposits During Earthquakes, Proc. of the Eleventh "" International Conference on Soil Mechanics and Foundation Engineering, San m Francisco, Vol. 1, No. 7, August 1-16, pg. 321-375. ""* Joyner, W.B., and Boore, D.M., 1981, Peak Horizontal Acceleration and Velocity from Strong- ,„ Motion Records Including Records from the 1979 Imperial Valley, California Earthquake, Seismology Society of America Bulletin, Vol. 71, pp. 2011-2038. A-l APPENDIX B GEOTECHNICAL BORING LOG KEY Date Projectct KEY TO BORING LOG GRAPHICS ngCo. Diameter Drive Weight tionTopofHole +/- ft. Ref. or Datum Sheet 1 of 1 Project No. Type of Rig Drop in. ?! LU i o — 1U GraphicLog |'////< *Y% A A A tA A A *A A A 4 \ II7> i 1 Y »*«*•* .••';.'.' :•. /%/ •vS ) V* C O' . '• o ^/ * - y/;3=i7 r"un^"i_ry« j&£SXf • *'\fx N \_ x tiW' ///$•/// 2"o r JUI •vi — <H>&<& 01i §1 s. •H It I"Mo i stureContent (JOSoi 1 Class.(U.S.C.S.)CL CH OL-OH ML MH CL-ML ML-SM CL-SC SC-SM SW SP SM SC GW GP GM GC GEOTECHNICAL DESCRIPTION Logged By Sampled By Inorganic clay of low to medium plasticity; gravelly clay; sandy clay; silty clay; lean clay Inorganic clay of high plasticity, fat clay Organic clay, silt or silty clay-clayey silt mixtures Inorganic silt; very fine sand; silty or clayey fine sand; clayey silt with low plasticity Inorganic silt; diatomaceous fine sandy or silty soils; elastic silt Low plasticity clay to silt mixture Sandy silt to silty sand mixture Sandy clay to clayey sand mixture Clayey sand to silty sand mixture Well graded sand; gravelly sand, little or no fines Poorly graded sand; gravelly sand, little or no fines Silty sand; poorly graded sand-silt mixture Clayey sand; poorly graded sand-clay mixture Well graded gravel; gravel-sand mixture, little or no fines Poorly graded gravel; gravel-sand mixture, little or no fines Silty gravel; gravel-sand-silt mixture Clayey gravel; gravel-sand-clay mixture Sandstone Siltstone Claystone Breccia (angular gravel and cobbles or matrix-supported conglomerate) Conglomerate (rounded gravel and cobble, clast-supported) Igneous granitic or granitic type rock Mctavolcanic or metamorphic rock Artificial or man-made fill Asphaltic concrete Portland Cement Concrete • 505AC11/77)LEIGHTON & ASSOCIATES GEOTECHNICAL BORING LOG B-1 Date 11-22-95 Project CMWD-Poinsettia Park Sewer Sheet 1 of 2 Project No. 4950368-001 Drilling Co.Barge's Drilling Type of Rig Hollow-Stem Auger Hole Diameter Sin. Drive Weight 140 pounds Drop 30 in. Elevation Top of Hole +/- 154 ft. Ref. or Datum Mean Sea Level Is1-UJ 150 145 140- 135- 130- 125- & <§5 0 — - - 5— _ 10— : 15 — - 20— - 25 — - U £« :-; :-; ! :-; :-; :-; :-; :-; :-; :-; :-; B_i • . * S S d « i to Bag-2 ©S'-lff 3 4 5 6 - - ! : 1 . - - ': ' 1 si 50/5" 50/5" 47/6" 73 81 31 cC °* a 125.7 120.7 118.6 115.6 114.8 UX5~ '5t CJ 1U 12.9 11.7 M52 13.7 • JBlO)Jz * _to co^ SM SM SM/ML GEOTECHNICAL DESCRIPTION Logged By SCB Sampled By SCB TOPSOIL <a>0-l': Red-brown^ dry^loose to medium dense silty SAND TERRACE DEPOSITS @1': Red-brown, damp, dense to very dense, silty SAND with clay binder - @5': Various shades of orange-brown, damp, very dense, silty SAND with slight day binder _ @ 10*: Red-brown with magnesium staining, damp very dense silty SAND, slightly cemented _ @ 15': Material becomes more clayey - @20': Orange-brown, moist to wet, very dense silty SAND with clay binder ; @25': Material becomes less cohesive, orange-brown, moist, very dense silty SAND with gravels to 1/4 inch in maximum SANTIAGO FORMATION @28': Pale gray, moist, very dense silty SAND 505AC11/77)LEIGHTON & ASSOCIATES GEOTECHNICAL BORING LOG B-1 «, Date 11-22-95 CMWD-Poinsettia Park Sewer Sheet 2 of 2 Project No. 4950368-001Project Drilling Co. Barge's Drilling Type of Rig Hollow-Stem Auger Hole Diameter Sin. Drive Weight 140 pounds Drop 30 in. Elevation Top of Hole +/- 154 ft. Ref. or Datum Mean Sea Level i,+-t;Jlm 120 115 110 105- 100- 95- ££•*•«;II 30 — - 35 — - 40 — - 45 — - 50 — - 55 —Graph i cLogin01i •o 01I §1!"