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HomeMy WebLinkAboutTract Map 32436 Geotechnical Plan Review, ' ' - GEOTECHNICAL PLAN REVIEW ' _ TRACT 32436 and 32437 HARVESTON PHASE 3 TEMECULA, CALIFORNIA ~ = ~ - ~ ° , _ Prepared For: ' = Lennar Communities 391 North Main Street, Suite 301 , == Corona, California 92880 ~ - ~ - - Project No. 110231-056 ~ = Revised March 22, 2005 ~ _ ~ - , - ~ ~ ~ Leighton and Associates, Inc. ~ ~ A LEIGHTON GROUP COMPANY ~ ' , ~ , • Leighton and Associates, Inc. A LEIGHTON GROUP COMPANY ' To: ' Lennaz Communities Mazch 22, 2005 391 North Main Street, Suite 301 Corona, California 92880 Attention: Mr. Kevin Lynch Project No. 110231-056 ' Subject: Geotechnical Plan Review, Tract 32436 and 32437, Harveston Phase 3, Temecula, California ' , 1 ' CI ' ' t ' ' 1 References: Leighton & Associates, Inc., 2004, As-Graded Report of Mass Grading far Tract 29639-2, I.ots 1 through 6 and 38, Future Residential Harveston, City of Temecula, California, by, Project No. 1 1 023 1-025, dated July 28, 2004. RBF Consulting, Rough Grading Plan and Erosion Control Plan, Tract No. 32436 and 32437 in the City ofTemecula, California, plot dated January 31, 2005. Introduction In accordance with your request, Leighton & Associates, Ina (Leighton) has completed a Geotechnical Plan Review of Tract 32436 and 32437 located within the Harveston Project. The subject property was previously sheet gaded under the geotechnical observation and testing services of Leighton (Leighton, 2004). The purpose of this review was to evaluate the proposed grading as presented on the referenced rough grading plans (RBF, 2005) and prepaze preliminary grading recommendations to minimize the potential effects of cuUfill transitions underlying future home sites. As discussed; we understand that remedial grading recommendations for the mitigation of highly expansive soils was not desired at this time. Cunently, the project site is vacant with a moderate growth of weeds and grasses. Recent prolonged storm events have created nuxnerous erosion rills and gullies. Retention basins have received a considerable amount of sand and silt. Slopes descending to the adjacent Arroyo Park Channel aze locally severely eroded and in locations have been subjected to surficial instability (slumping). Weeds currently mask most of the erosion and slump features. The surface soils appeazed to be locally dry to over optimum (wet) with local ponded water. ~ 41715 Enterprise Circle N., Suite 103 ^ Temecula, CA 92590-5661 909.296.0530 ^ Fax 909.296.0534 ^ www.leightongeo.com ' 110231-056 March 22, 2005 ' Findings and Conclusions Based on our review of the referenced rough-grading plans (RBF, 2005), it is our professional ' opinion that future residential development of the site as planned is feasible from a geotechnical standpoint provided that the previous (Leighton, 2004) and cunent recommendations aze incorporated during grading and construction. ' Site rough grading will consist of cuts and fills on the order of up to 7 feet. Due to the existence of cuUfill transition between existing fill and Pauba formation bedrock, or the creation of cut fill ' transitions between planned fill and bedrock, recommendations of over-excavations of specific building pads are presented in the following section. Additionally, during previous site mass grading,topsoil, colluvium or highly weathered bedrock may be locally encountered along the , limits of existing compacted fill (i.e. mass grade design cuUfill limit), which will require removal and recompaction during future grading. ' Based on previous laboratory expansion index test results and our observations during previous mass grading, the subject site soils possess expansion potentials ranging from low to very high and the sulfate exposure to concrete appeazs negligible (Leighton, 2004). , Site Preoaration, Earthwork and Over-Excavation Recommendations ' We anticipate that future earthwork at the site will consist of site preparation (clear and grub), rough