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Home My WebLink AboutCT 81-10; Carlsbad Research Center Lot 9; Foundation Investigation; 1986-07-18- - - - - - - - - SAN DIEGO GEOTECHNICAL CONSULTANTS, INC SOlL ENGlNEERlNG 8 ENGlNEERlNG GEOLOGY July 18, 1986 Cardon‘Meadows Development 9339 Genessee Avenue, Suite 250 San Diego, California 92121 Attention: Mr. Jerry McClenny Job No. 30038-00 Log No. 6-6042 SUBJECT: FOUNDATION INVESTIGATION Proposed Commercial Development Lot 9, Phase I, Carlsbad Research Center Carlsbad, California Gentlemen: As requested, we have completed our Foundation Investigation for the site of the proposed commercial project. Presented herein are our findings and recommendations. If you should have any questions after reviewing our report please do not hesitate to contact the undersigned at your convenience. This opportunity to be of professional service is sincerely - Very truly yours, SAN DIEGO GEOTECHNICAL CONSULTANTS, INC. -- - ENGINEERING DEPT. LIBRARY City of Carl&ad 2075 Las Palmas Drive CarlsbaQ CA 92009-4859 MJM:WLV:m i 6466 NANCY RIDGE DRIVE . SUITE 200. SAN DIEGO, CALIFORNIA 92121 l (619) 567-0250 ttct-- /D - - - - - - - - - TABLE OF CONTENTS Page 1 .O, INTRODUCTION ....................................... 1 1.1 Proposed Development ........................... 2 1.2 Scope of Services .............................. 3 2.0 -EXECUTIVE SUMMARY .................................... 3 3.0 SITE DESCRIPTION ..................................... 3 4.0 SITE INVESTIGATION ................................... 4 4.1 Field Investigation ............................ 4 4.2 Soil Types ..................................... 4 4.3 Laboratory Testing Program .................. ...5 4.3.1 Classification ...................... ...5 4.3.2 Particle-Size Analysis .............. ...5 4.3.3 Atterberg Limits .................... ...5 4.3.4 Expansion Tests ..................... ...6 4.3.5 Direct Shear Tests .................. ...6 4.3.6 In-Situ Moisture-Density ............... 6 4.3.7 R-Value ................................ 7 5.0 GEOLOGY ....................................... 7 5.1 Geologic Setting ............................... 7 5.2 Geologic Units ................................. 8 5.2.1 Point Loma Formation ................... R 5.2.2 Fill ................................... 8 5.3 Cut/Fill Transitions ........................... 9 5.4 Groundwater .................................... 9 6.0 SEISMICITY ...................................... 10 6.1 Regional Seismicity ........................... 10 6.2 Earthquake Effects ............................ 10 7.0 GEOTECHNICAL EVALUATION AND RECOMMENDATIONS.........1 2 7.1 General Discussion ............................ 12 7.2 Grading and Earthwork.........................1 2 7.2.1 General ............................... 12 7.2.2 Geotechnical Observation .............. 13 TABLE OF CONTENTS (Continued) - - - - - - - - - - - - - - - 7.2.3 Site Preparation......................1 3 7.2.4 Compacted Fill........................1 3 7.2.5 Trench Backfill.......................1 4 7.2.6 Pavement Subgrade..................... 7.3 Settlement Considerations.....................1 6 7.4 Surface and Subgrade Drainage.................1 7 7.5 Foundation and Slab Recommendations...........1 7 7.5.1 Foundations ........................... 18 7.5.2 Slabs ................................. 19 7.5.3 Foundation Observation................1 9 7.5.4 Lateral Load Resistance...............2 0 7.5.5 Review of Plans.......................2 0 7.5.6 Reactive Soil.........................2 1 8.0 LIMITATIONS OF INVESTIGATION........................2 1 FIGURES Follows Page 1 Location Map ....................................... 1 2 Plot Plan ....................................... 3 3 Regional Fault Map .................................. 11 APPENDICES A References B Logs of Rorings C Laboratory Data D Standard Earthwork and Grading Recommendations - - - - - - - - - - - - - - FOUNDATION INVESTIGATION PROPOSED COMMERCIAL DEVELOPMENT LOT 9, PHASE 1. CARLSBAD RESEARCH CENTER CARLSBAD. CALIFORNIA 1.0 INTRODUCTION 1.1 Proposed Development This report presents the results of our foundation investigation for the proposed commercial develop- ment. Specifically, the site encompasses approx- imately 5 acres and is known as Lot 9, Phase 1 of Carlsbad Research Center. The subject site was pre- viously graded under the observation and testing of this office (Reference 1). The location of the site is shown on the Location Map, Figure 1. The proposed development consists of construction of three concrete tilt-up buildings, with panel heights ranging from approximately 20 feet to 28 feet and concrete slabs on-grade. The location of the three buildings are shown on the Plot Plan, Figure 2. The proposed development will also include the construc- tion of parking and driving areas surrounding the three buildings. To assist in our investigation, we were provided with a Site Analysis Plan prepared by L. Owen Chrisman Architects, Inc. dated March 18, 1986. - - - - - - - Cardon Meadows Development Co. July 18, 1986 Log No. 30038-00 Job No. 6-6042 Page 2 1.2 Scope of Services The purpose of our investigation was to evaluate the surface and subsurface soil and geologic conditions at the site and, based on conditions encountered, to provide recommendations pertaining to the geotech- nical aspects of the proposed site development, as previously described. The conclusions and recom- mendations included herein are based on an analysis of the data obtained from our field explorations, laboratory testing program, and our experience with similar soil and geologic conditions in the area. Specifically, the scope of our geotechnical investi- gation consisted of the following: 1.2.1 Review of previous geologic and soils engineering reports; - - - - - - 1.2.2 Subsurface exploration utilizing a truck- mounted 8 inch hollow stem auger. The subsur- face exploration program included the collec- tion of both relatively undisturbed and bulk soil samples for laboratory testing; 1.2.3 Evaluation of laboratory and field test data gathered during the exploration program. 1.2.4 Evaluation of groundshaking potential resulting from seismic events occuring on significant faults in the area; 1.2.5 Development of site preparation recommenda- tions; .- - - - - - - - - - - - - - - - - - - Cardon Meadows Development Co. July 18, 1986 Log No. 30038-00 Job No. 6-6042 Page 3 1.2.6 Recommendation of an appropriate foundation system for the anticipated structures, development of geotechnical criteria for the foundation design and development of pavement section recommendations for the proposed park- ing areas and driving lanes. 2.0 EXECUTIVE SUMMARY The project site is considered geotechnicallv suitable for the proposed development, provided the recommendations contained herein are complied with. The primary geotechnical constraints identified is part of this investigation include expansive soils on-site and the presence of a cut-fill transition. Recommendations to mitigate these conditions are contained herein. The project site is a previously graded site underlain by up to 23.5 feet of fill as encountered in our borings. The fill is compact and suitable to support the proposed structures. 3.0 SITE DESCRIPTION As mentioned earlier, the subject site was previously graded as Lot 9, Phase 1 of Carlsbad Research Center, under the observation and testing of this office. The site con- sists of an approximately level lot (elevation 290f) bounded by Rutherford Road on the south and lots 8, 10, and 40 to the north, east and west respectively. The lot drains to Rutherford Road by sheet flow. The site is presently void of any significant vegetation, and no sur- face or subsurface improvements exist. The lot configur- ation along with the proposed building locations are de- picted on the Plot Plan, Figure 2. OF BORING CUT/FILL LINE PLOT PLAN-PRO”;)OSEi) Rl@R~ROAD---- OFFICE BIJILDINGs-cARLsBAD, CALIFORNIA 38 NO.: DATE: 30038-00 JULY 1033 FIGURE: 2 CON SU LTA~PiTS .-I NC - - - - - 7 - - - - 4.2 Soil Types Lines defining the change between soil or rock types on the boring logs were determined by interpolation between sample locations and are, therefore, approxi- mations. The transition between soil types may be abrupt or may be gradual. Cardon Meadows Development Co. July 18, 1986 Log No. 30038-00 Job No. 6-6042 Page 4 4.0 SITE INVESTIGATION 4.1 Field Investigation A field investigation was performed on June 9 and 10, 1986 and consisted of a site reconnaissance by our geotechnical personnel and the drilling of seven exploration borings. The exploration borings were located in the vicinity of the proposed structures to obtain a generalised cross section of the subsurface conditions at the site. The locations were marked in the field by pacing and use of a Brunton compass, further accuracy of boring locations is not implied. Eight-inch diameter borings were drilled using a continuous flight auger to depths ranging from approximately 11 feet to 26 feet below existing grade. Samples were obtained using a standard Split Spoon Sampler, a 2.5-inch I.D. Modified California Sampler and by bulk methods. Logs describing the subsuface conditions encountered are presented in Appendix B. Approximate location of our exploration borings are shown on the Plot Plan, Figure 2. - - - - - - - Cardon Meadows Development Co. July 18, 1986 Log No. 30038-00 Job No. 6-6042 Page 5 4.3 Laboratory Testing Program Lahoratory tests were performed on representative soil samples to determine their relative engineering properties. Tests were performed in accordance with test methods of the American Society for Testing Materials (ASTM) or other accepted standards. The following presents a brief description of the various test methods used. 4.3.1 Classification Soils were classified visually according to the Unified Soil Classification System. Visual classifications were supplemented by laboratory testing of selected samples and classification in accordance with ASTM D 2487. The soil classifications are shown on the Exploration Boring Logs, 4.3.2 Particle-Size Analysis Particle-Size Analysis were performed on selected representative samples in accordance with ASTM D 422. The results are shown on Figures 11 and 12 in Appendix C. 4.3.3 Atterberg Limits The liquid limit, plastic limit and plasticity index of selected representative samples were determined in accordance with ASTM D 4318. The results are presented in Appendix C. - - - - - - - - - - - - Cardon Meadows Development Co. July 18, 1986 Log No. 30038-00 Job No. 6-6042 Page 6 4.3.4 Expansion Tests Expansion tests were performed on representa- tive samples which were visually determined to contain a sufficient percentage of clay to be detrimentally expansive. Tests were per- formed in accordance with the Uniform Building Code (UBC) No. 29-2. Samples were remolded and surcharged to 144 psf prior to satu- ration. The test results are summarized on the attached Table I. 4.3.5 Direct Shear Tests Consolidated, drained direct shear tests were performed in accordance with ASTM D 3080. Tests were performed using relatively undis- turbed samples from the liner rings of a 2.5 inch I.D. Modified California Sampler, and tested in a saturated condition using normal loads of 1 ksf, 2 ksf, and 4 ksf. The result of the shear test presented on Figure 13 in Appendix C. 4.3.6 In-Situ Moisture/Density The in-situ moisture content and dry unit weight of selected samples were determined using relatively undisturbed samples from the liner rings of a 2.5 inch Modified California Sampler. The dry unit weight and moisture contents are shown on the attached Boring LORS , in Apendix B. - - - - - - - - - - -. - - Cardon Meadows Development Co. July 18, 1986 Log No. 30038-00 Job No. 6-6042 Page 7 4.3.7 R-Value R-Value (Resistance Value) tests were per- formed on selected samples in accordance with ASTM D 2844. R-Value tests are a means to evaluate the supportive characteristics of subgrade soil for pavement section design. 