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Home My WebLink About105132001; Rancho Carlsbad Channel and Basin Project; Rancho Carlsbad Channel and Basin Project; 2004-01-07Geotechnical and Environmental Sciences Consultants January 7, 2004 Project No. 105132001 City of Carlsbad c/o Mr. Glen K. Van Peski GVP Consultants 3764 Cavern Place Carlsbad, California 92008-6585 Subject: Limited Geotechnical Evaluation Rancho Carlsbad Channel and Basin Project Carlsbad, California Dear Mr. Van Peski: In accordance with your authorization, we have performed a limited geotechnical evaluation for the proposed Rancho Carlsbad Channel and Basin Project in Carlsbad, California. This report pre- sents our geotechnical findings, conclusions, and recommendations regarding the proposed project. We appreciate the opportunity to be of service on this project. If you have any questions or comments regarding our report, please contact the undersigned. Sincerely, NINYO & MOORE Erik Olsen, G.E. Chief Geotechnical Engineer RTW/EO/RI/rlm/msf Distribution: (4) Addressee Randal L. Irwin, C.E.G Chief Engineering Geologist 5710 Ruffin Road • San Diego, California 92123 • Phone (858) 576-1000 • Fax (858) 576-9600 San Diego • Irvine • Ontario • Los Angeles • Oakland • Las Vegas • Salt Lake City • Phoenix Rancho Carlsbad Channel and Basin Project January 7, 2004 Project No. 105132001 TABLE OF CONTENTS 1. INTRODUCTION 1 2. SCOPE OF SERVICES 1 3. SITE AND PROJECT DESCRIPTION 2 4. FIELD EXPLORATION AND LABORATORY TESTING 2 5. GEOLOGY AND SUBSURFACE CONDITIONS 3 5.1. Regional Geologic Setting 3 5.2. Site Geology 4 5.2.1. Fill 4 5.2.2. Alluvium 4 5.3. Groundwater 4 5.4. Faulting and Seismicity 5 5.4.1. Strong Ground Motion and Ground Surface Rupture 5 5.4.2. CBC Seismic Design Parameters 6 5.4.3. Liquefaction and Seismically Induced Settlement 6 5.5. Landslides 6 5.6. Slope Stability 7 6. CONCLUSIONS AND RECOMMENDATIONS 7 6.1. Channel Restoration 8 6.2. Surface Drainage 8 6.3. Slope Maintenance 9 7. LIMITATIONS 9 8. SELECTED REFERENCES 11 Tables Table 1 - Seismic Design Parameters 6 Table 2 - Cut Slope Stability Shear Strength Parameters 7 Figures Figure 1 - Site Location Map Figure 2 - Boring Location Map Appendices Appendix A - Boring Logs Appendix B - Laboratory Testing Appendix C - Typical Earthwork Guidelines 105132001 R2 Carlsbad Channel doc Rancho Carlsbad Channel and Basin Project January 7,2004 Project No. 105132001 1. INTRODUCTION In accordance with your request, we have performed a geotechnical evaluation for the design of the proposed Rancho Carlsbad Channel and Basin Project in Carlsbad, California (see Figure 1). This report presents the results of our field exploration and laboratory testing, our conclusions regarding the geotechnical conditions at the subject site, and our recommendations for the design and earthwork construction of this project. 2. SCOPE OF SERVICES Ninyo & Moore's scope of services for the project included review of pertinent background data, performance of a geologic reconnaissance, subsurface exploration, laboratory testing, and engi- neering analysis with regard to the proposed project. Specifically, we performed the following tasks: • Review of background information including a geotechnical report, geologic maps, and stereoscopic aerial photographs. • Preparation and submittal of boring permit information to the County of San Diego Depart- ment of Environmental Health (DEH). • Performance of a geologic reconnaissance and mark-out of the proposed exploratory boring locations, hi addition, Underground Service Alert (USA) was notified to mark-out/clear pos- sible underground utilities at the proposed boring locations. • Drilling, logging, and sampling of two 8-inch diameter hollow stem auger borings. The borings were advanced to depths of up to approximately 21.5 feet below the existing ground surface. Samples were obtained at selected intervals and transported to our laboratory for testing. • Laboratory testing of selected samples including in-situ moisture content and dry density, grain size analyses, and shear strength. • Compilation and engineering analysis of the data obtained. • Preparation of this geotechnical design report presenting our findings and conclusions and geotechnical recommendations regarding the proposed project. 105132001 R2 Carlsbad Channel.doc Rancho Carlsbad Channel and Basin Project January 7, 2004 Project No. 105132001 3. SITE AND PROJECT DESCRIPTION The proposed Rancho Carlsbad Channel and Basin Project is located within the Rancho Carlsbad Mobile Home Park, in Carlsbad, California (Figure 2). The proposed improvements include the portion of the channel, also known as Agua Hedionda Creek, that is bounded by the Rancho Carlsbad Drive bridge on the east, and the El Carnino Real bridge on the west. Paved residential streets associated with the mobile home park, are present along portions of the north and south sides of the channel, while some residences are situated on the banks of the channel. The subject channel consists of an earthen channel, which generally flows from east to west and discharges into the Calaveras Creek drainage. During our study, flowing surface water was ob- served within the channel. Currently, the channel is estimated to be less than 10 feet deep, and is bounded by banks which vary in gradient from roughly 3:1 (horizontal:vertical), to locally near 1.5:1, particularly in areas which have been subject to erosion. Elevations along the channel banks generally range from approximately 50 feet relative to mean sea level (MSL) on the east, to near 43 feet MSL on the west. We understand that the mobile home park and the Agua Hedionda Creek channel were graded and developed in 1970. Over time, sediment has filled the channel to a depth of approximately 4 feet above the original graded channel bottom. This additional sediment, as well as the deterioration of the side slopes, has raised concerns about the potential for flooding of nearby residences during periods of wet weather. To reduce the potential for flooding, the City of Carlsbad has proposed dredging the channel and rebuilding the slopes to an inclination of 2:1. In addition, we understand that due to site con- straints, buttress fills, overexcavation and recompaction, etc. of the channel banks is not considered feasible. 4. FIELD EXPLORATION AND LABORATORY TESTING Our field exploration of the subject site included a geologic reconnaissance and subsurface ex- ploratory work conducted on December 12, 2003. The subsurface evaluation consisted of drilling yinyo 105132001 R2 Carlsbad Channel doc <•) Rancho Carlsbad Channel and Basin Project January 7, 2004 Project No. 105132001 two, 8-inch diameter continuous flight, and hollow-stem auger borings. The borings were located near the top of the existing channel banks; one on the north and one on the south side of the sub- ject channel. The purposes of the borings were to observe and sample the underlying earth materials. Relatively undisturbed and bulk samples were obtained from the excavations at se- lected intervals and transported to our laboratory for testing. The approximate locations of the borings are shown on Figure 2, and the boring logs are presented in Appendix A. Laboratory testing of samples obtained during our subsurface exploration included an evaluation of in-situ density and moisture content, grain size analyses, and shear strength tests. The labora- tory tests were performed at our in-house laboratory. The results of the in-situ moisture content and dry density tests are shown at the corresponding sample depth on the boring logs in Appen- dix A. The results of the other laboratory tests performed are presented in Appendix B. 5. GEOLOGY AND SUBSURFACE CONDITIONS The following sections provide information regarding the regional geologic setting, as well as a discussion of site geologic conditions. 5.1. Regional Geologic Setting The project area is situated in the western San Diego County section of the Peninsular Ranges Geomorphic Province. This geomorphic province encompasses an area that extends approximately 900 miles from the Transverse Ranges and the Los Angeles Basin south to the southern tip of Baja California (Norris and Webb, 1990). The province varies in width from approximately 30 to 100 miles. In general, the province consists of rugged mountains underlain by Jurassic metavolcanic and metasedimentary rocks, and Cretaceous igneous rocks of the southern California batholith. The portion of the province in San Diego County that includes the project area consists generally of uplifted and dissected Tertiary-age sedi- mentary rock. The Peninsular Ranges Province is traversed by a group of sub-parallel faults and fault zones trending roughly northwest. Several of these faults, which are shown on Figure 3, 105132001 R2CarlsbadChannel.doc Rancho Carlsbad Channel and Basin Project January 7, 2004 Project No. 105132001 Fault Location Map, are considered active faults. The Elsinore, San Jacinto, and San Andreas faults are active fault systems located northeast of the project area and the Rose Canyon, Agua Blanca-Coronado Bank, and San Clemente faults are active faults located west of the project area. Major tectonic activity associated with these and other faults within this re- gional tectonic framework consists primarily of right-lateral, strike-slip movement. Further discussion of faulting relative to the site is provided in the Faulting and Seismicity section of this report. 5.2. Site Geology Geologic units encountered during our field reconnaissance and subsurface evaluation in- cluded fill and alluvium. Generalized descriptions of the earth units encountered during our field reconnaissance and subsurface exploration are provided in the subsequent sections. More detailed descriptions are provided on the boring logs in Appendix A. 5.2.1. Fill Fill material was encountered in both of our exploratory borings to depths ranging from approximately 4.5 to 9 feet below the existing ground surface. In general, the fill con- sists of dark gray, and brown, moist, loose, clayey fine to medium sand with scattered gravel and cobbles. 5.2.2. Alluvium Alluvium was encountered underlying the fill materials in both borings. In general, the alluvium consists of brown, moist to saturated, very stiff, fine sandy clay, and brown, light brown and light gray, saturated, loose to medium dense, silty fine to coarse sand and fine sandy silt (locally interlayered). 5.3. Groundwater Groundwater was encountered in both exploratory borings at depths of approximately 12 feet below the existing ground surface. Fluctuations in the groundwater level may occur 105)32001 R2 Carlsbad Channel doc Rancho Carlsbad Channel and Basin Project January 7,2004 Project No. 105132001 due to rainfall, irrigation, and other factors. As mentioned, flowing water was observed within the channel at the time of our study. 