grading, precise grading, foundation installation, trench excavation and backfill, permanent slope construction, and construction of street sections. We recommend that any ' additional earthwork on the site be performed in accordance with the reference reports, the following recommendations, and the City of Temecula grading requirements. ' Exis6ng ground surfaces should be cleared of debris, vegetation, loose silt, or undocumented fill soils. Prior to placement of additional fills, the upper 12 to 18 inches should be moisture conditioned (dry back or add moisture) and compacted to a minimum 90 percent relative ' compaction based on ASTM D1557. Any stockpiles encountered aze considered undocumented fill and should be removed. Any topsoil, colluvium or highly weathered bedrock located along the existing cut-fill contact should be removed. Erosion gullies and shallow rills should be ' thoroughly benched or removed to expose competent fill or formational bedrock. In azeas where fill is proposed along the top of the existing Arroyo Park slope, a minimum 12-foot wide (equipment width) bench should be excavated into existing competent fill. Erosion and slumping , of the Arroyo Park slopes should be repaired as necessary. Building pads on proposed cuUfill transitions (i.e. exposing Pauba formation, bedrock and ' compacted fill) or shaliow varying fill or existing cut Pauba formation., should be over- excavated below nad elevation to the minimum depth presented in the following table to achieve a more uniform fill thiclrness. In many locations, only a relatively small portion of the lot will ' require overexcavation (See Plate 1). The limits of over-excavation should extend laterally a minimum of five feet outside the building £ootprint (on the bedrock side of the building footprint) and extend laterally into the existing compacted fill, until a similaz thickness of ' e , -z- 3 ' Leighton ' 110231-056 March 22, 2005 ' existing fill is observed. The estimated lots or building pads to be over-excavated are presented in the following table and aze identified on Plate 1, Geotechnical Map. ' LJ ~ ' ~ Building Pads with Recommended Over-Excavation Depth Below Design Finish Grade Tract No. 2 Ft. 3 Ft. 32437-1 12 8, 10, 17, 32, 33 32437-2 58 through 62, 69,70 8, 9, 21, 22, 23, 24, 3Q 42 through 47, 49, 50, 51, 63 32437-3 21, 22 17, 23, 35, 43, 44 32437-F 22,23, 29, 30, 39, 40, 44 15, 18, 21, 54, 55, 60, 61, 62, 63 32436 None None 32436-1 5, 6, 25, 26, 27, 28, 35, 36, 38 10, 11 ' The determination of the lots or portion of lot to be over-excavated as presented above is based on our review of the rough grade plans (design and topography presented therein) and the as-graded documents. Actual over-excavation limits may vary pending the actual field conditions ' encountered. The subject lots should be reviewed carefully based on site field survey construction staking. Dozer test pits (3 to 5 feet deep) will be requested of the grading contractor during grading to confirm these findings and recommendations as well as to obtain neaz surface subgrade ' soils for laboratory testing. The excavations should be backfilled with site soils compacted uniformly to minimum 90 percent relative compaction (based on ASTM D1557). Expansion potential testing of actual building pad subsurface soils should be performed during grading fill or ' through dozer test pits (for shallow fill or cut lots). Altematively, if the recommended subsurface expansion sampling is not performed, high expansion potential design criteria will be implemented for these lots. , Excavations ' Temporary excavations with vertical sides, such as utility trenches, should remain stable to depths of 4 feet or less for the period required to construct the utility. However, in accordance with OSHA requirements, excavations greater than 4 feet in depth should be shored, or laid-back , to inclinations of 1:1 (horizontal to vertical) or flatter, if workers are to enter such excavations. Leighton does not consult in the azea of safety