5.0 .GEOLOGY 5.1 Geologic Setting The subject site is located in the Peninsular Ranges Geomorphic Province of California near the western margin of the southern California batholith. At the edge of the batholith, the topography changes from the typically rugged landforms developed over the granitic rocks to the flatter, more subdued landforms underlain by sedimentary bedrock associated with the coastal plain. The predominate material at the site consists of a variable thickness of compacted fill overlying Point Loma Formation bedrock, placed during rough grading for Phase I of Carlsbad Research Center. The results of observations and testing are cited in our As-Graded Geotechnical Report, Reference 1 in Appendix A. The structural fill placed during rough grading is considered capable of supporting additional fill or structural foundations. -- - - -. - .- - - - - - Cardon Meadows Development Co. July 18, 1986 5.2 Geologic Units Log No. 30038-00 Job No. 6-6042 Page 8 5.2.1 Point Loma Formation The Point Loma Formation bedrock underlying the site is predominately a thinly interbedded light brown to olive, moist, stiff to very stiff silty claystone with some orange stain- ing. The bedrock is exposed in the extreme northern portion of the pad and is covered by as much as 25 feet of fill throughout the rest of the lot. No laboratory testing was performed during this investigation on the bedrock material. Engineering properties of the Point Loma For- mation bedrock are documented in the refer- enced reports in Appendix A. The bedrock material exhibits a high expansion potential as documented by previous laboratory testing. The bedrock is considered suitable to support compacted fill or structural loads. 5.2.2 Fill At all boring locations compacted light brown, moist, stiff to very stiff silty clay overlies the Point Loma Formation bedrock. The fill is generally classified as a CL in the Unified Soil Classification System. The existing fill was placed and compacted in the early 1980s (Reference 1). The fill varies in thickness from approximately 4.5 feet to 23.5 feet in the area explored. - - - - - - - - - Cardon Meadows Development Co. July 18, 1986 Log No. 30038-00 Job No. 6-6042 Page 9 Results of the evaluation of the engineering properties of the existing compacted fill are presented in Appendix C. Generally, the existing fill is considered suitable to support additional compacted fill or structural loads. The fill has a medium to low expansion potential as determined by 1aborator.y testing and the results are summarized in Table I. Table I Summary of Expansion Testing TEST DEPTH EXPANSION EXPANSION LOCATION (feet) INDEX POTENTIAL B-l 3 85.0 MEDIUM B-2 3 45.4 LOW B-4 5 65.4 MEDIUM B-5 3 29.0 LOW B-6 3 39.0 LOW B-J 3 50.0 LOW-MEDIUM 5.3 Cut/Fill Transitions A transition from cut to fill soils occurs in the area north of proposed building III. The transition runs east to west as shown on the attached Plot Plan, Figure 2. 5.4 Groundwater Groundwater or caving was not encountered in any of the exploratory borings. However, minor seepage was - - - -, - - - - - - - LOS No. 30038-00 Job No. 6-6042 Page 10 encountered in boring No. 5 at a depth of approxi- mately 21.5 feet below existing grade. The apparent seepage was confined to a relatively thin sand lense within the fill. This minor seepage is not con- sidered to be significant from a geotechnical engineering standpoint. 6.0 .SEISMICITY 6.1 Regional Seismicity The site can be considered to be a seismically active area, as can all of Southern California. There are, however, no known active faults on or adjacent to the site. The relationship of the site with respect to known faults in the area is shown on the Regional Fault Map, Figure 3. Seismic risk is considered low, as compared to other areas of southern California, due to the distance from active faults. Faults near the pro.ject are listed in Table II along with the estimated peak bedrock accelerations that could be expected on site. 6.2 Earthquake Effects Based on available information, the most significant event for the intended development is, in our opinion, a 7.0 Magnitude earthquake located on the Elsinore Fault Zone. The anticipated accelerations produced at the site by such an event would exceed those events which might occur on other known active faults. A magnitude 7.0 earthquake on Elsinore Fault Zone could produce a peak ground acceleration of 0.2Og at Cardon Meadows Development Co. July 18, 1986 Los No. 30038-00 Job No. 6-6042 Page 11 the subject site with the duration of strong shaking exceeding 30 seconds. Peak accelerations are not, however, representative of the accelerations for which structures are actually designed. Design of structures should be in compliance with the require- ments of the Roverning jursidictions and standard practices of the Structural Engineers Association of California. - - - - - - - - - - - - - - - - -~ - - - - - - - - .- - FAULT Elsinore San Jacinto Coronado Banks San Clemente Rose Canyon4 San Andreas Newport/ Inglewood TABLE II - SEISMICITY FOR MAJOR FAULTS DISTANCE 22 Miles 45 Miles 21 Miles 56 Miles 7 Miles 66 Miles 40 Miles MAXIMUM PROBABLE EARTHQUAKE' 7.0 7.5 6.0 6.0 6.0 8.0 6.5 ESTIMATED PEAK BEDROCK ACCELERATION' 0.20 g 0.12 g 0.12 8 0.04 g 0.32 I: 0.09 g 0.06 g REPEATABLE HIGH BEDROCK ACCELERATIONS3 0.20 g 0.12 g 0.08 g 0.04 g 0.22 8 0.09 g 0.06 g 1. Seismic Safety Study, City of San Diego (June 1983) & Bonilla (1970) 2. Seed and Idriss (1983) 3. Ploessel & Slosson (1974) 4. Potentially Active / I I I I I I / I I I I I I I I I I REGIONAL FAULT MAP ^- ..A_ Jvm Iv”.; hATI=. 30033-00 -... -. JULY 1886 IFIGURE: I L1 SAN DIEGO GEOTECHNICAL CONSULTANTS, INC. T- - - - - - - - Cardon Meadows Development Co. July 18, 1986 Log No. 30038-00 Job No. 6-6042 Page 12 7.0 GEOTECHNICAL EVALUATION AND RJXOMMENDATIONS 7.1 General Discussion No geotechnical conditions were apparent in our explorations which would preclude the site develop- ment as planned, provided the recommendations discussed in this report are fully complied with. The major constraints identified at the subject site are the expansive soils conditions and the cut/fill transition north of proposed building III. At the present time finalized plans with finish pad elevations for the three proposed concrete tilt-up buildings are not available. Our investigation utilized a 30 scale, Site Analysis Plan, prepared by L. Owen Chrisman Architects, Inc. Final pad grades should be designed such that a minimum of three feet of fill is present below the bottom of the lowest footing. Our primary concern is with the northerly portion of building III where presently 4.5 feet of fill exists below existing grade. Generally, grading should be confined to moisture conditioning the upper two (2) feet of soils within the slab areas and recompacting the upper approximate one (1) foot of surface soils within, and to five (5) feet outside the proposed building limits. 7.2 Grading and Earthwork 7.2.1 General All earthwork and grading for site development should be accomplished in accordance with the - - - - - - - - - - - - Log No. 30038-00 Job No. 6-6042 Page 13 attached Standard Earthwork and Grading Recom- mendations Appendix D, and chapter 70 of the UBC. All special site preparation recommendations presented in the following paragraphs will supercede those in the attached Standard Earthwork and Grading Recommendations. 7.2.2 Geotechnical Observation Continuous observation by the Geotechnical Consultant is essential during grading to confirm conditions anticipated from our foundation investigation and to determine that grading proceeds in general accordance with the recommendations contained herein. 7.2.3 Site Preparation The site should be cleared of existing weeds and grasses. Holes resulting from the removal of any buried obstructions which extend below finished site grades should be backfilled with compacted fill. 7.2.4 Compacted Fill The loose and dry surface soils (12"f) within the building area and to 5-feet beyond, should he moisture conditioned and compacted to a minimum relative compaction of 90 percent in accordance with ASTM D 1557. Prior to placing fill or asphaltic concrete, the exposed subgrade soils should be scarified Cardon Meadows Development Co. July 18, 1986 Log No. 30038-00 Job No. 6-6042 Page 14 - - - - - - - to a depth of 8 to 12-inches, brought to near optimum moisture conditions and compacted to at least 90 percent relative compaction. Fill placed at the site should be compacted to a minimum relative compaction of 90 percent, based on ASTM Laboratory Test Designation D 1557. Fill placed within 18-inches of finish subgrade should be placed at 4% over optimum moisture content. Fill should be compacted by mechanical means in uniform lifts of 6 to 8- inches in thickness. Rock fragments greater than 6-inches in maximum dimension should not be placed within the compacted fill. Fills should also be placed and all grading performed in accordance with the City of Carlsbad Grading Ordinance and the requirements of the Uniform Building Code. 7.2.5 Trench Backfill Utility trench backfill should be compacted by mechanical means to a minimum of 90 percent of the laboratory maximum density. 