5.4. Faulting and Seismicity Our review of readily available published geological maps and literature indicates that there are no known active faults underlying the site. The site is not within a designated State of California Earthquake Fault Zone (Alquist-Priolo Earthquake Fault Zoning Act). The most significant seismic event likely to affect the proposed improvements would be an event on the Rose Canyon fault, which can generate a magnitude 6.9 earthquake (California Division of Mines and Geology [CDMG], 1998). The Rose Canyon fault is mapped approximately 6 miles west of the project site. According to the 2001 California Building Code (CBC), the site is not within a CBC Near-Source zone. The Rose Canyon fault is classified as a "B" seismic source type, and the site is within Seismic Zone 4. In general, hazards associated with seismic activity include: strong ground motion, ground surface rupture, liquefaction, and seismically-induced settlement. These hazards are discussed in the following sections. 5.4.1. Strong Ground Motion and Ground Surface Rupture Based on a Probabilistic Seismic Hazard Assessment for the Western United States, is- sued by the United States Geological Survey (2002), the project site is located in a zone where the horizontal peak ground acceleration having a 10 percent probability of ex- ceedance in 50 years is 0.28g (28 percent of the acceleration of gravity). The requirements of the governing jurisdictions and the 2001 California Building Code (CBC) should be considered in the design. The principal seismic considerations in southern California are surface rupture, ground shaking, and damage caused by seismically induced settlement. The probability of dam- age due to ground rupture at the site appears to be low since our research and field reconnaissance do not indicate the presence of any known active faults underlying the site. Lurching or cracking of the ground caused by seismic events on nearby active faults is not considered a significant hazard, however, it is a possibility. 105132001 R2 Carlsbad Channel doc Rancho Carlsbad Channel and Basin Project January 7, 2004 Project No. 105132001 5.4.2. CBC Seismic Design Parameters The following table provides parameters for seismic design. Table 1 - Seismic Design Parameters Parameter Seismic Zone Factor, Z Soil Profile Type Seismic Coefficient Ca Seismic Coefficient Cv Near-Source Factor, Na Near-Source Factor, Nv Seismic Source Type Value 0.40 So 0.44Na 0.64NV 1.0 1.0 B 2001 CBC Reference Table 16 -I Table 16 -J Table 16 -Q Table 16 -R Table 16 -S Table 16 -T Table 16 -U 5.4.3. Liquefaction and Seismically Induced Settlement Liquefaction of cohesionless soils can be caused by strong vibratory motion due to earthquakes. Research and historical data indicate that loose granular soils and non- plastic silts that are saturated by a relatively shallow groundwater table are susceptible to liquefaction. Based on the presence of shallow groundwater and the relatively granu- lar nature of the soils underlying the site, it is our opinion that the potential for liquefaction and seismically induced settlement at the subject site is moderate. 5.5. Landslides As part of our study, we reviewed background data, including, geologic maps, and stereo- scopic aerial photographs pertaining to the site. Based on our background review and field reconnaissance, there are no known landslides mapped underlying the subject site. Based on the relatively flat topography of the site, landsliding is not a design consideration. However, due to the loose, granular nature of the side slopes along the subject channel, some slough- ing and ravelling resulting from current or future erosional processes is a possibility. 105132001 R2CarlsbadChanncl.doc tyinyo Rancho Carlsbad Channel and Basin Project January 7, 2004 Project No. 105132001 5.6. Slope Stability Slope stability analyses were performed for the new slopes proposed for the improvements addressed in this report. Stability analyses were performed using Janbu's dimensionless sta- bility charts considering the geologic conditions discussed previously. Our analyses included a post-flood phreatic water surface occurring within the proposed new slopes. Shear strength parameters used in our analyses were based on laboratory test results performed on samples obtained from the exploratory borings, and our professional judgment. The shear strength parameters used in our analyses are presented in Table 2. Table 2 - Slope Stability Shear Strength Parameters Geologic Unit Fill/Alluvium Total Unit Weight (pci) 120 Friction Angle (degrees) 28 Cohesion (psf) 190 Our analyses indicated that the proposed new slopes will have calculated factors of safety for deep-seated stability greater than 1.5 for static conditions. Our analyses also indicated that the slopes will have calculated factors of safety greater than 1.5 for surficial stability. However, the materials encountered in our borings are considered subject to surficial erosion. For this reason, periodic local maintenance of the slopes should be anticipated. 6. CONCLUSIONS AND RECOMMENDATIONS Based on our review of the referenced background data, geologic field reconnaissance, subsur- face evaluation, and laboratory testing, it is our opinion that construction of the proposed project is feasible from a geotechnical standpoint. Based on our analysis, the following recommenda- tions are provided for the design and construction of the proposed project. These recommendations anticipate that regular channel maintenance will be performed and that some surficial sloughing and erosion is anticipated. 105132001 R2 Carlsbad Channel.doc tyinyo Rancho Carlsbad Channel and Basin Project January 7, 2004 Project No. 105132001 6.1. Channel Restoration We recommend that the accumulated channel sediments be removed to restore the original channel configuration. The channel banks, up to approximately 15 feet in height, should be shaped to a slope angle of 2:1 or flatter. Where toe erosion has produced banks steeper than 2:1, we recommend that the channel bank be shaped to a slope angle of 2:1, or as an alterna- tive, those portions of the slope may be armored with riprap to reduce the potential for future erosion. The project civil engineer should size the recommended riprap based on the site hy- drology. Where riprap is used, we recommend that a woven filter fabric be placed between the slope and the riprap. The fabric should possess the puncture strength and permeability characteristics of Mirafi Filterweave 700, or equivalent. If planned, fill placement should be performed in general accordance with the recommenda- tions presented in Appendix C under the observation of the geotechnical consultant. On-site materials should be generally suitable for reuse as fill material provided the material consist predominantly of granular soils with some fines (approximately 15 to 35 percent material that passes the No. 200 sieve). The soils should be free of organic debris, deleterious materi- als, and oversize material (rocks or hard lumps exceeding 3 inches in diameter). Proposed fill materials soils should be evaluated for suitability by the geotechnical engineer, prior to placement. Groundwater and surface water within the Rancho Carlsbad channel may require special handling, discharge permits, and Best Management practices, during dredging and slope re- construction activities. The contractor should check with local and state agencies regarding the proposed project. 6.2. Surface Drainage We recommend that the project civil engineer design surface drainage away from the top of slopes and that runoff not be allowed to overtop and run down the face of slopes. Further, it is imperative that all drainage facilities be maintained and kept in good functioning condi- tion. These might consist of berms, swales, collectors, inlets, pipes, and energy dissipaters. yinyo 105132001 R2 Carlsbad Channel doc O Rancho Carlsbad Channel and Basin Project January 7, 2004 Project No. 105132001 6.3. Slope Maintenance To reduce the potential for the loss of surficial slope materials, we recommend that the graded slopes be replanted with a combination of shallow and deep-rooted drought tolerant vegetation. Ice plant should not be used. We recommend that a qualified landscape architect be consulted so that the slopes can be appropriately planted without the addition of an irriga- tion system and to assist in the selection of plant varieties. 7. LIMITATIONS The field evaluation, laboratory testing, and geotechnical analyses presented in this geotechnical report have been conducted in general accordance with current practice and the standard of care exercised by geotechnical consultants performing similar tasks in the project area. No warranty, expressed or implied, is made regarding the conclusions, recommendations, and opinions pre- sented in this report. There is no evaluation detailed enough to reveal every subsurface condition. Variations may exist and conditions not observed or described in this report may be encountered during construction. Uncertainties relative to subsurface conditions can be reduced through addi- tional subsurface exploration. Additional subsurface evaluation will be performed upon request. Please also note that our evaluation was limited to assessment of the geotechnical aspects of the project, and did not include evaluation of structural issues, environmental concerns, or the pres- ence of hazardous materials. This document is intended to be used only in its entirety. No portion of the document, by itself, is designed to completely represent any aspect of the project described herein. Ninyo & Moore should be contacted if the reader requires additional information or has questions regarding the content, interpretations presented, or completeness of this document. This report is intended for design purposes only. It does not provide sufficient data to prepare an accurate bid by contractors. It is suggested that the bidders and their geotechnical consultant per- form an independent evaluation of the subsurface conditions in the project areas. The independent evaluations may include, but not be limited to, review of other geotechnical reports 105132001 R2 Carlsbad Channel doc tyinyo Rancho Carlsbad Channel and Basin Project January 7, 2004 Project No. 105132001 prepared for the adjacent areas, site reconnaissance, and additional exploration and laboratory testing. Our conclusions, recommendations, and opinions are based on an analysis of the observed site conditions. If geotechnical conditions different from those described in this report are encoun- tered, our office should be notified and additional recommendations, if warranted, will be provided upon request. It should be understood that the conditions of a site could change with time as a result of natural processes or the activities of man at the subject site or nearby sites. In addition, changes to the applicable laws, regulations, codes, and standards of practice may occur due to government action or the broadening of knowledge. The findings of this report may, there- fore, be invalidated over time, in part or in whole, by changes over which Ninyo & Moore has no control. This report is intended exclusively for use by the client. Any use or reuse of the findings, conclu- sions, and/or recommendations of this report by parties other than the client is undertaken at said parties' sole risk. 105132001 R2 Carlsbad Chaimel.doc | Q "r' X Kl^-1W/>fVS'^/l^^^^^i^- *** S-'M*-*£«,-- ^i , AV s'J, «f-v J« ^RJ— S , •* ,-^*-i |g|!