•mfc 0- 31 sc01 Ua a.w31 h Ho i stureContent <5O |8~:» o^_co c?3 GEOTECHNICAL DESCRIPTION Logged By SCB Sampled By SCB Total Depth = 30 FeetNo Ground Water Encountered at Time of Drilling Hole Backfilled on November 22, 1995 - - - - - - - - - - - 505A(11/77)LEIGHTON & ASSOCIATES GEOTECHNICAL BORING LOG B-2 . Date_ Project 11-22-95 CMWD-Poinsettia Park Sewer Sheet 1 of 2 Project No. 4950368-4)01 Drilling Co.Barge's Drilling Type of Rig Hollow-Stem Auger Hole Diameter Sin. Drive Weight 140 pounds Drop 30 in. Elevation Top of Hole +/- 153 ft. Ref. or Datum Mean Sea Level °u 15« 1"_ Is' LU 150 145 140- 135 130- 125- •c?••-aiQ-OJ«•*-oU 0 — _ - 5 — - 10 — - 15 — - 20 — - - 25 — - in— 0 i J§ . • • - . • :- -; •; L-; NH X_J '•• • T 18i •o 01 1& N.R. I 1 §1 I11- ID QJ 42/6" 50/3" 1 31 SC01 OQ Q.s^ 31h 119.9 ^\ «S IsorE3 9£ 2 8^S<« o^_«•&- SM SM SM SP SM/ML GEOTECHNICAL DESCRIPTION Logged Bv SCB Sampled Bv SCB TOPSOIL <^0-l': Red-brown^dry^looseLSilt^SAND TERRACE DEPOSITS @1': Orange-brown, damp, dense silty SAND with trace of clay binder - - - @ 10': Orange-brown, damp, very dense silty SAND with trace of clay binder, very hard drilling - - - . @21': Ground water encountered - @25': Same as at 10 feet @26": Tan, wet, medium dense, coarse SAND with gravels to 1/4 inch maximum dimension - SANTIAGO FQRMATION ©29': Pate erav. wet verv dense siltv SAND 505A<11/77)LEIGHTON & ASSOCIATES GEOTECHNICAL BORING LOG B-2 «• Date.11-22-95 CMWD-Poinsettia Park Sewer Sheet 2 of 2 Project No. 4950368-001Project Drilling Co. Barge's Drilling Type of Rig Hollow-Stem Auger Hole Diameter Sin. Drive Weight 140 pounds Drop 30 in. Elevation Top of Hole +/- 153 ft. Ref. or Datum Mean Sea Level || LJ 120 115 110 105 100- 95- 0-801 g 30 — - 35 — - 40— - 45 — - 50 — - 55 — /in — o Q.O CD W01i 01 a. (0 +•§8 a. 3, CH- 3»^ a ^Mo i stureContent (X• J5 . _cotmf • GEOTECHNICAL DESCRIPTION Logged BY SCB Sampled BY SCB Total Depth = 30 FeetPerched Ground Water at 21 Feet Hole Backfilled on November 22, 1995 - . - - - - - - - - - 505AC11/77)LEIGHTON & ASSOCIATES GEOTECHNICAL BORING LOG B-3 m Date.11-22-95 Project Drilling Co. CMWD-Poinsettia Park Sewer Barge's Drilling m Hole Diameter 8 in.Drive Weight Elevation Top of Hole +/- 134 ft. Ref. or Datum Sheet 1 of 1 Project No. 4950368-001 Type of Rig Hollow-Stem Auger 140 pounds Drop 30 in. Mean Sea Level c li LU 130- 125 120- 1 115- 110- 105- .C~ °£ 0 — - _ - 5 — - - 10 — — _ 15— 20 - - tyf - U 1 cn • • • •; •; 0)o_l • in01 o £ 01 1 & l 1 Bag-2 @5'-101 3 1 [ •r +- It (L 1 24 1 41/6" 1 ! 50/4" 314- QJ o£2 Q± yt h 12Z1 108.4 /^«S ^"c = 0 123 19.5 S«5 -^(O^ SM SM SM SM GEOTECHNICAL DESCRIPTION Logged By SCB Sampled By SCB TOPSOIL @0-1': Red-brown, damp, loose to medium dense silty SAND FHJ. @ 2': Red-brown, moist to wet, medium dense silty SAND with slight clay binder - . TERRACR DRPOSTTS @6': Red-brown, moist, dense silty SAND with clay binder - SANTTAGO FORMATldN @ 10': Pale gray, damp to moist, fine silty SAND • - - ~\@20': Same as at 10 feet ' Total Depth = 20 Feet No Ground Water Encountered at Tune of Drilling Hole Backfilled on November 22, 1995 - - - 505AC11/77)LEIGHTON & ASSOCIATES 1 i i i t i i i I 1 I tlliiiiififliliillliiiiiii LOG OF TRENCH NO.: T-l Pro.iect Name: Carlsbad/Sewer Project Number; 4950368-001 Equipment: 310 J.D. Backhoe Logged bv: SCB Elevation: 57' Mean Sea Level Location;40' S. of MH #1 eno GEOLOGIC ATTITUDES DATE: 11/22/95 DESCRIPTION: GEOLOGIC UNIT ENGINEERING PROPERTIES uses Sampl e No. Moist.Density (pcf) (Oo TOPSOIL/ALLUVIUM @ 0-2': Tan, damp, loose, fine silty sand with roots ALLUVIUM @ 2' -10': Tan, damp to wet, medium dense silty sand (no caving observed) @ 10': Ground water table encountered @ 10': Tan, wet, loose to medium dense silty sand (caving observed) heavy seepage in sidewalls of trench Bottom of Trench at 12 Feet Below Existing Grade Ground Water at 10 Feet at Time of Trenching Trench Backfilled on 11/22/95 Qtop/ Qal Qal SM COo CO GRAPHIC REPRESENTATION SCALE: 1 5'SURFACE SLOPE:TREND: ' Roots O ii t i i i iiiililiflfililitJIiiiiit LOG OF TRENCH NO.; T-2 Olo 1 o 0 to* O"* P« > 0»oo 55'r-p(D0» Project Name: Carlsbad/Sewer Pro.iect Number: 4950368-001 Equipment: 310 J.D. Backhoe GEOLOGIC ATTITUDES Loaded bv: SCB Elevation: 60' Mean Sea Level Location: Toe of SI one. N of MH#2 DATE: 11/22/95 DESCRIPTION: TOPSOIL/SLOPE WASH @ 0'-2.5': Red-brown, wet, loose, silty