7.2.6 Pavement Subgrade Areas to be paved with asphaltic concrete should be graded in accordance with the site preparation recommendations given above. The following preliminary pavement sections are recommended based on an R-value of 21. - - - - - - Cardon Meadows Development Co. July 18, 1986 Log No. 30038-00 Job No. 6-6042 Page 15 Light Vehicles (T.I. =4.0) 3-inches of asphaltic concrete placed in two lifts over 4.5 inches of untreated Class II aggregate base or - 5-inches of untreated Class III aggregate base (D.G.) Driveways (T.I. = 5.5) 3-inches of asphaltic concrete placed in two lifts over 9-inches of untreated Class II aggregate base or - lo-inches of untreated Class III aggregate base (D.G.) We recommend that the upper 8 to 12-inches of pavement subgrade soils should be scarified and moistened to near optimum conditions and compacted to 90 percent of the maximum density. Specifications for aggregate Class II base may be selected from Section 200-2 of the "Standard Specifications for Public Works Construction" and should have an R-value of 78 or more. Specifications for Class III aggregate base may be selected from Section 400-2.3.2. of this reference, and should have a minimum R-value of 73 and a minimum sand - - - - - Cardon Meadows Development Co. July 18, 1986 Log No. 30038-00 Job No. 6-6042 Page 16 equivalent of 30. We recommend that you require the Contractor or supplier to assure conformance with specifications. In addition, we recommend that verification testing be performed prior to placing base materials. It should be noted that verification testing may require 5 to 7 days. We recommend that all aggregate base be compacted to 95 percent of the maximum laboratory density. Asphalt con- crete type and class should be as required by the project specifications. We recommend that the area within and around the trash enclosure be paved with Portland Cement Concrete (P.C.C.). P.C.C. paving should be a minimum 5-inches thick, reinforced with 6x6x10/10 welded wire mesh. Subgrade soils and aggregate bases should be prepared as recommended above for asphalt paving. Concrete paving should be provided with appropriate contraction joints at a maximum interval of 20-feet and divided into a nearly square panels as possible. 7.3 Settlement Considerations The anticipated total and/or differential settlements for the proposed structures may be considered to be within tolerable limits provided the recommendations in this report are followed. In general, total settlements are estimated to be less than 1 inch, with differential settlements less than 0.50 inches across the structure. If more exact settlement - _- .- .~- - - Cardon Meadows Development Co. July 18, 1986 Log No. 30038-00 Job No. 6-6042 Page 17 determinations are desired, it will be necessary to perform a detailed review of the actual foundation plans and loading conditions. 7.4 Surface and Subgrade Drainage The performance of foundations is highly dependent upon maintaining adequate surface drainage both during and after construction. The ground surface around structures should be graded so that surface water will be carried quickly away from the building without ponding. The minimum gradient within ten feet of the building will depend upon surface landscaping. In general, paved or lawn areas should have a minimum gradient of 2 percent, while heavily landscaped areas should have a minimum gradient of 5 percent. Roof drains should be carried across all backfilled areas and discharged at least ten feet away from structures. Planters should be constructed so that moisture is not allowed to seep into the foundation areas or beneath slabs and pavements. 7.5 Foundation and Slab Recommendations Our investigation indicates that the existing soils exhibit a low to medium expansion potential. The following recommendations are provided for the design of footings and slabs based on the soils presently on site. Our recommendations are considered generally consistent with the Standards of Practice. The implementation of these recommendations should serve to reduce the risk of distress resulting from expansive soils. The potential for favorable - - - _- - .- ..,,_ .- .- _- Cardon Meadows Development Co. July 18, 1986 Log No. 30038-00 Job No. 6-6042 Page 18 foundation performance can be further enhanced by maintaining uniform moisture conditions. The footing configurations and reinforcements recom- mendations herein do not preclude more restrictive criteria by the governing agencies or by structural considerations. A Structural Engineer should evaluate configurations and reinforcement requirements for structural considerations. 7.5.1 Foundations The results of expansion testing are summerized in Table I. The recommended type of foundation is conventional spread footings, either square or continuous. No footings should straddle a cut/fill interface. All .~. footings for a given building should be founded either entirely in bedrock or entirely in compacted fill. Foundations may be designed for a maximum allowable bearing capacity of 2,000 pounds per square foot with a one-third increase for short-term wind or seismic loads. Footings should be at least 12-inches wide and should extend a minimum of 18-inches below lowest adjacent finish grade. Continuous footings should be continuously reinforced with at least two number four bars placed both at the top and bottom of the footing. If the struc- ture is to be supported on isolated spread footings, a moisture cut-off wall should be ..- - .- ..- _- .- - Cardon Meadows Development Co. July 18, 1986 Log No. 30038-00 Job No. 6-6042 Page 19 poured around the perimeter of the building to a depth of 24-inches below lowest adjacent finish subgrade. 7.5.2 Slabs Slabs should be designed by a Structural Engineer for anticipated use and loading based on a modulus of subgrade reaction of 150 kcf for on site compacted fill soils. Following general recommendations are provided as a guide based on the expansion potential of on- site soils. Slabs should be of 5-inch actual thickness re- inforced with welded wire mesh located at mid- height supported on concrete chairs. Slabs should be underlain with 6-inches of crushed aggregate followed by a 6-mil "visqueen" (or equivalent) moisture barrier. The moisture barrier should be sealed at all splices and overlain by at least 2-inches of clean sand. Slab subgrade soils should be moisture conditioned to at Least 4 percent above optimum moisture content to a depth of lS- inches below slab subgrade prior to placement of concrete. The moisture content should he verified by the Soils Engineer prior to placing visqueen. 7.5.3 Foundation Observation All foundation excavations should be observed by the Soils Engineer prior to the placement ,~- _- .- - .- Cardon Meadows Development Co. July 18, 1986 Log No. 30038-00 Job No. 6-6042 Page 20 of forms, reinforcement, or concrete, for determination of conformance with the intent of the recommendations herein. All excavations should be trimmed neat, Level and square. All Loose or unsuitable material should be removed prior to the placement of concrete. Materials from footing excavations should not be spread in slab-on-grade areas unless compacted. Presaturation should be verified prior to the placement of concrete. 7.5.4 Lateral Load Resistance Resistance to lateral loads may be provided by a passive pressure against the vertical faces of the foundations or walls and by the frictional resistance between concrete and soil. Passive pressure for compacted on-site fills may be considered to be 125 pounds per square foot per foot. A coefficient of friction for soil to concrete may be assumed to be 0.3. When combining frictional and passive resistance, the Later should be reduced by one third. 7.5.5 Review of Plans As foundation and grading plans are completed, they should be forwarded to the Soils Engineer for review for conformance with the intentions of these recommendations. .- ..- .- .- .- -~- _- Cardon Meadows Development Co. July 18, 1986 7.5.6 Reactive Soil Log No. 30035-00 Job No. 6-6042 Page 21 The results of previous sulfate testing indicate that either type I or II cement may be utilized for concrete in contact with the subgrade soil. 8.0 'LIMITATIONS OF INVESTIGATION Our investigation was performed using the degree of care and skill ordinarily exercised, under similar circumstances, by reputable Soils Engineers and Geologists practicing in this or similar localities. No other warranty, expressed or implied, is made as to the conclusions and professional advice included in this report. The samples taken and used for testing and the observations made are believed representative of the entire project; however, soil and geologic conditions can vary significantly between borings. As in most major projects, conditions revealed by excavation may be at variance with preliminary findings If this occurs, the changed conditions must he evaluated by the Project Soils Engineer and Geologist and designs adjusted as required or alternate designs recommended. 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 ..- Cardon Meadows Development Co. July 18, 1986 Log No. 30038-00 Job No. 6-6042 Page 22 engineer for the pro,ject and incorporated into the plans, and the necessary steps are taken to see that the contractor and subcontractors carry out such recommendations in the field. 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. - - _- - - - - *** _- -. - _- - -. __ - ..- -- .- _- .,- __ ,- APPENDIX A REFERENCES APPENDIX A - .- -. - .- - REFERENCES 1. "As-Graded Geotechnical Report, Rough Grading Completed, Carlsbad Research Center, Phase I, Carlsbad Tract No. 81- 10, Carlsbad, California" prepared by San Diego Soils Engineering, Inc. dated June 7, 1984, Job No. SD1144-10: 2. "Preliminary Soil and Geologic Investigation, Carlsbad Research Center, Carlsbad, California," prepared by Woodward-Clyde Consultants, dated April 27, 1981; 3. Additional Studies, Carlsbad Research Center, Phase I, Carlsbad, California," prepared by Woodward-Clyde Consultants, dated August 17, 1981; 4. "Addendum to Additional Studies, Carlsbad Research Center, Phase I, Carlsbad, California," prepared by Woodward-Clyde Consultants, dated September 3, 1981; - - _- - - - APPENDIX B BORING LOGS Figure 4 through 10 ._ .- - .- - - - - .- _. .- -, ,~- .~- .- .- ,~._ ,.- .