engineering. The contractor is responsible for the safety of all excavations. , Backfill. Fill Placement and Compaction , The onsite soils are suitable for reuse as compacted fill provided they aze relatively free of organic materials and debris. Crushed asphalt concrete should not be placed as fill per City of ' Temecula. ' ~ -3- Leighton \ , 110231-056 March 22, 2005 ' All backfill or fill soils should be brought to optimum moishue conditions and compacted in uniform lifts to at least 90 percent relative compaction based on the laboratory maacimum dry density (ASTM Test Method D1557). The optimum lift thickness required to produce uniform ' compaction will depend on the type, size and condition of compaction equipment used. In general, the onsite soils should be placed in lifts not exceeding 8 inches in compacted thickness and placed on dense existing compacted fill or other eatth material approved by the geotechnical ' consultant. The backfill that coincides with pavement subgrade wil] be reworked and compacted in accordance with pavement design requirements. The slope face of permanent slopes should ' be compacted to the minimum requirement. All grading should be performed in accordance with the General Earthwork and Grading Specification presented in Appendix A. Water should not drain over the tops of slopes. ' Canvon Subdrains A total of eight canyon subdrains terminate into the Airoyo Pazk. These subdrains should be ' located and protected in place. The appmximate locations are depicted in the referenced as graded report (Leighton, 2004). ' Construction Review - Construc6on observation and tes6ng should be performed by the geotechnical consultant during fuhue excavations, grading operations, and utility trench bac~ll at the site. Site specific foundation recommendations should be provided based on observations and ' laboratory testing performed during site rough grading. Addirionally, footing excavations should be observed and moisture determination tests of subgrade soils should be performed by the geotechnical , consultant prior to the pouring of concrete. Plans and Speci£cations - Foundation design plans and specifications should be reviewed by the ' geotechnical consultant prior to excavation or installation of residential development. If you have any questions regazding this report, please do not hesitate to contact this office, we ' appreciate this opportunity to be of service. Respectfully submitted, ' LEIGHTON AND ASSOCIATES, INC. ~~PED QFp i . ~~~~~~ v oEPT F 9~~~ ' ¢~ Q~ No. 1921 y Ni CEHT~F!ED Robert F. Riha, CEG 1921 (Exp. 02/28/06) * OEOLOa1ST ° Vice President/Principal Geologist ~'~ ~~~' ' ~~aF ~~~0 RFR/mm/dlm ' Plate 1- Geotechnical Map In Pocket Appendix A- General Earthwork and Grading Specifications ' Distribution: (6) Addressee (1-Unbound) (1) RBF Consulting, Attention: Mr. John Tanner ~ ' ~ S -4- ' Leighton ~ - m (~ ~ ~ ~ u D U~ z N ~ o N 1~ ~ ~ T/ •~ N ~ 1 . t O ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ _ ~ W ~ ~ n + ~ ~ u ~ ~ Z o ~. ~ ~ ~ . g ~ ~ 1 l ! ~ i ~ . _ _ o _ P ~ - - ~ -- ! N a C , , C ~ ~ ~ PP "0 ~ ~ ' D r N U W m '~' m Z c ~ ?. l~1 ~ N i N ~ _ ~ - m~ ~ N ~ ~j . ~ ~' ~ ~ ~ :~ `o ~o ~ -- - ~ ~ - ~~ ~ ~ ~ ~ ~ to , LEIGHTON AND ASSOCIATES, INC GENERAL EARTHWORK t1ND GRADING SPECIFICATIONS FOR ROUGH GRADING ' 1.0 General ' 11 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 shali supersede these more general Specifications. Observarions 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 recommendarions in the geotechnical report(s). t 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 fmdings, conclusions, and tecommendations prior to the commencement of the gading. , 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 operaHons, the Geotechnical Consultant shall observe, map, and document the subsurface exposures to verify the geotechnical design , assumptions. If the observed condirions aze found to be sigiificantly different than the interpreted assumprions 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, elevaHons 