sand @ 2.5': Perched ground water observed @ 2.5': Red-brown, wet, loose, silty sand, heavy seepage from sidewalls of trench, caving ALLUVIUM/SLOPE WASH observed @ 3': Dark gray, wet, medium stiff silty sandy clay. No seepage observed or caving Trench stable from 3 to 10 feet Bottom of Trench 10 Feet Below Ground Surface Heavy Seepage at 2.5 Feet at Time of Trenching Hole Backfilled on 11/22/95 GRAPHIC REPRESENTATION SCALE: 1" 1 1 1 1I I I i - - 1 1 1 1i i i i '• 1 1 1 1i i i i Roots, 1 1 1 ' lY 1 I'?' • ' " " *•*'/-' ' • • * — GEOLOGIC UNIT Qtop/ Qsw Qal/Qsw ENGINEERING PROPERTIES uses SM CH Sampl e No. Moist. (%) Density (pcf) = 5' SURFACE SLOPE: TREND: ) 1 F 1 VlJ:V\ • .• ' 9 * * • » v » 4 . 1 / 1 1 1\f \ \ \ • . ' / •••./ ' 7j^/ 1 1 1 11 1 1 1 Perched Grouj 1 1 1 1i i i i d Water 1 1 1 1i i i i _ _ 1 1 1 1i i i i - - - II i i i i ii I i f i I t i I i i i t I I i I I i i LOG OF TRENCH NO.: T-3 Project Name; Carlsbad/Sewer Project Number: 4950368-001 Equipment: 310 J.D. Backhoe Logged bv: SCB Elevation: 90' Mean Sea Level Location: 85 Feet S. of 1-2 01 GEOLOGIC ATTITUDES DATE: 11/22/95 DESCRIPTION: GEOLOGIC UNIT ENGINEERING PROPERTIES uses Sample No. Moist. W Density (pcf) <D O TOPSOIL/SLOPE WASH @ 0-1.5': Red-brown, wet, very loose, caving silty sand @ 1.5': Perched ground water observed @ 1.5': Dark gray, wet, medium stiff, silty sandy clay Bottom of Trench at 10 Feet Perched Ground Water at 1.5 Feet at Time of Trenching Hole Backfilled on 11/22/95 Qtop/ Qsw SM CL to GRAPHIC REPRESENTATION SCALE: 1" - 5*SURFACE SLOPE:TREND: COooiCO APPENDIX C 4950368-001 APPENDIX C Laboratory Testing Procedures and Test Results Direct Shear Tests: Direct shear tests were performed on selected remolded and/or undisturbed samples which were soaked for a minimum of 24 hours under a surcharge equal to the applied normal force during testing. After transfer of the sample to the shear box, and reloading the sample, pore pressures set up in the sample due to the transfer were allowed to dissipate for a period of approximately 1 hour prior to application of shearing force. The samples were tested under various normal loads, a motor-driven, strain-controlled, direct-shear testing apparatus at a strain rate of 0.05 inches per minute (depending upon the soil type). The test results are presented in the test data. Sample Location B-3, 5' B-3, 11' Sample Description Silty Sand Silty Sand Friction Angle (degrees) 41 43 Apparent Cohesion (psf) 460 430 Moisture and Density Determination Tests: Moisture content and dry density determinations were performed on relatively undisturbed samples obtained from the test borings trenches. The results of these tests are presented in the boring logs. Where applicable, only moisture content was determined from "undisturbed" or disturbed samples. Maximum Density Tests: The maximum dry density and optimum moisture content of typical materials were determined in accordance with ASTM Test Method D1557. The results of these tests are presented in the table below: Sample Location B-l, 5' - 10' B-3, 5' - 10' Sample Description Silty Sand Silty Sand Maximum Dry Density (pcf) 130.0 134.5 Optimum Moisture Content (%) 9.5 8.0 Minimum Resistivity and pH Tests: Minimum resistivity and pH tests were performed in general accordance with California Test Method 643. The results are presented in the table below: Sample Location 1-1, 5' - 10' B-3, 5' - 10' Sample Description Silty Sand Silty Sand PH 6.8 6.0 Minimum Resistivity (ohms-cm) 1,900 2,760 C-l 4950368-001 Laboratory Testing Procedures (Cont'd.) Soluble Sulfates: The soluble sulfate contents of selected samples were determined by standard geochemical methods. The test results are presented in the table below: Sample Location B-l, 5' - 10' B-3, 5' - 10' Sample Description Silly Sand Silty Sand Sulfate Content (%) <0.005 <0.005 Potential Degree of Sulfate Attack* Negligible Negligible * Based on the 1994 edition of the Uniform Building Code, Table No. 19-A-3, prepared by the International Conference of Building Officials (ICBO, 1994). C-2 APPENDIX D LEIGHTON AND ASSOCIATES, INC. GENERAL EARTHWORK AND GRADING SPECIFICATIONS FOR ROUGH GRADING 