- umETnANnALF (LESS THAN 5% CLEAN SANDS BILTS AND CLAYS LlamLMTlsGREATERTnAN5D% DEFINITION OF TERMS U.S. STAH)ARO SERIES SIEVE CLEAR SOUARE SIEVE OPENINGS 200 40 10 4 314’ 3’ 12’ SILTS AND CLAYS SAND I GRAVEL FINE MEDIUM COARSE FINE COARSE COBBLES GRAIN SIZES SANDS,GRAVELS AND BLOWS/FOOT’ CLAYS AND NON-PLASTICS SILTS PLASTIC SILTS STRENGTH’ BLOWSlFOOTt VERY LOOSE O-4 VERY SOFT o- 114 o-2 LOOSE 4 - 10 SOFT 114 - 112 2-4 MEDIUM DENSE lo- 30 FIRM 112- 1 4-s STIFF l-2 8- 16 DENSE 30 - 50 VERY STIFF 2-4 16 - 32 VERY DENSE OVER 50 HARD OVER 4 OVER 32 RELATIVE DENSlTY CONSISTENCY tN”mber of blows of 140 pound ha”.,w, fallkg 30 k,chbb 10 drive P 2 inch OD. (t-310 inch LD., SPYI swan (ASTM D-1585). ‘t.kxonikwd c~rr~~~sske strength h tonsl8q tt. as detmminsd by laboratory t~stinp 01 approximated by the atsndard oawtration test (ASTM O-1556). pocket pemtrometer. tot-vane. a viwal obsenstion. KEY TO EXPLORATORY BORING LOGS Unified Soil Classification System (ASTM D-2487) 08 NO: DATE: FIGURE: SAN DlEGO SOILS ENGINEER,NG.lNC _.~~ - - - - - - - - - - - - - - - - - DATE OBSERVED: 6-g-86 METHOD OF DRILLING: 8" Solid Flight Auger 140 Lb. Hammer, 30" Drop I- LEVATION: 2X3!: LOCATION: CRC, Lot 9 LOGGEI F: Ii g ‘i s G z 5 i :: .o-hii IY z ci 2 5 d !2 37 i9 34 I BORING NO. 1 iR0 - II&l! 5 -z t?: 2: - SOIL TEST = Itl 2 is 5 ii x - - - DE - $ u- St ig E# - DESCRIPTION -I- 'ILL: Light brown silty CLAY, moist rery stiff to hard _ CH 5- _ CL c L I 1 1 Particle-Size itterberg Limits, sxpansion lo- _ CL _ CL 15- _ CL - - - - BEDROCK: Point Loma Fm (Kpl): Light ,rown to grey silty CLAYSTONE, moist, lard, orange staining 20- COTAL DEPTH: 16.5' Jo water backfilled 6-10-86 25- 30- 35- go- IOB NO. - - 0038-O LOG OF BORING FIGURE: 4 SAN DIEGO GEOTECHNICAL CONSULTANTS.~ INC - .~~~ -.~ -.~ - - - - - - - - - - - - - ..VF anrrnrr.zn. ,n,c “maE”“CY; fG-,n-jlf, ” __ -- WC I ““Y VT YmlLLIlv” ..pyLIAn ,.- . . . . . ..,.-: 8” Solid Flight Auger 140 Lb. Hammer, 30" Drop LEVATION: 294* LOCATION: CRC, Lot 9 .O ‘GC c ii k ? & 0 0. 23 z 5 0 ii z 2 5 :L - :L :L IY - & ,o 2 z i 2i - 5C 9c -( s- -I IO. , 6 ‘0. 15, 10, 2% 0. -L 5 - !O. 11. - c BORING NO. 2 DESCRIPTION 'ILL: Light brown silty CLAY, moist, G stiff to hard #EDROCK: Point Loma Fm (Kpl): Light mm to olive silty CLAYSTONE, moist, .ard, orange staining :OTAL DEPTH: 11.5' lo water mzkfilled 6-10-86 SOIL TEST LOG OF BORING FIGURE: 5 SAN DIEGO GEOTECt+NlCAL CONSULTANTS, INC direct Shear kQtXlSiOIl Wisture/Density .~ - - - - - - - - - - - - - - - - - )ATE OBSERVED: G-LO-86 ,&ZT,.,OD OF DRILLING: 8" Solid Flight Auger 140 Lb. Hammer, 30" Drop -0GGEO By: PAT GROUND ELEVATION: 29% LOCATION: CRC. Lot 9 BORING NO. 1 SOIL TEST DESCRIPTION FILL: Light brown silty CLAY, moist, very stiff to hard -CL 19 5- -CL 27' IO- -CL 49 I& -CL 89 to- BEDROCK: Point Loma Fm (Kpl): Light brown to olive silty CLAYSTONE, moist, hard TOTAL DEPTH: 16.5' No Water Backfilled 6-10-86 ?5- IO- l5- LO- lw-,P Yr-l- - - - / I A_ nr “~rt1.1~ ,EmIme. - '"" ""..3~~3~-~~, ~uc4 vr cwnwdu """"-. 8 SAN DIEGO GEOTECliNlCAL CONSULTANTS. INC - - - - - - - - - - IATE OBSERVED: 6-10-86 METHOD 0~ DRILLING: 8" Solid Flight Auger .OGGEl F i? i 5 k 0 Y F v) % : ,o,d _ Cl s- _ CI IO- _ Cl l5- -cI !O- !5- IO- !5 !8 i9 - 4 - rI - : 2 !! ?: ;” > - x - x - x - - x !2.’ 7 24., , 01. 95. - - - VATION: 2942 LOCATION: CRC. Lot 9 BORING NO. 4 DESCRIPTION FILL: Light brown silty CLAY, moist, very stiff to hard SOIL TEST ?oisture Density Gzisture Density ?article Size ltterberg Limits lxpansion BEDROCK: Point Loma Fm (Kpl): I.i,ght brown to olive silty CLAYSTONE, moist! hard TOTAL DEPTH: 16.5' No Water Backfilled S-IO-86 0 LOG OF BORING FIGURE: 7 SAN DIEGO GSOTECHNICAL CONSULTANTS, INC. - - - - - .- ,- )ATE OBSERVED: 6-10-86 METHOD 0~ DRILLING: 8" Solid Flight Auger 140 Lb. Hammer. 30" Drop LEVATION: 2922 LOCATION: CRC. IJot 9 -01 - F Y k z % ,o- J- IO- I!?#- !O- !5- IO- 15- ;o- 72 iEl z 5 0 ic z 2 d :L :L ZL ZL 3L - ZL 3Y - 0’ i? G z 2 m - u : :z 2 2: 1” > I I I I 1 - 1 iROl - us 5 $E 55 “Z - BORING NO. 5 SOIL TEST DESCRIPTION FILL: Light brown silty CLAY, moist, -., very stiff to hard 29 Zxpansion 16 19 14 19 - 75 g 2%' sand lens & seepage - - 0 - - - \ BEDROCK: Point Loma Fm (Kpl): Light brown to olive silty CLAYSTONE, moist, hard TOTAL DEPTH: 26.5' seepage at 21.5' Backfilled 6-10-86 - LOG OF BORING IFIGu~~E: 8 SAN DIEGO GEOTECHNICAL CONSULTANTS, INC. 7 - - - - ,- 7 - 7 - .OGGEl i: z Y 2 k 0 k E co ! z o- 2 - CL s- _ CL 'O- _ CL 15- SC ‘o- - CL !5- io- S- o-, OB NO. )ATE OBSERVED: 6-10-86 METHOD 0~ DRILLIN@ 8" Solid Flight Auger 140 Lb. Ilammer, 30" Drop iROl - 3 <- ;; 5; 2 - ILEVATION: 29 li LOCATION: CRC, Lot 9 BORING NO. 6 SOIL TEST DESCRIPTION + FILL: Light brown silty CLAY, moist, -.- very stiff to hard 2: Ixpansion 1E I 2: 16 - i0 - - - \ - ledium brown sandy CLAY, moist, medium iense BEDROCK: Point Loma Fm (Kpl): Light ,rown to olive silty CLAYSTONE, moist, lard :OTAL DEPTH: 21.5' io seepage lackfilled 6-10-86 ;a - FIGURE: g -~ - - r- IATE OBSERVED: 6-10-86 METHOD OF DRILLING: 8" Solid Flight Auger 140 Lb. Hammer, 10" Drop .OGGED BY: PAT GROUND ELEVATION: 29Ok LOCATION: CRC, Lot 9 i: 5 ii 2 EE Y ,3 ii& BORING NO. 7 k 0 0 gy g cc- on t 3P < iJ s 2s zz’ w- z 02 +s m co: !$ SOIL TEST : 0 ou) 5 25 2: DESCRIPTION 0 d d 5 2 0 z; FILL: Light brown silty CLAY, moist, verv stiff to hard BEDROCK: Point Loma Fm (Kpl): Light Moisture/Density Direct Shear Expansion R-Value Moisture/Density _-- .--‘.-’ I ” SAN DIEGO GEOTECHNICAL CONSULTANTS, IN< - - r- -~ - -. APPENDIX C LABORATORY DATA Figures 11 through 13 I I I 1 I I I 1 I 1 I I I I I I I I GRAVEL SAND SILT CLAY COARSE MEDIUM FINE SIEVE SIZES-U.S. STANDARD SIEVE SIZES-U.S. STANDARD 3/4” 3/4” 112” 112” 114” 114” 4 4 10 10 20 20 40 40 100 200 100 100 100 90 90 90 60 60 60 70 70 70 : 60 60 :: :: z z -( 50 50 1: z 40 40 0 30 30 20 20 10 IO 0 0 Id.0 1:0 d.1 .61 .Obl PARTICLE SIZE-MILLIMETERS BORING NO. DEPTH (FEET) SYMBOL LIQUID LIMIT ~~As~lclTy INDEX CLASSIFICATION 1 3 58.3 32.0 CH I 1 1, 1 1 'I 1 I I 1 I ~1 I 1 I I I I GRAVEL SAND 1 SILT CLAY COARSE MEDIUM FINE - SIEVE SIZES-U.S. STANDARD 3/4” 112” 114” 4 10 20 40 100 200 100 I 1 liii+UU 100 90 so so 60 70 70 I?+ 60. \. 60 :: \ 30 30 I lilii / / / 20 20 IO 10 I 1 lllll1I I I III,, I I I I 0” 0 rd.0 1.b 0:r .dl .Obl PARTICLE SIZE-MILLIMETERS BORING NO. DEPTH (FEET) SYMBOL L~GUID LIMIT PLASTICITY INDEX CLASSIFICATION 4 5 - 57.7 29.4 CH - - - - -, ,- - - BORING DEPTH NO. (FEET) COrpE&ON. ANGLE 0% SAMPLE DESCRIPTION FRICTION. 2 I 3 3000 3000 G: 2 E : w E 2000 2000 * W 3 p: 001 001 1000 2000 3000 4000 5000 600( 1000 2000 3000 4000 5000 600( NORMAL LOAD (PSF) NORMAL LOAD (PSF) 1000 _ 1000 _ OO OO 1000 2000 3000 4000 5000 6000 1000 2000 3000 4000 5000 6000 NORMAL LOAD (PSF) 08 NO.: 30038-00 SHEARING STRENGTH TEST FIGURE: 13 SAN DIEGO GEOTE CHNICAL CONSULTANTS. INC. - -~ - - - - ,- - - APPENDIX D STANDARD EARTHWORK AND GRADING RECOMMENDATIONS - - - 1 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. APPENDIXD STANDARD GUIDELINES FOR GRADING PROJECTS -- TABLE OF CONTENTS GENERAL ..................... DEFINITION OF TERMS ............... OBLIGATIONS OF PARTIES ............. SITE PREPARATION ................ SITE PROTECTION ................. EXCAVATIONS ................... 6.1 UNSUITABLE MATERIALS ........... 6.2 CUT SLOPES ................ 6.3 PADAREAS ................. COMPACTED FILL ................. 7.1 PLACEMENT ................. 7.2 MOISTURE ................. 7.3 FILL MATERIAL ... '. .......... 7.4 FILL SLOPES ................ 7.5 OFF-SITE FILL ............... DRAINAGE .................... STAKING ..................... SLOPE MAINTENANCE ............... 10.1 LANDSCAPE PLANTS ............. 10.2 IRRIGATION ................ 10.3 MAINTENANCE ............... 10.4 REPAIRS ................. TRENCH BACKFILL ................ STATUS OF GRADING ................ Page 1 1 5 6 7 9 9 9 10 10 11 13 13 15 17 18 18 19 19 19 20 20 20 22 STANDARD GUIDELINES FOR GRADING PROJECTS - - - ,- 1. GENERAL -- 1.1 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 guidelines should be considered a portion of the project specifi- cations. 1.2 All plates attached hereto shall be considered as part of these guidelines. 1.3 The Contractor should not vary from these guidelines without prior recommendation by the Geotechnical Consultant and the approval of the Client or his authorised representative. Recommendation by the Geotechnical Consultant and/or Client should not be considered to preclude requirements for approval by the controlling agency prior to the execution of any changes. 1.4 These Standard Grading Guidelines and Standard Details may be modified and/or superseded by recommendations contained in the text of the preliminary geotechnical report and/or subsequent reports. * 1.5 If disputes arise out of the interpretation of these grading guidelines or standard details, the Geotechnical Consultant shall provide the governing interpretation. 2. DEFINITIONS OF TERMS 2.1 2.2 2.3 2.4 2.5 ALLUVIUM -- Unconsolidated detrital deposits resulting from flow of water, including sediments deposited in river beds, canyons, flood plains, lakes, fans at the foot of slopes and estuaries. AS-GRADED (AS-BUILT) -- The surface and subsurface conditions at completion of grading. BACKCUT -- A temporary construction slope at the rear of earth retaining structures such as buttresses, shear keys, stabilisation fills or retaining walls. BACKDRAIN -- Generally a pipe and gravel or similar drainage system placed behind earth retaining structures such buttresses, stabilization fills, and retaining walls. BEDROCK -- A more or less solid, relatively undisturbed rock in place either at the surface or beneath superficial deposits of soil. - Standard Guidelines - for Grading Projects Page 2 - - - - - ,- - 2.6 2.1 2:3 2.9 2.10 2.11 2.12 2.13 2.14 2.15 2.16 BENCH -- A relatively level step and near vertical rise excavated into sloping ground on which fill is to be placed. BORROW (Import) -- Any fill material hauled to the project site from off-site areas. BUTTRESS FILL -- A fill mass, the configuration of which is designed by engineering calculations to retain slope conditions containing adverse geologic features. A buttress is generally specified by minimum key width and depth and by maximum backcut angle. A buttress normally contains a backdrainage system. CIVIL ENGINEER -- The Registered Civil Engineer or consulting firm responsible for preparation of the grading plans, surveying and verifying as-graded topographic conditions. CLIENT -- The Developer or his authorised represen- tative who is chiefly in charge of the project. He shall have the responsibility of reviewing the findings and recommendations made by the Geotechnical Consultant and shall authorise the Contractor and/or other consultants to perform work and/or provide services. COLLUVIUM -- Generally loose deposits usually found near the base of slopes and brought there chiefly by gravity through slow continuous downhill creep (also see Slope Wash). COMPACTION -- Is the densification of a fill by mechanical means. CONTRACTOR -- A person or company under contract or otherwise retained by the Client to perform demoli- tion, grading and other site improvements. DEBRIS -- All products of clearing, grubbing, demoli- tion, contaminated soil material unsuitable for reuse as compacted fill and/or any other material so designated by the Geotechnical Consultant. ENGINEERING GEOLOGIST -- A Geologist holding a valid certificate of registration in the specialty of Engineering Geology. ENGINEERED FILL -- A fill of which the Geotechnical Consultant or his representative, during grading, has - - Standard Guidelines Page 3 for Grading Projects - - - - 2:17 EROSION -- The wearing away of the ground surface as a result of the movement of wind, water, and/or ice. 2.18 2 :19 EXCAVATION -- The mechanical removal of earth materials EXISTING GRADE -- The ground surface configuration prior to grading. 