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1997-4813 GT Y O F E N C I N I T A EI atERING .SERVICES DEPAD—IME vl.LC'AN AVE. ENCINITAS, CA 52024 GRADING PERMIT PARCEL NO. JOB SITE ADDRESS: SAXvNY WEST PLANNING APPLICANT NAME D.R. HORTON CUSTOM HOMES MAILING ADDRESS: 1010 SOUTH COAST HIGHWAY 101 CITY: ENCINITAS STATE: CA ZIP: CONTRACTOR : PERRY & SHAW, INC. LICENSE NO.: 715408 ENGINEER : HUNSAKER & ASSOCIATES SAN DIEGO INC. PERMIT ISSUE DATE: 6 /17/97 PERMIT EXP. DATE: 6/17/58 PERMIT ISSUED BY INSPECTOR: GEOPACIFICA /GREG SHIELDS 1. PLAN CHECK FEE INSPECTION FEE 3. PLAN CHECK DEPOSIT: PERMIT FEES & DEPOSITS 1``.._911 PERMIT NO.: 4813GI PLAN NO.: 4813 —G PHONE NO.: 760- 634-670v 92024— PHONE NO.: 619- 448 -9554 LICENSE TYPE: A F'HO NO . 558 -45vv 21100.00 4. INSPECTION DEPOSIT: .00 15,488.00 5. SECURITY DEPOSIT 582,525.00 .00 DESCRIPTION OF WORK --------------------- ---- - - - - -- STORM DRAINAGE /EARTHWORK /EROSION CONTROL TO ROUGH GRADE FOR TM 96 -170, A PROPOSED MAJOR SUBDIVISION OF 138EA ATTACHED RESIDENTIAL CONDOMINIUM. NO SITE ROAD /SEWER/WATER OR OFF —SITE IMPROVEMENTS PER THIS PERMIT. LETTER DATED JUN 09 1597 APPLIES. HAUL ROUTE PER TRAFFIC ENGINEERING DIVISION, IF APPLICABLE. - - -- INSPECTION - ------ --------- DATE -- - - - - -- INSPECTOR'S SIGNATURE - - -- INITIAL INSPECTION COMPACTION REPORT RECEIVED ENGINEER CERT. RECEIVED ROUGH GRADING INSPECTION FINAL INSPECTION I HEREBY ACF24OWLEDGE THAT I HAVE READ THE APPLICATION AND STATE THAT THE INFORMATION IS CORRECT AND AGREE TO COMPLY WITH ALL CITY ORDINANCES AND STATE LAWS REGULATING EXCAVATING AND GRADING, AND THE PROVISIONS AND CONDITIONS OF ANY PE T ISSUED PURSUANT TO THIS APPLICATION. SIGN TUBE I� Lam. 1104 -J-1^3 PRINT NAME CI:cCLE ONE: 1. OWNER %. AG 3. 6 -/7-97 DATE SIGNED (N (v-700 TELEPHONE 147JMBER ENGINEERING SER VICES DEPARTMENT City Of Encinitas October 11. 2001 Attn: NationsBank, N.A. 901 Main Street 9`h Floor Dallas, Texas 75202 RE: TM 96 -170 Saxony West D.R. Horton A.P.N. 256- 330 - 15,17,18,19,23,40 Grading Plan 4813 -G Final release of security Capital Improvement Projects District Support Services Field Operations Sand Replenishment/Stormwater Compliance Subdivision Engineering Traffic Engineering Permit 4813 -GI authorized earthwork, private road and drainage improvements, site retaining walls, and erosion control, all needed to build the described project. The Field Operations Division has approved this grading, therefore, release of the security deposit is merited. Letter of Credit 94007, in the amount of $67,163.10, is hereby fully exonerated. The document original is enclosed. Should you have any questions or concerns, please contact Debra Geishart at (760) 633- 2779 or in writing, attention this Department. Sincerely, Masih Maher Senior Civil Engineer Cc: Leslie Suelter, Financial Manager D.R. Horton file enc. eslie Sue ter financial Services Manager Financial Services TEL -60- 633 -2610 / FAX 760- 633 -262- +0i S. Vulcan .Avenue. Encinitas. California 94024 -3633 TDD - 60-03 -2 -00 0 recycled paper MAY 26 '99 04:06PM CITY rK ENCINITAS Z2V 0 P. 2/6 ENGINEERING MR VICES DEPART MSN1' COpital Improvement Projects tatty Of DislnCt Support Services Field OPerotlons Encinitas Subdivision Engineering Traffic Engineering July 22, 1998 NationsBank, N.A- 901 Main Street, 9th Floor Dallas, TX 75202 Re: Tract 96 -170 (TM) "Saxony West" Grading Permit 4813GI (300+ Saxony Rd/D.R- Horton San Diego) A.P -N, 256 -330 - 15,17,18,19,23,40 Partial release of security Permit 4813GI authorized the earthwork, storm drainage, site retaining walls, and erosion control necessary to construct 138 residential condominiums in 46 triplexes, 4 private access roads, and I recreational center, all on a common lot, and to mass grade 3 mixed use lots and 1 passive recreational lot, all within the named subdivision. Rough grading approval has been granted by the Field Operations Division for 26 triplexes - Therefore, a reduction in the posted security deposit is merited. Letter of Credit 940007, in the amount of $116,585.00, may be reduced by $49,421.90 to a new amount of $67,163.10. The original document shall be retained. The balance may be subject to further modification upon verification of substantial progress of the following: a)rough grading inspections on 20 triplexes, and b) final grading inspection on all of the ,rite. Performance bonds have been posted as complimentary securities. Should you have any questions or concerns, please contact Jeff Garami at (760) 633 -2780 or in writing, attention this Department. Sincerely, r �c Hans llensen Senior ivil Engineer Subdivision Engineering cc Leslie Suelter, Financial Services Manager D.R. Horton San Diego 17 Inc., Developer/Property Owner (point of delivery) HCJijsg/4813 Gl.doc 1 TEL 760- 633.26UO r FAX 760 - 633.2627 505 S. Vulcan Avcnue, kncinisas, California 92o2A•3633 TDD 760633 -2700 f� recycled paper ENGINEERING SERVICES DEPARTMENT City Of Encinitas October 11, 1001 Capital Improvement Projects District Support Services Field Operations Sand Replenishment/Stormwater Compliance Subdivision Engineering Traffic Engineering Attn: United States Fidelity & Guaranty Co. 1515 West 22nd Street Oak Brook, I160521 RE: TM 96 -170 Saxony West D.R. Horton A.P.N. 256-330-15,17,18,19,23,40 Grading Plan 4813 -G Final release of security Permit 4813 -GI authorized earthwork, private road and drainage improvements, site retaining walls, and erosion control, all needed to build the described project. The Field Operations Division has approved this grading, therefore, release of the security deposit is merited. Performance Bond 12- 0120 - 31685 -974, in the remainder amount of $268,652.39, is hereby fully exonerated. The document original is enclosed. Should you have any questions or concerns, please contact Debra Geishart at (760) 633- 2779 or in writing, attention this Department. Sincerely, ILA.M`E Masih Maher Senior Civil Engineer Cc: Leslie Suelter, Financial Manager D.R. Horton file enc. e e Fi ancial Services Manager Financial Services TEL 760403 -2WO f FAX 760- 633 - 2627 i0; S. Vulcan .Avenue, Enciniras. California 920]1 -3633 I-DD -60.633- 2700 0 recycled paper ENGINEERING SERVICES DEPARTMENT city Of Capital Improvement Projects District Support Services Encinitas Field Operations Sand Rep lenishment/Stormwater Compliance Subdivision Engineering Traffic Engineering October 11, 2001 Attn: Seaboard Surety Company 385 Washington Street Suite 102F St. Paul, MN 55102 -1396 RE: TM 96 -170 Saxony West D.R. Horton A.P.N. 256 - 330 - 15,16,17,18,19,23,40 Sewer Plan DES242 Final release of security Permit DES242 authorized sewer improvements, all needed to build the described project. The Field Operations Division has approved these improvements, therefore, release of the security deposit is merited. Performance Bond 352468, in the amount of $243,473.00, is hereby fully exonerated. The document original is enclosed. Should you have any questions or concerns, please contact Debra Geishart at (760) 633- 2779 or in writing, attention this Department. Sincerely, Masih Maher Senior Civil Engineer Cc: Leslie Suelter, Financial Manager D. R. Horton file enc. slie Suelter Financial Services Manager Financial Services TEL - 60 -613 -2600 1 FA)( 'an -r, i3 -2r�2- su; ti. Vulcan �crnur. I iicinira,. California 9202.1 -;(,33 IM) -60- 631 -2 -n0 recycled paper r PLANNING ENGINEERING SURVEYING HUNSAKER &ASSOATES S A N D I r CI �. (, i N c March 19. 1999 IRVINE LAS VEGAS RIVERSIDE City of Encinitas SAN DIEGO Engineering Department 505 South Vulcan Avenue Encinitas, CA 92024 Attn: Mr. Greg Shields Inspector Subject: Civil Engineer's Certification of Rough Grade Project: Grading Plan 4813 -G West Saxony Building Pads 23 through 27, 36 Elevations: Pad 23 at an elevation of 180.4 Pad 24 at an elevation of 179.4 Pad 25 at an elevation of 178.4 Pad 26 at an elevation of 179.0 Pad 27 at an elevation of 177.5 Pad 36 at an elevation of 180.1 0 I hereby approve the rough grading for the referenced pads in accordance with my responsibilities under the City of Encinitas Grading Ordinance. Rough Grading has been completed substantially in conformance with the approved grading plan (within a tenth of a foot). Sincerely, Hunsaker & Associates San Diego, Inc. DAVE HAMMAR � <:-i) /%� ACR HILL LEX WILLIMAN Daniel P. Smith L.S. 6854 Hunsaker & Associates San Diego, Inc. 10179 Huennekens St. Suite 200 San Diego, CA 92121 (619) 558 -4500 PH (619) 5 58- 14 14 E X ..hunsakeccom Info®HunsakerSD.com r,� SAN DrPO ;0 L.S. 6854 L \ Exp. 9/30100/ / WW 013751(a cft r.o. 13 S 1 PLANNING ENGINEERING SURVEYING IRVINE LAS VEGAS RIVERSIDE SAN DIEGO DAVE HAMMAR JACK HILL LE% WILUMAN 10179 Huennekens St. Suite 200 San Diego, CA 92121 (6191558-4500 PH (619) 558 -1414 F x .hunsakeccom Info ®HunsakerSD.com HUNSAKER &ASSOCIATES A N D I E Gi O, 1 N C. December 14, 1998 City of Encinitas Engineering Department 505 South Vulcan Avenue Encinitas, CA 92024 Attn: Mr. Greg Shields Inspector Subject: Civil Engineer's Certification of Rough Grade Project: Grading Plan 4813 -G West Saxony Building Pads 28 through 31, 33 through 35 Elevations: Pad 28 at an elevation of 176.5 Pad 29 at an elevation of 175.5 Pad 30 at an elevation of 174.5 Pad 31 at an elevation of 173.6 Pad 33 at an elevation of 174.1 Pad 34 at an elevation of 175.1 Pad 35 at an elevation of 175.8 I hereby approve the rough grading for the referenced pads in accordance with my responsibilities under the City of Encinitas Grading Ordinance. Rough Grading has been completed substantially in conformance with the approved grading plan (within a tenth of a foot). Sincerely, Hunsaker & Associates San Diego, Inc. Daniel P. Smith L.S. 6854 Hunsaker & Associates San Diego, Inc. LAND 57? <1 O ;1] L.S. 6854 Exp. 9/30/00 DS M %b e,n, mrn"no1375 %159e0 9,kc wo 137541 HUNSAKER &ASSOCIATES S A N 1) 1 E G O, 1 N C. PLANNING ENGINEERING SURVEYING IRVINE December 15, 1997 LAS VEGAS RIVERSIDE SAN DIEGO City of Encinitas Engineering Department 505 S. Vulcan Avenue Encinitas, CA 92024 -3633 Attn: Greg Shields Re: Street Subgrade Certification Project: Encinitas Ranch West Saxony Planning Area Improvement Plan 4813 -1 ES -242 Lots: All of streets Saxony Road, Saxony Place, Silver Berry Place at site entrance, Sweet Pea Place South and the portion of Sweet Pea Place East between Stations 10 +00 to 13 +50. Owner: D.R. Horton 1010 South Coast Highway Suite 101 Encinitas. CA 92924 The subgrade for the above referenced streets have been completed in conformance with the approved improvement plan. Daniel P. Smith L.S. 6854 DAVE HAMMAR Hunsaker & Associates San Diego, Inc. JACK HILL LEX WILLIMAN cc: Jerry Sims 10179 Huennekens St. Suite 200 San Diego, CA 92121 (619) 558 -4500 PH (619) 558 -1414 F X w .hunsakerxom Info ®HunsakerSD.com LAND 57—P e .0 O L.S. 6854 Exp. 9/30/0 DsMms. ftllVt wme uts41 ii i ail E "J I I I I I i I II! I I I I I � Ii 1, f ! UPDATE GEOTECHNICAL INVESTIGATION AND GEOTECHNICAL ENGINEER OF RECORD ENCINITAS RANCH (WEST SAXONY PLANNING AREA) ENCINITAS, CALIFORNIA PREPARED FOR D. R. HORTON INCORPORATED -SAN DIEGO SAN DIEGO, CALIFORNIA NOVEMBER 1996 GEOCON I N C O R P O R A T E D GEOTECHNICAL CONSULTANTS Project No. 05799 -42 -01 November 1, 1996 D. R. Horton Incorporated —San Diego 10179 Huennekens Street, Suite 100 San Diego, California 92121 Attention: Mr. Marc Perlman Subject: ENCINITAS RANCH (WEST SAXONY PLANNING AREA) ENCINITAS, CALIFORNIA UPDATE GEOTECHNICAL INVESTIGATION AND GEOTECHNICAL ENGINEER OF RECORD O Reference: 1. Geotechnical Investigation, West Saxony Property, Encinitas, California, prepared by Geotechnics, Incorporated, dated January 9, 1996. 2. Preliminary Geotechnical Evaluation, West Saxony Planning Area, City of Encinitas, California, prepared by Geosoils, Incorporated, dated June 28, 1996. Gentlemen: In accordance with your authorization of our proposal dated September 19, 1996, we have prepared an update geotechnical investigation for the subject project. The accompanying report updates previous geotechnical work by others, and acknowledges that Geocon Incorporated has been retained as the geotechnical engineer of record for the project- Additional subsurface investigation was not performed for this report, however, based on our review of the referenced studies, Geocon generally concurs with the conclusions and recommendations provided in the reports. General discussion and pertinent conclusions and recommendations from the reports have been incorporated into this update. Revised grading specifications and foundation design criteria have also been included in this report. Based on the results of the previous studies, it is our opinion that the site can be developed as proposed, provided the recommendations of this report are followed. If you should have any questions regarding this update, or if we may be of further service, please contact the undersigned at your convenience. Very truly yours, U JAN GEOCON INCORPORATED James L. Brown RCE 43824 DBE:JLB:dmc (6) Addressee y �g110, 5 - .y s a30 1 9,t r. ?� 1 <- f C .3 1 David B. Ev vEVNts CEG 1860 W N �StD CL ��tNrjj sj �¢ • GEO isst OQ2 'so F CP�vQ 6960 Flonders Drive ■ Son D.ego, CaLFornia 92121 -2974 ■ Telephone 16191 558 -6900 ■ Fox 16191 558 -6159 z s E TABLE OF CONTENTS 1. PURPOSE AND SCOPE .................................. ............................... 2. SITE AND PROJECT DESCRIPTION ............ ............................... 3. SOIL AND GEOLOGIC CONDITIONS ......... ............................... 3.1. Undocumented Fill ( Qaf) ............................. ............................... 3.2. Topsoil ( Unmapped) .................................... ............................... 3.3. Alluvium (Qal) ............................................ ............................... 3.4. Terrace Deposits ( Qt) ................................... ............................... 3.5. Torrey Sandstone ( Tt) .................................. ............................... 4. GROUNDWATER / SEEPAGE .......................... ............................... 5. GEOLOGIC HAZARDS ................................... ............................... 5.1. Faulting and Seismicity ............................... ............................... 5.2. Liquefaction ................................................ ............................... 6. CONCLUSIONS AND RECOMMENDAT IONS ........................... 6.1. General ........................................................ ............................... 6.2. Groundwater ............................................... ............................... 6.3. Soil and Excavation Characteristics ........... ............................... 6.4. Grading ....................................................... ............................... 6.5. Subdrains ..................................................... ............................... 6.6. Slope Stability ............................................. ............................... 6.7. Cut Slopes ................................................... ............................... 6.8. Fill Slopes ................................................... ............................... 6.9. Foundation Recommendations ................... ............................... 6.10. Retaining Walls and Lateral Loads ............ ............................... 6.11. Slope Maintenance .................................... ............................... 6.12. Drainage .................................................... ............................... 6.13. Grading Plan Review ................................ ............................... LIMITATIONS AND UNIFORMITY OF CONDITIONS MAPS AND ILLUSTRATIONS Figure 1, Vicinity Map Figure 2, Geologic Map Figure 3, Typical Canyon Subdrain Detail Figure 4, Typical Retaining Wall Drain Detail Figures 5 -6, Slope Stability Analysis APPENDIX A RECOMMENDED GRADING SPECIFICATIONS .. I .. 2 .. 2 .. 3 .. 3 .. 4 .. 4 .. 4 .. 4 .. 4 .. 5 .. 6 .. 6 .. 6 .. 6 .. 7 .. 9 .. 9 .. 9 10 10 13 15 IS 15 UPDATE GEOTECHNICAL INVESTIGATION AND GEOTECHNICAL ENGINEER OF RECORD 1. PURPOSE AND SCOPE This report presents an update geotechnical investigation of the for the proposed Encinitas Ranch, West Saxony Planning Area development, located in Encinitas, California (see Vicinity Map, e Figure 1). The purpose of the update was to evaluate previous subsurface studies performed by others (Reference Nos. 1 and 2) and acknowledge that Geocon Incorporated has been retained as the geotechnical engineer of record for the project. This report presents revised grading specifications and foundation design criteria to be used during development of the project as presently proposed. Excerpts from the referenced geotechnical investigations have been incorporated into this report for continuity and to assist in describing the site conditions. The scope of this investigation included a review of aerial photographs, readily available published and unpublished geologic literature and previous geotechnical reports prepared by Geosoils Incorporated, and Geotechnics Incorporated (Reference Nos. I and 2). Our scope did not include a subsurface investigation, however, a field reconnaissance was performed by an engineering geologist from our firm to generally compare the previous geologic maps to the conditions exposed at the site. The base map used to depict the site soil and geologic conditions is entitled Tentative Map And Design Review Permit, Encinitas Ranch (West Saxony Planning Area), scale 1 inch equals 40 feet, prepared by Hunsaker & Associates, stamped October 9, 1996 (see Figure 2, map pocket). The Geologic Map shows the existing topography, proposed development, and site geology (as presented in Reference Nos. 1 and 2). The exploratory trench locations and descriptive trench logs from the previous studies are not presented in this update. Reference Nos. I and 2 should be reviewed if this information is desired. The conclusions and recommendations presented herein are based on a review of the data obtained from the referenced field investigations and our experience with similar soil and geologic conditions. 2. SITE AND PROJECT DESCRIPTION The proposed Encinitas Ranch project is roughly rectangular in shape and occupies approximately 13 acres in the City of Encinitas, California (see Figure 1). The property is bounded to the east by Saxony Road, and Interstate 5 freeway to the west. The Magdalena Ecke Sports Park borders the site to the south, while the adjacent northern property consists of mixed residential and agricultural development. Topographically, the site is situated on a gentle, west facing slope with relief of Project No. 05799 -42 -01 - 1 - November 1, 1996 approximately 60 to 70 feet. Slope gradients vary from near flat -lying (adjacent to Saxony Road) to approximately 8:1 (horizontal:vertical) towards Interstate 5. A northwest trending drainage traverses the western property margin and storm runoff is collected off site adjacent to the freeway. Existing improvements on the site consist of approximately 5 residential structures with associated outbuildings, asphalt and dirt access roads and driveways, a shallow irrigation system and cultivated acreage. Vegetation on the property consists predominantly of commercial flower agriculture, several large trees and "weedy thickets" in fallow areas of the site. A review of the referenced tentative map indicates that site development will consist of the construction of a 47 -lot residential subdivision with interior streets and associated underground utilities. The buildings are anticipated to consist of duplex and triplex condominiums constructed of wood frame and stucco, supported by conventional foundations. In addition, four, approximately 1 to 1.5 acre, "mixed use" lots are planned for the south and west margins of the site. A recreation area, pool, spa, and cabana will be built across from the main entryway. Cuts and fills on the order of 10 and 25 feet, respectively, are anticipated to accomplish the proposed grading. Slopes inclined at 2:1, with maximum heights of approximately 30 feet are planned. The locations and descriptions of the site and proposed improvements are based upon a site reconnaissance, and a review of the previous geotechnical reports and the grading plans. If project details vary significantly from those described herein, Geocon Incorporated should be notified for review and possible revision to this report 3. SOIL AND GEOLOGIC CONDITIONS Two geologic formations and three surficial soil deposits were identified at the site during previous investigations. The surficial deposits consist of undocumented fill, topsoil and alluvium. The two geologic formations include Pleistocene Terrace deposits and the Eocene -age Torrey Sandstone. Each of the soil and geologic units identified are discussed below in order of increasing age. Their estimated areal extent is shown on the Geologic Map, Figure 2 (map pocket). 