1.0 General 1.1 Intent: These General Earthwork and Grading Specifications are for the grading and earthwork shown on the approved grading plan(s) and/or indicated in the geotechnical report(s). These Specifications are a part of the recommendations contained in the geotechnical report(s). In case of conflict, the specific recommendations in the geotechnical report shall supersede these more general Specifications. Observations of the earthwork by the project Geotechnical Consultant during the course of grading may result in new or revised recommendations that could supersede these specifications or the recommendations in the geotechnical report(s). 1.2 The Geotechnical Consultant of Record: Prior to commencement of work, the owner shall employ the Geotechnical Consultant of Record (Geotechnical Consultant). The Geotechnical Consultants shall be responsible for reviewing the approved geotechnical report(s) and accepting the adequacy of the preliminary geotechnical findings, conclusions, and recommendations prior to the commencement of the grading. Prior to commencement of grading, the Geotechnical Consultant shall review the "work plan" prepared by the Earthwork Contractor (Contractor) and schedule sufficient personnel to perform the appropriate level of observation, mapping, and compaction testing. During the grading and earthwork operations, the Geotechnical Consultant shall observe, map, and document the subsurface exposures to verify the geotechnical design assumptions. If the observed conditions are found to be significantly different than the interpreted assumptions during the design phase, the Geotechnical Consultant shall inform the owner, recommend appropriate changes in design to accommodate the observed conditions, and notify the review agency where required. Subsurface areas to be geotechnically observed, mapped, elevations recorded, and/or tested include natural ground after it has been cleared for receiving fill but before fill is placed, bottoms of all "remedial removal" areas, all key bottoms, and benches made on sloping ground to receive fill. The Geotechnical Consultant shall observe the moisture-conditioning and processing of the subgrade and fill materials and perform relative compaction testing of fill to determine the attained level of compaction. The Geotechnical Consultant shall provide the test results to the owner and the Contractor on a routine and frequent basis. 1.3 The Earthwork Contractor: The Earthwork Contractor (Contractor) shall be qualified, experienced, and knowledgeable in earthwork logistics, preparation and processing of ground to receive fill, moisture-conditioning and processing of fill, and compacting fill. The Contractor shall review and accept the plans, geotechnical report(s), and these Specifications prior to commencement of grading. The 3030L1094 Leighton and Associates, Inc. GENERAL EARTHWORK AND GRADING SPECIFICATIONS Page 2 of 6 Contractor shall be solely responsible for performing the grading in accordance with the plans and specifications. The Contractor shall prepare and submit to the owner and the Geotechnical Consultant a work plan that indicates the sequence of earthwork grading, the number of "spreads" of work and the estimated quantities of daily earthwork contemplated for the site prior to commencement of grading. The Contractor shall inform the owner and the Geotechnical Consultant of changes in work schedules and updates to the work plan at least 24 hours in advance of such changes so that appropriate observations and tests can be planned and accomplished. The Contractor shall not assume that the Geotechnical Consultant is aware of all grading operations. The Contractor shall have the sole responsibility to provide adequate equipment and methods to accomplish the earthwork in accordance with the applicable grading codes and agency ordinances, these Specifications, and the recommendations in the approved geotechnical report(s) and grading plan(s). If, in the opinion of the Geotechnical Consultant, unsatisfactory conditions, such as unsuitable soil, improper moisture condition, inadequate compaction, insufficient buttress key size, adverse weather, etc., are resulting in a quality of work less than required in these specifications, the Geotechnical Consultant shall reject the work and may recommend to the owner that construction be stopped until the conditions are rectified. 