2.20 FILL -- Any deposits of soil, rock, soil-rock blends or other similar materials placed by man. 2.21 FINISH GRADE -- The ground surface configuration at which time the surface elevations conform to the approved plan. 2.22 GEOFABRIC -- Any engineering textile utilised in geotechnical applications including subgrade stabilization and filtering. 2.23 GEOLOGIST -- A qepresentative of the Geotechnical Consultant educated and trained in the field of geology. 2.24 GEOTECHNICAL CONSULTANT -- The Geotechnical Engineering and Engineering Geology consulting firm retained to provide technical services for the project. For the purpose of these specifications, observations by the Geotechnical Consultant include observations by the Soil Engineer, Geotechnical Engineer, Engineering Geologist and those performed by persons employed by and responsible to the Geotechnical Consultants. 2.25 GEOTECHNICAL ENGINEER -- A licensed Civil Engineer who applies scientific methods, engineering principles and professional experience to the acquisition, interpre- tation and use of knowledge of materials of the earth's crust 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. 2.26 GRADING -- Any operation consisting of excavation, made sufficient tests 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. - - - Standard Guidelines Page 4 for Grading Projects - - - - - -. - - 2.27 2.28 2.29 2.30 2.31 2.32 2.33 2.34 2.35 2.36 2.37 2.38 filling or combinations thereof and associated operations. LANDSLIDE DEBRIS -- Material, generally porous and of low density, produced from instability of natural of man-made slopes. 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 Method of Test D 1557-78. OPTIMUM MOISTURE -- Test moisture content at the maximum density. RELATIVE COMPACTION -- The degree of compaction (expressed as a percentage) of dry unit weight of a material as compared to the maximum dry unit weight of the material. ROUGH GRADE -- The ground surface configuration at which time the surface elevations approximately conform to the approved plan. SITE -- The particular parcel of land where grading is being performed. SHEAR KEY -- Similar to buttress! however, it is generally constructed by excavating a slot within a natural slope in order to stabilize the upper portion of the slope without grading encroaching into the lower portion of the slope. SLOPE -- Is an inclined ground surface the steepness of which is generally specified as a ratio of horizontal: vertical (e.g., 2:l). SLOPE WASH -- Soil and/or rock material that has been transported down a slope by mass wasting assisted by runoff water not confined by channels (also see Colluvium). SOIL -- Naturally occurring deposits of sand, silt, clay, etc., or combinations thereof. SOIL ENGINEER -- Licensed Civil Engineer experienced in soil mechanics (also see Geotechnical Engineer). STABILIZATION FILL -- A fill mass, the configuration of which is typically related to slope height and is - - - - Standard Guidelines for Grading Projects Page 5 2.39 2.40 2.41 2.42 2.43 2.44 specified by the standards of practice for enhancing the stability of locally adverse conditions. A stabilization fill is normally specified by minimum key width and depth and by maximum backcut angle. A stabilization fill may or may not have a backdrainage system specified. SUBDRAIN -- Generally a pipe and gravel or similar drainage system placed beneath a fill in the alignment of canyons or former drainage channels. SLOUGH -- Loose, noncompacted fill material generated during grading operations. TAILINGS -- Nonengineered fill which accumulates on or adjacent to equipment haul-roads. TERRACE -- Relatively level step constructed in the face of graded slope surface for drainage control and maintenance purposes. TOPSOIL -- The presumably fertile upper zone of soil which is usually darker in color and loose. WINDROW -- A string of large rock buried within engineered fill'in accordance with guidelines set forth by the Geotechnical Consultant. 3. OBLIGATIONS OF PARTIES 3.1 The Geotechnical Consultant should provide observation and testing services and should make evaluations in order to advise the Client on geotechnical matters. The Geotechnical Consultant should report his findings and recommendations to the Client or his authorized representative. 3.2 The Client should be chiefly responsible for all aspects of the project. He or his authorized representative has the responsibility of reviewing the findings and recommendations of the Geotechnical Consultant. He shall authorize or cause to have authorized the Contractor and/or other consultants to perform work and/or provide services. During grading the Client or his authorized representative should remain on-site or should remain reasonably accessible to all concerned parties in order to make decisions necessary to maintain the flow of the project. - -~ - - - Standard Guidelines for Grading Projects Page 6 3.3 The Contractorshould be responsible for the safety of the project and satisfactory completion of all grading and other associated operations on construction projects, including but not limited to, earthwork in accordance with the project plans, specifications and controlling agency requirements. During grading, the Contractor or his authorized representative should remain on-site. Overnight and on days off, the Contractor should remain accessible. 4. SITE PREPARATION 4.1 4.2 4.3 4.4 4.5 The Client, prior to any site preparation or grading, should arrange and attend a meeting among the Grading Contractor, the Design Engineer, the Geotechnical Consultant, representatives of the appropriate governing authorities as well as any other concerned parties. All parties should be given at least 48 hours notice. Clearing and grubbing should consist of the removal of vegetation such as brush, grass, woods, stumps, trees, roots of trees and otherwise deleterious natural materials from the areas to be graded. Clearing and grubbing should,extend to the outside of all proposed excavation and fill areas. 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 pipe- lines at the project perimeter and cutoff and capping of wells in accordance with the requirements of the governing authorities and the recommendations of the Geotechnical Consultant at the time of demolition. Trees, plants or man-made improvements not planned to be removed or demolished should be protected by the Contractor from damage or injury. Debris generated during clearing, grubbing and/or demolition operations should be wasted from areas to be graded and disposed off-site. Clearing, grubbing and demolition operations should be performed under the observation of the Geotechnical Consultant. Standard Guidelines for Grading Projects Page 7 - 4.6 The Client or Contractor should obtain the required approvals from the controlling authorities for the project prior, during and/or after demolition, site preparation and removals, etc. The appropriate approvals should be obtained prior to pFoceeding with grading operations. - 5. SITE PROTECTION - - - - - - - 5.1 Protection of the site during the period of grading should be the responsibility of the Contractor. Unless other provisions are made in writing and agreed upon among the concerned parties, completion of a portion of the project should not be considered to preclude that portion or adjacent areas from the requirements for site protection until such time as the entire project is complete as identified by the Geotechnical Consultant, the Client and the regulating agencies. 5.2 The Contractor should be responsible for the stability of all temporary excavations. Recommendations by the Geotechnical Consultant pertaining to temporary exca- vations (e.g., backcuts) are made in consideration of stability of the completed project and, therefore, should not be considered to preclude the respon- sibilities of the Contractor. Recommendations by the Geotechnical Consultant should not be considered to preclude more restrictive requirements by the regulating agencies. - - 5.3 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. Where low areas cannot be avoided, pumps should be kept on hand to continually remove water during periods of rainfall. 5.4 During periods of rainfall, plastic sheeting should be kept reasonably accessible to prevent unprotected slopes from becoming saturated. Where necessary during periods of rainfall, the Contractor should install checkdams! desilting basins, riprap, sand bags or other devices or methods necessary to control erosion and provide safe conditions. .~,~ _ ,,~ .~i.~:.~-,.l--~~.~,-rr . ..~.. . :. ,.=.. _ ~.~ , ~. _. ,,,~,. _~I ~. - - - - - - - - - - - - Standard Guidelines for Grading Projects Page 8 5.5 5 . . 6 5.7 5.8 5.9 During periods of rainfall, the Geotechnical Consultant 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, other labor, dozing, etc.). Following periods of rainfall, the Contractor should contact the Geotechnical Consultant and arrange a walk-over of the site in order to visually assess rain related damage. The Geotechnical Consultant may also recommend excavations and testing in order to aid in his assessments. At the request of the Geotechnical Consultant, the Contractor shall make excavations in order to evaluate the extent of rain related damage. Rain related damage should be considered to include, but may not be limited to, erosion, silting, satura- tion! swelling, structural distress and other adverse conditions identified by the Geotechnical Consultant. 