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HomeMy WebLinkAboutCT 82-23; Tentative Development CT 82-23; Soils Report; 1983-05-25-. ENGlNEERlNQ DEPT, LIBRARY City of Carlsbad 2075 Las Palmas Drive Carisbad, CA 92009-4859 BOG 3J-2 2.W.ze) GEOTECHNICAL INVESTIGATION FOR TENTATIVE PLANNED DEVELOPMENT, 82-23 CARLSBAD, CALIFORNIA For MOLA DEVELOPMENT CORPORATION Huntington Beach, California CEOCON, INCORPORATED San Diego, California May, 1983 GEOCON rn TI ,1501,011100 -1 u Geotechnical Engineers and Engineering Geologists -; 7 File No. 0-2904-501 - May 25, 1983 Mola Development Corporation Huntington Beach, California 92648 808 Adams Attention: Mr. Ed Wale Subject : TENTATIVE PLANNED DEVELOPMENT MAP 82-23 CARLSBAD, CALIFORNIA REPORT OF GEOTECHNICAL INVESTIGATION Gentlemen: In accordance with your authorization, we have performed a geotechnical investigation for the subject project. The accompanying report presents the findings from our study and our recommendations pertaining to the geotechnical engineering aspects of project development. Should you have any questions concerning the contents of this report or if we may be of further service, please contact us at your convenience. Very truly yours, GEOCON, INCORPORATED James E. Likins RCE 17030 SRP:JEL:ln (6) addressee Michael W. Hart CEG 706 Steven R. Penn RS 4007 9530 Dowdy Drive San Diego. CA 92126 619 6952880 "1,. ..... -1 - '? i TABLE OF CONTENTS Page SOIL INVESTIGATION AND GEOLOGIC RECONNAISSANCE Purpose and Scope. ..................... 1 Site and Project Description ................ 3 1 Groundwater......................... Soil Conditions 5 Geologic Hazards/Seismicity. ................ 5 CONCLUSIONS AND RECObPlENDATIONS. ................ 7 General. .......................... 7 Grading. .......................... 8 Foundations......................... 9 Concrete Slabs-on-Grade. .................. 10 Retaining Walls and Lateral Loads. ............. 10 Site Drainage and Moisture Protection. ........... 11 Grading and Foundation Plan Review ............. 11 LIMITATIONS AND UNIFORMITY OF CONDITIONS ............ 12 Figure 1, Site Plan. ...................... 13 APPENDIX A ...................... FIELD INVESTIGATION Figures A-3 - A-7, Logs of Test Trenches Figures A-1 - A-2, Logs of Test Borings APPENDIX B LABORATORY TESTING Table I, Moisture-Density and Direct Shear Test Results Table 11, Compaction Test Results Table 111, Expansion Index Test Results APPENDIX C Recommended Grading Specifications .I File No. D-2904-J01 May 25, 1983 GEOTECHNICAL INVESTIGATION Purpose and Scope We have performed a geotechnical investigation for the Tentative Planned Development Map 82-23 located in Carlsbad, California. The purpose of our investigation was to evaluate the surface and subsurface soil and geologic conditions at the site and, based on the conditions encountered, to provide recommendations relative to the geotechnical engineering aspects of project development. The scope of our field investigation consisted of a site reconnaissance, the drilling of two exploratory borings and the excavation of seven exploratory trenches. In addition, a review of relevent soil and geologic literature concerning the site was performed. Laboratory tests were performed on selected representative soil samples to evaluate pertinent physical properties. The recommendations presented herein are.based on an analysis of the data obtained in the various phases of our investigation and our experience with similar soil and geologic conditions. Site and Project Description The site is a 17.77+ - acre parcel which is situated on the vest side of El Camino Real north of Alga Road in Carlsbad, California. The parcel contains approximately 783+ - feet of frontage along El Camino Real and approximately 1063 feet along Alga Road. Topographically, the parcel is divided into western and eastern portions by a north- to south-trending, well defined -1- J -'I:, .; R, I, -1 May 25, 1983 File No. D-2904-301 "I natural drainage course. At the time of our investigation, there was a - small amount of water flowing in this drainage course. - The western portion of the parcel ranges in elevation from a high point of 225 feet MSL along the western property line to a low of 110 feet MSL in the bottom of the drainage swale as it exits the site to the south. The eastern portion of the site ranges from a high point of 195 feet MSL in the northwest corner of the parcel to a low point of 160 feet MSL in the bottom - -. _. of the central drainage channel/ravine at the north property line. - The preliminary grading plan for the project prepared by Sowards Engineer- ing dated November 8, 1982 was utilized as a guide in the investigation. - In general, development plans call for a balanced grading operation, with cuts of 10 to 20 feet on the west and east slopes, and filling of the north- to-south-trending central ravine. The maximum depth of fill soils will be approximately 45 feet at the south-central portion of the site. - -. The plans indicate that the eastern portion~of the site will be a shopping/ commercial center and the western portion will be residential. , The commercial