2.0 Preparation of Areas to be Filled 2.1 Clearing and Grubbing: Vegetation, such as brush, grass, roots, and other deleterious material shall be sufficiently removed and properly disposed of in a method acceptable to the owner, governing agencies, and the Geotechnical Consultant The Geotechnical Consultant shall evaluate the extent of these removals depending on specific site conditions. Earth fill material shall not contain more than 1 percent pf organic materials (by volume). No fill lift shall contain more than 5 percent of organic matter. Nesting of the organic materials shall not be allowed. If potentially hazardous materials are encountered, the Contractor shall stop work in the affected area, and a hazardous material specialist shall be informed immediately for proper evaluation and handling of these materials prior to continuing to work in that area. As presently defined by the State of California, most refined petroleum products (gasoline, diesel fuel, motor oil, grease, coolant, etc.) have chemical constituents that are considered to be hazardous waste. As such, the indiscriminate dumping or spillage of these fluids onto the ground may constitute a misdemeanor, punishable by fines and/or imprisonment, and shall not be allowed. 3030.1094 Leighton and Associates, Inc. GENERAL EARTHWORK AND GRADING SPECIFICATIONS Page 3 of 6 2.2 Processing: Existing ground that has been declared satisfactory for support of fill by the Geotechnical Consultant shall be scarified to a minimum depth of 6 inches. Existing ground that is not satisfactory shall be overexcavated as specified in the following section. Scarification shall continue until soils are broken down and free of large clay lumps or clods and the working surface is reasonably uniform, flat, and free of uneven features that would inhibit uniform compaction. 2.3 Overexcavation: In addition to removals and overexcavations recommended in the approved geotechnical report(s) and the grading plan, soft, loose, dry, saturated, spongy, organic-rich, highly fractured or otherwise unsuitable ground shall be overexcavated to competent ground as evaluated by the Geotechnical Consultant during grading. 2.4 Benching: Where fills are to be placed on ground with slopes steeper than 5:1 (horizontal to vertical units), the ground shall be stepped or benched. Please see the Standard Details for a graphic illustration. The lowest bench or key shall be a minimum of 15 feet wide and at least 2 feet deep, into competent material as evaluated by the Geotechnical Consultant. Other benches shall be excavated a minimum height of 4 feet into competent material or as otherwise recommended by the Geotechnical Consultant Fill placed on ground sloping flatter than 5:1 shall also be benched or otherwise overexcavated to provide a flat subgrade for the fill. 2.5 Evaluation/Acceptance of Fill Areas: All areas to receive fill, including removal and processed areas, key bottoms, and benches, shall be observed, mapped, elevations recorded, and/or tested prior to being accepted by the Geotechnical Consultant as suitable to receive fill. The Contractor shall obtain a written acceptance from the Geotechnical Consultant prior to fill placement A licensed surveyor shall provide the survey control for determining elevations of processed areas, keys, and benches. 3.0 Fill Material 3.1 General: Material to be used as fill shall be essentially free of organic matter and other deleterious substances evaluated and accepted by the Geotechnical Consultant prior to placement Soils of poor quality, such as those with unacceptable gradation, high expansion potential, or low strength shall be placed in areas acceptable to the Geotechnical Consultant or mixed with other soils to achieve satisfactory fill material 3.2 Oversize: Oversize material defined as rock, or other irreducible material with a maximum dimension greater than 8 inches, shall not be buried or placed in fill unless location, materials, and placement methods are specifically accepted by the Geotechnical Consultant Placement operations shall be such that nesting of oversized material does not occur and such that oversize material is completely surrounded by compacted or densified fill. Oversize material shall not be placed within 10 vertical feet of finish grade or within 2 feet of future utilities or underground construction. 