^nv^'* 31 >is> I? * •-''i vi*. .-^/Vd . ^..-.-;w *.« •- /^ s,?-^ .-•" . ^ • s>( ?..' cr ir *. AV L.,, ,'•' -,cv*i* *» °" -- :••--* ^^ ." r>-> vi»a wl -2 /K-fe'* ^v -jyj; Y.--/--«..3»^| ,* <^ /V^^t s/ iftSR cr Hf-^^/^asS* 1900 Approximate Scale in Feet 3800 E*J § \^REFERENCE: 2003 THOMAS GUIDE FOR SAN DIEGO COUNTY, STREET GUIDE AND DIRECTORY SITE LOCATION MAP RANCHO CARLSBAD CHANNEL CARLSBAD, CALIFORNIA ( PROJECT NO. L 105132001 DATE ^ 1/04 J FIGURE 1 J LEGEND -A- B"2 Approximate location of exploratory boring 200 400 Approximate Scale in Feet \ X BORING LOCATION MAP RANCHO CARLSBAD CHANNEL CARLSBAD, CALIFORNIA r PROJECT NO. \^ 105132001 DATE "\ 1/04 J FIGURE A 2 J APPENDIX A Rancho Carlsbad Channel and Basin Project January 7, 2004 Project No. 105132001 APPENDIX A BORING AND TEST PIT LOGS Field Procedure for the Collection of Disturbed Samples Disturbed soil samples were obtained in the field using the following methods. Bulk Samples Bulk samples of representative earth materials were obtained from the exploratory excava- tions. The samples were bagged and transported to the laboratory for testing. The Standard Penetration Test (SPT) Spoon Disturbed drive samples of earth materials were obtained by means of a Standard Penetra- tion Test spoon sampler. The sampler is composed of a split barrel with an external diameter of 2 inches and an unlined internal diameter of 1 -3/8 inches. The spoon was driven into the ground with a 140-pound hammer free-falling from a height of 30 inches in general accor- dance with ASTM D 1586-99. The blow counts were recorded for every 6 inches of penetration; the blow counts reported on the logs are those for the last 12 inches of penetra- tion. Soil samples were observed and removed from the spoon, bagged, sealed and transported to the laboratory for testing. Field Procedure for the Collection of Relatively Undisturbed Samples Relatively undisturbed soil samples were obtained in the field using the following methods. The Modified Split-Barrel Drive Sampler The sampler, with an external diameter of 3.0 inches, was lined with 1-inch long, thin brass rings with inside diameters of approximately 2.4 inches. The sample barrel was driven into the ground with the weight of a 140-pound hammer, in general accordance with ASTM D 3550-84. The driving weight was permitted to fall freely. The approximate length of the fall, the weight of the hammer, and the number of blows per foot of driving are presented on the boring logs as an index to the relative resistance of the materials sampled. The samples were removed from the sample barrel in the brass rings, sealed, and transported to the labo- ratory for testing. 105132001 R2 Carlsbad Channel doc I UJQ 0 5- 20 SAMPLES |Js r -i\\\BLOWS/FOOTXX/XX MOISTURE (%)9 DRY DENSITY (PCF)SYMBOL 111 CLASSIFICATIONU.S.C.S.SM BORING LOG EXPLANATION SHEET Bulk sample. Modified split-barrel drive sampler. No recovery with modified split-barrel drive sampler. Sample retained by others. Standard Penetration Test (SPT). No recovery with a SPT. Shelby tube sample. Distance pushed in inches/length of sample recovered in inches. No recovery with Shelby tube sampler. Continuous Push Sample. Seepage. Groundwater encountered during drilling. Groundwater measured after drilling. ALLUVIUM: Solid line denotes unit change. Dashed line denotes material change. Attitudes: Strike/Dip b: Bedding c: Contact j: Joint f: Fracture F: Fault cs: Clay Seam s: Shear bss: Basal Slide Surface sf: Shear Fracture sz: Shear Zone sbs: Sheared Bedding Surface The total depth line is a solid line that is drawn at the boring. bottom of the j BORING LOG 'fimlmmwmmf *^ vl^vDUV^S EXPLANATION OF BORING LOG SYMBOLS * ** f PROJECT NO. D/ Rev.^TE FIGURE01/03 A-0 U.S.C.S. METHOD OF SOIL CLASSIFICATION MAJOR DIVISIONS SYMBOL TYPICAL NAMES COARSE-GRAINED SOILS(More than 1/2 of soil>No. 200 sieve size)FINE-GRAINED SOILS(More than 1/2 of soil<No. 200 sieve size)GRAVELS (More than 1/2 of coarse fraction > No. 4 sieve size) SANDS (More than 1/2 of coarse fraction <No. 4 sieve size) SILTS & CLAYS Liquid Limit <50 SILTS & CLAYS Liquid Limit >50 •.»•.•.••.•.•.-.•-.•»:••:•• V.'."*.:: ' • ,*1 1. 1• J1" £^ %w•xjW'iv' H •T .-. *. GW ; GP ' GM •4s /—t f~* % GC sw SP SM I sc **/ ML |CL 1 OL MH ICH 'filrt i|3=HloH HIGHLY ORGANIC SOILS Well graded gravels or gravel-sand mixtures, little or no fines Poorly graded gravels or gravel-sand mixtures, little or no fines Silty gravels, gravel-sand-silt mixtures Clayey gravels, gravel-sand-clay mixtures Well graded sands or gravelly sands, little or no fines Poorly graded sands or gravelly sands, little or no fines Silty sands, sand-silt mixtures Clayey sands, sand-clay mixtures Inorganic silts and very fine sands, rock flour, silty or clayey fine sands or clayey silts with Inorganic clays of low to medium plasticity, gravelly clays, sandy clays, silty clays, lean Organic silts and organic silty clays of low plasticity Inorganic silts, micaceous or diatomaceous fine sandy or silty soils, elastic silts Inorganic clays of high plasticity, fat clays Organic clays of medium to high plasticity, organic silty clays, organic silts Peat and other highly organic soils GRAIN SIZE CHART CLASSIFICATION BOULDERS COBBLES GRAVEL Coarse Fine SAND Coarse Medium Fine SILT & CLAY RANGE OF GRAIN SIZE U.S. Standard Sieve Size Above 12" 12" to 3" 3" to No. 4 3" to 3/4" 3/4" to No. 4 No. 4 to No. 200 No. 4 to No. 10 No. 10 to No. 40 No. 40 to No. 200 Below No. 200 Grain Size in Millimeters Above 305 305 to 76.2 76.2 to 4.76 76.2 to 19.1 19.1 to 4.76 4.76 to 0.074 4.76 to 2.00 2.00 to 0.420 0.420 to 0.074 Below 0.074 PLASTICITY CHART ** *.J f/ / Cl-ti / . s / CL /S ML / / ,OL / / / CM / , MH ' OH / 0 10 20 30 40 50 60 70 80 90 100 LIQUID LIMIT (LL), '/. U.S.C.S. METHOD OF SOIL CLASSIFICATION Revised U.S.C.S. Classification Chart '5£ i 0. HI Q 0 10- 20- 40 cL ^«< C A:3LLJ I 0LJ > 0 c(D> Q I ' | j ooLL 12CD 18 18 " » 54 M «Jy/F g HIo: =3 W O 1.5.0 10.8 18.1 _xz 09•/ 0Q. £w LU Q >-a:Q 114.5 114.9 ro* oCO ^w ^1 Ip1 •^/i *j 0I—< wyd "- w W-Sw =>< o SC CL SM n ™VV10 T DATE DRILLED 12/12/03 BORING NO. B-l GROUND ELEVATION 52'±(MSL) SHEET 1 OF 1 METHOD OF DRILLING 8" Diameter Hollow Stem Auger (Tri-County Drilling) DRIVE WEIGHT 140 Ib. Spooling Cable DROP 30" SAMPLED BY EP LOGGED BY EP REVIEWED BY RI DESCRIPTION/INTERPRETATION FILL: Dark gray to dark brown, moist, loose, clayey, fine to medium SAND; some gravel and cobbles; abundant rootlets. Decrease in clay content. ALLUVIUM: Brown, moist, very stiff, fine sandy CLAY; scattered white streaks. Saturated. Brown, light brown, and light gray, saturated, medium dense, silty fine to coarse SAND; few gravel; scattered iron oxide staining. Fine-grained. Total Depth = 21 .5 feet. Groundwater encountered during drilling at approximately 12 feet. Backfilled with bentonite grout on 12/12/03. BORING LOG •mWB^m RANCHO CARLSBAD CHANNEL AND BASIN PROJECT %fM %5 CARLSBAD, CALIFORNIA PROJECT NO. DATE FIGURE 105132001 01/04 A-l 15 £LUQ 0 10- 20- 3U 40 SAMPLES |3m _ J c0 D BLOWS/FOOT19 38 4 5 11 MOISTURE (%)26.9 13.2 52.DRY DENSITY (PCF)\ '"1 % 109.0 : i FICATION3.C.S.- wl^0 w => o i sc 1 1 SM+ML ML Nlngo&typ DATE DRILLED 12/12/03 BORING NO. B-2 GROUND ELEVATION 45'±(MSL) SHEET 1 OF 1 METHOD OF DRILLING 8" Diameter Hollow Stem Auger (Tri-County Drilling) DRIVE WEIGHT 1 40 Ib. Spooling Cable DROP 30" SAMPLED BY EP LOGGED BY EP REVIEWED BY RJ DESCRIPTION/INTERPRETATION FILL: Dark brown to light brown, moist, loose, clayey, fine SAND; abundant rootlets. ALLUVIUM: Light yellowish brown, moist, medium dense, silty fine to medium SAND interlayered with gray, moist, medium dense, fine sandy SILT with iron oxide staining. Loose. Saturated. Gray and brown (mottled), saturated, loose, fine sandy SILT; abundant rootlets. Medium dense; increase in sand content. Total Depth = 2 1.5 feet. Groundwater encountered during drilling at approximately 12 feet. Backfilled with bentonite grout on 12/12/03. BORING LOG •WMk^% RANCHO CARLSBAD CHANNEL AND BASIN PROJECT ml^ ^5 CARLSBAD, CALIFORNIA PROJECT NO. DATE FIGURE 105132001 01/04 A-2 APPENDIX B Rancho Carlsbad Channel and Basin Project January 7, 2004 Project No. 105132001 APPENDIX B LABORATORY TESTING Classification Soils were visually and texturally classified in accordance with the Unified Soil Classification System (USCS) in general accordance with ASTM D 2488-00. Soil classifications are indicated on the logs of the exploratory excavations in Appendix A. Iii-Place Moisture and Density Tests The moisture content and dry density of relatively undisturbed samples obtained from the ex- ploratory excavations were evaluated in general accordance with ASTM D 2937-00. The test results are presented on the logs of the exploratory excavations in Appendix A. Gradation Analysis Gradation analysis tests were performed on a selected representative soil sample in general ac- cordance with ASTM D 422-63. The grain-size distribution curve is shown on Figure B-l. These test results were utilized in evaluating the soil classifications in accordance with the Unified Soil Classification System. Shear Strength Tests Shear strength tests were performed on undisturbed samples in general accordance with ASTM D 3080-98 to evaluate the shear strength characteristics of selected materials. The samples were inundated during shearing to represent adverse field conditions. The results are shown on Figures B-2 and B-3. 