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" azeas, all key bottoms, and benches made on sloping gound to receive fill. The Geotechnical Consultant shall observe the moisturecondifioning and processing of the ' subgrade and fill materials and perfom~ relative compacrion testing of fill to determine the attained level of compacrion. The Geotechnical Consultant shall provide the test results to the owner and the Contractor on a rourine and frequent basis. ' 1.3 The Earthwork Contractor: The Earthwork Contractor (Contractor) shall be qualified, experienced, and ]mowledgeable in earthwork logistics, prepazafion 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 gading. The Contractor shall be solely responsible for perfornilng the grading in accordance with the plans and specificarions. ' ' , 3030.1094 ~ ' Leighton and Associates, Inc. GENERAL EARTHWORK AND GRADING SPECIFICATIONS Page 2 of 6 1 ~ `I'he Contractor shall prepaze 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 esrimated quantities of daily eatthwork 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 ]east 24 hours in ' advance of such changes so that appropriate observarions and tests can be planned and accomplished. The Contractor shall not assume that the Geotechnical Consultant is awaze of all grading operations. ' T'he 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 condirions, such as unsuitable soil, improper moisture condi6on, inadequate compaction, insufficient buttress key size, adverse weather, etc., aze resulting in ' a quality of work less than required in these specificarions, the Geotechnical Consultant shall reject the work and may recommend to the owner that construcrion be stopped until the conditions aze rectified. , 2.0 Preparation of Areas to be Filled , 2.1 Clearing and Grubbine: 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, goveming agencies, and the Geotechnical Consultant. The Geotechnical Consultant st~all evaluate the extent of these removals depending on ~ speeific site conditions. Earth fill material shall not contain more than 1 percent of organic materials (by volume). No fil] 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 ha7ardous material specialist shall be informed immediately for proper evaluarion and handling of these materials prior to continuing to work in that area. ' As presently defined by the Shate of Califomia, most refined petroleum products (gasoline, diesel fuel, motor oil, gcease, coolant, etc.) have chemical consNtuents that aze 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. ' 2.2 Processine: Existing ground that has been declazed 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. Scarificarion shall conrinue unril soils aze broken down and free of large clay lumps or ' 3030.1094 I.J Leighton and Associates, Inc. GENERAL EARTHWORK AND GRADING SPECIFICATIONS Page 3 of 6 clods and the worldng surface is reasonably uniform, flat, and free of uneven features that would inhibit uniform compaction. 23 Overexcavation: In addition to removals and overexcavations recommended in the approved geotechnical report(s) and the grading plan, soft, loose, dry, saturated, spongy, organiarich, highly fractured or otherwise unsuitable ground shall be overexcavated to competent ground as evaluated by the Geotechnical Consultant during grading. 2.4 Benchine: Where fills ue 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 illustrarion. 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 othenvise overexcavated to provide a flat subgrade for the fill. 2.5 Evaluation/Accentance of Fill Areas: All areas to receive fill, including removal and processed areas, key bottoms, and benches, sl~all be observed, mapped, elevations recorded, and/or tested prior to being accepted by the Geotechnical Consultant as suitable to receive fill. The Contractor shal] 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. 