3.1. Undocumented Fill (Qaf] Undocumented fill soils consisting predominantly of silty sand with minor amounts of clayey sand were encountered within the eastern, and extreme northwestern portions of the site. The fill in the eastern portion of the site contains locally thick zones of plastic highly expansive clay. Where Project No. 0579942.01 - 2 - November I, 1996 observed, the existing fills are up to 15 feet thick and typically dry to moist, loose, and slightly porous. The two major fill areas shown on Figure 2 appear to be placed as canyon fills adjacent to Saxony road, and within the northwest trending drainage located in the northwest comer of the site. Additional minor fills not encountered in the test pits, but observed during a reconnaissance are located throughout the site. These fills appear to be associated with residential structures and 1 roadways. Undocumented fill materials will require complete removal and compaction in areas of proposed site development. } 3.2. Topsoil (Unmapped) Topsoils occur as a thin surface or near surface layer of material on slopes and within flat -lying areas adjacent to Saxony Road. Where observed, topsoils were approximately 1 to 1.5 feet thick. Within flat -lying areas adjacent to Saxony road, topsoils consist of mottled dark gray to dark yellowish brown sandy clay. Within sloping areas in the central and western portions of the site, topsoils consist of grayish brown silty sand. The clayey materials are typically moist, stiff and porous while sandy materials are dry, loose and porous. Previous laboratory test results indicate that the clayey portions possess a medium expansion potential. Due to the unconsolidated nature of the topsoils, as well as their expansive potential, remedial grading consisting of removal and compaction and/or extensive benching will be required. The clayey portions should be placed at least 3 feet below proposed finish grade. 3.3. Alluvium (Qal) Alluvial soils were encountered during previous studies in the main northwest trending drainage along the western margin of the property (mapped as undifferentiated undocumented filValluvium on Figure 2). Alluvium was also observed within a filled canyon adjacent to Saxony Road, and within a northwest and southwest trending drainage within the western portion of the property. Logs from the Geosoils report (Reference No. 2), indicate the alluvium consists of loose, moist, dark grayish brown silty sand. The alluvial soils encountered ranged in thickness from 6 to 22 feet below existing grade, with the thickest section along the western margin of the property. Although bedrock was encountered in previous studies at a depth of 22 feet, thicker alluvium should be anticipated where the center of the main drainage crosses the northwestern property boundary. The alluvial deposits are poorly consolidated and compressible and will require remedial grading in the form of complete removal and compaction. Typically, alluvial cleanouts are extended horizontally beyond structural fill areas a distance equal to the depth of overexcavation. In order to accomplish this, removal of the alluvium may require excavations beyond the property boundaries in Project No. 05799 -42 -01 - 3 . November 1, 1996 order to provide properly compacted fills within the zone influencing the building pads. This procedure may be necessary along the northwest edge of "mixed use" Lot No. 4, and residential Lot Nos. 6 through 9. In the event that off -site grading is not permitted along the northwestern property margin, building setbacks on the aforementioned lots will likely be required. 3.4. Terrace Deposits (Qt) Terrace Deposits underlying the site consist of brownish yellow, reddish brown, and yellow brown silty sand with minor amounts of clayey sand. Where observed, terrace deposits are typically damp to moist and medium dense. Weathered zones occur locally within the uppermost 1 to 1.5 Results of laboratory testing from previous studies performed on two samples of Terrace Deposits indicate that the material is suitable in a natural condition to support the proposed structural improvements. 3.5. Torrey Sandstone (Tt) The bedrock unit underlying the site is the Eocene -age Torrey Sandstone. The Torrey Sandstone consists of thickly bedded, cross stratified, pale yellow gray, silty fine to medium sand. The formation is very dense to locally cemented, typically has a low expansion potential, and possess high shear strength characteristics. The Torrey Sandstone is suitable in its natural condition for support of fill and /or structures. 4. GROUNDWATER/SEEPAGE Previous studies indicate that very moist to wet soil (seepage) was observed in fills and alluvium near the contact with the underlying formational material. In this regard, remedial grading may encounter wet soils and excavation and compaction difficulty in the main northwest trending drainage, particularly if construction is planned during the winter months. A canyon subdrain will be necessary in the main drainage along the western portion of the site to prevent the buildup of perched water. The recommended subdrain location is shown on Figure 2. The final subdrain location will be determined during grading when the when actual canyon cleanout can be observed. 5. GEOLOGIC HAZARDS 5.1. Faulting and Seismicity A review of the geologic literature indicates that no known active or potentially active faults are located within the subject site or in the immediate vicinity. The rose Canyon Fault zone is located Project No. 05799 -42 -01 -4 - November 1, 1996 approximately 3.6 miles west of the site and is presently considered active. The Rose Canyon Fault Zone is postulated as having the potential to generate a Maximum Credible Magnitude earthquake of 7.0 and Maximum Probable Magnitude earthquake of 6.5, respectively. The "maximum credible earthquake" is defined as the maximum earthquake that appears capable of occurring under the presently known tectonic framework, while the "maximum probable earthquake" is the maximum earthquake that is considered likely to occur during a 100 -year time interval (California Division of Mines and Geology Notes, Number 43). Estimated maximum credible and maximum probable ground accelerations were determined to be approximately 0.508 and G.32g, respectively. Major earthquakes occurring on the Rose Canyon Fault, or other regional active faults located in the southern California area, could subject the site to moderate -to- severe ground shaking within the life span of the proposed structures. However, the seismic risk at the site is not considered significantly different than that of the adjacent properties. 5.2. Liquefaction The potential for liquefaction during a strong earthquake is limited to those soils which are in a relatively loose, unconsolidated condition and located below the water table. Since the existing alluvial soils will be removed and compacted with a subdrain placed beneath the fills (main drainage), and the formational soils are very dense, it is our opinion that the risk of liquefaction occurring at the site is relatively low. Project No. 05799 -42 -01 - 5 - November 1, 1996 6. CONCLUSIONS AND RECOMMENDATIONS 6.1. General 6.1.1. No soil or geologic conditions were observed during our site reconnaissance, or identified during a review of the previous reports or published geologic literature which, in our opinion, would preclude the development of the property as proposed provided that the recommendations of this report are followed. Geocon Incorporated generally concurs with the findings of previous studies, however, the information provided herein, supersedes all previous recommendations relative to the property. 6.1.2. The surficial soils (undocumented fill, topsoil, and alluvium) are not considered suitable for the support of fill or structural loads in their present condition and will require remedial grading in the form of complete removal and compaction. 6.2. Groundwater 6.2.1. The geologic units encountered on the site have permeability characteristics that could be susceptible under certain conditions to groundwater seepage. This is particularly evident in r the main northwest trending drainage. If grading is planned during the winter months, it should be anticipated that alluvial soils will be wet and difficult to excavate and compact. A canyon subdrain should be constructed in the bottom of the alluvium removal in the main drainage to reduce the potential for groundwater buildup within the canyon fill. The drain should be constructed in accordance with Figures 2 and 3. 6.3. Soil and Excavation Characteristics 6.3.1. The soil conditions encountered range from low expansive silty sands derived from the Torrey Sandstone to possibly highly expansive materials observed within the undocumented fill deposits. Medium to highly expansive soils should be placed a minimum of 3 feet below proposed finish grade. 6.3.2. It is anticipated that the surficial deposits and terrace deposits can be excavated with light effort using conventional heavy duty grading equipment. A moderate effort to heavy effort could be required if excavations are planned within cemented portions of the Torrey Sandstone. Project No. 05799 -02 -01 - 6 - November 1, 1996 6.4. Grading 6.4.1. All grading should be performed in accordance with the attached Recommended Grading Specifications in Appendix A. Where the recommendations of this section conflict with Appendix A, the recommendations of this section take precedence. All earthwork should be observed and all fills tested for proper compaction by Geocon Incorporated. 6.4.2. Prior to commencing grading, a preconstruction conference should be held at the site with the owner or developer, grading contractor, civil engineer, and geotechnical engineer in attendance. Special soil handling and/or the grading plans can be discussed at that time. 6.4.3. Site preparation should begin with the removal of all deleterious material and vegetation. The depth of removal should be such that material exposed in cut areas or soils to be used as fill are relatively free of organic matter. Material generated during stripping and/or site demolition should be exported from the site. 6.4.4. All compressible surficial soil deposits, including undocumented fill, topsoil, and alluvium within areas of planned grading should be removed to firm natural ground and properly s recompacted prior to placing additional fill and/or structural loads. Removals on the order of 25 feet, or more, should be anticipated along the northwestern property boundary. It should be noted that remedial grading in this area may need to extend off -site to remove compressible deposits in a zone that could influence the proposed structural improvements. If this is not possible, a structural setback within the building pads will likely be required. Deeper than normal benching and/or stripping operations for sloping ground surfaces will be required where the thickness of potentially compressible surficial deposits exceed 3 feet. 6.4.5. The actual extent of unsuitable soil removals will be determined in the field during grading by the soil engineer and /or engineering geologist. Overly wet, surficial materials will require drying and /or mixing with drier soils to facilitate proper compaction. 6.4.6. After removal of unsuitable materials as described above is performed, the site should then be brought to final subgrade elevations with structural fill compacted in layers. In general, soils native to the site are suitable for re -use as fill if free from vegetation, debris and other deleterious material. Layers of fill should be no thicker than will allow for adequate bonding and compaction. All fill, including backfill and scarified ground surfaces, should be compacted to at least 90 percent of maximum dry density at approximately 2 percent over optimum moisture content, as determined in accordance with ASTM Test Procedure Project No. 05799 -42 -01 - 7 - November 1, 1996 D1557 -91. Fill materials with moisture contents below optimum moisture content will require additional moisture conditioning prior to placing additional fill. 6.4.7. Grading operations should be planned so as to place expansive soils in the deeper fills and away from slope faces, and to cap the building pads with granular materials having a "low" expansive potential. 6.4.8. To reduce the potential for differential settlement, it is recommended that the cut portion of cuttfill transition building pads be undercut at least 3 feet and replaced with properly compacted "low" expansive fill soils. The undercut subgrade should be inclined a minimum of 1 percent towards the front of the lot and extend into the roadway prism. 6.4.9. Although cuts are on the order of 10 feet, or less, and will be performed predominantly in Terrace Deposits, it is possible that oversize material (defined as material greater than 12 inches in nominal dimension) could be generated during ripping of cemented formational materials. Placement of oversize material within fills should be conducted in accordance with the recommendations in Appendix A. Grading operations on the site should be scheduled such that oversize materials are placed in designated disposal areas and/or deeper fills. 6.4.10. For fill areas, it is recommended that oversize materials not be placed within 10 feet of proposed finish grade for residential building pads. This recommendation is intended to facilitate excavation for future improvements, such as swimming pools. Where such improvements are not planned, oversize materials may be placed within 5 feet of finish grade elevations. In streets, oversize material should be placed a minimum of 10 feet below finish grade, or 3 feet below the deepest utility. 6.4.11. Where practical, the upper 3 feet of all building pads (cut or fill) and 12 inches in pavement areas should be composed of "Low" expansive soils. The more highly expansive fill soils should be placed in the deeper fill areas and properly compacted. "Low" expansive soils are defined as those soils that have an Expansion Index of 50 or less when tested in accordance with UBC 18 -1 -B (1994). Cobbles, rock fragments, and concretions greater than 6 inches in maximum dimension should not be placed within 3 feet of finish grade in building pad areas. Project No. 05799 -42 -01 - 8 - November I, 1996 6.5. Subdrains 6.5.1. A subdrain should be installed during remedial grading in the main northwest/southwest - trending drainage. Due to the anticipated depth of remedial grading along the drainage, and the fixed elevation of the outlet point, it is likely that at least portions of the subdrain will be r extended through fill material and will not be positioned at the bedrock/fill interface. This condition will be evaluated in the field during construction. A typical subdrain detail is presented on Figure 3. The subdrain should be placed no closer than 10 feet from proposed finish grade, and at least 2 feet below proposed utilities. 6.5.2. The lower 20 feet of the subdrain exiting the base of compacted fill slope should consist of nonperforated pipe. A cutoff wall should be constructed immediately below the junction of the perforated pipe with the nonperforated pipe. The cutoff wall should extend at least 6 inches beyond the sides and the bottom of the subdrain trench and 6 inches above the top of the pipe. The outlet pipe should be provided with a concrete headwall, riprap, or similar device. 6.5.3. After installation of the subdrains, the project civil engineer should survey the locations and prepare accurate as -built plans of the subdrain locations. The project soils engineer should F verify the as -built subdrain outlet. The contractor should ensure that an adequate drainage gradient is maintained throughout the system, and that the subdrain outlet is free of obstructions. 6.6. Slope Stability 6.6.1. Slope stability analyses were performed for proposed cut and fill slopes using shear strength parameters based upon laboratory test results from previous studies, and experience with similar soil and geologic conditions. The strength values utilized were derived from a remolded sample of undocumented fill (TPI at 3 feet, silty sand) presented in Reference No. 2. The results of the analysis indicate that proposed cut and fill slopes excavated in or constructed of the site soil materials have a factor -of -safety of at least 1.5 against deep seated and surficial instability for the slope heights proposed. The results of the analyses are presented on Figures 5 and 6. Project No. 05799 -42 -01 - 9 - November 1, 1996 6.7. Cut Slopes 6.7.1. It is recommended that all cut slopes be observed during grading by an engineering geologist to verify that the soil and geologic conditions do not differ significantly from those anticipated and to determine if adverse bedding, fractures or joints exist. Remedial grading procedures may be recommended should adverse geologic conditions be observed. 6.8. Fill Slopes 6.8.1. The outer 15 feet of fill slopes, measured horizontal to the slope face, should be composed of properly compacted granular "soil' fill to reduce the potential for surface sloughing. 6.8.2. All fill slopes should be overbuilt at least 3 feet horizontally, and cut to the design finish grade. As an alternative, fill slopes may be compacted by back - rolling at vertical intervals not to exceed 4 feet and then track- walking with a D -8 dozer, or equivalent, upon completion such that the fill soils are uniformly compacted to at least 90 percent relative compaction to the face of the finished slope. 6.8.3. All slopes should be planted, drained and properly maintained to reduce erosion. 6.9. Foundation Recommendations 6.9.1. The following foundation recommendations are for one - and/or two -story structures and are based upon the assumption that the soil conditions within 3 feet of finish pad subgrade consist of granular `low" expansive soil (Expansion Index less than 50). The recom- mendations are separated into categories dependent upon the depth and geometry of fill underlying a particular building pad and/or lot. Final foundation design recommendations for each building will be presented in the final compaction report after the grading for the individual building pads has been completed and the finish grade soil expansion index for each lot has been determined. 6.9.2. Foundations for either Category 1, II, or III as described on the following page, may be designed for an allowable soil bearing pressure of 2,000 pounds per square foot (psf) (dead plus live load). This bearing pressure may be increased by one -third for transient loads such as wind or seismic forces. No. 05799 -42 -01 - to- November I. 1996 6.9.3. No special subgrade preparation is deemed necessary prior to placing concrete. however, the exposed foundation and slab subgrade soils should be sprinkled, as necessary, to maintain a moist soil condition as would be expected in any such concrete placement. TABLE 6.9.1 FOUNDATION RECOMMENDATIONS BY CATEGORY Foundation Minimum Continuous Footing Interior Slab Category Footing Depth Reinforcement Reinforcement (inches) I 12 One No. 4 bar top and bottom 6 x 6 - 10 110 welded wire mesh at slab mid -point II 18 Two No. 4 bars top and bottom No. 3 bars at 24 inches on center, both directions III 24 Two No. 5 bars top and bottom No. 3 bars at 18 inches on center, both directions CATEGORY CRITERIA Category I: Maximum fill thickness is less than 20 feet and Expansion Index is less than or equal to 50. Category II: Maximum fill thickness is less than 50 feet and Expansion Index is less than or equal to 90, or variation in fill thickness is between 10 feet and 20 feet. Category III: Fill thickness exceeds 50 feet, or variation in fill thickness exceeds 20 feet, or Expansion Index exceeds 90, but is less than 130. Notes: 1. All footings should have a minimum width of 12 inches. 2. Footing depth measured from lowest adjacent subgrade. 