105132001 R2 Carlsbad Channel doc GRAVEL Coarse Fine SAND Coarse | Medium Fine FINES sin Clay U.S. STANDARD SIEVE NUMBERS HYDROMETER 3" 1-1/2" 1" 3/4" 1/2" 3/8" 4 8 16 30 50 100 200 t§ 5 60 LL m 30 10 - - I III I I | I II I I | I iI I I I i ri t- |•^iks 100 10 •symbol • Hole No. B-1 Depth (ft) 0-5.0 •i k s ^, \ \sS s i I Ii 1 0.1 0.01 GRAIN SIZE IN MILLIMETERS Liquid Limit - Plastic Limit - Plasticity Index - D10 - DSO Deo - cu - '• - PERFORMED IN GENERAL ACCORDANCE WITH ASTM D 422-63 ^ f~ ^ ^ «re_ > 0.001 0.0001 Passing No. 200 48 u.s.c.s sc J r GRADATION TEST RESULTS ^ Rancho Carlsbad Channel and Basin Project ^ Carlsbad, California ^ (PROJECT NO. 105132001 DATE \ f FIGURE A 1/04 ) ^ B-1 ) 105132001 Gfada6wiSVBI@0-50 4000 3000 u.co COV)Ul 2000 COo: CO 1000 1000 2000 NORMAL STRESS (PSF) 3000 4000 Description Sandy CLAY Symbol Boring Number B-1 Depth (ft) 10.0-11.5 Shear Strength Peak Cohesion (psf) 190 Friction Angle (deg) 33 Soil Type CL SHEAR STRENGTH TEST RESULTS Rancho Carlsbad Channel and Basin Project Carlsbad, California (PROJECT NO. 105132001 DATE A 1/04 J 105132001 Shear Strength DSB1@10.0-11.5 2000 1600 1200 V)UJa: V) £ uj V) 800 400 400 800 1200 NORMAL STRESS (PSF) 1600 2000 Description Clayey SAND Symbol Boring Number B-2 Depth (ft) 2.0-3.5 Shear Strength Peak Cohesion (psf) 230 Friction Angle (deg) 28 Soil Type SC \ /SHEAR STRENGTH TEST RESULTS Rancho Carlsbad Channel and Basin Project Carlsbad, California f PROJECT NO. \^ 105132001 DATE ^ 1/04 J 105132001 Shear Strength DSB2@2-3.5 APPENDIX C Rancho Carlsbad Channel and Basin Project January 7, 2004 Project No. 105132001 APPENDIX C TYPICAL EARTHWORK GUIDELINES Rancho Carlsbad Channel and Basin Project January 7, 2004 Project No. 105132001 TABLE OF CONTENTS Page 1. GENERAL 1 2. OBLIGATIONS OF PARTIES 2 3. SITE PREPARATION 3 4. REMOVALS AND EXCAVATIONS 4 5. COMPACTED FILL 5 6. OVERSIZED MATERIAL 7 7. SLOPES 8 8. TRENCH BACKFILL 11 9. DRAINAGE 13 10. SITE PROTECTION 14 11. DEFINITIONS OF TERMS 16 Figures Figure A - Fill Slope Over Natural Ground or Cut Figure B - Transition and Undercut Lot Details Figure C - Canyon Subdrain Detail Figure D - Oversized Rock Placement Detail Figure E - Slope Drainage Detail Figure F - Shear Key Detail Figure G - Drain Detail 105132001 earthworks-doc Rancho Carlsbad Channel and Basin Project January 7, 2004 Project No. 105132001 TYPICAL EARTHWORK GUIDELINES FOR SLOPES 1. GENERAL These guidelines and the standard details attached hereto are presented as general procedures for earthwork construction. They are to be utilized in conjunction with the project grading plans. These guidelines are considered a part of the geotechnical report, but are superseded by recommendations in the geotechnical report in the case of conflict. Evaluations performed by the consultant during the course of grading may result in new recommendations which could super- sede these specifications and/or the recommendations of the geotechnical report. It is the responsibility of the contractor to read and understand these guidelines as well as the geotechni- cal report and project grading plans. 1.1. The contractor shall not vary from these guidelines without prior recommendations by the geotechnical consultant and the approval of the client or the client's author- ized representative. Recommendations by the geotechnical consultant and/or client shall not be considered to preclude requirements for approval by the jurisdictional agency prior to the execution of any changes. 1.2. The contractor shall perform the grading operations in accordance with these speci- fications, and shall be responsible for the quality of the finished product notwithstanding the fact that grading work will be observed and tested by the geo- technical consultant. 1.3. It is the responsibility of the grading contractor to notify the geotechnical consult- ant and the jurisdictional agencies, as needed, prior to the start of work at the site and at any time that grading resumes after interruption. Each step of the grading operations shall be observed and documented by the geotechnical consultant and, where necessary, reviewed by the appropriate jurisdictional agency prior to pro- ceeding with subsequent work. 1.4. If, during the grading operations, geotechnical conditions are encountered which were not anticipated or described in the geotechnical report, the geotechnical con- sultant shall be notified immediately and additional recommendations, if applicable, may be provided. 1.5. An as-graded report shall be prepared by the geotechnical consultant and signed by a registered engineer and registered engineering geologist. The report documents the geotechnical consultants' observations, and field and laboratory test results, and 105132001 earthworks doc Rancho Carlsbad Channel and Basin Project January 7, 2004 Project No. 105132001 provides conclusions regarding whether or not earthwork construction was per- formed in accordance with the geotechnical recommendations and the grading plans. Recommendations for foundation design, pavement design, subgrade treat- ment, etc., may also be included in the as-graded report. 1.6. For the purpose of evaluating quantities of materials excavated during grading and/or locating the limits of excavations, a licensed land surveyor or civil engineer shall be retained. 1.7. Definitions of terms utilized in the remainder of these specifications have been provided in Section 11. 2. OBLIGATIONS OF PARTIES The parties involved in the projects earthwork activities shall be responsible as outlined in the following sections. 2.1. The client is ultimately responsible for the aspects of the project. The client or the client's authorized representative has a responsibility to review the findings and recommendations of the geotechnical consultant. The client shall authorize the con- tractor and/or other consultants to perform work and/or provide services. During grading the client or the client's authorized representative shall remain on site or remain reasonably accessible to the concerned parties to make the decisions that may be needed to maintain the flow of the project. 2.2. The contractor is responsible for the safety of the project and satisfactory comple- tion of grading and other associated operations, including, but not limited to, earthwork in accordance with the project plans, specifications, and jurisdictional agency requirements. During grading, the contractor or the contractor's authorized representative shall remain on site. The contractor shall further remain accessible during non-working hours times, including at night and during days off. 2.3. The geotechnical consultant shall provide observation and testing services and shall make evaluations to advise the client on geotechnical matters. The geotechnical consultant shall report findings and recommendations to the client or the client's authorized representative. 2.4. Prior to proceeding with any grading operations, the geotechnical consultant shall be notified two working days in advance to schedule the needed observation and testing services. 105132001 earthworks.doc Rancho Carlsbad Channel and Basin Project January 7, 2004 Project No. 105132001 2.4.1. Prior to any significant expansion or reduction in the grading operation, the geotechnical consultant shall be provided with two working days notice to make appropriate adjustments in scheduling of on-site personnel. 2.4.2. Between phases of grading operations, the geotechnical consultant shall be provided with two working days notice in advance of commencement of ad- ditional grading operations. 3. SITE PREPARATION Site preparation shall be performed in accordance with the recommendations presented in the following sections. 3.1. The client, prior to any site preparation or grading, shall arrange and attend a pre-grading meeting between the grading contractor, the design engineer, the geo- technical consultant, and representatives of appropriate governing authorities, as well as any other involved parties. The parties shall be given two working days no- tice. 3.2. Clearing and grubbing shall consist of the substantial removal of vegetation, brush, grass, wood, stumps, trees, tree roots greater than 1/2-inch in diameter, and other deleterious materials from the areas to be graded. Clearing and grubbing shall ex- tend to the outside of the proposed excavation and fill areas. 3.3. Demolition in the areas to be graded shall include removal of building structures, foun- dations, reservoirs, utilities (including underground pipelines, septic tanks, leach fields, seepage pits, cisterns, etc.), and other manmade surface and subsurface improvements, and the backfilling of mining shafts, tunnels and surface depressions. Demolition of utilities shall include capping or rerouting of pipelines at the project perimeter, and abandonment of wells in accordance with the requirements of the governing authorities and the recommendations of the geotechnical consultant at the time of demolition. 3.4. The debris generated during clearing, grubbing and/or demolition operations shall be removed from areas to be graded and disposed of off site at a legal dump site. Clearing, grubbing, and demolition operations shall be performed under the observation of the geotechnical consultant. 3.5. The ground surface beneath proposed fill areas shall be stripped of loose or unsuit- able soil. These soils may be used as compacted fill provided they are generally free of organic or other deleterious materials and evaluated for use by the geotech- nical consultant. The resulting surface shall be evaluated by the geotechnical consultant prior to proceeding. The cleared, natural ground surface shall be scari- 105132001 earthworks.doc Rancho Carlsbad Channel and Basin Project January 7, 2004 Project No. 105132001 fled to a depth of approximately 8 inches, moisture conditioned, and compacted in accordance with the specifications presented in Section 5. of these guidelines. 3.6. Where fills are to be constructed on hillsides or slopes, topsoil, slope wash, collu- vium, and other materials deemed unsuitable shall be removed. Where the exposed slope is steeper than 5 horizontal units to 1 vertical unit, or where recommended by the geotechnical consultant, the slope of the original ground on which the fill is to be placed shall be benched and a key as shown on Figure A of this document shall be provided by the contractor in accordance with the specifications presented in Section 7. of this document. The benches shall extend into the underlying bedrock or, where bedrock is not present, into suitable compacted fill as evaluated by the geotechnical consultant. 4. REMOVALS AND EXCAVATIONS Removals and excavations shall be performed as recommended in the following sections. 4.1. Removals 4.1.1. Materials which are considered unsuitable shall be excavated under the ob- servation of the geotechnical consultant in accordance with the recommendations contained herein. Unsuitable materials include, but may not be limited to, dry, loose, soft, wet, organic, compressible natural soils, frac- tured, weathered, soft bedrock, and undocumented or otherwise deleterious fill materials. 4.1.2. Materials deemed by the geotechnical consultant to be unsatisfactory due to moisture conditions shall be excavated in accordance with the recommenda- tions of the geotechnical consultant, watered or dried as needed, and mixed to a generally uniform moisture content in accordance with the specifications presented in Section 5. of this document. 4.2. Excavations 4.2.1. Temporary excavations no deeper than 5 feet in firm fill or natural materials may be made with vertical side slopes. To satisfy CAL OSHA requirements, any excavation deeper than 5 feet shall be shored or laid back at a 1:1 inclina- tion or flatter, depending on material type, if construction workers are to enter the excavation. 105132001 earthwolte.doc Rancho Carlsbad Channel and Basin Project January 7, 2004 Project No. 105132001 5. COMPACTED FILL Fill shall be constructed as specified below or by other methods recommended by the geotechni- cal consultant. Unless otherwise specified, fill soils shall be compacted to 90 percent or greater relative compaction, as evaluated in accordance with ASTM Test Method D 1557-00. 