2.6 ' 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 gadation, high expansion potential, or low strength shall be placed in azeas 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 ureducible material with a malcimum dimension greater than 8 inches, shall not be buried or placed in fill unless location, ' materials, and placement methods aze specifically accepted by the Geotechnical Consultant. Placement opera6ons 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 gade or within 2 feet of future uriliries or underground conshuction. ' 33. Imroort: If importing of fill material is required for grading, proposed import material shall meet the requirements of Secrion 3.1. The potenrial 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. Import fill should be free , 3030.1094 of all deleterious material and l~azardous waste. Testing for hazardous waste typically takes ~ Leighton and Associates, lnc. GENERAL EARTHWORK AND GRADING SPECIFICATIONS Page 4 of 6 between 7 and 14 working days. 4.0 Fill Placement and Compaction 4.1 Fill Layers: Approved fill material shall be placed in ueas prepazed to receive fill (per Secrion 3.0) in near-horizontal layers not exceeding 8 inches in loose thiclrness. The Geotectuucal 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 unifornvty of material and moisture throughout. ' 4.2 Fill Moisture Conditionine: Fill soils shall be watered, dried back, blended, and/or mixed, as necessary to attain a relatively uniform moisture content at or slightly over opHmum. Ma~cimum density and optimum soil moisture content tests shall be performed in accordance with the American Society of Testing and Materials (AST'M Test Method D1557-91). 43 Compaction of Fill: After each layer has been moishueconditioned, mixed, and evenly . sptead, it shall be uniformly compacted to not less than 90 percent of maximum dry density (AST'M Test Method D1557-91). Compaction equipment shall be adequately sized and be either specifically designed for soil compacfion or of proven reliability to efficiently achieve the specified level of.compacfion with unifornuty. 4.4 Compaction of Fill Slones: In addirion to normal compaction procedures specified above, compaction of slopes shall be accomplished by bacla~olling of slopes with sheepsfoot rollers at increments of 3 to 4 feet in fill elevation, or by other methods producing sarisfactory results acceptable to the Geotechnical Consultant. Upon complerion of grading, relafive compac6on of the fill, out to the slope face, shall be at least 90 percent of maximum density per ASTM Test Method D 1557-91. 4.5 Compaction Tesring: Field tests for moisture content and relaHve compac6on of the fill soils shall be pedormed by the Geotechnical Consultant. Locadon 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 compacrion levels in azeas that are judged to be prone to inadequate compacrion (such as close to slope faces and at the filWedrockbenches). 4.6 Freauency of Compacrion Testine: Tests shall be taken at intervals not exceeding 2 feet in vertical rise and/or 1,000 cubic yazds of compacted fill soils embanlnnent. 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 Compacrion Test L.ocarions: The Geotechnical Consultant shall document the approximate ' aoao.iova ~~ , Leighton and Associates, Inc. GENERAL EAR'I'EiWORK AND GRADING SPECIFICATIONS Page 5 of 6 ' ' elevation and horizontal coordinates of each test location. The Contractor shall coordinate with the project surveyor to assure that sufficient grade stakes aze established so that the Geotechnical Consultant can deternvne the test locafions 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 locarions shall be provided. ' S.0 Subdrain Installarion ' Subdrain systems shall be installed in accordance with the approved geotechnical report(s), the grading plan, and the Standazd Details. The Geotechnical Consultant may recommend addirional subdrains and/or changes in subdrain extent, location, gade, or material depending on conditions ' encountered during grading. All subdrains shall be surveyed by a land surveyor/civil engineer for line