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 the Geotechnical Consultant. Relatively levei areas, where saturated soils and/or erosion gullies exist to depths of greater than l.O-foot, should be overexcavated to unaffected, competent material. Where less than l.O-foot in depth, unsuitable materials may be processed in-place to achieve near optimum moisture conditions, then thoroughly recompacted in accordance with the appli- cable specifications. If the desired results are not achieved, the affected materials should be over- excavated, then replaced in accordance with the applicable specifications. In slope areas, where saturated soil and/or erosion gullies exist to depths of greater than l.O-foot, they should be overexcavated and replaced as compacted fill in accordance with the applicable specifications. Where affected materials exist to depths of l.O-foot or less below proposed finished grade, remedial grading by moisture conditioning in-place, followed by thorough recompaction in accordance with the applicable grading guidelines herein may be attempted. If the desired results are not achieved, all affected materials should be overexcavated and replaced as compacted fill in accordance with the slope repair Standard Guidelines for Grading Projects Page 9 - recommendations herein. As field conditions dictate, other slope repair procedures may be recommended by the Geotechnical Consultant. - 6. EXCAVATIONS - 6.1 UNSUITABLE MATERIALS - - - -. - - - - 6.1.1 Materials which are unsuitable should be excavated under observation and recommendations of the Geotechnical Consultant. Unsuitable materials include, but may not be limited to, dry, loose, soft, wet, organic compressible natural soils and fractured, weathered, soft bedrock and nonengineered or otherwise deleterious fill materials. 6.1.2 Material identified by the Geotechnical Consultant as unsatisfactory due to its moisture conditions should be overexcavated, watered or dried, as needed, and thoroughly blended to a uniform near optimum moisture condition (as per guidelines reference 7.2.1) prior to placement as compacted fill. 6.2 CUT SLOPES ' 6.2.1 Unless otherwise recommended by the Geotechnical Consultant and approved by the regulating agencies, permanent cut slopes should not be steeper than 2:l (horizontal:vertical). 6.2.2 If excavations for cut slopes expose loose, cohesionless, significantly fractured or other- wise unsuitable material, overexcavation and replacement of the unsuitable materials with a compacted stabilization fill should be accomplished as recommended by the Geotechnical Consultant. Unless otherwise specified by the Geotechnical Consultant, stabilization fill construction should conform to the requirements of the Standard Details. 6.2.3 The Geotechnical Consultant should review cut slopes during excavation. The Geotechnical Consultant should be notified by the contractor prior to beginning slope excavations. 6.2.4 If, during the course of grading, adverse or potentially adverse geotechnical conditions are - Standard Guidelines for Grading Projects Page 10 - - - ,- 6.2.5 encountered which were not anticipated in the preliminary report, the Geotechnical Consultant should explore, analyze and make recommendations to treat these problems. When cut slopes are made in the direction of the prevailing drainage, a non-erodible diversion swale (brow ditch) should be provided at the top-of-cut. 6 ..3 PAD AREAS 6.3.1 All lot pad areas, including side yard terraces, above stabilization fills or buttresses should be overexcavated to provide for a minimum of 3-feet (refer to Standard Details) of compacted fill over the entire pad area. Pad areas with both fill and cut materials exposed and pad areas containing both very shallow (less than 3-feet) and deeper fill should be overexcavated to provide for a uniform compacted fill blanket with a minimum of 3-feet in thickness (refer to Standard Details). Cut areas exposing signifi- cantly varying material types should also be overexcavated to provide for at least a 3-foot thick compacted fill blanket. Geotechnical conditions may require greater depth of over- excavation. The actual depth should be delineated by the Geotechnical Consultant during grading, 6.3.2 For pad areas created above cut or natural slopes, positive drainage should be established away from the top-of-slope. This may be accomplished utilising a berm and/or an appropriate pad gradient. A gradient in soil areas away from the top-of-slopes of 2 percent or greater is recommended. 7. COMPACTED FILL All fill materials should be compacted as specified below or by other methods specifically recommended by the Geotechnical Consultant. Unless otherwise specified, the minimum degree of compaction (relative compaction) should be 90 percent of the laboratory maximum density. 7.1 PLACEMENT 7.1.1 Prior to placement of compacted fill, the Contractor should request a review by the Standard Guidelines for Grading Projects Page 11 .- - -~ - - - - 7.1.2 Geotechnical Consultant of the exposed ground surface. Unless otherwise recommended, the exposed ground surface should then be scarified (6-inches minimum), watered or dried as needed, thoroughly blended to achieve near optimum moisture conditions, then thoroughly compacted to a minimum of 90 percent of the maximum density. The review by the Geotechnical Consultant should not be considered to preclude requirement of inspection and approval by the governing agency. Compacted fill should be placed in thin horizontal lifts not exceeding 8-inches in loose thickness prior to compaction. Each lift should be watered or dried as needed, thoroughly blended to achieve near optimum moisture conditions then thoroughly 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. 7.1.3 The Contractor should have suitable and sufficient mechanical compaction equipment and watering apparatus on the job site to handle the amount of'fill being placed in consideration of moisture retention proper,ties of the materials. If necessary, excavation equipment should be "shut down" temporarily in order to permit proper compaction of fills. Earth moving equip- ment should only be considered a supplement and not substituted for conventional compaction equipment. 7.1.4 When placing fill in horizontal lifts adjacent to areas sloping steeper than 5:l (horizontal: vertical), horizontal keys and vertical benches should be excavated into the adjacent slope area. Keying and benching should be sufficient to provide at least 6-foot wide benches and a minimum of 4-feet of vertical bench height within the firm natural ground, firm 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 the Geotechnical Consultant. Material generated by the benching operation should be moved sufficiently away from the bench area to allow for the recommended review of the horizontal Standard Guidelines for Grading Projects Page 12 - - - -~ - - - bench prior to placement of fill. Typical keying and benching details have been included within the accompanying Standard Details. 7.1.5 Within a single fill area where grading proce- dures 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. At least a 3-foot vertical bench should be established within the firm core of adjacent approved compacted fill prior to placement of additional fill. Benching should proceed in at least 3-foot vertical increments until the desired finished grades are achieved. 7.1.6 Fill should be tested for compliance with the recommended relative compaction and moisture conditions. Field density testing should con- form to ASTM Method of Test D 1556-64, D 2922-78 and/or D 2937-71. Tests should be provided for about every two vertical feet or 1,000 cubic yards of fill placed. Actual test interval may vary as field conditions dictate. Fill found not to be in conformance with the grading recom- mendations should be removed or otherwise handled as recommended by the Geotechnical Consultant. 7.1.7 The Contractor should assist the Geotechnical Consultant and/or his representative by digging test pits for removal determinations and/or for testing compacted fill. 7.1.8 As recommended by the Geotechnical Consultant, the Contractor should "shut down" or remove grading equipment from an area being tested. 7.1.9 The Geotechnical Consultant should maintain a plan with estimated locations of field tests. Unless the client provides for actual surveying of test locations, the estimated locations by the Geotechnical Consultant should only be considered rough estimates and should not be utilized for the purpose of preparing cross sections showing test locations or in any case for the purpose of after-the-fact evaluating of the sequence of fill placement. r- .- Standard Guidelines for Grading Projects Page 13 .~. ..,- -- - - - - .- - - 7.2 MOISTURE 7.2.1 7.2.2 7.2.3 For field testing purposes, "near optimum" moisture will vary with material type and other factors including compaction procedure. "Near optimum" may be specifically recommended in Preliminary Investigation Reports and/or may be evaluated during grading. Prior to placement of additional compacted fill following an overnight or other grading delay, the exposed surface or previously compacted fill should be processed by scarification, watered or dried as needed, thoroughly blended to near- optimum moisture conditions, then recompacted to a minimum of 90 percent of laboratory maximum dry density. Where wet or other dry,or other unsuitable materials exist to depths of greater than one foot, the unsuitable materials should be overexcavated. Following a period of flooding, rainfall or overwatering by other means, no additional fill should be placed until damage assessments have been made,and remedial grading performed as described under Section 5.6 herein. 7.3 FILL MATERIAL 7.3.1 7.3.2 7.3.3 Excavated on-site materials which are acceptable to the Geotechnical Consultant may be utilised as compacted fill, provided trash, vegetation and other deleterious materials are removed prior to placement. Where import materials are required for use on-site, the Geotechnical Consultant should, be notified at least 72 hours in advance of importing, in order to sample and test materials from proposed borrow sites. No import materials should be delivered for use on-site without prior sampling and testing by Geotechnical Consultant. Where oversized rock or similar irreducible material is generated during grading, it is recommended, where practical, to waste such material off-site or on-site in areas Page 14 .~ -_ - .