3 All interior living area concrete slabs should be at least four inches thick for Categories I and II and 5 inches thick for Category III. 4. All interior concrete slabs should be underlain by at least 4 inches (3 inches for Category III) of clean sand or crushed rock. 5. All slabs expected to receive moisture sensitive floor coverings or used to store moisture sensitive materials should be underlain by a vapor barrier covered with at least 2 inches of the clean sand recommended in I2=F-t630 f:7 6.9.4. Where buildings or other improvements are planned near the top of a slope steeper than 3:1 (horizontal:vertical), special foundations and /or design considerations are recommended due to the tendency for lateral soil movement to occur. Project No. 05799 -42 -01 - 11 - November 1, 1996 • For fill slopes less than 20 feet high, building footings should be deepened such that the bottom outside edge of the footing is at least 7 feet horizontally from the face of the slope • Where the height of the fill slope exceeds 20 feet, the minimum horizontal distance should be increased to H/3 (where H equals the vertical distance from the top of the slope to the toe) but need not exceed 40 feet. For composite (fill over cut) slopes, H equals the vertical distance from the top of the slope to the bottom of the fill portion of the slope. An acceptable alternative to deepening the footings would be the use of a post- tensioned slab and foundation system or increased footing and slab reinforcement. Specific design 1 parameters or recommendations for either of these alternatives can be provided once the building location and fill slope geometry have been determined. • For cut slopes in dense formational materials, or fill slopes inclined at 3:1 (hori- zontal:vertical) or flatter, the bottom outside edge of building footings should be at least 1 7 feet horizontally from the face of the slope, regardless of slope height. • Swimming pools located within 7 feet of the top of cut or fill slopes are not recommended. Where such a condition cannot be avoided, it is recommended that the portion of the swimming pool wall within 7 feet of the slope face be designed assuming that the adjacent soil provides no lateral support. This recommendation applies to fill slopes up to 30 feet in height, and cut slopes regardless of height. For swimming pools located near the top of fill slopes greater than 30 feet in height, additional recommenda- tions may be required and Geocon Incorporated should be contacted for a review of specific site conditions. • Although other improvements which are relatively rigid or brittle, such as concrete flatwork or masonry walls may experience some distress if located near the top of a slope, it is generally not economical to mitigate this potential. It may be possible, however, to incorporate design measures which would permit some lateral soil movement without causing extensive distress. Geocon Incorporated should be consulted for specific recommendations. 6.9.5. As an alternative to the foundation recommendations for each category, consideration should be given to the use of post- tensioned concrete slab and foundation systems for the support of the proposed structures. The post- tensioned systems should be designed by a structural engineer experienced in post- tensioned slab design and design criteria of the Post - Tensioning Institute (UBC Standard No. 294, Part 11). Although this procedure was developed for expansive soils, it is understood that it can also be used to reduce the potential for foundation distress due to differential fill settlement. The post- tensioned design should incorporate the geotechnical parameters presented on the following table entitled Post - Tensioned Foundation System Design Parameters for the particular Foundation Category designated. Project No. 05799 -42 -01 - 12- November 1, 1996 TABLE 6.9.2 POST- TENSIONED FOUNDATION SYSTEM DESIGN PARAMETERS POST - TENSIONING INSTITUTE (PTI) DESIGN PARAMETERS FOUNDATION CATEGORY 1 11 Ill 1. Thomthwaite Index -20 -20 -20 2. Clay Type - Montmorillonite Yes Yes Yes 3. Clay Portion (Maximum) 30% 50% 70% 4. Depth to Constant Soil Suction 7.0 ft. 7.0 ft. 7.0 ft. 5. Soil Suction 3.6 ft. 3.6 ft. 3.6 ft. 6. Moisture Velocity 0.7 indmo. 2.6 ft. 0.7 indmo. 2.6 ft. 0.7 indmo. 2.6 ft. 7. Edge Lift Moisture Variation Distance 8. Edge Lift 0.41 in. 0.78 in. 1.15 in. 9. Center Lift Moisture Variation Distance 5.3 ft. 5.3 ft. 5.3 ft. 10. Center Lift 2.12 in. 3.21 in. 4.74 in. 6.9.6. UBC Standard No. 29 -4 Part II uses interior stiffener beams in its structural design procedures. If the structural engineer proposes a post- tensioned foundation design method other than UBC Standard No. 29 -4, Part 1I, it is recommended that interior stiffener beams be used for Foundation Categories 11 and III. The depth of the perimeter foundation should be at least 12 inches for Foundation Category 1. Where the Expansion Index for a particular building pad exceeds 50 but is less than 91, the perimeter footing depth should be at least 18 inches; and where it exceeds 90 but is less than 130, the perimeter footing depth should be at least 24 inches. Geocon Incorporated should be consulted to provide additional design parameters as required by the structural engineer. 6.10 Retaining Walls and Lateral Loads 6.10.1. Retaining walls not restrained at the top and having a level backfill surface should be designed for an active soil pressure equivalent to the pressure exerted by a fluid density of 35 pounds per cubic foot (pcf) for . Where the backfill will be inclined at no steeper than 2.0 to 1.0, an active soil pressure of 45 pcf is recommended. These soil pressures assume that the backfill materials within an area bounded by the wall and a 1:1 plane extending upward from the base of the wall possess an Expansion Index of less than 50. For those lots with finish grade soils having an Expansion Index greater than 50 and /or where backfill materials do not conform to the above criteria, Geocon Incorporated should be consulted for additional recommendations. Project No. 05799 -42 -01 .13 - November 1, 1996 6.10.2. Unrestrained walls are those that are allowed to rotate more than 0.001H at the top of the wall. Where walls are restrained from movement at the top, an additional uniform pressure of 7H psf (where H equals the height of the retaining wall portion of the wall in feet) should be added to the above active soil pressure. 6.10.3. All retaining walls should be provided with a drainage system adequate to prevent the buildup of hydrostatic forces and should be waterproofed as required by the project architect. The use of drainage openings through the base of the wall (weep holes, etc.) is not recommended where the seepage could be a nuisance or otherwise adversely impact the property adjacent to the base of the wall. The above recommendations assume a properly compacted granular (Expansion Index less than 50) backfill material with no hydrostatic forces or imposed surcharge load. If conditions different than those described are anticipated, or if specific drainage details are desired, Geocon Incorporated should be contacted for additional recommendations. A typical retaining wall drain detail is shown on Figure 4. 6.10.4. In general, wall foundations having a minimum depth and width of one foot may be designed for an allowable soil bearing pressure of 2,000 psf, provided the soil within 3 feet below the base of the wall has an Expansion Index of less than 90. The proximity of the foundation to the top of a slope steeper than 3:1 could impact the allowable soil bearing pressure. Therefore, Geocon Incorporated should be consulted where such a condition is anticipated. 6.10.5. For resistance to lateral loads, an allowable passive earth pressure equivalent to a fluid density of 300 pcf is recommended for footings or shear keys poured neat against properly compacted granular fill soils or undisturbed natural soils. The allowable passive pressure assumes a horizontal surface extending at least 5 feet or three times the surface generating the passive pressure, whichever is greater. The upper 12 inches of material not protected by floor slabs or pavement should not be included in the design for lateral resistance. An allowable friction coefficient of 0.4 may be used for resistance to sliding between soil and concrete. This friction coefficient may be combined with the allowable passive earth pressure when determining resistance to lateral loads. 6.10.6. The recommendations presented above are generally applicable to the design of rigid concrete or masonry retaining walls having a maximum height of 8 feet. In the event that walls higher than 8 feet or other types of walls are planned, such as crib -type walls, Geocon Incorporated should be consulted for additional recommendations. Project No. 05799 -42 -01 - 14- November 1. 1996 r 6.11. Slope Maintenance 6.1 I.1. Slopes that are steeper than 3:1 (horizontal:vertical) may, under conditions which are both difficult to prevent and predict, be susceptible to near surface (surficial) slope instability. The instability is typically limited to the outer three feet of a portion of the slope and usually does not directly impact the improvements on the pad areas above or below the slope. The occurrence of surficial instability is more prevalent on fill slopes and is generally preceded by a period of heavy rainfall, excessive irrigation, or the migration of subsurface seepage. The disturbance and/or loosening of the surficial soils, as might result from root growth, soil expansion, or excavation for irrigation lines and slope planting, may also be a significant contributing factor to surficial instability. It is, therefore, recommended that, to the maximum extent practical: (a) disturbed/loosened surficial soils be either removed or properly recompacted, (b) irrigation systems be periodically inspected and maintained to eliminate leaks and excessive irrigation, and (c) surface drains on and adjacent to slopes be periodically maintained to preclude ponding or erosion. It should be noted that although the incorporation of the above recommendations should reduce the potential for surficial slope instability, it will not eliminate the possibility, and, therefore, it may be necessary to rebuild or repair a portion of the project's slopes in the future. 6.12. Drainage 6.12.1. Establishing proper drainage is imperative to reduce the potential for differential soil movement, erosion and subsurface seepage. Positive measures should be taken to properly finish grade the building pads after structures and other improvements are in place, so that drainage water from the building pads and adjacent properties is directed to streets away from foundations and tops of slopes. Experience has shown that even with these provisions, a shallow groundwater or subsurface condition can and may develop in areas where no such condition existed prior to site development. This is particularly true where a substantial increase in surface water infiltration results from an increase in landscape irrigation. 6.13. Grading Plan Review 6.13.1. The geotechnical engineer and engineering geologist should review the grading plans prior to finalization to verify their compliance with the recommendations of this report and determine the necessity for additional comments, recommendations and/or analysis. Project No. 05799.42 -01 - 15- November 1, 1996 LIMITATIONS AND UNIFORMITY OF CONDITIONS 1. The recommendations of this report pertain only to the site investigated and are based upon the assumption that the soil conditions do not deviate from those disclosed in the investigation. If any variations or undesirable conditions are encountered during construction, or if the proposed construction will differ from that anticipated herein, Geocon Incorporated should be notified so that supplemental recommendations can be given. The z evaluation or identification of the potential presence of hazardous or corrosive materials was not part of the scope of services provided by Geocon Incorporated. 2. This report is issued with the understanding that it is the responsibility of the owner, or of his representative, to ensure that the information and recommendations contained herein are brought to the attention of the architect and engineer for the project and incorporated into the plans, and the necessary steps are taken to see that the contractor and subcontractors cant' out such recommendations in the field. 3. The findings of this report are valid as of the present date. However, changes in the conditions of a property can occur with the passage of time, whether they be due to natural processes or the works of man on this or adjacent properties. In addition, changes in applicable or appropriate standards may occur, whether they result from legislation or the broadening of knowledge. Accordingly, the findings of this report may be invalidated wholly or partially by changes outside our control. Therefore, this report is subject to review and should not be relied upon after a period of three years. Project No. 0579942 -01 November 1, 1996 t GEOCON �� I N C O R P O R A T E D GEOTECHNICAL CONSULTANTS 6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974 PHONE 619 558 -6900 • FAX 619 558 -6159 DH If IT DSK / GOOOO I%ncwp VICINITY MAP ENCINITAS RANCH (WEST SAXONY PLANNING AREA) ENCINITAS, CALIFORNIA DATE PROJECT NO. 05799 -42 - 01 1 FIG t. • \ 35 �� t '� ® y" _� 344`. rd �j e w Iva S 13S�J ) e 44•rP�y ru � �. I \\ �A IM' I 1 . � ' SuxRIW RM1 ap I � I I ............ iFI— --- L . �YwV y' Im V ,a � 3I I Z 3 ,I. � � �i.s•�dr v !V NH Ml BLVD BL I 111 I 1 1 4 s RID a sr I I ___ rcur r , 10CL w r 1 b 9 In ". MNa ST LL I6 �C �s in MM I ruR NR'• ?- ° sur ws $ ? t. _ '°^BL .. a ? — • REr rosy . �^ �� 1 • p mn .9rMlr VA a' BLV -q14 �uPAM tltlst` o $r ENCINITAS BLVD- •i Imo w i,B 0 FL r y1 T 'T °j[� 6,W F L�.E "1'S \idl I _ - i r f1 Rf E 15 tnuo via s, n SOURCE: 1996 THOMAS BROTHERS MAP SAN DIEGO COUNTY, CALIFORNIA REFIIFt CEO YrtfM PERMISSION ORANTEO BY TMCN.S BROTHERS MAPS jr THIS MAP IS COPYRIOMTEO BY TN01MS BROS MAPS IT IS UNLAYYPIIL TO COPY at REMO 4E ALL OR ANY PART TNEREOF, M'HETNER FOR PERSONAL USE OR NO SCALE RESALE. AITNOIR PERMISSION GEOCON �� I N C O R P O R A T E D GEOTECHNICAL CONSULTANTS 6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974 PHONE 619 558 -6900 • FAX 619 558 -6159 DH If IT DSK / GOOOO I%ncwp VICINITY MAP ENCINITAS RANCH (WEST SAXONY PLANNING AREA) ENCINITAS, CALIFORNIA DATE PROJECT NO. 05799 -42 - 01 1 FIG t. NATURAL GROUND �� ALLUVIUM AND COLLUVIUM REMOVAL / o►sTa► SEE DETAIL BELOW NOTE: FINAL 20' OF PIPE AT OUTLET SHALL BE NON - PERFORATED 5" DIA. PERFORATED SUBDRAIN PIPE 9 CUBIC FEET /FOOT OF OPEN GRADED GRAVEL SUROUNDED BY MIRAFI 140N (OR EQUIVALENT) FILTER FABRIC NOTES: 1 ..... 6 -INCH DIAMETER SCHEDULE 80 PVC PERFORATED PIPE FOR FILLS IN EXCESS OF 100 -FEET IN DEPTH 2 .... 6 -INCH DIAMETER SCHEDULE 40 PVC PERFORATED PIPE FOR FILLS LESS THAN 100 -FEET IN DEPTH L TYPICAL CANYON SUBDRAIN DETAIL GEOCON / IN C O R P O R A T E D GEOTECHNICAL CONSULTANTS 6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 -2974 PHONE 619 558 -6900 - fAX 619 5586159 JB ! J.T DSK / G0000 CVNOTAIL NO SCALE ENCINITAS RANCH (WEST SAXONY PLANNING AREA) ENCINITAS, CALIFORNIA 1 DATE (PROJECT NO. 05799 - 42 - 01 1 FIG 3 1 GROUND SURFACE PROPERLY COMPACTED j BACKFILL CONCRETE 2.0 BROWDITCH � 1� r PROPOSED RETAINING WALL 1 3/4 APPROVED FILTER FABRIC Q .. 2/3 H �. °.'Q OPEN GRADED 1" MAX. AGGREGATE 5' MAX. PROPOSED GRADE a al FOOTING 1' 4- DIA. PERFORATED PVC PIPE MIN. 1/2% FALL TO APPROVED OUTLET nau NO SCALE TYPICAL RETAINING WALL DRAIN DETAIL GEOCON INCORPORATE D GEOTFCHNICAL CONSULTANTS 6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 -297 4 PHONE 619 5586900 - FAX 619 5586159 JB /J.T DSK /G0000 e,v�e ENCINITAS RANCH (WEST SAXONY PLANNING AREA) ENCINITAS, CALIFORNIA DATE I PROJECT NO. 05799 -42 -01 I FIG.4 PROJECT NO. 05799 -42 -0: ASSUMED CONDITIONS: Slope Height H = 30 Slope Inclination 2:1 (Ho Total Unit Weight of Soil y, = 125 Angle of Internal Friction = 27 Apparent Cohesion C = 417 No Seepage Forces ANALYSIS: y, -tH tan6 Equation (3 -3), Reference 1 C FS = NC Equation (3 -2), Reference 1 YH ya 4.62 Calculated Using Eq. (3 -3) Ncf = 20 Determined Using Figure 10, Reference 2 FS = 21 Factor of Safety Calculated Using Eq. (3 -2) REFERENCES: feet izontal :Vertical) pounds per cubic foot degrees pounds per square foot (1) Janbu, N., Stability Analysis of Slopes with Dimensionless Parameters, Harvard Soil Mechanics, Series No. 46, 1954. (2) Janbu, N., Discussion of J.M. Bell, Dimensionless Parameters for Homogeneous Earth Slopes, Journal of Soil Mechanics and Foundation Design, No. SM6, November 1967. SLOPE STABILITY ANALYSIS ENCINITAS RANCH (WEST SAXONY PLANNING AREA) ENCINITAS, CALIFORNIA FIGURE 5 PROJECT NO. 05799 -32 -01 ASSUMED CONDITIONS: Slope Height H = Infinite Depth of Saturation Z = 3 feet Slope Inclination 2:1 (Horizontal :Vertical) Slope Angle i = 27 degrees Unit Weight of Water Y. = 62.4 pounds per cubic foot Total Unit Weight of Soil Y, = 125 pounds per cubic foot Angle of Internal Friction $ = 27 degrees Apparent Cohesion C = 417 pounds per square foot Slope saturated to vertical depth Z below slope face. Seepage forces parallel to slope face ANALYSIS: FS = C +(yt — yw)Zcoslitano = 3.2 ytZsinicosi REFERENCES: (1) Haefeli, R. The Stability of Slopes Acted Upon by Parallel Seepage, Proc. Second International Conference, SMFE, Rotterdam, 1948, 1, 57 -62. (2) Skempton, A. W., and F. A. Delory, Stability of Natural Slopes in London Clay, Proc. Fourth International Conference, SMFE, London, 1957, 2, 378 -81. SURFICIAL SLOPE STABILITY ANALYSIS ENCINITAS RANCH (WEST SAXONY PLANNING AREA) ENCINITAS, CALIFORNIA FIGURE 6 APPENDIX A APPENDIX A RECOMMENDED GRADING SPECIFICATIONS Fai; ENCINITAS RANCH (WEST SAXONY PLANNING AREA) ENCINITAS, CALIFORNIA PROJECT NO. 05799 -42 -01 RECOMMENDED GRADING SPECIFICATIONS 1. GENERAL 1.1. These Recommended Grading Specifications shall be used in conjunction with the Geotechnical Report for the project prepared by Geocon Incorporated. The recom- mendations contained in the text of the Geotechnical Report are a part of the earthwork and grading specifications and shall supersede the provisions contained hereinafter in the case of conflict. 12. Prior to the commencement of grading, a geotechnical consultant (Consultant) shall be employed for the purpose of observing earthwork procedures and testing the fills for substantial conformance with the recommendations of the Geotechnical Report and these specifications. It will be necessary that the Consultant provide adequate testing and observation services so that he may determine that, in his opinion, the work was performed in substantial conformance with these specifications. It shall be the responsibility of the Contractor to assist the Consultant and keep him apprised of work schedules and changes so that personnel may be scheduled accordingly. 1.3. It shall be the sole responsibility of the Contractor to provide adequate equipment and methods to accomplish the work in accordance with applicable grading codes or agency ordinances, these specifications and the approved grading plans. If, in the opinion of the Consultant, unsatisfactory conditions such as questionable soil materials, poor moisture condition, inadequate compaction, adverse weather, and so forth, result in a quality of work not in conformance with these specifications, the Consultant will be empowered to reject the work and recommend to the Owner that construction be stopped until the unacceptable con- ditions are corrected. 2. DEFINITIONS 2.1. Owner shall refer to the owner of the propem or the entity on whose behalf the grading work is being performed and who has contracted with the Contractor to have grading performed. 2.2. Contractor shall refer to the Contractor performing the site grading work. 2.3. Civil Engineer or Engineer of Work shall refer to the California licensed Civil Engineer or consulting firm responsible for preparation of the grading plans, surveying and verifying as- graded topography. 2.4. Consultant shall refer to the soil engineering and engineering geology consulting firm retained to provide geotechnical services for the project. 2.5. Soil Engineer shall refer to a California licensed Civil Engineer retained by the Owner, who is experienced in the practice of geotechnical engineering. The Soil Engineer shall be responsible for having qualified representatives on -site to observe and test the Contractor's work for conformance with these specifications. 2.6. Engineering Geologist shall refer to a California licensed Engineering Geologist retained by the Owner to provide geologic observations and recommendations during the site gradin-. 2.7. Geotecbnical Report shall refer to a soil report (including all addendums) which may include a geologic reconnaissance or geologic investigation that was prepared specifically for the development of the project for which these Recommended Grading Specifications are intended to apply. 3. MATERIALS 3.1. Materials for compacted fill shall consist of any soil excavated from the cut areas or imported to the site that, in the opinion of the Consultant. is suitable for use in construction of fills. In general, fill materials can be classified as soil fills, soil -rock fills or rock fills, as defined below. Soil fills are defined as fills containing no rocks or hard lumps greater than 12 inches in maximum dimension and containing at least 40 percent by weight of material smaller than 3/4 inch in size. Soil -rock fills are defined as fills containing no rocks or hard lumps larger than 4 feet in maximum dimension and containing a sufficient matrix of soil fill to allow for proper compaction of soil fill around the rock fragments or hard lumps as specified in Paragraph 6.2. Oversize rock is defined as material greater than 12 inches. • Rock fills are defined as fills containing no rocks or hard lumps larger than 3 feet in maximum dimension and containing little or no fines. Fines are defined as material smaller than 3/4 inch in maximum dimension. The quantity of fines shall be less than approximately 20 percent of the rock fill quantity. 