and grade after installarion and prior to burial. Sufficient time should be allowed by the Contractor for these surveys. ' 6.0 Excavation ' Excavarions, as well as overcxcavafion for remedial purposes, shall be evaluated by the Geotechnical Consultant during gading. Remedial removal depths shown on geotechnical plans , aze esrimates only. The actual extent of removal shall be detemiined by the Geotechnical Consultant based on the field evaluation of exposed conditions duting grading. Where filloveo-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 consh~uction of the fill portion of the slope, unless otherwise recommended by the Geotechnical Consultant. ' 7.0 Trench Bacl~ills 7.1 The Contractor shall follow all OHSA and CaUOSHA requirements for safety of hench t excavarions. 72 All bedding and bac~ll of utiliTy trenches shall be done in accordance with the applicable ' provisions of Standard Specifications of Public Works Construction. Bedding material shali have a Sand Equivalent geater than 30 (SF>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 azound the conduits shall be observed by the Geotechnical Consultant. ' 7.4 The Geotechnical Consultant shall test the trench backfill for relative compacrion. At least one test should be made for every 300 feet of trench and 2 feet of fill. ' 3030.1094 \` 1 1 , ' ' ' , ' ' , , , ' ' ' ' ' ' ' I.eighton and Associates, Inc. GENERAL EARTHWORK AND GRADING SPECIFICAT[ONS Page 6 of 6 7.5 Lifr thiclmess of trench bacld'ill shall not exceed those allowed in the Standazd Specificafions 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 alternarive equipment and method. 3030.1094 \~ PA0.IELTED W.Al7E 1 TO 1 MAbMUM FiiOM TOE OF SLOPE TO APPF70Vm\ N~ WP~TUR/lL GAOUND \ r v~H.- KEYDEPTH ' LOWEST BENC}t (K~'1 t+a.7uwLL GAOUND ~ ! ' _- _- - / ' ~' / - 2' MIN. KEYOEPiH , dJT F3lCE SiiALL BE COP16f~ED PAIOR ~ TO F31 Pl.ACcil@~(TTO AS3UflE ACECUA7E fiEOIOGiC CCNIXTfOtJ3 ' ' ' ' PRWECTED P1ANE 1 TO 1 MJWMUM FrxM , TOE CF. SLCPE TO ' APPfiOVED C~F'~C)UND~ ' ~ ~ OYEABUILT TA11N BACX ISLOPE 4' TYPlCAL flE~IOVE 'NSiI(TA9L MA7EAtAL CLi'T-OYE~2-F3LL SLOPE For Subdrains 8e~ Standard Detail C HEQiiT . ' 2'~UN. LOWES781 ~_ .... ~_~E~ . ~•IKE,Y) BQ~iINf3 SFW1 BE OGWE YVHEAI SLOPE3 MK3LE 19 EWAL TO CR GFIFATE-1 THAN S:t MfMMUM EE'~C7i HEC3FIT Si~W.1 BE 4 F-ci MINIMUM FlLL WiOTH SFWLL BE 9 FET ~ GENERAL EARTHWORK AND GRADING ~ I~YING AND BENCHING SPECIFICATIONS STANDARD DEfAILS A ~~ rT~~u. ~BF31CH HDGHT -~+ave UNS111TA8LE ~IIUE3ilAL F1LL SLOPE FiLi.-OVEr'~-CiJT SLOPE ~ ~r Trric.a~ H ` BENCH HEIGHT IiEiIOVE 1HSUITABL ~AAA7'EAUiL C71T FACE TO BE CONSlRUCtED q~YCp TO faL PL.ACF~E+1T / / NA7IJHAL / GAOUND ~ ~ // r. ' ' ' ' ' ' ' , ' :: . I ' :t ' ' . , ' ' 1 1 1 ~ ~ \.~~ _ = COMPACTm FILL - _ _ ~ _ ~r~~ -~--- -- -- --- -- \n~ -- ~- ---~'--- \~,` ~rrnrca~ BENCFQNG ~ -- _- - - - ~ - ----- RB~10VE \>.~ ~~ - ~~, \,~~ UNSUITABLE MATFRIAL ~~~ SUBDRAIN (See Aiternates A and B) SUBDRAIN ALIERNAIE A P~~~~~ ~~ ~~~Dm - WITH FILTHt MAT621A1 FILiERMATERULL(9FTJF~ ~ . COIE0. li - ; ; t•: n. 4° M[N~ ~ :. ~ . SUBDR4IN ALTERNATE A-1 _D~T~~ SUBDRAINAL7ERNATEA-2 6° 0 MlN. SUBDRAIN ALTERNA'1E B , GRAVEL WRAPPED IN FILTQ2 FABRIC ` 12" MIN. OVHtIAP 1 FAiER FABRIC - ~ (hIIRAFI 140NC OR APPROVED EQUNPJBJT) •t" (!; .~C~'~ ALTERNA'fE B-1 3/4^ MqX. GRAVaOR ALTERNATE B-2 APPROVED EQUNALB~li (9FT3/FT) 3 PERFOR4TED PIPE IS OPfIONN. PER GOYERNING AGENCY5 R~UIRFMBJTS o~ rwrsxm ur,mE DETAIL OF CANYON SUBDRAIN TERMINAL L~---~ 1SlIDL - ~CN-19ilOPAIID ce r~. - CANYON GENERAL EARTHWORK AND GRADING SUBDRAIN SPECIFICATIONS 5TANDARD DE~'AILS C FILTER MhlERLiL FILTER MATERIAL SHALL BE CLASS 2 PBU4FABLE MA7QUALpQ157q7E pP CAL[FORNIA SfANDARD SPEQF[CATIpN, qt AGPROVED ALlIIWATE CIA~2GPADINGASPoLLON75: - SleveSpe PajrnMPazsirq 1" 300 ' 3/q" 90-300 , 3/8" 40-100 No. q 2540 No. e 1&33 No, 30 S15 No.50 ~-~ No.200 0-3 ~ fIlTERp.WiR (ma~r~ uw aa ~V'm~.ataaal nwao~ocGUrvnuxr) WlE- - I 3N~WENGN ~, ORMHlOl~ ~~ . ' ' ' ' ' ' ' . ' ' 1 ' ' ' 1 CUT-FILL'TRANSI7ION LOT OVEREXCAVATlON REMOaE UNSIIITABIE ~ GPAUND ~ / / i / . - - {OMPARED F7LL - - -~ ~-~ - _ -_ - - _ _ - _ _ - _ y _'- _~,~ -•_ _~ '_ _---_y. _ _ _ _-_. T_ _ . _ __,~°'__-_~__ 7-_- --- . _ -- '--~ ------- j ~--------= _ _ _ _ _ ~ _ \~l OVERE%CAVA7E- - - - - - ti~ - - AND RECOMPACf - - - - - - TYPICLL - ~ BQVCMNG ~ ~- ~ j UNWEAiHERmBEDImOC ORM47ERIPLAPPfmVFD ~ `~ ~ ~ ~ BY 7HE GEO~KFNIC~L CCNSIRTMlf ~` SIDE HILL FILL FOR CUTPAD RFSTRICfED USEPNFA OVEREXC4VATE AND RKOMPACf l i ~ / / / ' ! 