site will consist of five buildings with associated parking and roadway areas. We snticipate that the tuildings will be one- and/or two- - - story structures and that the small buildings will be of wood-frame construction and that the larger buildings will be of concrete tilt-up construction. We also anticipate that spread and/or continuous footings with slab-on-grade floors will be utilized. The residential complex - -i -1 -2- -J -1 File No. D-2904-J01 i May 25, 1983 proposed for the western part of the site will consist of 10 one- and/or two-story multi-plex structures and associated parking and driveway areas. We anticipate that construction will be of wood-frame and stucco with spread and/or continous footings and slab on-grade floors. Should project details vary significantly from those outlined, Geocon, Incorporated should be notified for review and possible revision of the recommendations - - presented herein. Soil Conditions As indicated by the exploratory borings and our review of relevant liter- ature, the site is generally underlain by Eocene-aged Torrey sandstone. In Boring 2 at a depth of approximately 12 to 13 feet, corresponding to a mean sea level elevation of approximately 156 feet, sandstones and claystones of the Delmar Formation were encountered. The Torrey sandstone consisted of moderately dense to very dense, white to yellow-tan, lightly to highly cemented, fine to medium sand. The Delmar Formation consisted of moderately dense to dense, greenish-gray to greenish-brown, clayey sands to very waxy claystone. The Torrey sandstone is expected to be the predominant soil type exposed at finish grade over the majority of the site at the comple- tion of grading. This material in either a natural or recompacted state should exhibit excellent foundation support characteristics with minimal postconstruction settlement or expansion potential. The Delmar Formation encountered in Boring 2 is highly expansive and, therefore, is not suitable as a foundation bearing material. Based upon the depth of the Delmar -3- -1 -1 -. -1 File NO. D-2904-J01 May 25, 1983 Formation in relationship to the anticipated grading, it appears that very little of this material will be exposed at finish grade. If encountered within 2 feet of finish grade, the affected area can be overexcavated 2 feet and capped with suitable material utilized to cap the pad. Overlying the formational soils in most areas of the site is a 1- to 3-foot-thick topsoil layer consisting of moderately to highly expansive clayey silty sands to sandy clays. This material is not suitable for use in capping pads but can be utilized in the bottom of the deeper fills in the central portion of the site. Saturated, loose and unconsolidated alluvial deposits were encountered within the confines of the well defined, deeply incised north- to south- trending drainage basin and, to a lesser extent, within the immediate vicinity of the small tributary drainage swales. As indicated by the logs of the exploratory trenches, the depth of the alluvium in the smaller drainage swales is 2 to 8 feet. The loose. and saturated condition of the sands encountered in the bottom of the large central drainage feature made exavation very difficult. In all of these trenches it was determined that the depth of the alluvial deposits were greater than the excavation depth of the backhoe. Based upon pertinent literature and our experience with similar sites, an alluvial depth fo 15 to 20 feet should be anticipated. - As the horizontal extent of the alluvium is limited by the well defined and deeply incised drainage swale, the total volume of alluvium should be -1 -4- File No. D-2904-J01 May 25, 1983 within acceptable limits. However, the saturated condition of these materials may hamper removal efforts. It will, however, be necessary to remove all loose alluvial deposits until firm natural soils are exposed prior to the placement of any fill soils. Groundwater Free groundwater was not encountered in the deep exploratory Borings 1 and 2 or the deep exploratory Trench 8. As mentioned previously, flowing surface water was present at the time of our investigation in the large drainage swale and a number of the smaller tributaries. This surface flow of water did result in the saturation of the alluvial soils in these areas with resultant groundwater infiltration into the excavated trenches. However, it is our opinion that this water is transitory and nature, and that water fron actual local water tables will surface in not affect project development as presently proposed. Geologic HazardsISeismicity It is our opinion, based on our site reconnaissance, evidence obtained in the exploratory borings and a review of published geologic maps and reports, that the site is not located on any known fault trace. The nearest known active faults are the Elsinore and San Jacinto Fault systems which lie approximately 27 and 49 miles to the northeast, respectively. A review of Special Report No. 123 (California Division of Mines and Geology) indicates the most northernly mapped location of the potentially active -5- -1 File No. D-2904-J01 May 25, 1983 -, Rose Canyon Fault lies approximately 7 miles to the southwest. It is our - opinion that the site could be subjected to moderate to severe ground shaking in the event of a major earthquake along any of the above mentioned faults. However, the seismic risk at the site is not significantly greater than that of the surrounding area. - - -6- - 7' '.. -1 File No. D-2904-J01 I May 25, 1983 CONCLUSIONS AND RECOMMENDATIONS General 1. It is our opinion no adverse soil or geologic conditions are present on the site which would preclude the development of the proposed commercial/ residential project as described herein, provided the recommendations of this report are followed. 