3 2. Material of a perishable, spongy, or otherwise unsuitable nature as determined by the Consultant shall not be used in fills. 3.3. Materials used for fill, either imported or on -site, shall not contain hazardous materials as defined by the California Code of Regulations, Title 22, Division 4, Chapter 30, Articles 9 and 10; 40CFR; and any other applicable local, state or federal laws. The Consultant shall not be responsible for the identification or analysis of the potential presence of hazardous materials. However, if observations, odors or soil discoloration cause Consultant to suspect the presence of hazardous materials, the Consultant may request from the Owner the termination of grading operations within the affected area. Prior to resuming grading operations, the Owner shall provide a written report to the Consultant indicating that the suspected materials are not hazardous as defined by applicable laws and regulations. 3.4. The outer 15 feet of soil -rock fill slopes, measured horizontally, should be composed of properly compacted soil fill materials approved by the Consultant. Rock fill may extend to the slope face, provided that the slope is not steeper than 2:1 (horizontal:vertical) and a soil laver no thicker than 12 inches is track - walked onto the face for landscaping purposes. This procedure may be utilized, provided it is acceptable to the governing agency, Owner and Consultant. 3.5. Representative samples of soil materials to be used for fill shall be tested in the laboratory by the Consultant to determine the maximum density, optimum moisture content, and. where appropriate, shear strength, expansion. and gradation characteristics of the soil. 3.6. During grading, soil or groundwater conditions other than those identified in the Geotechnical Report may be encountered by the Contractor. The Consultant shall be notified immediately to evaluate the significance of the unanticipated condition. 4. CLEARING AND PREPARING AREAS TO BE FILLED 4.1. Areas to be excavated and filled shall be cleared and grubbed. Clearing shall consist of complete removal above the ground surface of trees, stumps, brush, vegetation, man -made structures and similar debris. Grubbing shall consist of removal of stumps, roots, buried logs and other unsuitable material and shall be performed in areas to be graded. Roots and other projections exceeding 1 -1 /2 inches in diameter shall be removed to a depth of 3 feet below the surface of the ground. Borrow areas shall be grubbed to the extent necessary to provide suitable fill materials. 4.2. Any asphalt pavement material removed during clearing operations should be properly disposed at an approved off -site facility. Concrete fragments which are free of reinforcing steel may be placed in fills, provided they are placed in accordance with Section 6? or 6.3 of this document. 4.3. After clearing and grubbing of organic matter or other unsuitable material, loose or porous soils shall be removed to the depth recommended in the Geotechnical Report. The depth of removal and compaction shall be observed and approved by a representative of the Consultant. The exposed surface shall then be plowed or scarified to a minimum depth of 6 inches and until the surface is free from uneven features that would tend to prevent uniform compaction by the equipment to be used. 4.14. Where the slope ratio of the original ground is steeper than 6:1 (horizontal:vertical), or where recommended by the Consultant, the original ground should be benched in accordance with the following illustration. TYPICAL BENCHING DETAIL FINISH GRADE EXISTING GROUND \\? FINISH SLOPE SURFACE \\ / REMOVE AS RECOMMENDED BY SOIL ENGINEER - SLOPE TO BE SUCH THAT `- SLOUGHING OR SLIDING DOES NOT OCCUR NOTES NOTE NO SCALE DETAIL NOTES: (1) Key width "B" should be a minimum of 10 feet wide, or sufficiently wide to permit complete coverage with the compaction equipment used. The base of the key should be graded horizontal, or inclined slightly into the natural slope. (2) The outside of the bottom key should be below the topsoil or unsuitable surficial material and at least 2 feet into dense formational material. 'A'here hard rock is exposed in the bottom of the key, the depth and conficuration of the key may be modified as approved by the Consultant. 4.5. After areas to receive fill have been cleared, plowed or scarified. the surface should be disced or bladed by the Contractor until it is uniform and free from large clods. The area should then be moisture conditioned to achieve the proper moisture content, and compacted as recommended in Section 6.0 of these specifications. 5. COMPACTION EQUIPMENT 5.1. Compaction of soil or soil -rock fill shall be accomplished by sheepsfoot or segmented -steel wheeled rollers, vibratory rollers, multiple -wheel pneumatic -tired rollers, or other types of acceptable compaction equipment. Equipment shall be of such a design that it will be capable of compacting the soil or soil -rock fill to the specified relative compaction at the specified moisture content. 5.2. Compaction of rock fills shall be performed in accordance with Section 6.3. 6. PLACING, SPREADING AND COMPACTION OF FILL MATERIAL 6.1. Soil fill, as defined in Paragraph 3.1.1, shall be placed by the Contractor in accordance with the following recommendations: Soil fill shall be placed by the Contractor in layers that, when compacted, should generally not exceed 8 inches. Each laver shall be spread evenly and shall be thoroughly mixed during spreading to obtain uniformity of material and moisture in each laver. The entire fill shall be constructed as a unit in nearly level lifts. Rock materials ¢rester than 12 inches in maximum dimension shall be placed in accordance with Section 6.2 or 6.3 of these specifications. In general, the soil fill shall be compacted at a moisture content at or above the optimum moisture content as determined by ASTNI D1557 -91. • When the moisture content of soil fill is below that specified by the Consultant, water shall be added by the Contractor until the moisture content is in the range specified. When the moisture content of the soil fill is above the ranee specified b} the Consultant or too wet to achieve proper compaction, the soil fill shall be aerated by the Contractor by blading/mixing. or other satisfactory methods until the moisture content is within the range specified. After each laver has been placed, mixed, and spread evenly, it shall be thoroughly compacted by the Contractor to a relative compaction of at least 90 percent. Relative compaction is defined as the ratio (expressed in percent) of the in -place dry density of the compacted fill to the maximum laboratory dn' density as determined in accordance with ASTh1 D1557 -91. Compaction shall be continuous over the entire area, and compaction equipment shall make sufficient passes so that the specified minimum relative compaction has been achieved throughout the entire fill. • Soils having an Expansion Index of greater than 50 may be used in fills if placed at least 3 feet below finish pad grade and should be compacted at a moisture content generally 2 to 4 percent greater than the optimum moisture content for the material. • Properly compacted soil fill shall extend to the design surface of fill slopes. To achieve proper compaction, it is recommended that fill slopes be over -built by at least 3 feet and then cut to the design grade. This procedure is considered preferable to track - walking of slopes, as described in the following paragraph. • As an alternative to over - building of slopes, slope faces may be back- rolled with a heavy -duty loaded sheepsfoot or vibratory roller at maximum 4 -foot fill height intervals. Upon completion, slopes should then be track- walked with a D -3 dozer or similar equipment, such that a dozer track covers all slope surfaces at least twice. 6.2. Soil -rock fill, as defined in Paragraph 3.1.2, shall be placed by the Contractor in accordance with the following recommendations: • Rocks larger than 12 inches but less than 4 feet in maximum dimension may be incorporated into the compacted soil fill, but shall be limited to the area measured 15 feet minimum horizontally from the slope face and 5 feet below finish grade or 3 feet below the deepest utility, whichever is deeper. Rocks or rock fragments up to 4 feet in maximum dimension may either be individually placed or placed in windrows. Under certain conditions, rocks or rock fragments up to 10 feet in maximum dimension may be placed using similar methods. The acceptability of placing rock materials greater than 4 feet in maximum dimension shall be evaluated during grading as specific cases arise and shall be approved by the Consultant prior to placement. • For individual placement, sufficient space shall be provided between rocks to allow for passage of compaction equipment. • For windrow placement, the rocks should be placed in trenches excavated in properly compacted soil fill. Trenches should be approximately 5 feet wide and 4 feet deep in maximum dimension. The voids around and beneath rocks should be filled with approved granular soil having a Sand Equivalent of 30 or greater and should be compacted by flooding. Windrows may also be placed utilizing an 'open- face" method in lieu of the trench procedure, however, this method should first be approved by the Consultant. • Windrows should generally be parallel to each other and may be placed either parallel to or perpendicular to the face of the slope depending on the site geometry. The minimum horizontal spacing for windrows shall be 12 feet center -to- center with a 5 -foot stagger or offset from lower courses to next overlying course. The minimum vertical spacing between windrow courses shall be 2 feet from the top of a lower windrow to the bottom of the next higher windrow. • All rock placement, fill placement and flooding of approved granular soil in the windrows must be continuously observed by the Consultant or his representative. 63. Rock fills, as defined in Section 3.1.3, shall be placed by the Contractor in accordance with the following recommendations: The base of the rock fill shall be placed on a sloping surface (minimum slope of 2 percent, maximum slope of 5 percent). The surface shall slope toward suitable subdrainage outlet facilities. The rock fills shall be provided with subdrains during construction so that a hydrostatic pressure buildup does not develop. The subdrains shall be permanently connected to controlled drainage facilities to control post- construction infiltration of water. Rock fills shall be placed in lifts not exceeding 3 feet. Placement shall be by rock trucks traversing previously placed lifts and dumping at the edge of the currently placed lift. Spreading of the rock fill shall be by dozer to facilitate seating of the rock. The rock fill shall be watered heavily during placement. Watering shall consist of water trucks traversing in front of the current rock lift face and spraying water continuously during rock placement. Compaction equipment with compactive energy comparable to or greater than that of a 20 -ton steel vibratory roller or other compaction equipment providing suitable energy to achieve the required compaction or deflection as recommended in Paragraph 63.3 shall be utilized. The number of passes to be made will be determined as described in Paragraph 6.3.3. Once a rock fill lift has been covered with soil fill, no additional rock fill lifts will be permitted over the soil fill. • Plate bearing tests, in accordance with ASTM DI 196 -64, may be performed in both the compacted soil fill and in the rock fill to aid in determining the number of passes of the compaction equipment to be performed. If performed, a minimum of three plate bearing tests shall be performed in the properly compacted soil fill (minimum relative compaction of 90 percent). Plate bearing tests shall then be performed on areas of rock fill having two passes, four passes and six passes of the compaction equipment, respectively. The number of passes required for the rock fill shall be determined by comparing the results of the plate bearing tests for the soil fill and the rock fill and by evaluatine the deflection variation with number of passes. The required number of passes of the compaction equipment will be performed as necessary until the plate bearing deflections are equal to or less than that determined for the properly compacted soil fill. In no case will the required number of passes be less than two. • A representative of the Consultant shall be present during rock fill operations to verify that the minimum number of "passes" have been obtained, that water is being properly applied and that specified procedures are being followed. The actual number of plate hearing tests will be determined by the Consultant during grading. In general, at least one test should be performed for each approximatel% 5.000 to 10,000 cubic yards of rock fill placed. • Test pits shall be excavated by the Contractor so that the Consultant can state that, in his opinion, sufficient water is present and that voids between large rocks are properly filled with smaller rock material. In -place density testing will not be required in the rock fills. • To reduce the potential for "piping" of fines into the rock fill from overlying soil fill material, a 2 -foot layer of graded filter material shall be placed above the uppermost lift of rock fill. The need to place graded filter material below the rock should be determined by the Consultant prior to commencing grading. The gradation of the graded filter material will be determined at the time the rock fill is being excavated. Materials typical of the rock fill should be submitted to the Consultant in a timely manner, to allow design of the traded filter prior to the commencement of rock fill placement. All rock fill placement shall be continuously observed during placement by representatives of the Consultant. 7. OBSERVATION AND TESTING 7.1. The Consultant shall be the Owners representative to observe and perform tests during clearing, grubbing, filling and compaction operations. In general, no more than 2 feet in vertical elevation of soil or soil -rock fill shall be placed without at least one field density test being performed within that interval. In addition, a minimum of one field density test shall be performed for every 2,000 cubic yards of soil or soil -rock fill placed and compacted. 7.2. The Consultant shall perform random field density tests of the compacted soil or soil -rock fill to provide a basis for expressing an opinion as to whether the fill material is compacted as specified. Density tests shall be performed in the compacted materials below any disturbed surface. When these tests indicate that the density of any laver of fill or portion thereof is below that specified, the particular layer or areas represented by the test shall be reworked until the specified density has been achieved. 7.3. During placement of rock fill, the Consultant shall verify that the minimum number of passes have been obtained per the criteria discussed in Section 6.3.3. The Consultant shall request the excavation of observation pits and may perform plate bearing tests on the placed rock fills. The observation pits will be excavated to provide a basis for expressing an opinion as to whether the rock fill is properly seated and sufficient moisture has been applied to the material. If performed, plate bearing tests will be performed randomly on the surfac: of the mast - recently placed lift. Plate bearing tests will be performed to provide a basis for expressing an opinion as to whether the rock fill is adequately seated. The maximum deflection in the rock fill determined in Section 6.33 shall be less than the maximum deflection of the properly compacted soil fill. When any of the above criteria indicate that a laver of rock fill or any portion thereof is below that specified, the affected laver or area shall be reworked until the rock fill has been adequately seated and sufficient moisture applied. 7.4. A settlement monitoring program designed b) the Consultant may be conducted in areas of rock fill placement. The specific design of the monitoring program shall be as recommended in the Conclusions and Recommendations section of the project Geotechnical Report or in the final report of testing and observation services performed during grading. 7.5. The Consultant shall observe the placement of subdrains, to verify that the drainage devices have been placed and constructed in substantial conformance with project specifications. 7.6. Testing procedures shall conform to the following Standards as appropriate: Soil and Soil -Rock Fills: Field Density Test, ASTM D1556 -82, Density of Soil In -Place By the Sand -Cone Method. Field Density Test, Nuclear Method, ASTM D2922 -81, Density of Soil and Soil- Aggregate In -Place by Nuclear Methods (Shallow Depth). • Laboratory Compaction Test, ASTM D1557 -91, Moisture- Density Relations of Soils and Soil- Aggregate Mixtures Using 10 -Pound Hammer and 18 -Inch Drop. Expansion Index Test, Uniform Building Code Standard 29 -2, Expansion Index Test. Rock Fills Field Plate Bearing Test, ASTM D1196 -64 (Reapproved 1977) Standard Method for Nonrepresentative Static Plate Load Tests of Soils and Flexible Pavement Components, For Use in Evaluation and Design of Airport and Highway Pavements. 8. PROTECTION OF WORK 8.1. During construction, the Contractor shall properly grade all excavated surfaces to provide positive drainage and prevent ponding of water. Drainage of surface water shall be controlled to avoid damage to adjoining properties or to finished work on the site. The Contractor shall take remedial measures to prevent erosion of freshly graded areas until such time as permanent drainage and erosion control features have been installed. Areas subjected to erosion or sedimentation shall be properly prepared in accordance with the Specifications prior to placing additional fill or structures. 8.2. After completion of grading as observed and tested by the Consultant, no further excavation or filling shall be conducted except in conjunction with the services of the Consultant. 9. CERTIFICATIONS AND FINAL REPORTS 9.1. Upon completion of the work, Contractor shall furnish Owner a certification by the Civil Engineer stating that the lots and /or building pads are graded to within 0.1 foot vertically of elevations shown on the grading plan and that all tops and toes of slopes are within 0.5 foot horizontally of the positions shown on the grading plans. After installation of a section of subdrain, the project Civil Engineer should survey its location and prepare an as -built plan of the subdrain location. The project Civil Engineer should verify the proper outlet for the subdrains and the Contractor should ensure that the drain system is free of obstructions. 9.2. The Owner is responsible for furnishing a final as- graded soil and geologic report satisfactory to the appropriate governing or accepting agencies. The as- graded report should be prepared and signed by a California licensed Civil Engineer experienced in geotechnical engineering and by a California Certified Engineering Geologist, indicating that the geotechnical aspects of the grading were performed in substantial conformance with the Specifications or approved changes to the Specifications. GI rcv. 9196 ,i _�-[ - LEGEND Qfai- _.UNDOCUMENYEIi ,FfILL - sx snrvc ° E %ti Resme "cs / /�_ QCL` �tYQI. 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TENTATIVE MAP AND sHEET sake DESIGN REVIEW PERMIT �ssnt s ENCINITAS RANCH °F EXIDDIG °A °A " " "° (WEST SAXONY PLANNING AREA) GEOLOGIC MAP CITY OF EN— NITAS. CALIFORNIA waisrsaT = �Geotechnics Incorporated Principals: Anthony F. Belfast Michael P. Imbrigliu W. Lee Vandcrhumt GEOTECHNICAL INVESTIGATION WEST SAXONY PROPERTY ENCINITAS, CALIFORNIA prepared for Caritas Company 5600 Avenida Encinas, Suite 100 i Carlsbad, California 92008 by GEOTECHNICS INCORPORATED Project No. 0054-003-00 Doc. #5 -0634 January 9, 1996 P.O. Boa 26500.224 • San Diego California • 92196' Phone(619)536.1000 • F=(619)536-8311 e 6 6.1 GEOTECHNICAL INVESTIGATION 6 WEST SAXONY PROPERTY Earthwork Construction ......... ............................... ENCINITAS, CALIFORNIA TABLE OF CONTENTS 1.0 INTRODUCTION ................... ............................... 1 2.0 SCOPE OF SERVICES .............. ............................... 1 3.0 SITE DESCRIPTION 2 4.0 PROPOSED DEVELOPMENT ......... ............................... 2 5.0 GEOLOGY AND SUBSURFACE CONDITIONS 3 f 5.1 Geology .................... ............................... 3 8 5.1.1 Torrey Sandstone ....... ............................... 3 6.2.5 Slope Stabilization ...... ............................... 5.1.2 3 5.1.3 .................... ............................... 4 8 5.1.4 Fill .................. ............................... 