5' i , 4' MIN. I NANRAL GRDUND ~ / / / / / / ~ // ~-~' / / / / / FIMSFiEDQJI'PPD / ~ / ---- _.Z \ J~ \ \ ~ ~ - -~- ••~~•• ••••••••••••••••••- • 01~EPBURDEN ~ '~ ~ - _ - ORUNSl1RPBlE ~. MATERiAL - - - - - _ ~~ ~ .. _ _ _ ~ -!~ PPD 04EREXfAVAi70N AND ftEWt~ACTIIXJ _ --- /- r_ 5 W1LL BE PERFORMED IF SPC~iFD ' - - - B ~ _ YiHE6EQfECHNICALCCNSIATPNT TYP1~.. f- - -_ / f BENCFIING / C \ ~ ~ _ _ = - Z~~ ` ' ~ -~~- SEE STANDPRD DETAIL FOR SUBDPAINS WHEN PEQl1INEp BY GEOfECHNICPI CCNSULTPM 9' MIN. 2' MIN. I~Y DEPIH UNWEI1lNERED BmPDOC OR M47EIIIPL APPPAVED BYIHE GEOfECFWIGI CQ45ULTPNf ~ ~ ~ TRANSITION LOT EILLS GENERALEAR'fiiWQRKANDp2ADING ' ~ SPECZFIGITlONS \'~ AND SIDE HILL FILLS sra~oa~ o~rnr~s e. 'I SUBDRAIN OPTTONS AND BACKFILL WHEN NATNE MATERIAL HAS IXPANSION INDEX OF <~0 OPifON 1: P1PE SURROUNDED WIfH CUSS 2 PERMEABLEM4TERIAL OP'TION 2: GRAVELWRAPPED IN FILTER FABRIC WITH PROPER . WITH PltOPER SURFA~ DRAINP,GE SURFALE DRAWAGE ~ SIAPE SfAPE ~ OR LEVEL OR LEVEI . ~ . 12" ~ , . ~Z, NATIVE NAt1VE - WATERPROOF[NG a ~ •: ~ (SEE GENERAL NQfES) WATEkPR00FING "r ~ ~ - '<' (SEE GENERAL NQfES) FLLTER FABR[C _ ~ 12" MINPIUM ~ (SEH N07E 4) CL1S5 2 PERMEABLE ~ ~' ~~ 12" MINIMUM WEEP HIXE FILIER MAIERUV. - WEEP HOtE (SEE GRADATION) ~ vs ro IYx ma 5~ (SEE NOTE,~ (SEE NOTE ~ 6RAYEL WRPPPED IN FILTER - ~ 4INCH D1AMt7ER ... ~ Faek[C LEVELOR PERFORATW PIPE LEVELOR SIDPE . (SEE NOTE 3) SIDPE . ~ Clas 2 Filter Permeable Materiai G2datlon _ ~ ~ Per Caltrans SpeciHCatians _ Sieve Size Percent Pa~na 1" 100 ~~ 3/4" 90-500 3/g° 40-1W No.4 z5-40 No. 8 18-33 No.30 5-15 Na 50 ~-7 Na 20~ . 0-3 GENERALNOIFS: * Waterproofing should be provided where moisture.nuisance p~oblem through the wall is undesi2ble. * Water pro~ng of the walls is not under purview of the geotechnfcal engfneer • All d21ns shouid have a gradient of 1 percent minimum *Outlet portion of the subdrain should have a 4-inch diameter solid pipe discharged into a suitable disposal area designed by the project engioeer. The subdrain pipe should be attessble for maintenance (radding) *Other subdrain backfill options are subject to the review by the geotechnical engineer and modification of design parameters. Notes: i) Sand should have a sand equlvalent of 30 or greater and may be densified by water Jetting. 2) 1 Cu, ft. per ft. of 1/4- to 1 1/Nnch size grdvel wrapped in filter fabric 3) Pipe type should 6e ASTM D1527 Acrylonitrile Butadfene Styrene (ABS) SDR35 or IISiM D1785 Polyvinyl Chloride plastlc (PVC), Schedule 40, Artnco A2000 PVC, m approved equlvalent. Pipe should 6e installed with perfarations down. Perforatlons should be 3/8 irxh in diameter placed at the ends of a 120-degree arc in two ~ows at 3-fnch on centes (stagger~ed) 4) (1lter fabdc should be Mirafi 140NC or approved equivalenk 5) Weephole should be 3-inch minimum iliameter and provided at 10-foot ma~dmum intervals. If e~osure is pertnttUed, weepholes should be located 12 inches above Flnished grade. If exposure is ~ot pertnltted sudi az fora wall adjacent to a sidewalk/curb, e pipe under the sidewalk to be discharged through the curb face or ecjuivalent should 6e provided. For a basemeM-type wall, a proper ~6drai~ oudet system should be provided. 6) Retaining wall plans should be revlewed and approved by the geotechnical engineer. 7) Walls over six feet in height are subject to a special review by the geotechnical engineer and modiflcatlwis to the above requiremenCs. RETAINING WALL BACKFILL AND SUBDRAIN DE?AIL FOR WALLS 6 FEEf OR LESS IN HQGHT `~ WHEN NATIVE MATERIAL HAS IXPANSION INDIX OF <50 Figure No.