5.1. Prior to placement of compacted fill, the contractor shall request an evaluation of the exposed ground surface by the geotechnical consultant. Unless otherwise rec- ommended, the exposed ground surface shall then be scarified to a depth of approximately 8 inches and watered or dried, as needed, to achieve a generally uni- form moisture content at or near the optimum moisture content. The scarified materials shall then be compacted to 90 percent or greater relative compaction. The evaluation of compaction by the geotechnical consultant shall not be considered to preclude any requirements for observation or approval by governing agencies. It is the contractor's responsibility to notify the geotechnical consultant and the appro- priate governing agency when project areas are ready for observation, and to provide reasonable time for that review. 5.2. Excavated on-site materials which are in general compliance with the recommenda- tions of the geotechnical consultant may be utilized as compacted fill provided they are generally free of organic or other deleterious materials and do not contain rock fragments greater than 6 inches in dimension. During grading, the contractor may encounter soil types other than those analyzed during the preliminary geotechnical study. The geotechnical consultant shall be consulted to evaluate the suitability of any such soils for use as compacted fill. 5.3. Where imported materials are to be used on site, the geotechnical consultant shall be notified three working days in advance of importation in order that it may sam- ple and test the materials from the proposed borrow sites. No imported materials shall be delivered for use on site without prior sampling, testing, and evaluation by the geotechnical consultant. 5.4. Soils imported for on-site use shall preferably have very low to low expansion po- tential (based on UBC Standard 18-2 test procedures). Lots on which expansive soils may be exposed at grade shall be undercut 3 feet or more and capped with very low to low expansion potential fill. Details of the undercutting are provided in the Transition and Undercut Lot Details, Figure B of these guidelines. In the event expansive soils are present near the ground surface, special design and construction considerations shall be utilized in general accordance with the recommendations of the geotechnical consultant. 5.5. Fill materials shall be moisture conditioned to near optimum moisture content prior to placement. The optimum moisture content will vary with material type and other 105132001 eaithworks.doc Rancho Carlsbad Channel and Basin Project January 7, 2004 Project No. 105132001 factors. Moisture conditioning of fill soils shall be generally uniform in the soilam mass. 5.6. Prior to placement of additional compacted fill material following a delay in the grading operations, the exposed surface of previously compacted fill shall be pre- pared to receive fill. Preparation may include scarification, moisture conditioning, and recompaction. 5.7. Compacted fill shall be placed in horizontal lifts of approximately 8 inches in loose thickness. Prior to compaction, each lift shall be watered or dried as needed to achieve near optimum moisture condition, mixed, and then compacted by mechani- cal methods, using sheepsfoot rollers, multiple-wheel pneumatic-tired rollers, or other appropriate compacting rollers, to the specified relative compaction. Succes- sive lifts shall be treated in a like manner until the desired finished grades are achieved. 5.8. Fill shall be tested in the field by the geotechnical consultant for evaluation of gen- eral compliance with the recommended relative compaction and moisture conditions. Field density testing shall conform to ASTM D 1556-00 (Sand Cone method), D 2937-00 (Drive-Cylinder method), and/or D 2922-96 and D 3017-96 (Nuclear Gauge method). Generally, one test shall be provided for approximately every 2 vertical feet of fill placed, or for approximately every 1000 cubic yards of fill placed. In addition, on slope faces one or more tests shall be taken for approxi- mately every 10,000 square feet of slope face and/or approximately every 10 vertical feet of slope height. Actual test intervals may vary as field conditions dic- tate. Fill found to be out of conformance with the grading recommendations shall be removed, moisture conditioned, and compacted or otherwise handled to accom- plish general compliance with the grading recommendations. 5.9. The contractor shall assist the geotechnical consultant by excavating suitable test pits for removal evaluation and/or for testing of compacted fill. 5.10. At the request of the geotechnical consultant, the contractor shall "shut down" or restrict grading equipment from operating in the area being tested to provide ade- quate testing time and safety for the field technician. 5.11. The geotechnical consultant shall maintain a map with the approximate locations of field density tests. Unless the client provides for surveying of the test locations, the locations shown by the geotechnical consultant will be estimated. The geotechnical consultant shall not be held responsible for the accuracy of the horizontal or verti- cal location or elevations. 5.12. Grading operations shall be performed under the observation of the geotechnical consultant. Testing and evaluation by the geotechnical consultant does not preclude the need for approval by or other requirements of the jurisdictional agencies. 105132001 earthworks doc Rancho Carlsbad Channel and Basin Project January 7, 2004 Project No. 105132001 5.13. Fill materials shall not be placed, spread or compacted during unfavorable weather conditions. When work is interrupted by heavy rains, the filling operation shall not be resumed until tests indicate that moisture content and density of the fill meet the project specifications. Regrading of the near-surface soil may be needed to achieve the specified moisture content and density. 5.14. Upon completion of grading and termination of observation by the geotechnical consultant, no further filling or excavating, including that planned for footings, foundations, retaining walls or other features, shall be performed without the in- volvement of the geotechnical consultant. 5.15. Fill placed in areas not previously viewed and evaluated by the geotechnical con- sultant may have to be removed and recompacted at the contractor's expense. The depth and extent of removal of the unobserved and undocumented fill will be de- cided based upon review of the field conditions by the geotechnical consultant. 5.16. Off-site fill shall be treated in the same manner as recommended in these specifica- tions for on-site fills. Off-site fill subdrains temporarily terminated (up gradient) shall be surveyed for future locating and connection. 5.17. Prior to placement of a canyon fill, a subdrain shall be installed in bedrock or com- pacted fill along the approximate alignment of the canyon bottom if recommended by the geotechnical consultant. Details of subdrain placement and configuration have been provided in the Canyon Subdrain Detail, Figure C, of these guidelines. 5.18. Transition (cut/fill) lots shall generally be undercut 3 feet or more below finished grade to provide a generally uniform thickness of fill soil in the pad area. Where the depth of fill on a transition lot greatly exceeds 3 feet, overexcavation may be in- creased at the discretion of the geotechnical consultant. Details of the undercut for transition lots are provided in the Transition and Undercut Lot Detail, Figure B, of these guidelines. 6. OVERSIZED MATERIAL Oversized material shall be placed in accordance with the following recommendations. 6.1. During the course of grading operations, rocks or similar irreducible materials greater than 6 inches in dimension (oversized material) may be generated. These materials shall not be placed within the compacted fill unless placed in general ac- cordance with the recommendations of the geotechnical consultant. 6.2. Where oversized rock (greater than 6 inches in dimension) or similar irreducible material is generated during grading, it is recommended, where practical, to waste such material off site, or on site in areas designated as "nonstractural rock disposal 105132001 eaithwoitedoc Rancho Carlsbad Channel and Basin Project January 7, 2004 Project No. 105132001 areas." Rock designated for disposal areas shall be placed with sufficient sandy soil to generally fill voids. The disposal area shall be capped with a 5-foot thickness of fill which is generally free of oversized material. 6.3. Rocks 6 inches in dimension and smaller may be utilized within the compacted fill, provided they are placed in such a manner that nesting of rock is not permitted. Fill shall be placed and compacted over and around the rock. The amount of rock greater than 3/4-inch in dimension shall generally not exceed 40 percent of the total dry weight of the fill mass, unless the fill is specially designed and constructed as a "rock fill." 6.4. Rocks or similar irreducible materials greater than 6 inches but less than 4 feet in dimension generated during grading may be placed in windrows and capped with finer materials in accordance with the recommendations of the geotechnical con- sultant, the approval of the governing agencies, and the Oversized Rock Placement Detail, Figure D, of these guidelines. Selected native or imported granular soil (Sand Equivalent of 30 or higher) shall be placed and flooded over and around the windrowed rock such that voids are filled. Windrows of oversized materials shall be staggered so that successive windrows of oversized materials are not in the same vertical plane. Rocks greater than 4 feet in dimension shall be broken down to 4 feet or smaller before placement, or they shall be disposed of off site. 7. SLOPES The following sections provide recommendations for cut and fill slopes. 7.1. Cut Slopes 7.1.1. Unless otherwise recommended by the geotechnical consultant and accepted by the building official, permanent cut slopes shall not be steeper than 2:1 (horizontal:vertical). The recommended height of a cut slope shall be evalu- ated by the geotechnical consultant. Slopes in excess of 30 feet high shall be provided with terrace drains (swales) in accordance with the recommenda- tions presented in the Uniform Building Code, Section 3315 and the details provided in Figure E of these guidelines. 7.1.2. The geotechnical consultant shall observe cut slopes during excavation. The geotechnical consultant shall be notified by the contractor prior to beginning slope excavations. 7.1.3. If excavations for cut slopes expose loose, cohesionless, significantly frac- tured, or otherwise unsuitable materials, overexcavation of the unsuitable material and replacement with a compacted stabilization fill shall be evalu- ated and may be recommended by the geotechnical consultant. Unless 105132001 earthworks doc Rancho Carlsbad Channel and Basin Project January 7, 2004 Project No. 105132001 otherwise specified by the geotechnical consultant, stabilization fill construc- tion shall be in general accordance with the details provided on Figure F of these guidelines. 