- - - - - Standard Guidelines for Grading Projects 7.3.4 7.3.5 7.3.6 designated as "nonstructural rock disposal areas". Rock placed in disposal areas should be placed with sufficient fines to fill voids. The rock should be compacted in lifts to an unyielding condition. The disposal area should be covered with at least three feet of compacted fill which is free of oversized material. The upper three feet should be placed in accordance with the guidelines for compacted fill herein. Rocks 12 inches in maximum dimension and smaller may be utilised within the compacted fill, provided they are placed in such a manner that nesting of the rock is avoided. Fill should be placed and thoroughly compacted over and around all rock. The amount of rock should not exceed 40 percent by dry weight passing the 3/4-inch sieve size. The 12-inch and 40 percent recommendations herein may vary as field conditions dictate. During the course of grading operations, rocks or similar irreducible materials greater than 12-inches maximum dimension (oversized material) may be generated. These rocks should not be placed within the compacted fill unless placed as recommended by the Geotechnical Consultant. 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 off-site. Rocks up to four feet maximum dimension should be placed below the upper 10 feet of any fill and should not be closer than 20-feet to any slope face. These recommendations could vary as locations of 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 clean, overexcavated or unyielding compacted fill or firm natural - - - .- Standard Guidelines for Grading Projects Page 15 ground surface. Select native or imported granular soil (S.E. 30 or higher) should be placed and thoroghly flooded over and around all windrowed rock, such that voids are filled. Windrows of oversized material should be staggered so that sucessive strata of oversized material are not in the same vertical plane. 7.3.7 It may be possible to dispose of individual- larger rock as field conditions dictate and as recommended by the Geotechnical Consultant at the time of placement. 7.3.8 Material that is considered unsuitable by the Geotechnical Consultant should not be utilized in the compacted fill. 7.3.9 During grading operations, placing and mixing the materials from the cut and/or borrow areas may result in soil mixtures which possess unique physical properties. Testing may be required of samples obtained directly from the fill areas in order to verify conformance with the specifications. Processing of these additional samples may take two or more working days. The Contractor may elect to move the operation to other areas within the project, or may continue placing compacted fill pending laboratory and field test results. Should he elect the second alternative, fill placed is done so at the Contractor's risk. 7.3.10 Any fill placed in areas not previously reviewed and evaluated by the Geotechnical Consultant, and/or in other areas, without prior notification to the Geotechnical Consultant may require removal and recompaction at the Contractor's expense. Determination of overexcavations should be made upon review of field conditions by the Geotechnical Consultant. 7.4 FILL SLOPES 7.4.1 Unless otherwise recommended by the Geotechnical Consultant and approved by the regulating agencies, permanent fill slopes should not be steeper than 2:l (horizontal to vertical). Standard Guidelines for Grading Projects Page 16 - 7.4.2 Except as specifically recommended otherwise or as otherwise provided for in these grading guidelines (Reference 7.4.31, compacted fill slopes should be overbuilt and cut back to grade, exposing the firm, compacted fill inner core The actual amount of overbuilding may vary as field conditions dictate. If the desired results are not achieved, the existing slopes should be overexcavated and reconstructed under the guidelines of the Geotechnical Consultant. The degree of overbuilding shall be increased until the desired compacted slope surface condition is achieved. Care should be taken by the Contractor to provide thorough mechanical compaction to the outer edge of the overbuilt slope surface. 7.4.3 Although no construction procedure produces a slope free from risk of future movement, overfilling and cutting back of slope to a compacted inner core is, given no other constraints, the most desirable procedure. Other constraints, however, must often be considered. These constraints may include property,line situations, access, the critical nature of the development and cost. Where such constraints are identified, slope face compaction may be attempted by conventional construction procedures including backrolling techniques upon specific recommendation by the Geotechnical Consultant. As a second best alternative for slopes of 2:l (horizontal to vertical) or flatter, slope construction may be attempted as outlined herein. Fill placement should proceed in thin lifts, i.e., six to eight inch loose thickness). Each lift should be moisture conditioned and thoroughly compacted. The desired moisture condition should be maintained and/or re-established, where necessary, during the period between successive lifts. Selected lifts should be tested to ascertain that desired compaction is being achieved. Care should be taken to extend compactive effort to the outer edge of the slope. Each lift should extend horizontally to the desired finished slope surface or more as needed to ultimately establish desired grades. Grade during _- -_ -. - ,- Standard Guidelines for Grading Projects Page 17 construction should not be allowed to roll off at the edge of the slope. It may be helpful to elevate slightly the outer edge of the slope. Slough resulting from the placement of individual lifts should not be allowed to drift down over previous lifts. At intervals not exceeding four feet in vertical slope height or the capability of available equipment, whichever is less, fill slopes should be thoroughly backrolled utilizing a conventional sheepsfoot-type roller. Care should be taken to maintain the desired moisture conditions and/or re-establishing same as needed prior to backrolling. Upon achieving final grade, the slopes should again be moisture conditioned and thoroughly backrolled. The use of a side-boom roller will probably be necessary and vibratory methods are strongly recommended. Without delay, so as to avoid (if possible) further moisture conditioning, the slopes should then be grid-rolled to achieve a relatively smooth surface and uniformly compact conditon. In order to monitor slope construction procedures, moisture and density tests will be taken at'regular intervals. Failure to achieve the desired results will likely result in a recommendation by the Geotechnical Consultant to overexcavate the slope surfaces followed by reconstruction of the slopes utilising overfilling and cutting back procedures and/or further attempt at the conventional backrolling approach. Other recommendations may also be provided which would be commensurate with field conditions. 7.4.4 Where placement of fill above a natural slope or above a cut slope is proposed, the fill slope configuration as presented in the accompanying Standard Details should be adopted. 7.4.5 For pad areas above fill slopes, positive drainage should be established away from the top-of-slope. This may be accomplished utilizing a berm and pad gradients of at least 2 percent in soil areas. Standard Guidelines for Grading Projects Page 18 - .,- - - - - - - - - - 7.5 OFF-SITE FILL 7.5.1 Off-site fill should be treated in the same manner as recommended in these specifications for site preparation, excavation, drains, compaction, etc. 7.5.2 Off-site canyon fill should be placed in preparation for future additional fill, as shown in the accompanying Standard Details. 7.5.3 Off-site fill subdrains temporarily terminated (up canyon) should be surveyed for future relocation and connection. 8. DRAINAGE 8.1 8.2 8.3 8.4 8.5 Canyon subdrain systems specified by the Geotechnical Consultant should be installed in accordance with the Standard Details. Typical subdrains for compacted fill buttresses, slope stabilizations or sidehill masses! should be installed in accordance with the specifications of the accompanying Standard Details. Roof, pad and slope drainage should be directed away from slopes and areas of structures to suitable disposal areas via non-erodible devices (i.e., gutters, downspouts, concrete swales). For drainage over soil areas immediately away from structures (i.e., within four feet) a minimum of 4 percent gradient should be maintajned. Pad drainage of at least 2 percent should be maintained over soil areas. Pad drainage may be reduced to at least 1 percent for projects where no slopes exist, either natural or man-made, of greater than lo-feet in height and where no slopes are planned, either natural or man-made, steeper than 2:l (horizontal to vertical slope ratio). Drainage patterns established at the time of fine grading should be maintained throughout the life of the project. Property owners should be made aware that altering drainage patterns can be detrimental to slope stability and foundation performance. 9. STAKING . 9.1 In all fill areas, the fill should be compacted prior to the placement of the skates. This particularly is Standard Guidelines for Grading Projects Page 19 - - - - - - - .- important on fill slopes. Slope stakes should not be placed until the slope is thoroughly compacted (backrolled). If stakes must be placed prior to the completion of compaction procedures, it must be recognised that they will be removed and/or demolished at such time as compaction procedures resume. 9'. 2 In order to allow for remedial grading operations, which could include overexcavations or slope stabilization, appropriate staking offsets should be provided. For finished slope and stabilization backcut areas, we recommend at least a lo-foot setback from proposed toes and tops-of-cut. 10. SLOPE MAINTENANCE 10.1 LANDSCAPE PLANTS In order to enhance surficial slope stability, slope planting should be accomplished at the completion of grading. Slope planting should consist of deep-rooting vegetation requiring little watering. Plants native to the southern California area and plants relative to native plants are generally desirable. Plants native to other semi-arid and arid areas may also be appropriate. A Landscape Architect would be the test party to consult regarding actual types of plants and planting configuration. 10 ,2 IRRIGATION 10.2.1 Irrigation pipes should be anchored to slope faces, not placed in trenches excavated into slope faces. 10.2.2 Slope irrigation should be minimized. If automatic timing devices are utilised on irrigation systems, provisions should be made for interrupting normal irrigation during periods of rainfall. 10.2.3 Though not a requirement, consideration should be given to the installation of near-surface moisture monitoring control devices. Such devices can aid in the maintenance of relatively uniform and reasonably constant moisture conditions. 