2. The site was found to be covered by a thin (approximately 1- to 3-fOOt) mantle of topsoil consisting of relatively loose, moderately to highly expansive, clayey sands and sandy clays on the western and eastern slopes. Underlying the topsoils are sands' of the Torrey Sandstone Formation. Underlying the Torrey Sandstone, in the southeast corner of the site in the vicinity of Boring 2, are clayey sands and claystones of the Delmar Formation. Loose, unconsolidated, saturated alluvium was encountered within the well defined confines of the large north-south-trending drainage swale bisecting the site and, to a lesser extent, is the center of many of the smaller drainage tributaries. These alluvial soils, in their present condition, are not considered suitable for foundation support and will require remedial grading prior to placement of fill. 3. Groundwater encountered in the drainage swales on the site is, in our opinion, transitory and caused by surface runoff and drainage through the site. The presence of this water, however, may increase the difficulty in removing the loose alluvium in the drainage swales. -7- -1 File No. D-2904401 May 25, 1983 4. No potential geologic hazards were observed or are known to exist on the site which would adversely affect the proposed project. Grading 5. All grading should be performed in accordance with the "Recommended Grading Specifications" contained in Appendix C and the City of Carlsbad Grading Specifications. Where the recommendations of Appendix C conflict with this section of the report, the recommendations of this section take precedence. 6. Site preparation should begin with removal of all deleterious matter and vegetation. 7. Loose, saturated alluvial deposits should be excavated and removed from all drainage swales until firm natural ground is exposed. The exposed natural ground should then be scarified to a depth of 12 inches, moisture conditioned and recompacted to at least 90 percent of maximum dry density as determined in accordance with ASTM Test 'Procedure D1557-70, Method A or C. 8. Fill soils derived from stockpiled alluvium, native topsoils and onsite cutting operations can then be placed in compacted layers until final elevations are reached. -a- -1 May 25, 1983 File No. D-2904-J01 Foundations 9. All pads should be capped with at least 24 inches of non- to low expansive soils. Where cut-fill daylight lines cross building pads, the pads should be overexcavated 24 inches and replaced with properly compacted non- to low expansive soils. It is our opinion that cut and fill slopes inclined at slopes of 2 horizontal to 1 vertical will possess a factor of safety of 1.5 or greater for near-surface sloughage and deep-seated rotational failure (static loading), provided that the site is graded as - recommended herein. 10. Fill slopes should be backrolled at intervals of at least 4 feet and/or trackwalked, grid rolled or otherwise compacted such that relative compactions of at least 90 percent are obtained within the top 12 inches of the slope face. 11. It is recommended that minimum footing reinforcement consist of two continuous No. 4 steel reinforcing bars placed horizontally in the foot- ings, one near the top of the footing and one near the bottom. The above minimum reinforcement is based on soil characteristics and is not intended to be in lieu of reinforcement necessary for structural considerations. 12. An allowable bearing capacity of 2000 psf may be used for foundations constructed as recommended above. The allowable bearing capacity is for dead plus live loads and may be increased by one-third for transient loads due to wind or seismic forces. . -9- - '7 File No. D-2904-JOI j May 25, 1983 13. It is estimated that .total and/or differential postconstruction settlement for foundations designed as recommended herein will be within normal tolerable limits for the proposed structures (less than 0.5-inch). Concrete Slabs-on-Grade 14. Concrete slabs should have a nominal thickness of 4 inches and be underlain by at least 4 inches of clean sand. Minimum reinforcement should consist of 6x6-10/10 welded wire mesh throughout. Care should be taken to place mesh in the middle of the slab. 15. Granular base would tend to act as a capillary barrier to moisture but will not provide a positive barrier against the rise of moisture through slabs. If moisture sensitive floor coverings are involved in any part of the structures, an impervious membrane vapor barrier should be utilized. Where used, a 2-inch layer of clean sand should be placed between the base of the slab and the membrane to minimize shrinkage cracking and allow proper curing of the concrete. Retaining Walls and Lateral Loads 16. Lateral loads may be resisted by "passive" earth pressures. Passive earth pressures against shallow spread-type or continuous wall footings in contact with properly compacted backfill should be considered as being equal to the forces exerted by a fluid of 300 pcf unit weight. 