3030.1094 Leighton and Associates, Inc. GENERAL EARTHWORK AND GRADING SPECIFICATIONS Page 4 of 6 3.3 Import: If importing of fill material is required for grading, proposed import material shall meet the requirements of Section 3.1. The potential import source shall be given to the Geotechnical Consultant at least 48 hours (2 working days) before importing begins so that its suitability can be determined and appropriate tests performed. 4.0 Fill Placement and Compaction 4.1 Fill Layers: Approved fill material shall be placed in areas prepared to receive fill (per Section 3.0) in near-horizontal layers not exceeding 8 inches in loose thickness. The Geotechnical Consultant may accept thicker layers if testing indicates the grading procedures can adequately compact the thicker layers. Each layer shall be spread evenly and mixed thoroughly to attain relative uniformity of material and moisture throughout. 4.2 Fill Moisture Conditioning: Fill soils shall be watered, dried back, blended, and/or mixed, as necessary to attain a relatively uniform moisture content at or slightly over optimum. Maximum density and optimum soil moisture content tests shall be performed in accordance with the American Society of Testing and Materials (ASTM Test Method D1557-91). 4.3 Compaction of Fill: After each layer has been moisture-conditioned, mixed, and evenly spread, it shall be uniformly compacted to not less than 90 percent of maximum dry density (ASTM Test Method D1557-91). Compaction equipment shall be adequately sized and be either specifically designed for soil compaction or of proven reliability to efficiently achieve the specified level of compaction with uniformity. 4.4 Compaction of Fill Slopes: In addition to normal compaction procedures specified above, compaction of slopes shall be accomplished by backrolling of slopes with , sheepsfoot rollers at increments of 3 to 4 feet in fill elevation, or by other methods producing satisfactory results acceptable to the Geotechnical Consultant Upon completion of grading, relative compaction of the fill, out to the slope face, shall be at least 90 percent of maximum density per ASTM Test Method D1557-91. 4.5 Compaction Testing: Field tests for moisture content and relative compaction of the fill soils shall be performed by the Geotechnical Consultant Location and frequency of tests shall be at the Consultant's discretion based on field conditions encountered. Compaction test locations will not necessarily be selected on a random basis. Test locations shall be selected to verify adequacy of compaction levels hi areas that are judged to be prone to inadequate compaction (such as close to slope faces and at the fill/bedrock benches). 3030L10M Leighton and Associates, Inc. GENERAL EARTHWORK AND GRADING SPECIFICATIONS Page 5 of 6 4.6 Frequency of Compaction Testing: Tests shall be taken at intervals not exceeding 2 feet in vertical rise and/or 1,000 cubic yards of compacted fill soils embankment In addition, as a guideline, at least one test shall be taken on slope faces for each 5,000 square feet of slope face and/or each 10 feet of vertical height of slope. The Contractor shall assure that fill construction is such that the testing schedule can be accomplished by the Geotechnical Consultant The Contractor shall stop or slow down the earthwork construction if these minimum standards are not met 4.7 Compaction Test Locations: The Geotechnical Consultant shall document the approximate elevation and horizontal coordinates of each test location. The Contractor shall coordinate with the project surveyor to assure that sufficient grade stakes are established so that the Geotechnical Consultant can determine the test locations with sufficient accuracy. At a minimum, two grade stakes within a horizontal distance of 100 feet and vertically less than 5 feet apart from potential test locations shall be provided. 