10.2.4 Property owners should be made aware that overwatering of slopes is detrimental to slope stability. - -.. Standard Guidelines for Grading Projects s Page 20 -- - - - - - - - - - 10.3 MAINTENANCE 10.3.1 Periodic inspections of landscaped slope areas should be planned and appropriate measures should be taken to control weeds and enhance growth of the landscape plants. Some areas may require occasional replanting and/or reseeding. 10.3.2 Terrace drains and downdrains should be periodically inspected and maintained free of debris. Damage to drainage improvements should be repaired immediately. 10.3.3 Property owners should be made aware that burrowing animals can be detrimental to slope stability. A preventative program should be established to control burrowing animals. 10.3.4 As a precautionary measure, plastic sheeting should be readily available, or kept on hand, to protect all slope areas from saturation by periods of heavy or prolonged rainfall. This measure is strongly recommended, beginning with the period of time prior to landscape planting. 10 4 REPAIRS . 10.4.1 If slope failures occur, the Geotechnical Consultant should be contacted for a field review of site conditions and development of recommendations for evaluation and repair. 10.4.2 If slope failures occur as a result of exposure to periods of heavy rainfall, the failure area and currently unaffected areas should be covered with plastic sheeting to protect against additional saturation. 10.4.3 In the accompanying Standard Details, appropriate repair procedures are illustrated for superficial slope failures (i.e., occurring typically within the outer one foot to three feet of a slope face). 11. TRENCH BACKFILL 11.1 Utility trench backfill should, unless otherwise recommended, be compacted by mechanical means. Unless otherwise recommended, the degree of compaction should - - - - - - - ,- Standard Guidelines for Grading Projects Page 21 be a minimum of 90 percent of the laboratory maximum density. 11.2 As an alternative, granular material (sand equivalent greater than 30) may be thoroughly jetted in-place. Jetting should only be considered to apply to trenches no greater than two feet in width and four feet in depth. Following jetting operations, trench backfill should be thoroughly mechanically compacted and/or wheel-rolled from the surface. 11.3 Backfill of exterior and interior trenches extending below a 1:l projection from the outer edge of foundations should be mechanically compacted to a minimum of 90 percent of the laboratory maximum density. 11.4 Within slab areas, but outside the influence of foundations, trenches up to one foot wide and two feet deep may be backfilled with sand and consolidated by jetting, flooding or by mechanical means. If on-site materials are utilized, they should be wheel-rolled, tamped or otherwise compacted to a firm condition. For minor interior trenches, density testing may be deleted or spot,testing may be elected if deemed necessary, based on review of backfill operations during construction. 11.5 If utility contractors indicate that it is undesirable to use compaction equipment in close proximity to a buried conduit! the Contractor may elect the utilization of light weight mechanical compaction equipment and/or shading of the conduit with clean, granular material, which should be thoroughly jetted in-place above the conduit, prior to initiating mechanical compaction procedures. Other methods of utility trench compaction may also be appropriate , upon review by the Geotechnical Consultant at the time of construction. 11.6 In cases where clean granular materials are proposed for use in lieu of native materials or where flooding or jetting is proposed, the procedures should be considered subject to review by the Geotechnical Consultant. 11.7 Clean granular backfill and/or bedding are not recommended in slope areas unless provisions are made for a drainage system to mitigate the potential build-up of seepage forces. - ,- - - I 15’ MINIh4UM- I - - - - - - - - - - - - 4’ DIAMETER PERFORATED PIPE SACKDRAIN 4’ DIAMETER NON-PERFORATED PIPE LATERAL DRAIN SLOPE PER PLAN PROVIDE SACK DRAIN PER SACKDRAIN DETAIL. AN ADDITIONAL SACKDRAIN AT MID-SLOPE WILL SE REQUIRED FOR SLOPE IN EXCESS OF 40 FEET HIGH. KEY-DIMENSION PER SOILS ENGINEER (GENERALLY 112 SLOPE HEIGHT. 15’ MINIMUM) TYPICAL STABILIZATION FILL DETAIL JOB NO.: 30038-00 DATE: JULY la86 FIGURE: D, -- _.. - - - - - - - - - - 15’ MINIMUM 4’ DIAMETER PERFORATED PIPE BACKDRAIN 4’ DIAMETER NON-PERFORATED PIPE LATERAL DRAIN SLOPE PER PLAN BENCHING PROVIDE BACKDRAIN PER BACKDRAIN DETAIL. AN ADDITIONAL BACKDRAIN AT MID-SLOPE WILL BE REQUIRED FOR SLOPE IN EXCESS OF 40 FEET HIGH. KEY-DIMENSION PER SOILS ENGINEER \ TYPICAL BUTTRESS FILL DETAIL OB NO.: DATE: FIGURE: .30038-00 JULY 1988 D2 - I - - - - - - - - - - NATURAL GROUND PROPOSED GRADING COMPACTED FILL PROVIDE SACKDRAIN PER SACKDRAIN DETAIL. AN ADDITIONAL SACKDRAIN AT MID-SLOPE WILL BE REQUIRED FOR SACK SLOPES IN EXCESS OF 40 FEET HIGH. LOCA- TIONS OF SACKDRAINS AND OUTLETS PER SOILS BASE WIDTH ‘W’ DETERMINED BY SOILS ENGINEER ENGINEER AND/OR EN- GINEERING GEOLOGIST DURING GRADING. I TYPICAL SHEAR KEY DETAIL JO3 NO.: 30038-00 DATE: JULY lS88 FIGURE: D 3 -3 - _- - - - - - - - OVEREXCAVATE FINISH PAD OVEREXCAVATE 3’ AND REPLAC WITH COMPACTED 20’ MAXIMUM - SOUND BEDROCK - - -- TYPICAL BENCHING 2’ MINIMUM OVERBURDEN (CREEP-PRONE) PROVIDE BACKDRAIN PER BACKDRAIN DETAIL. LOCATION OF BACKDRAIN AND OUTLETS PER SOILS ENGINEER AND/OR ENGINEERING GEOLOGIST DURING GRADING EQUIPMENT WIDTH (MINIMUM 15’) DAYLIGHT SHEAR KEY DETAIL 06 NO.: DATE: 30038-00 JULY 1986 FIGURE: 04 -. - - - - - - - - BENCHING FILL OVER NATURAL SURFACE OF FIRM- , EARTH MATERIAL FILL SLOPE I IO’ MIN. (INCLINED 2% MIN. INTO SLOPE) BENCHING FILL OVER CUT 9 FINISH FILL SLOPE SURFACE OF FIRM EARTH MATERIAL FINISH CUT BENCHING FOR COMPACTED FILL DETAIL 108 NO.; DATE: FIGURE: 30038-00 JULY lS86 D5 - .- - - - - -. ,- - FINISH SURFACE SLOPE 3 FT3 MINIMUM PER LINEAL FOOT APPROVED FILTER ROCK* COMPACTED FILL 4. MINIMUM APPROVED PERFORATED PIPE** (PERFORATIONS OowN) 4’ MINIMUM DIAMETER SOLID OUTLET PIPE SPACED PER SOIL ENGINEER REOUIRE- MENTS DURING GRADING MINIMUM 2% GRADIENT TO OUTLET BENCH INCLINED TOWARD DRAIN TYPICAL BENCHING DETAIL A-A TEMPORARY FILL LEVEL COMPACTED 4’ MINIMUM DIAMETER APPROVED SOLID OUTLET PIPE 12’ MINIMUM COVER 12’ MINIMUM **APPROVED PIPE TYPE: SCHEDULE 40 POLYVINYL CHLORIDE (P.V.C.) OR APPROVED EOUAL. MINIMUM CRUSH STRENGTH 1000 PSI. *FILTER ROCK TO MEET FOLLOWING SPECIFICATIONS OR APPROVED EQUAL: SIEVE PERCENTAGE PASSING I’ 100 314. 00-100 3/S’ 40-100 NO.4 25-40 NO.30 5-15 NO.50 o-7 NO.200 o-3 TYPICAL BACKDRAIN DETAIL JOB NO.: 30038-00 DATE: JULY 1986 FIGURE: D6 -~ ..- .~ -~ - -. - - - - - - FINISH SURFACE SLOPE MINIMUM 3 FT3 PER LINEAL FOOT OPEN GRADED AGGREGATE* TAPE AND SEAL AT CONTACT COMPACTED FILL 4” MINIMUM DIAMETER SOLID OUTLET PIPE SPACED PER SOIL ENGINEER REQUIREMENTS SUPAC S-P FABRIC OR APPROVED EQUAL 4’ MINIMUM APPROVED PERFORATED PIPE (PERFORATIONS DOWN) MINIMUM 2% GRADIENT TO OUTLET BENCH INCLINED BENCHING TOWARD DRAIN DETAIL A-A TEMPORARY FILL LEVEL I 1 COMPACTED MINIMUM BACKFILL 12” COVER MINIMUM 4” DIAMETER APPROVED L SOLID OUTLET PIPE *NOTE: AGGREGATE TO MEET FOLLOWING SPECIFICATIONS OR APPROVED EOUALr SIEVE SIZE PERCENTAGE PASSING 1 112” 100 1 ” 5-40 314” o-17 3/S” o-7 NO. 200 o-3 BACKDRAIN DETAIL (GEOFABRIC) 08 NO.: DATE: FIGLIRE: 30038-00 JULY lS86 D7 .~, .- - -~ --. - - - - -~ TYPICAL BENCHING SURFACE OF FIRM EARTH MATERIAL REMOVE UNSUITABLE MATERIAL INCLINE TOWARD DRAIN SEE DETAIL BELOW DETAIL AINIMUM 9 FT3PER LINEAR FOOT IF APPROVED FILTER MATERIAL ,--MINIMUM 4’ DIAMETER APPROVED PERFORATED PIPE (PERFORATIONS DOWN) I- 6’ FILTER MATERIAL BEDDING , ‘ILTER MATERIAL TO MEET FOLLOWING ;PEClFlCATlON OR APPROVED EQUAL: SIEVE SIZE PERCENTAGE 1’ 100 314. 90-100 316’ 40-100 NO.4 25-40 NO.30 5-15 NO.50 o-7 NO.200 o-3 APPROVED PIPE TO BE SCHEDULE 40 POLY-VINYL-CHLORIDE (P.V.C.) OR APPROVED EQUAL. MIN,lMUM CRUSH STRENGTH 1000 psi PIPE DIAMETER TO MEET THE FOLLOWING CRITERIA. SUBJECT TO FIELD REVIEW BASED ON ACTUAL GEOTECHNICAL CONDITIONS ENCOUNTERED DURING GRADING LENGTH OF RUN PIPE DIAMETER UPPER 500’ 4’ NEXT 1000’ 6’ > 1500’ 8’ TYPICAL CANYON SUBDRAIN DETAIL 06 NO.: 30038-00 DATE: JULY 1986 FIGURE: D3 - -~~ - - - - - - - - - - - CANYON SUBDRAIN DETAILS SURFACE OF FIRM EARTH __------- COMPACTED FILL TYPICAL BENCHING REMOVE UNSUITABLE MATERIAL INCLINE TOWARD DRAIN SEE DETAILS BELOW TRENCH DETAIL 6’ MINIMUM OVERLAP ----- OPTIONAL V-DITCH DETAIL MINIMUM 9 FT3 PER LINEAL /FOOT OF APPROVED DRAIN MATERIAL SUPAC 6-P FABRIC SUPAC 5-P FABRIC OR APPROVED EQUAL 6’ MINIMUM OVERLAP _----- MINIMUM 9 FT3 PER LINEAL FOOT MINIMUM OF APPROVED DRAIN MATERIAL DRAIN MATERIAL TO MEET FOLLOWING SPECIFICATION OR APPROVED EOUAL: SIEVE SIZE PERCENTAGE PASSING 1 112’ 66-100 1’ 5-40 314’ O-17 316’ o-7 NO.200 o-3 ADD MINIMUM 4’ DIAMETER APPROVED PERFORATED PIPE WHEN GRADIENT IS LESS THAN 2% APPROVED PIPE TO SE SCHEDULE 40 POLY-VINYL- CHLORIDE (P.V.C.) OR APPROVED EQUAL. MINIMUM CRUSH STRENGTH 1000 psi. GEOFABRIC SUBDRAIN OS NO.: 3003a-Qo DATE: JULY 1986 FIGURE: ~~ _- _,- - - - - - - - - r- 15’ MINIMUM BASE KEY WIDTH’ MlNlMUM ‘\ DOWNSLOPE KEY DEPTH COMPETENT EARTH MATERIAL / TYPICAL BENCH/ HEIGHT -PROVIDE SACKDRAIN AS REQUIRED PER RECOM- MENDATIONS OF SOILS ENGINEER DURING GRADING WHERE NATURAL SLOPE GRADIENT IS 5:l OR LESS. BENCHING IS NOT NECESSARY. HOWEVER. FILL IS NOT TO SE PLACED ON COMPRESSISLE OR UNSUIT- ABLE MATERIAL. FILL SLOPE ABOVE NATURAL GROUND DETAIL IO8 NO.: 30038-00 DATE: JULY 1088 FIGURE: DIO FINAL NATURAL SLOPE LIMITS OF FINAL EXCAVATION f- TOE OF SLOPE SHOWN ON GRADING PLAN 10’ TYPICAL BENCH WIDTH VARIES I I I I I I I I I I I I I I 1, I I REMOVE ALL TOPSOIL. COLLUVIUM- AND CREEP MATERIAL.FROM TRANSITION \ CUT/FILL CONTACT SHOWN ON GRADING PLAN CUT/FILL CONTACT SHOWN ON ‘AS-BUILT’ NATURAL TOPOGRAPHY -J /---- .- //--- CUT SLOPE” BEDROCK OR APPROVED FOUNDATION MATERIAL *NOTE: CUT SLOPE PORTION SHALL BE MADE PRIOR TO PLACEMENT OF FILL 808 No.: 30038-00 FILL SLOPE ABOVE CUT SLOPE DETAIL DATE: JULY 1088 FIGURE: D11 - .- _- - - - - - - - .- - - - - ,- - - GENERAL GRADING RECOMMENDATIONS CUT LOT -ORIGINAL GROUND TOPSOIL. COLLUVIUM AND ,. WEATHERED BEDROCK ,’ /’ .A/ OVEREXCAVATE AND *’ 4’ UNWEATHERED BEDROCK REGRADE . CUT/FILL LOT (TRANSITION) / ORIGINAL HA/ GROUND COMPACTED FILL OVEREXCAVATE AND REGRADE .COLLUVIUf.f AND WEATHERED UNWEATHERED BEDROCK BEDROCK ,’ A .y TRANSITION LOT DETAIL 06 NO.: 30038-00 DATE: JULY 1086 F’G”RE: D12 - .- - - - - - - - - - - - - - - BUlLDiNG FINISHED GRADE 5’ 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 38 NO.: 30038-00 DATE: JULY 1088 FIGURE: D,3