7.1.4. If, during the course of grading, adverse or potentially adverse geotechnical conditions are encountered in the slope which were not anticipated in the pre- liminary evaluation report, the geotechnical consultant shall evaluate the conditions and provide appropriate recommendations. 7.2. Fill Slopes 7.2.1. When placing fill on slopes steeper than 5:1 (horizontalrvertical), topsoil, slope wash, colluvium, and other materials deemed unsuitable shall be re- moved. Near-horizontal keys and near-vertical benches shall be excavated into sound bedrock or firm fill material, in accordance with the recommenda- tion of the geotechnical consultant. Keying and benching shall be accomplished in general accordance with the details provided on Figure A of these guidelines. Compacted fill shall not be placed in an area subsequent to keying and benching until the area has been observed by the geotechnical consultant. Where the natural gradient of a slope is less than 5:1, benching is generally not recommended. However, fill shall not be placed on compressi- ble or otherwise unsuitable materials left on the slope face. 7.2.2. Within a single fill area where grading procedures dictate two or more sepa- rate fills, temporary slopes (false slopes) may be created. When placing fill adjacent to a temporary slope, benching shall be conducted in the manner de- scribed in Section 7.2.1. A 3-foot or higher near-vertical bench shall be excavated into the documented fill prior to placement of additional fill. 7.2.3. Unless otherwise recommended by the geotechnical consultant and by the building official, permanent fill slopes shall not be steeper than 2:1 (horizon- tahvertical). The height of a fill slope shall be evaluated by the geotechnical consultant. Slopes in excess of 30 feet high shall be provided with terrace drains (swales) and backdrains in accordance with the recommendations pre- sented in the Uniform Building Code, Section 3315 and the details provided in Figure E of these guidelines. 7.2.4. Unless specifically recommended otherwise, compacted fill slopes shall be overbuilt and cut back to grade, exposing firm compacted fill. The actual amount of overbuilding may vary as field conditions dictate. If the desired re- sults are not achieved, the existing slopes shall be overexcavated and reconstructed in accordance with the recommendations of the geotechnical consultant. The degree of overbuilding may be increased until the desired compacted slope face condition is achieved. Care shall be taken by the con- 105132001 earthworks doc Rancho Carlsbad Channel and Basin Project January 7, 2004 Project No. 105132001 tractor to provide mechanical compaction as close to the outer edge of the overbuilt slope surface as practical. 7.2.5. If access restrictions, property line location, or other constraints limit over- building and cutting back of the slope face, an alternative method for compaction of the slope face may be attempted by conventional construction procedures including backrolling at intervals of 4 feet or less in vertical slope height, or as dictated by the capability of the available equipment, whichever is less. Fill slopes shall be backrolled utilizing a conventional sheeps foot-type roller. Care shall be taken to maintain the specified moisture condi- tions and/or reestablish the same, as needed, prior to backrolling.. 7.2.6. The placement, moisture conditioning and compaction of fill slope materials shall be done in accordance with the recommendations presented in Sec- tion 5. of these guidelines. 7.2.7. The contractor shall be ultimately responsible for placing and compacting the soil out to the slope face to obtain a relative compaction of 90 percent or greater as evaluated by ASTM D 1557-00 and a moisture content in accor- dance with Section 5. The geotechnical consultant shall perform field moisture and density tests at intervals of one test for approximately every 10,000 square feet of slope face and/or approximately every 10 feet of verti- cal height of slope. 7.2.8. Backdrains shall be provided in fill slopes in accordance with the details pre- sented on Figure A of these guidelines, or as recommended by the geotechnical consultant. 7.2.9. Fill shall be compacted prior to placement of survey stakes. This is particu- larly important on fill slopes. Slope stakes shall not be placed until the slope is compacted and tested. If a slope face fill does not meet the recommenda- tions presented in this specification, it shall be recognized that stakes placed prior to completion of the recompaction effort will be removed and/or demol- ished at such time as the compaction procedures resume. 7.3. Top-of-Slope Drainage 7.3.1. For pad areas above slopes, positive drainage shall be established away from the top of slope. This may be accomplished utilizing a berm and pad gradient of 2 percent or steeper at the top-of-slope areas. Site runoff shall not be per- mitted to flow over the tops of slopes. 7.3.2. Gunite-lined brow ditches shall be placed at the top of cut slopes to redirect surface runoff away from the slope face where drainage devices are not oth- erwise provided. 105132001 earthworks doc 10 Rancho Carlsbad Channel and Basin Project January 7, 2004 Project No. 105132001 7.4. Slope Maintenance 7.4.1. In order to enhance surficial slope stability, slope planting shall be accom- plished at the completion of grading. Slope plants shall consist of deep- rooting, variable root depth, drought-tolerant vegetation. Native vegetation is generally desirable. Plants native to semiarid and arid areas may also be ap- propriate. Large-leafed ice plant should not be used on slopes. A landscape architect shall be consulted regarding the actual types of plants and planting configuration to be used. 7.4.2. Irrigation pipes shall be anchored to slope faces and not placed in trenches excavated into slope faces. Slope irrigation shall be maintained at a level just sufficient to support plant growth. Property owners shall be made aware that over watering of slopes is detrimental to slope stability. Slopes shall be moni- tored regularly and broken sprinkler heads and/or pipes shall be repaired immediately. 7.4.3. Periodic observation of landscaped slope areas shall be planned and appropri- ate measures taken to enhance growth of landscape plants. 7.4.4. Graded swales at the top of slopes and terrace drains shall be installed and the property owners notified that the drains shall be periodically checked so that they may be kept clear. Damage to drainage improvements shall be repaired immediately. To reduce siltation, terrace drains shall be constructed at a gra- dient of 3 percent or steeper, in accordance with the recommendations of the project civil engineer. 7.4.5. If slope failures occur, the geotechnical consultant shall be contacted immedi- ately for field review of site conditions and development of recommendations for evaluation and repair. 8. TRENCH BACKFILL The following sections provide recommendations for backfilling of trenches. 8.1. Trench backfill shall consist of granular soils (bedding) extending from the trench bottom to 1 or more feet above the pipe. On-site or imported fill which has been evaluated by the geotechnical consultant may be used above the granular backfill. The cover soils directly in contact with the pipe shall be classified as having a very low expansion potential, in accordance with UBC Standard 18-2, and shall contain no rocks or chunks of hard soil larger than 3/4-inch in diameter. 8.2. Trench backfill shall, unless otherwise recommended, be compacted by mechanical means to 90 percent or greater relative compaction as evaluated in accordance with 105132001 earthworks.doc 11 Rancho Carlsbad Channel and Basin Project January 7, 2004 Project No. 105132001 — ASTM D 1557-00. Backfill soils shall be placed in loose lifts 8-inches thick or thinner, moisture conditioned, and compacted in accordance with the recommenda- -» tions of Section 5. of these guidelines. The backfill shall be tested by the an, geotechm'cal consultant at vertical intervals of approximately 2 feet of backfill placed and at spacings along the trench of approximately 100 feet in the same lift. "W* ^ 8.3. Jetting of trench backfill materials is generally not a recommended method of den- sification, unless the on-site soils are sufficiently free-draining and provisions have '"* been made for adequate dissipation of the water utilized in the jetting process. $S.-B* 8.4. If it is decided that jetting may be utilized, granular material with a sand equivalent greater than 30 shall be used for backfilling in the areas to be jetted. Jetting shall generally be considered for trenches 2 feet or narrower in width and 4 feet or shal- lower in depth. Following jetting operations, trench backfill shall be mechanically compacted to the specified compaction to finish grade. 4s.--,- 8.5. Trench backfill which underlies the zone of influence of foundations shall be me- chanically compacted to 90 percent or greater relative compaction, as evaluated in accordance with ASTM D 1557-00. The zone of influence of the foundations is generally defined as the roughly triangular area within the limits of a 1:1 projection from the inner and outer edges of the foundation, projected down and out from both edges. 8.6. Trench backfill within slab areas shall be compacted by mechanical means to a ^ relative compaction of 90 percent or greater relative compaction, as evaluated in accordance with ASTM D 1557-00. For minor interior trenches, density testing may be omitted or spot testing may be performed, as deemed appropriate by the geotechnical consultant. 8.7. When compacting soil in close proximity to utilities, care shall be taken by the grading contractor so that mechanical methods used to compact the soils do not damage the utilities. If the utility contractors indicate that it is undesirable to use compaction equipment in close proximity to a buried conduit, then the grading con- „, tractor may elect to use light mechanical compaction equipment or, with the approval of the geotechnical consultant, cover the conduit with clean granular ma- *" terial. These granular materials shall be jetted in place to the top of the conduit in m accordance with the recommendations of Section 8.4 prior to initiating mechanical compaction procedures. Other methods of utility trench compaction may also be "" appropriate, upon review by the geotechnical consultant and the utility contractor, «• at the time of construction. ** 8.8. Clean granular backfill and/or bedding materials are not recommended for use in «, slope areas unless provisions are made for a drainage system to mitigate the poten- tial for buildup of seepage forces or piping of backfill materials. 