5.0 Subdrain Installation Subdrain systems shall be installed in accordance with the approved geotechnical report(s), the grading plan, and the Standard Details. The Geotechnical Consultant may recommend additional subdrains and/or changes in subdrain extent, location, grade, or material depending on conditions encountered during grading. All subdrains shall be surveyed by a land surveyor/civil engineer for line and grade after installation and prior to burial. Sufficient time should be allowed by the Contractor for these surveys. 6.0 Excavation Excavations, as well as over-excavation for remedial purposes, shall be evaluated by the Geotechnical Consultant during grading. Remedial removal depths shown on geotechnical plans are estimates only. The actual extent of removal shall be determined by the Geotechnical Consultant based on the field evaluation of exposed conditions during grading. Where fill-over-cut slopes are to be graded, the cut portion of the slope shall be made, evaluated, and accepted by the Geotechnical Consultant prior to placement of materials for construction of the fill portion of the slope, unless otherwise recommended by the Geotechnical Consultant. 7.0 Trench Backfills 7.1 The Contractor shall follow all OHSA and Cal/OSHA requirements for safety of trench excavations. 3030.1094 Leighton and Associates, Inc. GENERAL EARTHWORK AND GRADING SPECIFICATIONS Page 6 of 6 7.2 All bedding and backfill of utility trenches shall be done in accordance with the applicable provisions of Standard Specifications of Public Works Construction. Bedding material shall have a Sand Equivalent greater than 30 (SE>30). The bedding shall be placed to 1 foot over the top of the conduit and densified by jetting. Backfill shall be placed and densified to a minimum of 90 percent of maximum from 1 foot above the top of the conduit to the surface. 7.3 The jetting of the bedding around the conduits shall be observed by the Geotechnical Consultant. 7.4 The Geotechnical Consultant shall test the trench backfill for relative compaction. At least one test should be made for every 300 feet of trench and 2 feet of fill. 7.5 Lift thickness of trench backfill shall not exceed those allowed in the Standard Specifications of Public Works Construction unless the Contractor can demonstrate to the Geotechnical Consultant that the fill lift can be compacted to the minimum relative compaction by his alternative equipment and method. 3030.1094 M <** innrcoMPACTED "—. PROJECTED PLANE 1 TO 1 MAXIMUM FROM TOE OF SLOPE TO APPROVED GROUND NATURAL GROUND REMOVE UNSUITABLE MATERIAL FILL SLOPE BENCH HEIGHT 2* MIN. KEY DEPTH —15' MIN. LOWEST BENCH (KEY) MPACTED —-•<?£- r_—IfJfckH FILL-OVER-CUT SLOPE NATURAL GROUND i .19* MIN. _J LOWEST BENCH1 1— 2' MIN. KEY DEPTH 4'TYPICAL > L_BENCH HEIGHT REMOVE UNSUITABLE MATERIAL CUT FACE SHALL BE CONSTRUCTED PRIOR TO FILL PLACEMENT TO ASSURE ADEQUATE GEOLOGIC CONOmONS CUT FACE TO BE CONSTRUCTED PRIOR TO FILL PLACEMEN^ NATURAL GROUND X OVERBUILT AND TRIM BACK DESIGN SLOPE PROJECTED PLANE 1 TO 1 MAXIMUM FROM TOE OF SLOPE TO APPROVED GROUND REMOVE ABLE MATERIAL CUT-OVER-FILL SLOPE For Subdrains See Standard Detail C BENCH HEIGHT LOWEST BENCH (KEY) BENCHMQ SHALL BE DONE WHEN SLOPES ANGLE IS EQUAL TO OR GREATER THAN 5:1 MIMMUM BENCH HEIGHT SHALL BE 4 FEET MMMUM FU. WOTH SHALL BE 9 FEET KEYING AND BENCHING GENERAL EARTHWORK AND GRADING SPECIFICATIONS STANDARD DETAILS A LL 4/95 FINISH GRADE SLOPE FACE HO' MIN.tnr-_r:COMPACTED FILL JETTED OR FLOODED GRANULAR MATERIAL • Oversize rock is larger than 8 inches in largest dimension. • Excavate a trench In the compacted fill deep enough to bury all the rock. • BackfiB with granular soil jetted or flooded In place to fill all the voids. • Do not bury rock withinIO feet of finish grade. • Windrow of buried rock shad be parallel to the finished slope fifl.ELEVATION A-A1 PROFILE ALONG WINDROW JETTED OR FLOODED GRANULAR MATERIAL OVERSIZE ROCK DISPOSAL GENERAL EARTHWORK AND GRADING SPECIFICATIONS STANDARD DETAILS B 4/85 RETAINING WALL DRAINAGE DETAIL .SOIL BACKFILL. COMPACTED TO 90 PERCENT RELATIVE COMPACTION* RETAINING WALL -^ WALL WATERPROOFING PER ARCHITECT'S SPECIFICATIONS FINISH GRADE — ^ S — -- ^COMPACTED FILL>— — ~- X 06" MIN. o OVERLAP o « 0 ,' 1' MIN. * o -»^. =9tU9=kB =-— : 12- • ^r~ -^zr. : — -i-~ - FILTER FABRIC E (MIRAFI 140N OF EQUIVALENT)** -3/4'- 1-1/2' CLEAI . 