4 Site Drainage ................ ............................... 5.3 Geologic Hazards ............. ............................... 5 6.4 Preliminary Foundation Recommendations ........................... 10 5.4 Groundwater ................. ............................... 5 ' 6.0 CONCLUSIONS AND RECOMMENDATIONS ............................. 6 6.1 General Discussion ............ ............................... 6 6.2 Earthwork Construction ......... ............................... 7 6.2.1 Geotechnical Observation .......................... 7 6.2.2 Site Preparation ... ............................... 7 6.2.3 Expansive Soil .......... ............................... 8 f 6.2.4 Cut/Fill Transitions ...... ............................... 8 6.2.5 Slope Stabilization ...... ............................... 8 6.2.6 Fill Slopes on Sloping Ground ............................. 8 6.3 Site Drainage ................ ............................... 9 6.4 Preliminary Foundation Recommendations ........................... 10 6.4.1 Design Parameters ...... ............................... 10 6.4.2 Slope Setback ......... ............................... 11 i6.4.3 Settlement ............ ............................... 11 6.5 Interior On -Grade Slabs ......... ............................... 11 6.5.1 Moisture Protection for Slabs ............................. 12 6.6 Exterior Slabs ................ ............................... 12 6.7 Earth Retaining Structures ....... ............................... 12 6.8 Pavements .................. ............................... 13 6.9 Reactive Soils ................ ............................... 13 1 7.0 LIMITATIONS OF INVESTIGATION ..... ............................... 14 C eotechnics Incorporated Cadtas Company January 9. 1996 APPENDICES Project No. 0054- 003-00 Doc. p5 -0634 Page No. 3 REFERENCES ................. ............................... Appendix A SUBSURFACE EXPLORATION .... ............................... Appendix B LABORATORY TESTING ......... ............................... Appendix C STANDARD GRADING GUIDELINES . ............................... Appendix D Geotechnics Incorporated GEOTECHNICAL INVESTIGATION WEST SAXONY PROPERTY ENCINITAS, CALIFORNIA 1 1.0 INTRODUCTION This report presents the results of our geotechnical investigation for the development of the West Saxony Property in Ei,cinitas, California. The conclusions and recommendations presented in this report are based on field exploration, laboratory testing, analysis of the proposed 1 development, and our experience with similar soils and geologic conditions in the area. This investigation was conducted in accordance with the authorization of Mr. Charlie Kahr. The scope of services provided during this investigation were consistent with those outlined in our Proposal No. 5 -133R dated October 19, 1995. 2.0 SCOPE OF SERVICES The purpose of the investigation was to provide geotechnical design criteria and e recommendations for site preparation, grading, and for foundation and retaining wall design. In 1 order to accomplish this task, the following services were performed: Review of published geologic maps, reports, and aerial stereoscopic photographs of the subject site and immediately adjacent properties. A geologic reconnaissance of the surface characteristics of the site. Subsurface exploration consisted of excavating 24 test pits with a rubber -tired backhoe mounted with a 24 -inch wide bucket. The test pits were excavated to depths up to 22 feet. Samples representative of the materials encountered were collected for laboratory analysis. Each exploration site was geologically logged and then backfilled. Backfill was not compacted. The approximate locations of the lest pits are shown in the Geotechnical Map, Plate 1. The test pit logs are presented in Appendix B. Laboratory testing of samples collected during the subsurface exploration to characterize pertinent engineering properties of the soil. Tests included gradation, Atterberg limits, expansion index, and pH and corrosivity. The results of the laboratory testing are presented in Appendix C. Ceotechnics Incorporated P Caritas Company Project No. 0054 -003 -00 January 9, 1996 Doc. 05 -0634 Page No. 2 Assessment of seismic conditions and geologic hazards affecting the area and their potential impact on the project. Engineering analysis of field and laboratory data in order to develop recommendations for f site preparation, earthwork construction, and the geotechnical aspects of the design of foundations including vertical and lateral loads, soil bearing capacities, foundation settlement potential, on -grade slabs, and earth retaining structures. Preparation of this report and accompanying illustrations. 3.0 SITE DESCRIPTION J The subject site is a roughly rectangular- shaped property located west of Saxony Road, 2,250 feet north of the intersection with Encinitas Boulevard in Encinitas, California (Site Location Map, Figure 1). The property encompasses approximately 14 acres of land situated along the western slope of a north -south trending ridge. The site is bound by Saxony Road to the east, the Magdelena Ecke YMCA facility to the south, Interstate 5 to the west and a private driveway to the north. The eastem third of the site is relatively flat, the central portion slopes gently to the west, and the western portion of the site is characterized by the confluence of two drainages and a low hill. Elevations within the property lines range from approximately 190 feet above mean sea level (MSL) in the northeast comer of the site, to approximately 125 feet MSL in the west central 1 portion of the site. At the time of this investigation, much of the subject site was being used to grow flowers. The site included a shallow irrigation system with some drainage control, graded dirt roads, one paved road, and a several residential structures (see Plate 1). Dumped vegetation and other debris was f observed in the drainages in the western portion of the site. 4.0 PROPOSED DEVELOPMENT At the time of our investigation, the development of the site was in the conceptual phases. In general, development of the site will likely require grading to provide level building pads. Preliminary drawings have shown three terraced pad areas separated by graded slopes up to 15- feet high. Development will encompass the entire property with the exception of the westemmost 115 of the property. Buildings will likely consist of single and two story, wood framed structures, with loads typical of lightweight construction. i Geotechnics Incorporated ri I Carltas Company January 9, 1996 5.0 GEOLOGY AND SUBSURFACE CONDITIONS Project No. 0054- 003 -00 Doc. #5-0634 Page No, 3 The subject site is located within the coastal plain of the Peninsular Range Geomorphic Province. The geology of the coastal plain is characterized by a thick, punctuated sequence of Late Mesozoic through Late Cenozoic sedimentary rocks resting on a basement of Mesozoic crystalline and melavolcanic rock. The sedimentary units are overlain by locally thick alluvial and colluvial deposits. The area has undergone broad uplift over the last 1.5 to 2 million years with little deformation of the bedrock. Active faulting now occurs along predominantly strike slip faults off- shore and within the Peninsular Ranges proper. 5.1 Geology The property is underlain by the Toney Sandstone and Pleistocene near -shore marine and non- marine sediments (Terrace Deposits). The sedimentary rocks are overlain by locally thick accumulations of recent alluvium and fill associated with the existing development. The distribution of the geologic units is shown on the Geotechnical Map, Plate 1. A j description of the units, from oldest to youngest follows. 1 5.1.1 Torrey Sandstone (Map Symbol - Tt) The Eocene Toney Sandstone underlies the entire site at depth. It was encountered in the exploratory test pits at the lower elevations of the site. The Torrey Sandstone consists of thickly bedded, cross - stratified, pale yellow gray, silty, medium to fine sand (SM using the Unified Soil Classification). The formation is very dense to locally cemented, is non expansive, and generally has a high ' shear strength. The Torrey Sandstone will be encountered where grading is conducted below elevation 140. f 5.1.2 Terrace Deposit (Map Symbol - Qt) Fourteen thousand years ago, relative sea level was much higher than today. As a result, the rivers also flowed at higher levels. The sediments deposited in the streams and beaches 14,000 years ago are now found perched on hillsides and E on the tops of mesas. The sediments were deposited on a terrace cut by wave action - hence the term "terrace deposit ". The wave cut terrace is marked by the f contact between the Torrey Sandstone and the Terrace Deposit at elevation 140. Ceotechnics Incorporated Caritas Company January 9, 1996 t Project No. 0054- 003 -00 Doc. #5 -0634 Page No. 4 1 The Bay Point Formation consists of a very dense to weakly cemented fine to coarse sand with local zones of clayey sand. The sand is reddish brown with greenish gray mottling. This formation has a very low to low expansion potential. 5.1.3 Alluvium (Map Symbol - Qal) Alluvium was encountered in the existing drainage areas and beneath rill soil in an old drainage next to Saxony Road. The alluvium ranged from 5 to at least 15 feet thick and is composed of loose, moist to wet, silty sand derived from the % surrounding soil and bedrock. Based on our experience in the area, the alluvium could be as thick as 20 to 25 feet locally. The alluvium is considered susceptible f to settlement under fill and foundation loads. This soil has no significant potential for expansion. ' 5.1.4 Fill (Map Symbol - fill) Man -made fill was encountered in the eastern third of the site, in the drainage in the western portion of the site, and locally in the graded pads along the northern site boundary. The fills appear to have been placed during grading for the residential pads, and to level a drainage area for use in the farming operation. The fills are composed primarily by non- expansive silty sand. However, the fill in the eastern portion of the site contained locally thick zones of plastic, highly expansive clay. The fills do not appear to have been placed in a controlled manner and as such are considered unsuitable for support of improvements as evident by the severe caving occurring during excavation of the exploration test 1 pits. The fills are susceptible to settlement under additional fill or structural loads. 5.1.5 Remedial Grading The estimated depth of compressible soil has been shown on the Geotechnical Map (Plate 1) next to each test pit. The compressible soil includes uncompacted rill, alluvium and the thin residual soil blanketing the Terrace Deposits. The estimates appear to be confirmed using aerial photographs taken prior to the fill t operations. It should be noted that thicker compressible soil may be encountered locally. Geotechnics Incorporated M e Caritas Company January 9, 1996 5.2 Seismicity Project No. 0054 -003 -00 Doc. #5 -0634 Page No. 5 The subject site is located approximately 3.6 miles east of the Rose Canyon fault zone. The Rose Canyon Fault is presently considered active, and is capable of a maximum ! probable earthquake of magnitude 6.4. The estimated peak ground acceleration for the site is 0.51g. This level of ground shaking could cause heavy cosmetic damage to the structures. Structural failure or collapse is unlikely if the design of structures complies with the requirements of the governing jurisdictions, building codes and standard practices of the Association of Structural Engineers of California. No faulting has been mapped or observed within the project site (see References, Appendix A). Groundbreaking due to active faulting is considered to have a low potential, due to the distance of the site from i known active faults. 5.3 Geolooic Hazards 1 I The subject site is not located within an area previously known for significant geologic hazards, nor was evidence of past soil failures noted in our investigation. 5.4 Groundwater Ground water or seepage was observed in fills and alluvium, near the contact with the underlying formational material. Shallow ground water will not likely affect the finished proposed development. It may, however, affect grading where deep removals may encounter wet conditions. Geotechnics Incorporated Caritas Company Project No. 0054 -003-00 January 9, 1996 Doe. #5 -0634 Page No. 6 i I 6.0 CONCLUSIONS AND RECOMMENDATIONS 6.1 General Discussion No geotechnical conditions were apparent during the investigation which would preclude construction of the proposed residential development as planned provided site constraints discussed herein are adequately addressed. The site is underlain by predominantly granular, non - expansive soil. The factors that will affect grading and construction at the site are as follows: Alluvium and old fills are recommended to be removed to bedrock and ■i recompacted back to original grade before receiving fill or structural loads. This ■ may require over excavating cuts within the pad areas. Transitions between bedrock and compacted rill are likely. To decrease the potential for differential settlement, the cut portion of the pad should be undercut to maintain uniform rill depth below building pads. Some of the undercut may be achieved during removal of old fills and alluvium. Buried structures (septic tanks and leach fields) will be encountered during grading and should be removed and replaced with compacted rill. Removals in drainage areas will likely encounter wet to saturated soil that may require special processing prior to being reused as rill. Difficult ripping in cemented sandstone may be expected locally. Oversized rock fragments generated from ripping the sandstone should be disposed off site or incorporated into fills as recommended below. The remainder of this report presents recommendations in detail. These recommendations are based on empirical and analytical methods typical of the standard of practice in southern California. If these recommendations appear not to cover any specific feature of the project, please contact our office for additions or revisions to the recommendations. Geotechnics Incorporated i Carltas Company January 9, 1996 i 6.2 Earthwork Construction Project No. 0054 -003 -00 Doc. 95 -0634 Page No. 7 I Grading and earthwork should be done in accordance with the "Standard Guidelines for Grading Projects" (Appendix D), with Chapter 70 of the Uniform Building Code, and the grading ordinance of the City of Encinitas. The following recommendations provide site- specific criteria, which should supersede those of Appendix D if conflicts occur. 6.2.1 Geotechnical Observation Geotechnics Incorporated personnel should continuously observe the grading and earthwork operations for this project. Such observations are essential to identify field conditions that differ from those predicted by preliminary investigations, to adjust designs to actual field conditions, and to see that the grading is in general accordance with the recommendations of this report. The recommendations of this report are contingent upon Geotechnics Incorporated performing this service. Our personnel should perform sufficient testing of fill during grading to support the I geotechnical consultant's professional opinion as to compliance of the fill with compaction recommendations. 1 6.2.2 Site Preparation The ground should be stripped and prepared to receive fill in accordance with the "Standard Guidelines for Grading Projects" (Appendix D). There are existing i structures on the site, including buildings, septic systems and pavements. These should be demolished and the resulting debris disposed of off -site. Soil disturbed by demolition operations should be removed to expose formational material. The existing topsoil, fill, and alluvium should be completely removed to expose formational material. Test pits did not indicate that the fills contained detrimental amounts of trash or debris. However, the use of the site as an agricultural site may have resulted in the disposal of trash and old vegetation in areas not explored during this investigation. Should trash fill be encountered, the trash fill should be segregated from clean fill and hauled off -site. The removal bottoms should be reviewed by our on -site representative during grading. Our subsurface explorations indicate removal depths should range from approximately 3 to 25 feet. Geotechnics Incorporated a Carltas Company '- January 9, 1996 6.2.3 Expansive Soil Project No. 0054 -003 -00 Doc. #5 -0634 Page No.6 Our explorations did indicate the local presence of detrimentally expansive soil in existing fill. Expansive clays should be removed from improvement areas. They I may be disposed of in deep fill areas if they are placed at least 4 feet below grade, and :,o closer than 8 feet from the face of slopes. 6.2.4 Cut/Fill Transitions l iStructures built across transitions between bedrock and compacted fill are susceptible to differential settlement. We recommend that the depth of fill from one side of a building to the other not exceed a ratio of 2:1. If the ratio is exceeded, we recommend that the cut or shallowest fill be undercut to achieve the ratio. The minimum undercut should be 3 feet. 6.2.5 Slope Stabilization I In general, cut slopes in formational materials or compacted fill slopes using on- site, low plasticity material should be stable with regard to deep- seated slope failures with a factor of safety of at least 1.5, at slope ratios of 2:1 (horizontal: vertical) or flatter, at heights of at least 20 feet. A representative of j Geotechnics Incorporated should evaluate materials exposed in planned cut slopes. If warranted, local stabilization fills may be recommended to improve surficial stability. It is recommended that all slopes be planted with vegetation to enhance slope stability. We recommend that plants be those adapted to semi -arid climates so that little or no irrigation is necessary. If possible, plants should include both deep I rooted woody varieties and ground cover. 6.2.6 Fill Slopes on Sloping Ground Grading plans indicate that fill slopes are planned to be constructed over natural y slopes. Because of the presence of loose colluvium on the slope, remedial grading is recommended to establish a stable base for the constructed slope. All Geotechnics Incorporated Caritas Company r January 9, 1996 i Project No. 0054.003 -00 Doc. #5-0634 Page No, 9 J s colluvium should be removed to expose undisturbed formational material, an benches should be constructed for fill placement. 6.2.7 Fill Compaction All fill and backfill to be placed in association with site development should be accomplished at slightly over optimum moisture conditions and using equipment that is capable of producing a uniformly compacted product. The minimum relative compaction recommended for fill is 90 percent of maximum density based on ASTM D1557 (modified Proctor). Sufficient observation and testing should be performed by the geotechnical consultant so that an opinion can be rendered as to the compaction achieved. As previously discussed, cuts in the Terrace Deposit may produce rock material because of localized cemented zones. Hard rocks over 12 inches in greatest dimension should not be used in fills during mass grading. Hard rocks over 6 ' inches in greatest dimension should not be used in trench or wall backfll. Oversized rocks should be segregated from the soil and be disposed of off -site. ' Representative samples of imported materials and on site soils should be tested by the geotechnical consultant in order to evaluate the maximum density, optimum moisture content, and where appropriate, shear strength, consolidation, and expansion characteristics of the soil. Soil having an expansive index greater than 20, based on the UBC test method, should not be used for on -site rills. During grading operations, soil types other than those analyzed in the geotechnical E reports may be encountered by the contractor. The geotechnical consultant should be notified to evaluate the suitability of these soils for use as fill and at finish } grade. 6.3 Site Drainage Foundation and slab performance depends greatly on how well the runoff waters drain from the site. This is true both during construction and over the entire life of the structure. The ground surface around structures should be graded so that water flows rapidly away from the str_;c:ures without ponding. The surface gradient needed to achieve this depends C eotechnics Incorporated i (t 3 Caritas Company Project No. 0054 -003 -00 January 9, 1996 Doc. #5-0634 Page No. 10 on the prevailing landscape. In general, we recommend that pavement and lawn areas t within rive feet of buildings slope away at gradients of at least two percent. Densely vegetated areas should have minimum gradients of at least five percent away from buildings in the first rive feet. Densely vegetated areas are considered those in which the planting type and spacing is such that the flow of water is impeded. Planters should be built so that water from them will not seep into the foundation, slab, or pavement areas. Roof drains are recommended, but they should discharge to a curb outlet. Site irrigation should be limited to the minimum necessary to sustain landscaping i plants. Should excessive irrigation, surface water intrusion, water line breaks, or unusually high rainfall occur, saturated zones or "perched" groundwater may develop in the underlying soils or bedrock. 