105I32001earthworlcs.doc 19 Rancho Carlsbad Channel and Basin Project January 7, 2004 Project No. 105132001 8.9. The contractor shall exercise the specified safety precautions, in accordance with OSHA Trench Safety Regulations, while conducting trenching operations. Such precautions include shoring or laying back trench excavations at 1:1 or flatter, de- pending on material type, for trenches in excess of 5 feet in depth. The geotechnical consultant is not responsible for the safety of trench operations or stability of the trenches. 9. DRAINAGE The following sections provide recommendations pertaining to site drainage. 9.1. Canyon subdrain systems recommended by the geotechnical consultant shall be in- stalled in accordance with the Canyon Subdrain Detail, Figure C, provided in these guidelines. Canyon subdrains shall be installed to conform to the approximate alignment and details shown on project plans. The actual subdrain location shall be evaluated by the geotechnical consultant in the field during grading. Materials specified in the attached Canyon Subdrain Detail shall not be changed or modified unless so recommended by the geotechnical consultant. Subdrains shall be sur- veyed by a licensed land surveyor/civil engineer for line and grade after installation. Sufficient time shall be allowed for the surveys prior to commence- ment of filling over the subdrains. 9.2. Typical backdrains for stability, side hill, and shear key fills shall be installed in accordance with the details provided on Figure A, Figure F, and Figure G of these guidelines. 9.3. Roof, pad, and slope drainage shall be such that it is away from slopes and struc- tures to suitable discharge areas by nonerodible devices (e.g., gutters, downspouts, concrete swales, etc.). 9.4. Positive drainage adjacent to structures shall be established and maintained. Posi- tive drainage may be accomplished by providing drainage away from the foundations of the structure at a gradient of 2 percent or steeper for a distance of 5 feet or more outside the building perimeter, further maintained by a graded swale leading to an appropriate outlet, in accordance with the recommendations of the project civil engineer and/or landscape architect. 9.5. Surface drainage on the site shall be provided so that water is not permitted to pond. A gradient of 2 percent or steeper shall be maintained over the pad area and drainage patterns shall be established to remove water from the site to an appropri- ate outlet. 9.6. Care shall be taken by the contractor during finish grading to preserve any berms, drainage terraces, interceptor swales or other drainage devices of a permanent na- 105132001 earthworks.doc JJ Rancho Carlsbad Channel and Basin Project January 7, 2004 Project No. 105132001 ture on or adjacent to the property. Drainage patterns established at the time of fin- ish grading shall be maintained for the life of the project. Property owners shall be made very clearly aware that altering drainage patterns may be detrimental to slope stability and foundation performance. 10. SITE PROTECTION The site shall be protected as outlined in the following sections. 10.1. Protection of the site during the period of grading shall be the responsibility of the contractor unless other provisions are made in writing and agreed upon among the concerned parties. Completion of a portion of the project shall not be considered to preclude that portion or adjacent areas from the need for site protection, until such time as the project is finished as agreed upon by the geotechnical consultant, the client, and the regulatory agency. 10.2. The contractor is responsible for the stability of temporary excavations. Recom- mendations by the geotechnical consultant pertaining to temporary excavations are made in consideration of stability of the finished project and, therefore, shall not be considered to preclude the responsibilities of the contractor. Recommendations by the geotechnical consultant shall also not be considered to preclude more restrictive requirements by the applicable regulatory agencies. 10.3. Precautions shall be taken during the performance of site clearing, excavation, and grading to protect the site from flooding, ponding, or inundation by surface runoff. Temporary provisions shall be made during the rainy season so that surface runoff is away from and off the working site. Where low areas cannot be avoided, pumps shall be provided to remove water as needed during periods of rainfall. 10.4. During periods of rainfall, plastic sheeting shall be used as needed to reduce the po- tential for unprotected slopes to become saturated. Where needed, the contractor shall install check dams, desilting basins, riprap, sandbags or other appropriate de- vices or methods to reduce erosion and provide the recommended conditions during inclement weather. 10.5. During periods of rainfall, the geotechnical consultant shall be kept informed by the contractor of the nature of remedial or precautionary work being performed on site (e.g., pumping, placement of sandbags or plastic sheeting, other labor, dozing, etc.). 10.6. Following periods of rainfall, the contractor shall contact the geotechnical consult- ant and arrange a walk-over of the site in order to visually assess rain-related damage. The geotechnical consultant may also recommend excavation and testing in order to aid in the evaluation. At the request of the geotechnical consultant, the 105132001 earthworks.doc 14 Rancho Carlsbad Channel and Basin Project January 7, 2004 Project No. 105132001 contractor shall make excavations in order to aid in evaluation of the extent of rain-related damage. 10.7. Rain- or irrigation-related damage shall be considered to include, but may not be limited to, erosion, silting, saturation, swelling, structural distress, and other ad- verse conditions noted by the geotechnical consultant. Soil adversely affected shall be classified as "Unsuitable Material" and shall be subject to overexcavation and replacement with compacted fill or to other remedial grading as recommended by the geotechnical consultant. 10.8. Relatively level areas where saturated soils and/or erosion gullies exist to depths greater than 1 foot shall be overexcavated to competent materials as evaluated by the geotechnical consultant. Where adverse conditions extend to less than 1 foot in depth, saturated and/or eroded materials may be processed in-place. Overexcavated or in-place processed materials shall be moisture conditioned and compacted in ac- cordance with the recommendations provided in Section 5. If the desired results are not achieved, the affected materials shall be overexcavated, moisture conditioned, and compacted until the specifications are met. 10.9. Slope areas where saturated soil and/or erosion gullies exist to depths greater than 1 foot shall be overexcavated and replaced as compacted fill in accordance with the applicable specifications. Where adversely affected materials exist to depths of 1 foot or less below proposed finished grade, remedial grading by moisture condi- tioning in-place and compaction in accordance with the appropriate specifications may be attempted. If the desired results are not achieved, the affected materials shall be overexcavated, moisture conditioned, and compacted until the specifica- tions are met. As conditions dictate, other slope repair procedures may also be recommended by the geotechnical consultant. 10.10. During construction, the contractor shall grade the site to provide positive drainage away from structures and to keep water from ponding adjacent to structures. Water shall not be allowed to damage adjacent properties. Positive drainage shall be main- tained by the contractor until permanent drainage and erosion reducing devices are installed in accordance with project plans. 105132001 earthwoAs.doc 15 Rancho Carlsbad Channel and Basin Project January 7, 2004 Project No. 105132001 urn 11. DEFINITIONS OF TERMS ALLUVIUM: AS-GRADED (AS-BUILT): BACKCUT: BACKDRAIN: BEDROCK: BENCH: BORROW (IMPORT): BUTTRESS FILL: CIVIL ENGINEER: CLIENT: COLLUVIUM: COMPACTION: Unconsolidated detrital deposits deposited by flowing water; includes sediments deposited in river beds, canyons, flood plains, lakes, fans at the foot of slopes, and in estuaries. The site conditions upon completion of grading. A temporary construction slope at the rear of earth-retaining structures such as buttresses, shear keys, stabilization fills, or retaining walls. Generally a pipe-and-gravel or similar drainage system placed behind earth-retaining structures such as buttresses, stabilization fills, and retaining walls. Relatively undisturbed in-place rock, either at the surface or beneath surficial deposits of soil. A relatively level step and near-vertical riser excavated into sloping ground on which fill is to be placed. Any fill material hauled to the project site from off-site areas. A fill mass, the configuration of which is designed by engi- neering calculations, to retain slopes containing adverse geologic features. A buttress is generally specified by a key width and depth and by a backcut angle. A buttress normally contains a back drainage system. The Registered Civil Engineer or consulting firm responsible for preparation of the grading plans and surveying, and evaluating as-graded topographic conditions. The developer or a project-responsible authorized represen- tative. The client has the responsibility of reviewing the findings and recommendations made by the geotechnical consultant and authorizing the contractor and/or other con- sultants to perform work and/or provide services. Generally loose deposits, usually found on the face or near the base of slopes and brought there chiefly by gravity through slow continuous downhill creep (see also Slope Wash). The densification of a fill by mechanical means. 105132001 earthworks doc 16 Rancho Carlsbad Channel and Basin Project January 7, 2004 Project No. 105132001 CONTRACTOR: DEBRIS: ENGINEERED FILL: ENGINEERING GEOLOGIST: EROSION: EXCAVATION: EXISTING GRADE: FILL: FINISH GRADE: GEOFABRIC: GEOTECHNICAL CONSULTANT: A person or company under contract or otherwise retained by the client to perform demolition, grading, and other site improvements. The products of clearing, grabbing, and/or demolition, or contaminated soil material unsuitable for reuse as compacted fill, and/or any other material so designated by the geotech- nical consultant. A fill which the geotechnical consultant or the consultant's representative has observed and/or tested during placement, enabling the consultant to conclude that the fill has been placed in substantial compliance with the recommendations of the geotechnical consultant and the governing agency requirements. A geologist registered by the state licensing agency who ap- plies geologic knowledge and principles to the exploration and evaluation of naturally occurring rock and soil, as re- lated to the design of civil works. The wearing away of the ground surface as a result of the movement of wind, water, and/or ice. The mechanical removal of earth materials. The ground surface configuration prior to grading; original grade. Any deposit of soil, rock, soil-rock blends, or other similar materials placed by man. The as-graded ground surface elevation that conforms to the grading plan. An engineering textile utilized in geotechnical applications such as subgrade stabilization and filtering. The geotechnical engineering and engineering geology con- sulting firm retained to provide technical services for the project. For the purpose of these specifications, observations by the geotechnical consultant include observations by the geotechnical engineer, engineering geologist and other per- sons employed by and responsible to the geotechnical consultant. 