4' (MIN.) DIAMET PVC PIPE (SCHE EQUIVALENT) Wl ORIENTED DOWN MINIMUM 1 PERC TO SUITABLE OU ,** WALL 3* MIN. SPECIFICATIONS FOR CALTRANS CLASS 2 PERMEABLE MATERIAL U.S. Standard Sieve Size 1" 3/4" 3/8" No. 4 No. 8 No. 30 No. 50 No. 200 % Passing 100 90-100 40-100 25-40 18-33 5-15 0-7 0-3 Sand Equivalent>75 COMPETENT BEDROCK OR MATERIAL AS EVALUATED BY THE GEOTECHNICAL CONSULTANT * BASED ON ASTM D1667 **IF CALTRANS CLASS 2 PERMEABLE MATERIAL (SEE GRADATION TO LEFT) IS USED IN PLACE OF 3/4'-1-1/2' GRAVEL. FILTER FABRIC MAY BE DELETED. CALTRANS CLASS 2 PERMEABLE MATERIAL SHOULD BE COMPACTED TO 90 PERCENT RELATIVE COMPACTION * NOTECOMPOSITE DRAINAGE PRODUCTS SUCH AS MRADRAIN OR J-DRAIN MAY BE USED AS AN ALTERNATIVE TO GRAVEL OR CLASS 2. INSTALLATION SHOULD BE PERFORMED IN ACCORDANCE WITH MANUFACTURER'S SPECIFICATIONS. 90% RELATIVE COMPACTION Qt (1:1 slope) or Ts (3/4:1 slope) 3/4 :1 to 1:1 MAXIMUM SLOPE PER GEOTECHNICAL . RECOMMENDATIONS f DATED 12/14/95 or see text. (TYPICAL) 3' MAXIMUM VERTICAL CUT Ts Geologic contact (only from station 17*90 to 45*20) 3/4' CLEAN CRUSHED ROCK AT 90% COMPACTION '€'•• 6' IF TRENCH SIDE SLOPE IS CUT BACK PER SAFETY STANDARDS, 8* IF SHIELD IS USED. Typical Section Station 13+50 to 45+20 CMWD Poinsettia Park Sewer Carlsbad, California Project NO. 4950368-001 Scale _N/A EngrVGeol.. Drafted By . Date 12-12-95 1042889 Figure No. E1 Material may require removal within 5.0' of trench due to perched ground water conditions 90% RELATIVE COMPACTION Qal (sandy) Qal (clayey) (Material not acceptable for use as trench backfill) 1:1 to 2 :1 (see text) MAXIMUM SLOPE PER GEOTECHNICAL RECOMMENDATIONS DATED 12/14/95 (TYPICAL) 3/4* CLEAN CRUSHED ROCK AT 90% COMPACTION •C'- 6* IF TRENCH SIDE SLOPE IS CUT BACK PER SAFETY STANDARDS, 8* IF SHIELD IS USED. Typical Section Station 12+00 to 13+50 CMWD Poinsettia Park Sewer Carlsbad, California Project No. Scale Engr/Geol. Drafted By Date 4950368-001 N/A JGF/MRS WJP 12-12-95 JU 1042889 Figure No. E2 90% RELATIVE COMPACTION Stabilization Fabric AMOCO 2002(or equivalent)or12" of pea gravel at bottom of trencn may be necessary Qal (sandy) 1:1 to 11/2 :1 MAXIMUM SLOPE PER GEOTECHNICAL RECOMMENDATIONS DATED 12/14/95 (TYPICAL) (Use of trenching shield required if ground water or excessive caving is encountered) 3/4f CLEAN CRUSHED ROCK AT 90% COMPACTION •C'- 6' IF TRENCH SIDE SLOPE IS CUT BACK PER SAFETY STANDARDS, 8* IF SHIELD IS USED. Typical Section Station 10+00 to 12+00 CMWD Poinsettia Park Sewer Carlsbad, California Project No. Scale EngrVGeol. Drafted By Date 4950368-001 N/A JGF/MRS WJP 12-12-95 1042889 Figure No. E3 8" min. . Trench Width 8"min... Blocks to be laid is tightly as possible to downstream side of notch. PLAN 4" diameter schedule 40 PVC tight drain line to slope face 8" x 8" x .16" concrete block. Fill cores with grout • 1/2" expansion joint material or jute around pipe. FRONT ELEVATION TYPE A NOTE: Type A or Type B is permissible, both require back drains NOTES Type B: 1. No vertical joints permitted. 2. Horizontal joints must overlay, by 2 corrugations. 3. Corrugations to run horizontally. 4. Front Elevation and Plan views similar to Type A. No. 9 wire ladder type reinforcement in all horizontal joints. Galvanized Corrugated Sheet Metal 18 Gage or heavier to be laid as tightly as possible to downstream side of notch. Make flush with ground surface • Typical back drain ; MIRAFI 140N filter fabric or equivalent .3/4" gravel (3cfVft) 4" diameter perforated PVC (schedule 40) SIDE ELEVATION ELEVATION TYPE B LEGEND ON PLANS Modified from: San Diego regional standard drawing, drawing number S-10 CMWD Poinsettia Park Sewer Carlsbad, California Project NO. 4950368-001 Scale _J/A EngrVGeol. JGF/MRS Drafted By WJP Date 12-12-95 JU 1042889 Figure No. E4 HHt