6.4 Preliminary Foundation Recommendations 6.4.1 Design Parameters These recommendations are considered generally consistent with methods typically used in southern California. Other alternatives may be available. The foundation recommendations herein should not be considered to preclude more restrictive criteria of governing agencies or by the structural engineer. The design of the foundation system should be performed by the project structural engineer, incorporating the geotechnical parameters described in the following sections. After grading is complete these preliminary recommendations should be reviewed f with regard to any unanticipated soil conditions revealed during grading. Our i recommendations assume conventional isolated or continuous shallow foundations bearing in fill uniformly compacted as recommended under "Earthwork Construction ", or bearing in undisturbed formational material. Based on conditions observed during our exploration, we are assuming that the soils are not detrimentally expansive. Allowable Soil Bearing: 2,000 Ibs /ft' (allow a one -third increase for I short-term wind or seismic loads) Minimum Footing Width: 12 inches Ceotechuics Incorporated I i Caritas Company January 9, 1996 Minimum Fooling Depth Minimum Reinforcement: Project No. 0054 -003 -00 Doc. 95 -0634 Page No. 11 16 inches below lowest adjacent soil grade for two story structures. Two no. 4 bars at both top and bottom in continuous footings. Lateral loads against structures may be resisted Ly friction between the bottoms of footings or slabs and the supporting soil. A coefficient of friction of 0.3 is recommended. Alternatively, a passive pressure of 300 Ibs /ft' is recommended for the portion of vertical foundation members embedded into bedrock. If friction and passive pressure are combined, the passive pressure value should be reduced by one - third. 6.4.2 Slope Setback The foundations for structures should be setback from slopes a minimum horizontal distance of 10 feet. The setback should be measured from the outside i bottom of the footing horizontally to the slope face. The horizontal setback can be reduced by deepening the foundation in order to achieve the required setback distance projected from the footing bottom to the face of the slope. It should be recognized that the outer few feet of all slopes are susceptible to gradual down - slope movements due to slope creep. This will affect hardscape such as concrete t slabs. We recommend that settlement sensitive hardscape not be constructed within five feet of the top of slope. f 6.4.3 Settlement Settlement resulting from the bearing loads recommended for shallow foundations are not expected to exceed one inch and three - fourths of an inch, respectively, for ! total and differential settlements across the length of the structure. 6.5 Interior On -Grade Slabs Slabs should be designed for the anticipated loading. If an elastic design is used, a modulus of subgrade reaction of 200 kips /ft' should be suitable. As a minimum, slabs should be at least 5'/2 inches in thickness and be reinforced with at least #3 bars on 24 inch centers, each way. Geotechnics Incorporated s Caritas Company January 9, 1996 i 6.5.1 Moisture Protection for Slabs Project No. 0054-003 -00 Doc. #5-0634 Page No, 12 Concrete slabs constructed on soil ultimately cause the moisture content to rise in the underlying soil. This results from continued capillary rise and the termination of normal evapotranspiration. Because normal concrete is permeable, the moisture will eventually penetrate the slab unless some protection is provided. To decrease the likelihood of problems related to damp slabs, suitable moisture protection measures should be used where moisture sensitive floor coverings or other factors warrant. A commonly used moisture protection consists of about four inches of clean sand covered by 'visqueen' plastic sheeting. In addition, two inches of sand are placed over the plastic to decrease concrete curing problems i associated with placing concrete directly on an impermeable membrane. However, 1 it has been our experience that such systems will transmit from approximately 6 to 12 pounds of moisture per 1000 square feet per day. This may be excessive for some applications. If more protection is needed, we recommend that the slab be underlain by at least 6- inches of minus 3/4 -inch crushed rock, with no plastic membrane. In addition, concrete should have a water to cement ratio no greater than 0.5 and should be moist cured for five to seven days in accordance with guidelines of the American Concrete Institute. On -site quality control should be used to confirm the design conditions. ! 6.6 Exterior Slabs Detrimentally expansive soils are not anticipated to occur on the project site. Therefore, no special recommendations are considered necessary for exterior on -grade slabs such as walkways and patios. 6.7 Earth Retaining Structures Retaining wall should be backfilled with soil having and expansive index of 20 or less (UBC test method). Cantilever retaining walls may designed for an active earth pressure r ! approximated by an equivalent Fluid pressure of 35 Ibs /ft' for level backfill conditions, and 50 Ibs /ft' for 2:1 sloping backfill. The active pressure should be used for walls free to yield at the lop at least 0.2 percent of the wall height. For malls restrained so that such Ceotechnics Incorporated I Carttas Company Project No. 0054 -003 -00 January 9, 1996 _ Doc. 95 -0634 Pape No. 13 t t movement is not permitted, an equivalent Fluid pressure of 45 Ibsift' should be used, based on at -rest soil conditions and level backfill conditions. The above pressures do not E consider any surcharge loads, or hydrostatic pressures. If these are applicable, they will increase the lateral pressures on the wall and we should be contacted for additional recommendations. Walls should be fully back - drained to relieve any hydrostatic pressure. Retaining wall backfill should be compacted to at least 90 percent relative compaction, based on ASTM D1557. Backfill should not be placed until walls have achieved adequate structural strength. Heavy compaction equipment which could cause distress to walls f should not be used. 6.8 Pavements A Traffic Index of 6 was assumed for traffic conditions on the access drives for the project. 1 The project civil engineer should review these values to determine if they are appropriate. Based on these assumptions, and an R -Value of 69 determined in the laboratory, our analysis indicates the following design section should be suitable. Thickness of Asphalt Concrete: 3 inches Thickness of Aggregate Base: 4 inches Subgrade: native subgrade The upper 12 inches of the pavement subgrade should be scarified, brought to about optimum moisture content, and compacted to at least 95 percent of maximum dry density as determined by ASTM D1557. Aggregate base should conform to Crushed Aggregate Base or Crushed Miscellaneous Base specifications of the current Standard Specifications for Public Works Construction, and should be compacted to at least 95 percent of ASTM D1557. 6.9 Reactive Soils Testing of the on -site soil indicates that Type II cement should be suitable for use in all concrete which will be in contact with soil. Geotechnics Incorporated t r 3 r i Y i Cadtas Company Project No. 0054 -003 -00 January 9. 1996 Doc #5-0634 Page No. 14 7.0 LIMITATIONS OF INVESTIGATION This investigation was performed using the degree of care and skill ordinarily exercised, under similar circumstances, by reputable geotechnical consultants practicing in this or similar localities. No other warranty, expressed or implied, is made as to the conclusions and professional opinions included in this report. The samples taken and used for testing and the observations made are believed representative of the project site; however, soil and geologic conditions can vary significantly between borings. As in most projects, conditions revealed by excavation may be at variance with preliminary findings. If this occurs, the changed conditions must be evaluated by the geotechnical consultant and additional recommendations made, if warranted. This report is issued with the understanding that it is the responsibility of the owner, or of his { representative, to ensure that the information and recommendations contained herein are brought to the attention of the necessary design consultants for the project and incorporated into the plans, and the necessary steps are taken to see that the contractors carry out such recommenda- tions in the field. The findings of this report are valid as of the present date. However, changes in the condition of a property can occur with the passage of time, whether due to natural processes or the work of man on this or adjacent properties. In addition, changes in applicable or appropriate standards of practice may occur from legislation or the broadening of knowledge. Accordingly, the findings of this report may be invalidated wholly or partially by changes outside our control. Therefore, this report is subject to review and should not be relied upon after a period of three years. GEOTECHNICS INCORPORATED w "LEE rr VANDERHURST No. 1125 CERnRED CLNoC�00410�_ ENGINEERING A GEOLOGI T iOF1 � Anthony F. Belfast, P.E. 40333 W. Lee Vanderhursl C.E.G. 1125 Principal Engineer Principal Geologist Geotechnics Incorporated 1 f i It J e APPENDIX A REFERENCES American Society for Testing and Materials, 1992, Annual Book of ASTM Standards Section 4 Construction Volume 04.08 Soil and Rock Dimension Stone Geosynlhetics, ASTM, Philadelphia, PA, 1296 p. Anderson, J. G. , Rockwell, T. K., Agnew, D. C. 1989, Past and Possible Future Earthquakes of Significance to the San Diego Region, Earthquake Spectra, Vol. 5, No. 2. pp 299 -335. California Department of Conservation, Division of Mines and Geology , 1992, Fault Rupture Hazard Zones in California. Alquist- Priolo Special Studies Zone Act of 1972: California Division of Mines and Geology, Special Publication 42. County of San Diego, 1975, Topographic Survey, Sheet No. 322 -1677 International Conference of Building Officials, 1991, Uniform Building Code (with California Amendments) Title 23. Jennings, C. W. 1975, Fault Map of California, with Locations of Volcanoes, Thermal Springs, and Thermal Wells, California Geologic Data Map Series, Map No. 1 Kennedy, M. P., and Peterson, G. L., 1975, Geology of San Diego Metropolitan Area California: California Division of Mines and Geology Bulletin 200, 56 p. Seed. H. B., and Idriss, L M., 1982, Ground Motions and Soil Liquefaction during Earthquakes: Berkeley, California, Earthquake Engineering Research Institute, 134p. Trieman, J. A., 1984, The Rose Canyon Fault Zone — A Review and Analysis: California Division of Mines and Geology unpublished report, 106 p. United States Department of Agriculture, 1953, Flight AXN, Strip No. 8M, Frames 76, 77 Wesnousky, S. G., 1986, Earthquakes, Quaternary Faults, and Seismic Hazard in California: Journal of Geophysical Research, v. 91, no. 812, p. 12587- 12631. Geotechnics Incorporated I 1 L APPENDIX B Field Exploration Field exploration consisted of a visual reconnaissance of the site, the excavation of twenty four j test pits with a John Deere 710 rubber -tire backhoe on November 28, 1995. The maximum depth excavated was 22 feet. The pits were backfilled the same day. No compactive effort was applied to the backfill and settlement of 1 to 2 feet is likely. The approximate location of the test pits and borings is shown on Plate 1, Geotechnical Map. Logs describing the subsurface conditions encountered are presented on the following Figures B -1 through B -15. Bulk samples were retrieved from the spoil, bagged and brought back to the laboratory for testing. The test pits were located by visually estimating distances from landmarks shown on the site plans. The locations shown should not be considered more accurate than is implied by the method of measurement used and the scale of the map. The lines designating the interface between differing soil materials on the logs may be abrupt or gradational. Further, soil conditions at locations between the excavations may be substantially different from those at the specific locations explored. It should be recognized that the passage of time can result in changes in the soil conditions reported in our logs. Geotechnics Incorporated i LOG OF EXPLORATION TEST PIT NO. 1 Logged by: wLV Date: 11/28195 Method of Excavation: JD 710 EXTENSION BACKHOE Elevation: 191 H LL u a v E `s N DESCRIPTION TESTS � Y a J o 1 FILL: Silly sand ISM) fine grained nonplastic, medium brown, dry, loose 1 2 Terrace Deposit: Silty sand (SM) fine- medium grained, nonplastic, Grain Size 2 Terrace Deposit: Sandy clay (CL) 30% fine sand, medium plastic, 3 _ _ - - _ medium brown, moist, stiff- medium hard 3 - - - --- ----------------------------------------------- 4 silty sand w/ trace of clay(SM) fine to medium grained moist, dense -very dense Grain Size 5 nonplastic, orange brown mottled dark red brown and gray, 5 6 _ -- moist, very dense - - - -- 6 silly sand w/ trace of clay (SM) fine- medium grained, low 7 plastic, medium brown, moist, dense, local roots. 7 8 Total Depth 6 Feel 8 No Water, No Caving 9 Total Depth 10 Feet Backfilled 11/28/95 9 No Water, No Caving Backfilled 11/28/95 LOG OF EXPLORATION TEST PIT NO. 2 Logged by: WLV Date: 11128195 Method of Excavation: JD 710 EXTENSION BACKHOE Elevation: 189 H LL Y 6 Y p DESCRIPTION TESTS o Y a - 1 FILL: Silty sand (SM) fine grained nonplastic, medium brown, dry, loose 2 Terrace Deposit: Silty sand (SM) fine- medium grained, nonplastic, Grain Size yellow brown mottled reddish brown and gray, moist, very 3 _ _ - - _ _ _ - dense contains indistinct zones of medium plastic clayey - sand 4 silty sand (SM) fine- medium grained, nonplastic, dark brown, moist, dense -very dense Grain Size 5 q 6 7 8 Total Depth 6 Feel No Water, No Caving 9 Backfilled 11/28/95 PROJECT NO. 0054- 003 -00 GEOTECHNICS INCORPORATED FIGURE: B -1 LOG OF EXPLORATION TEST PIT NO. 3 Logged by: WLV Date: 11128195 Method of Excavation: JD 710 EXTENSION BACKHOE Elevation: 187 LL - Y E t a T_t y DESCRIPTION TESTS o m a m 1 FILL: Silty sand (SM) fine- medium grained, nonplastic, pale yellow 11 brown, dry loose, moderate caving 2 3 Alluvium: Silly sand (SM) rine grained, nonplastic, medium brown 4 dry, loose, scattered cobbles to 8" diameter, roots 13 5 14 6 15 7 8 Terrace Deposit: Silty sand (SM) medium grained, nonplastic, dark 16 9 brown, moist, dense -very dense LOG OF EXPLORATION TEST PIT NO. 3 (cont.) Logged by: WLV Date: 2/23/95 Method of Excavation: JD 710 EXTENSION BACKHOE Elevation: 187 LL Y E E t a N y DESCRIPTION TESTS o m a s m' FILL: Silty sand (SM) fine - medium grained, nonplastic, pale yellow 11 brown, dry loose, moderate caving 12 Alluvium: Silly sand (SM) rine grained, nonplastic, medium brown dry, loose, scattered cobbles to 8" diameter, roots 13 14 15 Terrace Deposit: Silty sand (SM) medium grained, nonplastic, dark 16 brown, moist, dense -very dense 17 Total Depth 16 Feet 18 No Water, Caving 2 to 11 feet Backfilled 11/28/95 19 PROJECT NO. 0054- 003 -o0 GEOTECHNICS INCORPORATED FIGURE: B -2 r i i J ■ ■ t I i i J (i LOG OF EXPLORATION TEST PIT NO. 4 Logged by: WLV Date: tinms Method of Excavation: JD 710 EXTENSION BACKHOE Elevation: 183 E E a H Y DESCRIPTION TESTS (5 m a ci m' 1 FILL: Silty sand (SM) fine- medium grained, nonplastic, pale yellow brown, dry loose, fragments of sandstone 2 3 4 5 6 16 Terrace Deposit: silty sand (SM) fine- medium grained, nonplastic, 7 Alluvium: Silty sand (SM) fine- medium grained, nonplastic, dark 17 brown, dry, loose, porous, roots 8 18 Total Depth 15 Feet 9 No Water, No Caving LOG OF EXPLORATION TEST PIT NO. 4 (cont.) Logged by: WLV Date: 11/28/95 Method of Excavation: JD 710 EXTENSION BACKHOE Elevation: 183 a H H DESCRIPTION TESTS 11 Alluvium: Silty sand (SM) fine- medium grained, nonplastic, dark brown, dry, loose, porous, roots 12 13 14 15 16 Terrace Deposit: silty sand (SM) fine- medium grained, nonplastic, dark brown mottled gray, moist, dense -very dense, weakly 17 cemented 18 Total Depth 15 Feet No Water, No Caving 19 Backfilled 11/28/95 PROJECT NO. 0054- 003 -00 GEOTECHNICS INCORPORATED FIGURE: B -3 LOG OF EXPLORATION TEST PIT NO. 5 Logged by: WLV Date: 11/28/95 Method of Excavation: JD 710 EXTENSION BACKHOE Elevation: 184 LL � H LL b 4 E a a N DESCRIPTION h DESCRIPTION TESTS © C a Y o 11 a m 1 moist, loose FILL: Silty sand (SM) medium grained, nonplastic, pale yellow brown, 12 w/ zones of red brown sand (SP), moist -wet, loose, severe 13 2 caving 14 3 15 - - 4 - - ----------------------------------------------- 16 5 becomes very dense - severe caving above 15' - abandoned pit 17 6 - - -- ----------------------------------------------- 18 7 Total Depth 15 Feet sandy clay (CL) medium grained, highly plastic, olive gray, No Water, Caving from 0 to 15 feel very moist, soft, fragments of olive green claystone 19 8 - - -- -------------- ---------------- -- - - - - -- - -- 9 sand (SP) medium grained, nonplastic, dark reddish brown, wet, loose LOG OF EXPLORATION TEST PIT NO. 5 (cont.) Logged by: WLV Date: 11/28/95 Method of Excavation: JD 710 EXTENSION BACKHOE Elevation: 189 H LL LL � a 6 E d E E a N N DESCRIPTION TESTS V � © C a Y o 11 Alluvium: silty sand (S M) fine- medium grained, nonplastic, dark brown moist, loose 12 13 14 15 - - - - - - ----------------------------------------------- 16 becomes very dense - severe caving above 15' - abandoned pit 17 18 Total Depth 15 Feet No Water, Caving from 0 to 15 feel 19 Backfilled 11/28/95 LPROJECT NO 0054- 003 -00 GEOTECHNICS INCORPORATED FIGURE: B -4 LOG OF EXPLORATION TEST PIT NO.6 Logged by: WLV Date: 11/28/95 Method of Excavation: JD 710 EXTENSION BACKHOE Elevation: 185 u E u E `s N h DESCRIPTION TESTS Q m C m 1 FILL: Silty sand (SM) fine - medium grained, nonplastic, pale yellow 1 brown, moist, loose 2 Residual Soil: sandy clay (CL) 30% medium sand, medium plastic 3 - - -- ----------------------------------------------- sand (SP) medium grained, nonplastic, dark reddish brown, 4 wet, medium dense 3 Residual Soil: Sandy clay (CL) fine- medium grained, low plastic, Alterberg 5 olive gray mottled reddish brown, soft -stiff Expansion 4 6 Terrace Deposit: silty sand w/ trace of clay (SM) nonplastic, 6 olive gray mottled reddish brown, moist, very dense 7 8 Total Depth 8 Feel 9 No Water, No Caving Backfilled 11/28/95 LOG OF EXPLORATION TEST PIT NO. 7 Logged by: WLV Date: 11/28/95 Method of Excavation: JD 710 EXTENSION BACKHOE Elevation: 184 d E d E r N h DESCRIPTION TESTS G Q W J FILL: silty sand (SM) fine- coarse grained. nonplastic, dry, medium 1 brown, loose Residual Soil: sandy clay (CL) 30% medium sand, medium plastic dark reddish brown mottled gray, damp, very stiff 2 3 Terrace Deposit: silty sand (SM) fine - medium grained, dark brown mottled pale gray and olive gray, moist, very dense 4 S 6 7 8 Total Depth 8 Feel 9 No Water, No Caving Backfilled 11128/95 PROJECT NO. 0054-003-00 GEOTECHNICS INCORPORATED FIGURE: B -5 LOG OF EXPLORATION TEST PI1 NO. 8 Logged by: WLV Date: 11/28/95 Method of Excavation: JD 710 EXTENSION BACKHOE Elevation: 187 LL LL d E v E G O N N Y DESCRIPTION TESTS o m d a m FILL: silly sand (SM) fine - coarse grained, nonplaslic, dry, pale 1 yellow brown, loose 2 Residual Soil: Clay (CH) highly plastic, reddish brown mottled 2 Residual Soil: Clay (CL) medium plastic, reddish brown mottled 3 - - - - -- gray, moist, stiff 3 - - - --- ----------------------------------------------- 4 Terrace Deposit: silty sand and dandy clay mix (SM. SC) nonplaslic to 5 medium plastic, dark reddish brown, mottled gray, moist Expansion 5 very dense to hard 6 7 Total Depth 7 Feet 8 No Water, No Caving 9 Total Depth 8 Feel 9 No Water, No Caving Backfilled 11/28/95 LOG OF EXPLORATION TEST PIT NO. 9 Logged by: WLV Date: 11/28/95 Method of Excavation: JD 710 EXTENSION BACKHOE Elevation: 187 LL LL a c d C E r G O N N DESCRIPTION TESTS 4 Q m C d a Y � m FILL: silty sand (SM) fine- coarse grained, nonplastic, dry, 1 medium brown, loose 2 Residual Soil: Clay (CH) highly plastic, reddish brown mottled gray, moist, stiff 3 - - - - -- ----------------------------------------------- 4 Terrace Deposit: sandy clay (CH) highly plastic, dark reddish brown mottled gray, moist, very stiff, mottled w/ silty sand (SM) 5 6 7 8 Total Depth 7 Feet No Water, No Caving 9 Backfilled 11128/95 PROJECT NO. 0054- 003 -00 GEOTECHNICS INCORPORATED