105132001 earthworks.doc 17 Rancho Carlsbad Channel and Basin Project January 7, 2004 Project No. 105132001 GEOTECHNICAL ENGINEER: GRADING: LANDSLIDE DEPOSITS: OPTIMUM MOISTURE: RELATIVE COMPACTION: ROUGH GRADE: SHEAR KEY: SITE: SLOPE: SLOPE WASH: SLOUGH: SOIL: A licensed civil engineer and geotechnical engineer, regis- tered by the state licensing agency, who applies scientific methods, engineering principles, and professional experience to the acquisition, interpretation, and use of knowledge of materials of the earth's crust to the resolution of engineering problems. Geotechnical engineering encompasses many of the engineering aspects of soil mechanics, rock mechanics, geology, geophysics, hydrology, and related sciences. Any operation consisting of excavation, filling, or combina- tions thereof and associated operations. Material, often porous and of low density, produced from instability of natural or manmade slopes. The moisture content that is considered optimum to compac- tion operations. The degree of compaction (expressed as a percentage) of a material as compared to the dry density obtained from ASTM test method D 1557-00. The ground surface configuration at which time the surface elevations approximately conform to the approved plan. Similar to a subsurface buttress; however, it is generally con- structed by excavating a slot within a natural slope in order to stabilize the upper portion of the slope without encroach- ing into the lower portion of the slope. The particular parcel of land where grading is being per- formed. An inclined ground surface, the steepness of which is gener- ally specified as a ratio of horizontal units to vertical units. Soil and/or rock material that has been transported down a slope by gravity assisted by the action of water not confined to channels (see also Colluvium). Loose, uncompacted fill material generated during grading operations. Naturally occurring deposits of sand, silt, clay, etc., or com- binations thereof. 105132001 earthworks.doc 18 Rancho Carlsbad Channel and Basin Project January 7, 2004 Project No. 105132001 STABILIZATION FILL: SUBDRAIN: TAILINGS: TERRACE: TOPSOIL: WINDROW: A fill mass, the configuration of which is typically related to slope height and is specified by the standards of practice for enhancing the stability of locally adverse conditions. A stabi- lization fill is normally specified by a key width and depth and by a backcut angle. A stabilization fill may or may not have a back drainage system specified. Generally a pipe-and-gravel or similar drainage system placed beneath a fill along the alignment of buried canyons or former drainage channels. Non-engineered fill which accumulates on or adjacent to equipment haul roads. A relatively level bench constructed on the face of a graded slope surface for drainage and maintenance purposes. The upper zone of soil or bedrock materials, which is usually dark in color, loose, and contains organic materials. A row of large rocks buried within engineered fill in accor- dance with guidelines set forth by the geotechnical consultant. 105132001 earthworks.doc 19 Rancho Carlsbad Channel and Basin Project January 7, 2004 Project No. 105132001 FILL SLOPE OVER NATURAL GROUND SWALE AT TOP OF SLOPE OUTLET PIPE DRAINS TO A SUITABLE OUTLET IN ACCORDANCE WITH THE RECOMMENDATIONS OF THE CIVIL ENGINEER NATURAL GROUND BACKDRAIN AND T-CONNECTION (SEE DRAIN DETAIL, FIGURE G) BEDROCK OR COMPETENT MATERIAL, AS EVALUATED BY THE GEOTECHNICAL CONSULTANT FILL SLOPE OVER CUT SWALE AT TOP OF SLOPE NATURAL GROUND OUTLET PIPE DRAINS TO A SUITABLE OUTLET IN ACCORDANCE WITH THE ' RECOMMENDATIONS OF THE CIVIL ENGINEER BEDROCK OR COMPETENT MATERIAL, AS EVALUATED BY THE GEOTECHNICAL CONSULTANT BACKDRAIN AND T-CONNECTION(SEE DRAIN DETAIL.FIGURE G) "MINIMUM KEY WIDTH DIMENSION. ACTUAL WIDTH SHOULD BE PROVIDED BY GEOTECHNICAL CONSULTANTBASED ON EVALUATION Of SITE-SPECIFIC GEOTECHNICAL CONDITIONS. NOTES: CUT SLOPE SHALL BE CONSTRUCTED PRIOR TO PLACEMENT OF FILL SLOPE DRAINAGE SHOULD BE PROVIDED IN ACCORDANCE WITH RECOMMENDATIONS PRESENTED ON FIGURE E NOT TO SCALE FILL SLOPE OVER NATURAL GROUND OR CUT FIGURE A 105132001 earthworks.doc Rancho Carlsbad Channel and Basin Project January 7, 2004 Project No. 105132001 TRANSITION (CUT-FILL) LOT OVEREXCAVATE AND RECOMPACT BEDROCK OR COMPETENT MATERIAL, ~ AS EVALUATED BY THE — GEOTECHNICAL CONSULTANT UNDERCUT LOT V NATURAL GROUND OVEREXCAVATE AND RECOMPACT BEDROCK OR COMPETENT MATERIAL, AS EVALUATED BY THE — GEOTECHNICAL CONSULTANT NOTE: DIMENSIONS PROVIDED IN THE DETAILS ABOVE ARE APPROXIMATE AND MAY BE MODIFIED IN THE FIELD BY THE GEOTECHNICAL CONSULTANT AS CONDITIONS DICTATE. «orlhfb.dwg NOT TO SCALE TRANSITION AND UNDERCUT LOT DETAILS 105132001 carthworks.doc Rancho Carlsbad Channel and Basin Project January 7, 2004 Project No. 105132001 CANYON SUBDRAIN NATURAL GROUND \ SEE FIGURE A FOR DETAILS OF BENCHES LOWEST BENCH INCLINED TOWARD DRAIN COMPACTED FILL REMOVE UNSUITABLE MATERIAL BEDROCK OR COMPETENT MATERIAL, AS EVALUATED BY THE GEOTECHNICAL CONSULTANT SUBDRAIN (SEE DRAIN DETAIL, FIGURE G) DETAIL OF CANYON SUBDRAIN TERMINATION DESIGN FINISH GRADE SUBDRAIN PIPE OUTLET PIPE DRAINS TO A SUITABLE OUTLET IN ACCORDANCE WITH THE RECOMMENDATIONS OF THE CIVIL ENGINEER -COMPACTED FILL / CUTOFF WALL CONSTRUCTED OF GROUT, CONCRETE, BENTONITE, OR OTHER SUITABLE MATERIAL AS EVALUATED BY THE GEOTECHNICAL CONSULTANT FILTER MATERIAL PERFORATED PIPE eorthfc.dwg NOT TO SCALE yy\oore CANYON SUBDRAIN DETAIL FIGURE C 105132001 earthworks.doc Rancho Carlsbad Channel and Basin Project January 7, 2004 Project No. 105132001 (H* WINDROW SECTION 30 S.E. SOIL (FLOODED) "V" OR RECTANGULAR TRENCH A MINIMUM OF 2 FEET DEEP AND 5 FEET WIDE EXCAVATED INTO COMPACTED FILL OR NATURAL GROUND PAD SECTION FINISH GRADE ZONE A MATERIAL STREET 5' MIN. BEDROCK OR COMPETENT MATERIAL AS EVALUATED BY GEOTECHNICAL CONSULTANT ZONE A: COMPACTED FILL WITH ROCK FRAGMENTS NO GREATER THAN 6 INCHES IN DIAMETER. ZONE B: COMPACTED FILL WITH ROCK FRAGMENTS BETWEEN 6 AND 48 INCHES IN DIAMETER MAY BE PLACED IN STAGGERED WINDROWS UP TO 100" LONG IN THIS ZONE AND SURROUNDED BY GRANULAR SOIL (30 SAND EQUIVALENT) DENSIFIED BY FLOODING. ROCK FRAGMENTS LESS THAN 6 INCHES IN DIAMETER MAY BE PLACED IN COMPACTED FILL SOIL. NOTE: SLOPE DRAINAGE SHOULD BE PROVIDED IN ACCORDANCE WITH RECOMMENDATIONS PRESENTED ON FIGURE E. aorthfd slopv.dwg NOT TO SCALE OVERSIZED ROCK PLACEMENT DETAIL FIGURE D 105132001 eanhworts.doc Rancho Carlsbad Channel and Basin Project January 7, 2004 Project No. 105132001 SWALE AT TOP OF SLOPE BENCH INCLINED SLIGHTLY INTO SLOPE H BEDROCK OR COMPETENT MATERIAL AS EVALUATED BY THE GEOTECHNICAL CONSULTANT WHEN POSSIBLE. LOWEST BACKDRAIN SHOULD BE PLACED IN THE BASE OF KEY (SEE DRAIN DETAIL, FIGURE G) MID-SLOPE BACKDRAIN (SEE DRAIN DETAIL, FIGURE G) NON-PERFORATED OUTLET PIPE TERRACE WIDTH REINFORCED CONCRETE - PAVED TERRACE (SWALE) MAXIMUM VERTICAL SLOPE HEIGHT. H (FEET) LESS THAN 30 60 120 GREATER THAN 120 TERRACE WIDTH AND LOCATION NO TERRACE REQUIRED ONE TERRACE AT LEAST 6 FEET WIDE AT MIDHEIGHT ONE TERRACE AT LEAST 12 FEET WIDE AT APPROXIMATELY MIDHEIGHT AND 6-FOOT WIDE TERRACES CENTERED IN REMAINING SLOPES DESIGNED BY CIVIL ENGINEER WITH APPROVAL OF GOVERNING AUTHORITIES NOTES: 1. MID-SLOPE BACKDRAINS SHOULD BE PLACED IN FILL SLOPES IN CONJUNCTION WITH EACH TERRACE. 2. TERRACES SHOULD HAVE AT LEAST A 5-PERCENT GRADIENT. AND RUN OFF SHOULD BE DIRECTED TO AN APPROPRIATE SURFACE DRAINAGE COLLECTOR. 3. TERRACES SHOULD BE CLEANED OF DEBRIS AND VEGETATION TO ALLOW UNRESTRICTED FLOW OF WATER. 4. TERRACES SHOULD BE KEPT IN GOOD REPAIR. 5. REFER TO UBC CHAPTER 70 FOR ADDITIONAL REQUIREMENTS. •oHhf«,c!wg NOT TO SCALE SLOPE DRAINAGE DETAIL FIGURE E 105132001 carthvrorks.doc Rancho Carlsbad Channel and Basin Project January 7, 2004 Project No. 105132001 PROPOSED GRADED SURFACE EXISTING GROUND SURFACE BENCH INCLINED SLIGHTLY INTO SLOPE (SEE FIGURE A) BEDROCK OR _ COMPETENT MATERIAL, ( AS EVALUATED BY THE GEOTECHNICAL CONSULTANT BACKDRAIN (SEE DRAIN DETAIL, FIGURE G)NON-PERFORATED OUTLET PIPE NOTES: 1. THE DEPTH AND WIDTH OF KEY WILL BE PROVIDED BY THE GEOTECHNICAL CONSULTANT BASED ON ANALYSIS OF SITE-SPECIFIC GEOTECHNICAL CONDITIONS. 2. AN ADDITIONAL MID-SLOPE BACKDRAIN AND TERRACE DRAIN MAY BE RECOMMENDED FOR SLOPES OVER 30 FEET HIGH. SEE SLOPE DRAINAGE DETAIL. FIGURE E. 3. SLOPE DRAINAGE SHOULD BE PROVIDED IN ACCORDANCE WITH RECOMMENDATIONS PRESENTED ON FIGURE E. •orttiff.dwg NOT TO SCALE SHEAR KEY DETAIL FK3UREF 105132001 earth\vorks.doc Rancho Carlsbad Channel and Basin Project January 7, 2004 Project No. 105132001 SUBDRAIN CONFIGURATION ALTERNATIVE A* ALTERNATIVE B FILTER MATERIAL (9 CUBIC FEET PER LINEAR FOOT) BACKDRAIN CONFIGURATION FILTER MATERIAL (3 CUBIC FEET PER LINEAR FOOT) T-CONNECTION (SEE DETAIL) " MINi^k PERFORATED PIPE INSTALLED WITH X PERFORATION DOWN {SEE SCHEDULE BELOW) * ALTERNATIVE A SUBDRAIN CONFIGURATION MAY BE USED IN FILLS LESS THAN 25 FEET DEEP NON-1 MIN. I PERFORATED PIPE, 4" MIN. SCHEDULE 40 PVC OR EQUIVALENT INSTALLED WITH PERFORATIONS DOWN T-CONNECTION DETAIL PERFORATED PIPE SLOPED AT TOWARD OUTLET PIPE MIN. NON-PERFORATED OUTLET PIPE UP TO 100' ON CENTER HORIZONTALLY FILTER MATERIAL FILTER MATERIAL SHALL BE CLASS II PERMEABLE MATERIAL PER STATE OF CALIFORNIA STANDARD SPECIFICATIONS OR APPROVED ALTERNATEGEOFABRIC DRAIN SYSTEM. CUSS II GRADATIONS SIEVE SIZE 3/4"3/8"No. 4 No. 8 No. 30 No. 50No. 200 PERCENT PASSING 100 90-100 40-10025-40 18-33 S-1S 0-7 0-3 END CAP PIPE SCHEDULE PERFORATED AND NON-PERFORATED PIPE: SHALL BE SCHEDULE 40 POLYVINYL CHLORIDE (PVC) OR ACRYLONITRILE BUTADIENE STYRENE (ABS) OREQUIVALENT, AND WILL HAVE A MINIMUM CRUSHINGSTRENGTH OF 1000 PSl FOR PEPTHS OF FILL UP TO50 FEET. FOR DEEPER FILLS, PERFORATED ANDNON-PERFORATED PIPE SHOULD BE DESIGNED WITHADEQUATE CRUSHING STRENGTH. THE PIPE DIAMETER WILL GENERALLY MEET THE FOLLOWINGCRITERIA, BUT MAY BE MODIFIED IN THE FIELD BY THEGEOTECHNICAL CONSULTANT AS CONDITIONS DICTATE. THE LENGTH OF RUN IS MEASURED FROM THE HIGHEST ELEVATION. NOTE: vorlhfg.dwg AS AN ALTERNATIVE THE FILTER MATERIAL MAY CONSIST OF UP TO 1" DIAMETER OPEN-GRADED GRAVEL WRAPPED IN AN APPROVED BEQFA8RIC WITH 6-INCH OR MORE OVERLAP. LENGTH OF RUN 0-500" 500-1500' >1SOO' PIPE DIAMETER 4" 6" 8" NOT TO SCALE DRAIN DETAIL FIGURE G 105132001 earthworks.**