FIGURE: B -6 1 ■ 1 LOG OF EXPLORATION TEST PIT NO. 10 Logged by: WLV Date: 11/28/95 Method of Excavation: JD 710 EXTENSION BACKHOE Elevation: 170 _ ~ a v E d ZL E o " N DESCRIPTION TESTS W 0 m a m 1 Residual Soil: Silty sand (SM) nonplastic, fine - medium grained 1 yellow brown, dry. loose 2 2 Terrace Deposit: silty sand (SM) medium- coarse grained, nonplastic, 4 - - - - -- medium reddish brown, dry very dense, weakly cemented 3 gravel (GP) poorly graded 2" diameter gravel, old leach field 4 5 pH 6 Terrace Deposit: silly sand (SM) medium - coarse grained, nonplastic, Resistivity 6 medium reddish brown, dry very dense, weakly cemented Sulfate 7 7 6 Total Depth 7 Feel 8 No Water, No Caving Total Depth 7 Feet 9 9 Backfilled 11/28/95 No Water, No Caving Backfilled 11/28/95 LOG OF EXPLORATION TEST PIT NO. 11 Logged by: WLV Date: 11/28/95 Method of Excavation: JD 710 EXTENSION BACKHOE Elevation: 170 LL a a E M ar E t Z. ; O N DESCRIPTION TESTS W 0 m C N a y j m 1 FILL: Silty sand (SM) nonplastic, fine - medium grained yellow brown, dry, medium dense 2 3 4 - - - - -- ----------------------------------------------- gravel (GP) poorly graded 2" diameter gravel, old leach field 5 6 Terrace Deposit: silly sand (SM) medium - coarse grained, nonplastic, medium reddish brown, dry very dense, weakly cemented 7 6 Total Depth 7 Feel No Water, No Caving 9 Backfilled 11/28/95 PROJECT NO. 0054- D03 -oo GEOTECHNICS INCORPORATED FIGURE: B -7 LOG OF EXPLORATION TEST PIT NO. 12 Logged by: WLv Date: 11/28/95 Method of Excavation: JD 710 EXTENSION BACKHOE Elevation: 168 F LL n n a h Y DESCRIPTION TESTS y Q m C W a J m Residual Soil: Silty sand (SM) nonplastic, fine- medium grained 1 yellow brown, dry, loose 2 Terrace Deposit: silly sand (SM) medium - coarse grained, nonplastic, medium reddish brown, dry very dense, weakly cemented 3 4 5 Total Depth 4 Feet No Water, No Caving 6 Backfilled 11/28/95 7 Backfilled 11/28/95 7 L 98 LOG OF EXPLORATION TEST PIT NO. 13 Logged by: WI_v Date: 11/28/95 Method of Excavation: JD 710 EXTENSION BACKHOE Elevation: 178 F LL v n o N N Y DESCRIPTION TESTS � in Y a � m Residual Soil: Silty sand (SM) nonplastic, fine - medium grained 1 yellow brown, dry, loose 2 Terrace Deposit: silty sand (SM) medium - coarse grained, nonplastic, medium reddish brown, dry very dense, weakly cemented 3 4 5 Total Depth 4 Feet 6 No Water, No Caving Backfilled 11/28/95 7 8 9 PROJECT NO. 0054- 003 -00 GEOTECHNICS INCORPORATED FIGURE B -8 i I LOG OF EXPLORATION TEST PIT NO. 14 Logged by: WLV Date: 11/28/95 Method of Excavation: JD 710 EXTENSION BACKHOE Elevation: 170 P7 LL 3 a a N y DESCRIPTION TESTS m � Y 1 Colluvium: Silly sand (SM), nonplastic, medium brown, dry, loose, roots 2 dry, dense 3 Residual Soil: Silty sand (SM) nonplastic, yellow brown, dry, loose, 4 Terrace Deposits: silty sand (SM) coarse grained, nonplastic, medium brown, dry, very dense, moderately cemented 5 Terrrace Deposits: Silty sand (SM) coarse grained, nonplastic, medium 6 5 Total Depth 4 Feet 7 No Water, No Caving 6 Backfilled 11/28195 8 9 7 LOG OF EXPLORATION TEST PIT NO. 15 Logged by: WLV Date: 11/28/95 Method of Excavation: JD 710 EXTENSION BACKHOE Elevation: 170 LL LL Y n Y E r h N DESCRIPTION TESTS m � Y 1 FILL: Silty sand (SM) medium -fine grained, nonplastic, yellow brown dry, dense 2 Residual Soil: Silty sand (SM) nonplastic, yellow brown, dry, loose, 3 roots 4 Terrrace Deposits: Silty sand (SM) coarse grained, nonplastic, medium reddish brown, dry, very dense, massive 5 6 Total Depth 5 Feet No Water, No Caving 7 Backfilled 11/28/95 8 9 PROJECT NO. 0054- 003 -00 GEOTECHNICS INCORPORATED FIGURE: B -9 LOG OF EXPLORATION TEST PIT NO. 16 Logged by: WLv Date: 11/28/95 Method of Excavation: JD 710 EXTENSION BACKHOE Elevation: 164 LL Y A Y E o j DESCRIPTION TESTS V Q © a m Residual Soil Silly sand (SM) coarse grained, nonplastic, dark reddish 1 brown, d , medium dense 2 Terrace Deposit: Sand (SP) coarse grained, nonplastic, dark reddish 2 brown, moist, very dense 3 brown, moist, very dense 4 5 5 6 6 Total Depth 5 Feel 7 No Water, No Caving 7 Backfilled 11/28195 8 Backfilled 11/28/95 9 LOG OF EXPLORATION TEST PIT NO.17 Logged by: WLV Date: 11/28/95 Method of Excavation: JD 710 EXTENSION BACKHOE Elevation: 15o Y Y a DESCRIPTION TESTS V Q © C V a Y 7 m Residual Soil: Silly sand (SM) coarse grained, nonplastic, dark reddish 1 brown, dry, medium dense 2 Terrace Deposit: Sand (SP) coarse grained, nonplastic, dark reddish brown, moist, very dense 3 4 5 6 Total Depth 5 Feet 7 No Water, No Caving Backfilled 11/28/95 8 9 fPROJECT NO. 0054- 003 -00 GEOTECHNICS INCORPORATED FIGURE' B -10 y I I t_U V Ur- cArL,UKA I ION i L51 HI i NO. 18 Logged by: WLV Date: 11128195 Method of Excavation: JD 710 EXTENSION BACKHOE Elevation: 137 _V _V ~ LL d E LL E N DESCRIPTION V a S TESTS m p u a m FILL: Silly sand (SIV) medium- coarse grained, nonplastic, pale yellow 1 --------- brown dry, loose 2 sand(SP) medium to coarse grained, nonplastic, dark reddish brown and dark brown, moist -very moist, loose to medium 3 dense, pipe and plastic fragments 4 S 6 7 Alluvium: sand(SP) medium to coarse grained, nonplastic, dark reddish brown and dark brown, moist -very moist, loose to medium 8 9 LOG OF EXPLORATION TEST PIT NO. 18 (cont.) Logged by: WLv Date: 11/28/95 Method of Excavation: JD 710 EXTENSION BACKHOE Elevation: 137 u u LL n a o d j DESCRIPTION TESTS m 11 Alluvium: sand(SP) medium to coarse grained, nonplastic, dark reddish brown and dark brown, moist -very moist, loose to medium 12 13 14 15 16 17 18 19 Total Depth 18 Feet No Water, Caving 2 to 11 feet Backfilled 11/28/95 PROJECT NO. 0054- 003 -00 GEOTECHNICS INCORPORATED FIGURE: B -11 .1 I j r fl J i Ur c.vNLUKATION TEST PIT NO. 19 Logged by: WLv Method of Excavation: JD 710 EXTENSION BACKHOE LL N N C o m d DESCRIPTION a m Date: 11/ Elevation: 147 1 FILL: Silty sand w/ gravel (SM) nonplastic, coarse grained, pale yellow brown, dry loose 2 Terrace Deposit: Slightly silly sand SM g rained, nonplastic, 3 dark reddish brown, damp, very dense 4 5 5 Total Depth 4 Feel No Water, No Caving 7 Backfilled 11/28/95 8 9 �vv Ur tAHLORATION TEST PIT NO. 20 Logged by: WLv Method of Excavation: JD 710 EXTENSION BACKHOE F P1 6 E n d m DESCRIPTION o d TE Date: 11/28 Elevation: 137 1 Terrace Deposit: Silty sand (SM) coarse grained, nonplastic, dark reddish brown, dry, dense, cobble stringer at 2- 2 3 Torrey Sandstone: Silty sand (SM), fine grained, nonplastic, pale yellow gray, dry, very dense 4 5 8 7 8 Total Depth 4 Feet No Water, No Caving 9 Backfilled 11/28/95 TES PROJECT NO. 0054- 003 -00 GEOTECHNICS INCORPORATFn _ CIIH inr. n •w i LOG OF EXPLORATION TEST PIT NO. 21 Logged by: WLv Date: 11128195 Method of Excavation: JD 710 EXTENSION BACKHOE Elevation: 130 LL F E c V E V n a o n N N DESCRIPTION TESTS O O � m w � 1 a m brown, dry, loose Residual Soil: silly sand (SM) fine grained, nonplastic, pale yellow 2 - - 1 ----------------------------------------------- brown, dry, loose, with scattered gravel 3 FILUColluvium? silly, clayey sand (SM), nonplastic, medium to fine 2 grained, medium brown to dark brown w/ depth, moist -wet Torrey Sandstone: silty sand (SM) fine grained nonplastic, pale yellow 4 w/ depth, loose gray w/ brown mottling on fractures, dry, very dense 5 3 6 7 4 I Total Depth 3 Feet B No Water, No Caving 9 5 Backfilled 11/28/95 7 8 t 96 LOG OF EXPLORATION TEST PIT NO.22 Logged by: WLv Date: 11/28/95 Method of Excavation: JD 710 EXTENSION BACKHOE Elevation: 127 _ LL LL v E E E c a o DESCRIPTION TESTS v 0 O c V a � m 1 FILL: Silty sand (SM) fine- medium grained, nonplastic, pale yellow brown, dry, loose 2 - - - --- ----------------------------------------------- 3 FILUColluvium? silly, clayey sand (SM), nonplastic, medium to fine grained, medium brown to dark brown w/ depth, moist -wet 4 w/ depth, loose 5 6 7 I B 9 PROJECT NO. 0054- 003 -00 GEOTECHNICS INCORPORATED FIGURE B -13 LOG OF EXPLORATION TEST PIT NO. 22 (cont.) Logged by: WLV Date: 11/28/95 Method of Excavation: JD 710 EXTENSION BACKHOE Elevation: 127 LL F _ d E d E L d 0 r a N y s DESCRIPTION TESTS m � m a m 21 11 Torrey Sandstone: Sand (SP) fine grained, nonplastic, orange brown FILUColluviL:m? silly, clayey sand ISM). nonplastic, medium to fine mottled gray, very moist, dense, highly weathered bedrock grained, medium brown to dark brown w/ depth, moist -wet 22 12 w/ depth, loose 23 13 Total Depth 22 Feet 14 No Water, No Caving 24 15 Backfilled 11128195 25 16 26 17 27 18 28 28 19 Torrey Sandstone: Sand (SP) fine grained, nonplastic, orange brown mottled gray, very moist, dense, highly weathered bedrock LOG OF EXPLORATION TEST PIT NO. 22 (cont.) Logged by: WLV Date: 11/28/95 Method of Excavation: JD 710 EXTENSION BACKHOE Elevation: LL LL v a d n L d 0 N DESCRIPTION TESTS m � s 21 Torrey Sandstone: Sand (SP) fine grained, nonplastic, orange brown mottled gray, very moist, dense, highly weathered bedrock 22 23 Total Depth 22 Feet No Water, No Caving 24 Backfilled 11128195 25 26 27 28 28 PROJECT NO. 0054 - 003 -00 GEOTECHNICS INCORPORATED FIGURE: B -14 LOG OF EXPLORATION TEST PIT NO. Logged by: WLV Date: 11/28/95 Method of Excavation: JD 710 EXTENSION BACKHOE Elevation: 142 F LL a a n o N Y DESCRIPTION TESTS a © N N x DESCRIPTION TESTS o m a a m Residual Soil: Silty sand (SM) coarse grained, nonplastic, dark reddish 1 Terrace Deposit: Sand (SP) coarse grainetl, nonplastic, dark reddish 1 brown, moist, dense -very dense 2 Terrace Deposit: Sand (SP) coarse grained, nonplastic, dark reddish 3 ------ ------------------ --- -------------------- - - - - - cobbles GM -SM 50% cobbles to 6° diameter in silly sand 4 matrix, nonplastic, dark reddish brown, dry, very dense 4 5 Torrey Sandstone: Silty sand ISM) fne grained, nonplastic, pale yellow 5 gray, moist, very dense 6 No Water, No Caving 6 Backfilled 11/28/95 7 Total Depth 6Feet 8 No Water, No Caving 8 Backfilled 11/28/95 9 LOG OF EXPLORATION TEST PIT NO. 24 Logged by: WLv Date: 11/28/95 Method of Excavation: JD 710 EXTENSION BACKHOE Elevation: 172 F LL a S a E n o N Y DESCRIPTION TESTS a O © c a C � � Residual Soil: Silty sand (SM) coarse grained, nonplastic, dark reddish 1 brown, dry, medium dense 2 Terrace Deposit: Sand (SP) coarse grained, nonplastic, dark reddish brown moist, very dense 3 4 5 Total Depth 4 Feel No Water, No Caving 6 Backfilled 11/28/95 7 8 9 PROJECT NO. 0054- 003 -oo GEOTECHNICS INCORPORATED FIGURE: B -15 i l I I I i LOG OF EXPLORATION TEST PIT NO. 23 Logged by: w v Date: 11128195 Method of Excavation: JD 71n FxTFn clnnl aervun� LOG OF EXPLORATION TEST PIT NO. 24 Logged by: WLv Date: 11/28/95 Method of Excavation: JD 710 EXTENSION BACKHOE Elevation: 172 v v a o N N DESCRIPTION TESTS a m Residual Soil: Silly sand (SM) coarse grained, nonplastic, dark reddish 1 brown, dry, medium dense 2 Terrace Deposit: Sand (SP) coarse grained, nonplastic, dark reddish brown moist, very dense 3 4 5 Total Depth 4 Feet No Water, No Caving 6 Backfilled 11/28/95 7 8 9 PROJECT NO. 0054- 003 -00 GEOTECHNICS INCORPORATED FIGURE: B -15 ( d n d ucYq \IV11. RL o `a '^ r DESCRIPTION TESTS u O m u a � m Terrace Deposit: Sand (SP) coarse grained, nonplastic, dark reddish 1 brown, moist, dense -very dense 2 3 - - - - - - ----------------------------------------------- cobbles (GM -SM) 50% cobbles to 6" diameter in silly sand 4 matrix, nonplastic, dark reddish brown, d , very dense 5 Torrey Sandstone: Silly sand (SM) tine grained, nonplastic, pale yellow gray, moist, very dense 6 7 Total Depth 6Feet No Water, No Caving 8 Backfilled 11/28/95 9 LOG OF EXPLORATION TEST PIT NO. 24 Logged by: WLv Date: 11/28/95 Method of Excavation: JD 710 EXTENSION BACKHOE Elevation: 172 v v a o N N DESCRIPTION TESTS a m Residual Soil: Silly sand (SM) coarse grained, nonplastic, dark reddish 1 brown, dry, medium dense 2 Terrace Deposit: Sand (SP) coarse grained, nonplastic, dark reddish brown moist, very dense 3 4 5 Total Depth 4 Feet No Water, No Caving 6 Backfilled 11/28/95 7 8 9 PROJECT NO. 0054- 003 -00 GEOTECHNICS INCORPORATED FIGURE: B -15 S i APPENDIX C LABORATORY TESTING Samples typical of the soils encountered were selected for laboratory testing. Testing was performed in accordance with methods of ASTM or other commonly accepted methods. Classification: Soils were classified visually according to the Unified Soil Classification System. Visual classification was supplemented by laboratory testing of selected samples and clas- sification in accordance with ASTM D2487. The soil classifications are shown on the test pit logs in Appendix B. Particle Size Analysis: Particle size analyses were performed in accordance with ASTM D422. The grain size distribution was used to determine presumptive strength parameters and to develop foundation design criteria. The results are provided in Figures C -1 through C -2. pH and Resistivity: To assess their potential for reactivity with metal pipe, a representative sample was tested for pH and resistivity, using CALTRANS method 643. The results are listed in Figure C -3 Sulfate Content: To assess their potential for reactivity with concrete, a representative sample was tested for content of water - soluble sulfate minerals using CALTRANS method 417 (Part I). The results are listed in Figure C -3. Gcolcchnics Inwrpornlcd toc 90 80 70 r 60 rn 50 T a 40 LL v 30 w d 20 10 0 1 1 0.1 0.01 Grain Size in Millimeters COARSE I FINE COARSE MEDIUM FINE SILT AND GRAVEL SANG CLAY SAMPLE EXPLORATION NUMBER: TP -2 SAMPLE DEPTH: 7 UNIFIED SOIL CLASSIFICATION; SM DESCRIPTION: Silty Sand 0 10 20 L of 30 T a 40 v `n 0 50 U c a 60 v a 70 M 90 100 0.001 ATTERBERG LIMITS LIQUID LIMIT: PLASTIC LIMIT: PLASTICILY INDEX: N. P. � `Gcofecltinics PARTICLE SIZE ANALYSIS PROJECT NO, D054- 003 -00 Incorporated AND ATTERBERG LIMITS DOC. tF 5 -0634 TFIGURE C -1 1 Z f rn a c LL C I v u v a 2 1 1 ■ 1 ' 1 ; 1 ' 1 ' 1 'I 1 .I� v COARSE FINE GRAVEL SAMPLE EXPLORATION NUMBER: TP -2 SAMPLE DEPTH: 2' GeotechnlcS � Incorporated 0.1 Grain Size in Millimeters COARSE MEDIUM FINE SAND UNIFIED SOIL CLASSIFICATION: SM DESCRIPTION: Silty Sand Hydrometer ---FFT-1 0.01 0 10 20 L 30 3 T D I 40d 50 U c , v 60 v 70 a i 80 90 i 100 0.001 SILT AND CLAY ATTERBERG LIMITS LIOUID LIMIT: PLASTIC LIMIT. PLASTICILY INDEX: N. P. PARTICLE SIZE ANALYSIS I PROJECT NO. 0054. 003 -00 I AND ATTERBERG LIMITS DOC. # 5.0634 FIGURE C -2 APPENDIX D STANDARD GUIDELINES FOR GRADING PROJECTS Ceotechnics Incorporated h STANDARD GUIDELINES FOR GRADING PROJECTS 1.0 GENERAL Appendix D Page I 1.1 Representatives of Geotechnics Incorporated should be present on -site during grading operations in order to make observations and perform tests so that professional opinions can be developed. The opinion will address whether grading has proceeded in accordance with the Geotechnical Consultant's ! recommendations and applicable project specifications; if the site soil and geologic conditions are as anticipated in the preliminary investigation; and if additional recommendations are warranted by any unexpected site conditions. Services do not include supervision or direction of the actual work of the contractor, his employees or agents. 12 The guidelines contained herein and the standard details attached hereto represent this firm's standard recommendations for grading and other associated operations on construction projects. These guide!ines should be considered a portion of the report to which they are appended. 1.3 All figures attached hereto shall be considered as part of these guidelines. 1.4 The Contractor should not vary from these guidelines without prior recommendation by Geotechnics Incorporated and the approval of the Client or his authorized representative. 1.5 These Standard Grading Guidelines and Standard Details may be modified and /or superseded by recommendations contained in the text of the geotechnical report and/or subsequent reports. Where a conflict may appear to exist, the recommendations of the body of the geotechnical reports will supersede those of the standard guidelines. 1.6 If disputes arise out of the interpretation of these grading guidelines or standard details, Geotechnics Incorporated should determine the appropriate interpretation. 2.0 DEFINITION OF TERMS Geotechnics Incorporated Appendix D Page II 2.1 ALLUVIUM — Detrital deposits resulting from (low of water, including sediments deposited in river beds, canyons, flood plains, lakes, fans at the foot of slopes and estuaries. 2.2 AS- GRADED — The surface and subsurface conditions at completion of grading. 2.3 BACKCUT — A temporary construction slope or excavation at the rear of buttresses, stabilization rills or retaining walls. 2.4 BACKDRAIN — Generally a perforated pipe and surrounding filter or similar drainage system placed behind earth retaining structures, buttresses, and stabilization rills. 2.5 BEDROCK — A relatively undisturbed consolidated sedimentary or igneous formational deposit, exposed either at the surface or beneath superficial deposits of soil. 2.6 BENCH — A relatively level step with a near vertical rise excavated into sloping ground on which fill is to be placed. See also "Terrace". 2.7 BORROW (Import) — Any fill material hauled to the project site from off -site areas. 2.8 BUTTRESS FILL — A fill mass, the configuration of which is designed by engineering calculations to enhance the stability of slopes, where deep-seated failure is of concem. A buttress is generally specified by minimum key width and depth, and by maximum steepness of the backcut angle. Fill materials with specified characteristics may be recommended for the buttress construction. A buttress may contain a back -drain system. 2.9 CIVIL ENGINEER — The Registered Civil Engineer or consulting firm responsible for preparation of the grading plans, surveying and verifying as- graded topographic conditions. 2.10 COLLUVIUM — Generally poorly consolidated deposits usually located near the base of slopes, and brought there primarily by gravity through slope creep (also see Slope Wash). 2.11 COMPACTION — Is the densification of a fill material by mechanical means. Ceotechnics Incorporated Appendix D Page III 2.12 CONTRACTOR — A person or company under contract or otherwise retained by the Client to perform demolition, earthwork, or other site improvements. 2.13 DEBRIS — All products of clearing, grubbing, demolition, and soil material unsuitable for reuse as compacted fill and /or any other material so designated by the Geotechnical Consultant. 2.14 ENGINEERING GEOLOGIST — A Geologist holding a valid certificate of registration in the specialty of Engineering Geology. 2.15 ENGINEERED FILL — A fill of which the Geotechnical Consultant or his representative, during grading, has made sufficient tests and observations to enable him to conclude that the fill has been placed in substantial compliance with the recommendations of the Geotechnical Consultant and the governing agency requirements. This generally requires that the consultants representative be present on a continuous basis when fill is placed. 2.16 EROSION — The wearing away of the ground surface as a result of the movement of wind, water, and /or ice. 2.17 EXCAVATION -- The mechanical removal of earth materials. 2.18 EXISTING GRADE — The ground surface configuration prior to new grading. 2.19 FILL — Any soil, rock, soil -rock blends or other similar materials placed by man. 2.20 FINISH GRADE — The ground surface configuration at which time the surface elevations conform to the approved plan. 2.21 GEOFABRIC — Any engineering textile utilized in geotechnical applications including subgrade stabilization, back - drains, subdrains, and earth reinforcement. 2.22 GEOLOGIST — A representative of the Geotechnical Consultant educated and trained in the field of geology. 2.23 GEOTECHNICAL CONSULTANT — The Geotechnical Engineering and Engineering Geology consulting firm retained to provide technical services for the project. For the purpose of these guidelines, observations by the Geotechnical Ceotechnics Incorporated Appendix D Page IV Consultant include observations by the Geotechnical Engineer, Engineering Geologist and those performed by persons employed by and responsible to the Geotechnical Consultant. 2.24 GEOTECHNICAL ENGINEER — A licensed Civil Engineer who applies scientific methods, engineering principles and professional experience to the acquisition, interpretation and use of knowledge of soil and bedrock materials for the evaluation of engineering problems. Geotechnical Engineering encompasses many of the engineering aspects of soil mechanics, rock mechanics, geology, geophysics, hydrology and related sciences. 2.25 GRADING —Any operation consisting of excavation, filling or combinations thereof, and associated operations. 2.26 LANDSLIDE DEBRIS — Soil or bedrock materials that has been transported 'within the landslide mass. 2.27 MAXIMUM DENSITY — Standard laboratory test for maximum dry unit weight. Unless otherwise specified, the maximum dry unit weight shall be determined in accordance with ASTM D1557. 2.28 OPTIMUM MOISTURE — Test moisture content at the maximum density, determined in accordance with ASTM D1557. 2.29 RELATIVE COMPACTION — The degree of compaction of a fill material, given as the in -place dry unit weight as a percentage of the maximum density. 2.30 ROUGH GRADE — The ground surface configuration where the surface elevations approximately conform to the approved grading plan. 2.31 SITE — The particular parcel of land where grading is being performed, as defined by the grading plan. 2.32 SLOPE — A natural or constructed inclined ground surface, the steepness of which is generally specified as a ratio of horizontal:vertical (e.g., 2:1). 2.33 SLOPE WASH — Soil and/or rock material that has been transported down a slope by mass wasting assisted by surface runoff water (also see Colluvium). Ceotechnics Incorporated Appendix D Page V 2.34 SOIL — Naturally occurring deposits of sand, silt, clay, etc., or combinations thereof, that is not cemented and typically unconsolidated. 2.35 SOIL ENGINEER — Licensed Civil Engineer experienced in soil mechanics (also see Geolechnical Engineer). 2.36 STABILIZATION FILL — A rill mass, the configuration of which is typically related to slope height ano is specified by the standards of practice for enhancing the stability of slopes which may be subject to excessive creep, erosion, or surficial instability. A stabilization rill is normally specified by minimum key width and depth, and by maximum steepness of the backcut angle. A stabilization fill may or may not have a back -drain system specified. Similar to a buttress fill, however the term buttress fill is generally reserved for fills used to stabilize deep-seated instabilities. 2.37 SUBDRAIN — Generally a perforated pipe surrounded with a gravel or geofabric filter, or similar drainage system placed beneath a rill in the alignment of canyons or former drainage channels. May include synthetic composite drain -panel systems. 2.38 SLOUGH — Loose, un- compacted rill material generated during grading operations. 2.39 TAILINGS — Non - engineered rill which accumulates on or adjacent to equipment haul- roads, as the result of spillage during transport. 2.40 TERRACE -- Relatively level step constructed in the face of a graded slope surface for drainage control and maintenance purposes. 2.41 TOPSOIL — The upper weathered zone of soil which is usually darker in color, soft or loose, and often contains vegetation debris. 2.42 WINDROW — A horizontal row of large rock buried within engineered fill in accordance with guidelines set forth by the Geotechnical Consultant for oversize rock placement. 3.0 SITE PREPARATION Ceotechnics Incorporated Appendix D Page VI 3.1 Clearing and grubbing should consist of the removal of vegetation such as brush, grass, wood, stumps, trees, roots to trees, and otherwise deleterious materials from the areas to be graded. Clearing and grubbing should extend to the outside of all proposed excavation and fill areas. 3.2 Demolition should include removal of buildings, structures, foundations, reservoirs, utilities (including underground pipelines, septic tanks, leach fields, seepage pits, cisterns, mining shafts, tunnels, etc.) and other man -made surface and subsurface improvements from the areas to be graded. Demolition of utilities should include proper capping and /or re- routing pipelines at the project perimeter and cutoff and capping of wells in accordance with the requirements of the governing authorities and the recommendations of Geotechnics Incorporated at the time of demolition. 13 Debris generated during Gearing, grubbing and /or demolition operations should be removed from areas to be graded and disposed off -site. Clearing, grubbing and demolition operations should be performed under the observation of Geotechnics Incorporated. 4.0 SITE PROTECTION 4.1 The Contractor should be responsible for the stability of all temporary excavations. Recommendations by Geotechnics Incorporated pertaining to temporary excavations (e.g., backcuts) are guidelines and should be evaluated by the contractor. Recommendations by Geotechnics Incorporated should not be considered to preclude more restrictive requirements by the regulating agencies. 4.2 Precautions should be taken during the performance of site clearing, excavations and grading to protect the work site from flooding, ponding or inundation by poor or improper surface drainage. Temporary provisions should be made during the rainy season to adequately direct surface drainage away from and off the work site. 4.3 During periods of rainfall, Geotechnics Incorporated should be kept informed by the Contractor as to the nature of remedial or preventative work being performed (e.g., pumping, placement of sandbags or plastic sheeting, temporary de- silting basins, other labor, grading, etc.). Geotechnics Incorporated Appendix D Page VII 4.4 Following periods of rainfall, the Contractor should contact Geotechnics Incorporated and arrange a review of the site in order to visually assess rain related damage. Geotechnics Incorporated may also recommend excavations and testing in order to aid in their assessments. t 4.5 Rain related damage should be considered to include, but may not be limited to, erosion, silting, saturation, erosion of underground utility backfill, structural distress and other adverse conditions identified by Geotechnics Incorporated. Soil adversely affected should be classified as unsuitable materials and should be subject to over - excavation and replacement with compacted fill or other remedial grading as recommended by Geotechnics Incorporated, 5.0 EXCAVATIONS 5.1 UNSUITABLE MATERIALS 5.1.1 Materials which are unsuitable should be excavated under observation and recommendations of Geotechnics Incorporated. Unsuitable materials include, but may not be limited to, dry, loose, soft, wet, compressible natural soils and fractured, weathered, soft bedrock, and non - engineered or otherwise deleterious rill material. 5.1.2 Material identified by Geotechnics Incorporated as unsatisfactory due to its moisture conditions should be over - excavated, watered or dried, as needed, and thoroughly mixed to a uniform near optimum moisture condition (as per .guidelines reference 7.2.1) prior to placement as compacted fill. 5.2 CUT SLOPES 5.2.1 If cut slope excavations expose loose, cohesionless, significantly fractured or otherwise unsuitable material, over - excavation and replacement of the unsuitable materials with a compacted stabilization fill may be recommended by Geotechnics Incorporated. Unless otherwise specified by Geotechnics Incorporated, stabilization fill construction should conform to the requirements of the Standard Details. Geotechnics Incorporated Appendix D Page VIII 5.2.2 A Geotechnics Incorporated representative should observe cut slopes during excavation. Geolechnics Incorporated should be notified by the contractor prior to beginning slope excavations. 5.2.3 If, during the course of grading, adverse or potentially adverse geotechnical conditions are encountered which were not anticipated in the geotechnical investigation report, Geotechnics Incorporated should evaluate and make recommendations to address these problems. 6.0 COMPACTED FILL All fill materials should be compacted to at least 90 percent of maximum density (ASTM D1557) unless otherwise recommended by Geotechnics Incorporated, 6.1 PLACEMENT 6.1.1 Prior to placement of compacted fill, the Contractor should request a review by Geotechnics Incorporated of the exposed ground surface. Unless otherwise recommended, the exposed ground surface should then be scarified watered or dried as needed, thoroughly mixed to achieve over I optimum moisture conditions, then compacted to a minimum of 90 percent of the maximum density. ► 6.12 Compacted fill should be placed in thin horizontal lifts. Each lift should be watered or dried as needed, mixed to achieve over optimum moisture conditions then compacted by mechanical methods to a minimum of 90 percent of laboratory maximum dry density. Each lift should be treated in a like manner until the desired finished grades are achieved. 6.1.3 When placing fill in horizontal lifts on areas sloping steeper than 5:1 (horizontal: vertical), horizontal benches should be excavated into the slope area. Benching should be sufficient to expose natural ground, bedrock or engineered compacted fill. No compacted fill should be placed in an area subsequent to keying and benching until the area has been reviewed by Geolechnics Incorporated. Material generated by the benching operation should be moved sufficiently away from the bench area to allow for the recommended review of the horizontal bench prior to placement fill. An adjacent thick lift of rill generated by the benching should be avoided. Geotechnics Incorporated Appendix D Page IX Typical keying and benching details have been included within the accompanying Standard Details. 6.1.4 Within a single fill area where grading procedures dictate two or more separate fills, temporary slopes (false slopes) may be created. When placing fill adjacent to a false slope, benching should be conducted in the same manner as above described. 6.1.5 Fill should be tested for compliance with the recommended relative compaction and moisture conditions. Density testing frequency should be adequate for Geotechnics Incorporated to provide professional opinions regarding fill compaction and adherence to recommendations. Fill found not to be in conformance with the grading recommendations should be removed or otherwise treated as recommended by Geotechnics Incorporated. 6.1.6 The Contractor should assist Geotechnics Incorporated representative by digging test pits for evaluation and/or for testing fill compaction. 6.1.7 As recommended by Geotechnics Incorporated, the Contractor may need to remove or stop grading equipment within the area being tested if personnel safety is considered to be a problem. 6.2 MOISTURE 6.2.1 Optimum moisture will vary with material type and will typically be determined by ASTM D1557. Unless otherwise recommended by Geotechnics Incorporated, fill should be mixed to achieve uniform soil moisture in excess of optimum moisture. 6.2.2 Prior to placement of additional compacted fill following an overnight or other grading delay, the exposed surface of previously compacted fill should be processed by scarification, watered or dried as needed, thoroughly mixed to over optimum moisture conditions, then compacted to at least 90 percent relative compaction. Where wet, dry, or other unsuitable materials exist to depths of greater than one fool, the unsuitable materials should be over - excavated. Geotechnics Incorporated Appendix D Page X 6.2.3 Following a period of flooding, rainfall or over - watering by other means, no additional fill should be placed until evaluation and recommendations have been made by Geotechnics Incorporated, and remedial grading performed as described under Section 5.6 herein. 1 6.3 FILL MATERIAL 6.3.1 Excavated on -site materials which are considered suitable to Geotechnics Incorporated may be utilized as compacted fill, provided trash, vegetation and other deleterious materials are removed prior to placement. 7 6.3.2 Where import fill materials are required for use on -site, Geotechnics Incorporated should be notified in advance of importing, to evaluate and /or sample and test materials from proposed borrow sites. No import rill materials should be delivered for use on -site without prior evaluation by Geotechnics Incorporated, 6.3.3 Rocks 12 inches in maximum dimension and smaller may be utilized within the compacted fill, provided they are placed in such a manner that nesting of the rock is avoided. The amount of rock should not exceed 40 percent by dry weight retained on the 3/4 -inch sieve, size. 6.3.4 Where rocks or similar irreducible materials of greater than 12 inches but less than four feet of maximum dimension are generated during grading, or otherwise desired to be placed within an engineered fill, special handling in accordance with the accompanying Standard Details is recommended. Rocks greater than four feet should be broken down or disposed of off -site. Rocks up to four feet maximum dimension should be placed below the upper 10 feet of any fill and should not by closer than 20 -feel to any slope face. These recommendations could vary as locations of underground utility improvements dictate. Where practical, oversized material should not be placed below areas where structures or deep utilities are proposed. Oversized material should be placed in windrows on a compacted fill or firm natural ground surface. Select native or imported granular soil (S.E. 30 or higher) should be placed and thoroughly flooded over and around all windrowed rock, such that voids are filled. Windrows of oversized material should be staggered so that successive strata of oversized material are not Geotechnics Incorporated Appendix D Page XI in the same vertical plane, in accordance with the attached Standard Details. 6.3.5 It may be possible to dispose of individual larger rock as field conditions dictate, as recommended by Geotechnics Incorporated at the time of placement. 6.3.6 The construction of a "rock fill" consisting primarily of rock fragments up to two feet in maximum dimension with little soil material may be feasible. Such material is typically generated on sites where extensive blasting is required. Recommendations for construction of rock rills should be provided by Geotechnics Incorporated on a site - specific basis. 6.3.7 During grading operations, placing and mixing materials from the cut and/or borrow areas may result in soil mixtures which possess unanticipated engineering properties. Testing may be required of samples obtained directly from the fill areas in order to determine conformance with the specifications. Processing of these additional samples may take two or more working days, and require that the contractor alter their operation. 6.3.8 Any fill placed in areas not previously observed and evaluated by Geotechnics Incorporated will require removal and re- compaction. Determination of over - excavations should be made upon review of field conditions by Geotechnics Incorporated. 6.4 FILL SLOPES 6.4.1 Fill slopes should be compacted in accordance with these grading guidelines and specific report recommendations. Two methods of slope compaction are typically utilized in mass grading, lateral over - building and cutting back to grade, and mechanical compaction to grade (i.e. sheepsfoot roller back - rolling). Constraints such as height of slope, fill soil type, access, property lines, and available equipment will influence the method of slope construction and compaction. Geotechnics Incorporated should be notified by the contractor what method will be employed prior to slope construction. Geotechnics Incorporated 0 Appendix D Page XII Over - building should be accomplished with horizontal fill lifts (reference Section 6), and compaction equipment working as close to the edge as practical. The amount of lateral over - building will vary as field conditions dictate. Compaction testing of slope faces will be required, and reconstruction of the slope may be recommended if testing does not meet project specifications. Mechanical compaction of the slope to grade during construction should utilize two types of compactive effort. First, horizontal fill lifts should be compacted during fill placement. The equipment should provide compactive effort to the outer edge of the fill slope. Sloughing of fill soils should not be permitted to drift down the slope. Secondly, at intervals not exceeding four feet in vertical slope height or the capability of available equipment, whichever is less, fill slopes should be back - rolled with a sheepsfoot -type roller, or other equipment that can be shown to compact the slope face to the specified compaction. Moisture conditions of the fill slope soils should be maintained above optimum throughout the compaction process. Generally upon slope completion, the entire slope should be compacted utilizing typical methods, (i.e. sheepsfoot rolling, bulldozer tracking, or rolling with rubber -tired heavy equipment). Final Slope compaction should be performed without grade stakes on the slope face. 6.4.2 Where placement of rill above a natural slope or above a cut slope is proposed, the fill slope configuration as presented in the accompanying Standard Details should be utilized. 6.4.3 For pad areas above fill slopes, positive drainage should be established away from the lop -of- slope, as designed by the project civil engineer. 6.5 TRENCH BACKFILL 6.5.1 Utility trench backfill should, unless otherwise recommended, be compacted by mechanical means. Unless otherwise recommended, the degree of compaction should be a minimum of 90 percent of maximum density (ASTM D1557). Ceotechnics Incorporated Appendix D Page XIII 6.5.2 Within slab areas, but outside the influence of foundations, trenches up to one fool wide and two feel deep may be backfilled with sand (S.E. > 30) and consolidated by jetting, or by mechanical means. 6.5.3 If utility contractors indicate that it is undesirable to use compaction equipment in close proximity to a buried conduit, the Contractor may elect to use clean, granular material, (S.E. > 30) in the pipe zone and one foot above the top of pipe. This material should be thoroughly jetted in place. Other methods of utility trench compaction may also be appropriate, upon review of Geotechnics Incorporated at the time of construction. 6.5.4 In cases where cean granular materials are proposed for use in lieu of native materials or where jetting is proposed, the procedures should be considered subject to review by Geotechnics Incorporated. 6.5.5 Gravel bedding or backfll are not recommended in utility trenches exceeding 20 percent gradient, because of the potential for piping. Bedding materials should consist of clean sand and backfll soil as recommended by Geotechnics Incorporated based on specific site conditions and available materials. 7.0 DRAINAGE 9192 7.1 Canyon and fill buttresses or slope stabilization subdrain systems recommended by Geotechnics Incorporated should be installed in accordance with the specifications of the accompanying Standard Details. 7.2 All subdrain outlets should be connected to a permanent structure such as a storm drain, or outletted to the surface. Surface or daylight outlets should be constructed using a concrete headwall in accordance with the Standard Details. All subdrain outlets should be surveyed by the project civil engineer. 7.3 Subdrains temporarily terminated should be surveyed at each end by the project civil engineer for future relocation and connection. Geotechnics Incorporated CANYON SUBDRAIN DETAILS SURFACE OF FIRM EARTH 1 \� COMPACTED FILL TYPICAL BENCHING \\ \ / / PEMOVE UNSUITABLE MATERIAL 0 INCLINE TOWARD DRAIN SEE DETAILS BELOW TRENCH DETAIL 8' MINIMUM OVERLAP OPTIONAL V -DITCH DETAIL — MINIMUM 8 FT3 PER LINEAL FOOT OF APPROVED DRAIN jMATERIAL SUPAC 8 -P FABRIC OR APPROVED EQUAL 6' MINIMUM OVERLAP 24' MINIMUM 24' MINIMUM PPROVED FILTER FABRIC DRAIN MATERIAL SHOULD CONSIST OF MINUS 1.5', MINUS 1', OR MINUS .75' CRUSHED ROCK MINIMUM B FT3 PER LINEAL FOOT OF APPROVED DRAIN MATERIAL 80° TO SOO ADD MINIMUM 4' DIAMETER APPROVED PERFORATED PIPE WHEN LARGE FLOWS ARE ANTICIPATED APPROVED PIPE TO BE SCHEDULE 40 POLY- VINYL- CHLORIDE (P.V_C.) OR APPROVED EQUAL. MINIMUM CRUSH STRENGTH 1000 pal. TYPICAL CANYON SUBDRAIN J08 NO-:0054-003-00 DATE S3RL1drV 9, 1996 FIGURED -1 7 4' DIAMETER PERFORATED PIPE BACKDRAIN 4' DIAMETER NON - PERFORATED PIPE LATERAL DRAIN SLOPE PER PLA 16' MINIMUM 0%L1 //,9L_ I BENCHING H/2 PROVIDE BACKDRAIN PER BACKDRAIN DETAIL. AN ADDITIONAL BACKDRAIN AT MID -SLOPE WILL BE REQUIRED FOR SLOPE IN EXCESS OF 40 FEET HIGH. KEY- DIMENSIONSPER SOILS ENGINEER TYPICAL BUTTRESS OR STABILIZATION FILL DETAIL 108 NO.: 0054- 003 -00 DATE: January 9, 1996 FIGURE: D -4 t IE FINISH SURFACE SLOPE MINIMUM 3 FT3 PER LINEAL FOOT OPEN GRADED AGGREGATE* TAPE AND SEAL AT CONTACT - 2% MINIMUM A- 4' MINIMUM DIAMETER SOLID OUTLET PIPE SPACED PER SOIL ENGINEER REQUIREMENTS MINIMUM 12" COVER T COMPACTED FILL APPROVED FILTER ADIENT FABRIC 4" MINIMUM APPROVED PERFORATED PIPE (PERFORATIONS DOWN) MINIMUM 2% GRADIENT TO OUTLET TYPICAL BENCH INCLINED BENCHING TOWARD DRAIN DETAIL A -A TEMPORARY FILL LEVEL COMPACTEDI BACKFILL MINIMUM 4' DIAMETER APPROVED SOLID OUTLET PIPE 2" --- MINI1MUM I 'NOTE: AGGREGATE TO MEET FOLLOWING SPECIFICATIONS OR APPROVED EQUAL: SIEVE SIZE PERCENTAGE PASSING 1 1/2" 100 1" 5 -40 3/4' 0 -17 3/8' 0 -7 NO. 200 0 -3 BACKDRAIN DETAIL JOB NO.: DATE: FIGURE: 0054- 003 -00 1 January 9, 1996 D -5 t BUILDING FINISHED GRADE CLEAR AREA FOR FOUNDATION, UTILITIES, 10' AND SWIMMING POOLS ELOPE FACE O O O\ O O 15' O O\ STREET -� 15' WINDROW S' OR BELOW DEPTH OF DEEPEST UTILITY TRENCH (WHICHEVER GREATER) TYPICAL WINDROW DETAIL (EDGE VIEW) GRANULAR SOIL FLOODED TO FILL VOIDS HORIZONTALLY PLACED COMPACTION FILL PROFILE VIEW ROCK DISPOSAL DETAIL JOB NO.: 0059- 003 -00 DATE: January 9, 1996 FIGURED -6