17. A coefficient of friction of 0.4 may be used between the bases of footings and slabs and the soil for computing resistance to sliding. -4 -10- -I 1 '1. . I' .. 7 File No. D-2904-J01 -1 j May 25, 1983 -i 18. Retaining walls, which are not fixed at the top, should be designed to - resist an active soil pressure of 30 pcf unit weight. Where the wall will be fixed or restrained at the top, an additional uniform horizontal pressure of 50 psf should be included. The values assume a drained and level granular backfill condition. Waterproofing and wall drainage details should be provided by the project architect. - - - Site Drainage and Moisture Protection 19. The provisions and maintenance of adequate site drainage and moisture - protection of supporting soils is an important design consideration. - Foundation recommendations presented herein assume proper site drainage will be established and maintained. - 20. Under no circumstances should water be allowed to pond adjacent to footings. The site should be graded such that surface drainage flow is directed away from structures and'into swales or other controlied drainage facilities. 21. Landscaped areas within parking areas should be designed such that excess irrigation water is positively drained. Ponding of water within thsse areas could cause localized high moisture within subgrade soil increasing the potential for pavenent failure and/or increased maintenance. Grading and Foundation Plan Review 22. Geocon, Incorporated should review the final grading and foundation plans to verify their compliance with this report. -11- -1 i I -7 May 25, 1983 File No. D-2904-J01 L .- - LIMITATIONS AND UNIFORMITY OF CONDITIONS - 1. The recommendations of this report pertain only to the site investi- gated 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 planned at the present time, Geocon, Incorporared should be notified so that supplemental recom- mendati0n.s can be given. 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 carry 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. -12- File No. D-2904-JO1 May 25, 1953 .I .. 0 .__.___PROPOSED STRUCTURE SITE PLAN TENTATIVE PLANNED DEVELOPHENT YAP 32-23 CARLSBAD, CALIFORNIA 'IGURE 1 GEOCON INCORPORATED PAGE 13 File No. D-2904-JOl - May 25, 1983 -. L- APPENDIX A FIELD INVESTIGATION _. 7' The field investigation was performed between March 12 and May 11, 1983. Inaccessability due to wet soil conditions hampered the completion of the field portion of our investigation. The investigation consisted of the excavation of two exploratory borings and eight exploratory trenches at the approximate location shown on the Site Plan, Figure 1. The borings were drilled to depths ranging from 21 to 26 feet below existing grade utilizing a truck-mounted rotary drill rig equipped with 8-inch-diameter hollow stem auger. The trenches were excavated using a Case 580 backhoe equipped with a 24-inch-wide bucket.Chunk samples and bulk samples were obtained from the backhoe excavations. For the exploratory borings, relatively undisturbed samples were obtained by driving a 3-inch O.D. split-tube sampler into the undisturbed soil mass with blows from a 140-pound hammer falling 30 inches. The sampler was equipped with 1-inch by 2-3/8-inch brass sampler rings to facilitare removal and testing. During the investigaticn, the soils encountered were continuously examined, visually classified and logged. Logs of the test borings and trenches are presented on Figures A-1 through A-5 herein. The logs depict the depth and description of the various soil types encountered and include the depths at which sampling was performed. "J i File No. D-2904-JOl -j May 25, 1983 APPENDIX B LABORATORY TESTING Laboratory tests were performed in accordance with generally accepted test methods of the American Society for Testing and Materials (ASTM) or other suggested procedures. Relatively undisturbed drive samples were tested for their in-place dry density, moisture content, shear strength, compaction and expansion potential characteristics. The results of these tests are summarized in tabular and graphical form in Appendix B. In addition, in- place moisture density relationships are presented on the logs of test borings in Appendix A. -. . . - I ,," File No. D-2904-J01 May 25, 1983 i - @Q n '! TABLE I Summary of In-Place Moisture-Density and Direct Shear Test Results Sample NO. 1-1 1-2 *1"3 1-4 1-5 2-2 2-3 2-4 2-5 2-7 8-1 8-2 Dry PCf 100.9 100.2 110.8 113.3 102.6 107.8 106.4 107.3 100.2 94.2 113.6 109.8 Density Moisture Content % 11.8 10.7 11.1 8.1 10.2 9.3 11.6 18.2 23.8 25.3 8.0 9.7 Unit Cohesion psf "- "- 460 140 "_ "_ "- 50 "- -I "_ 1110 Angle of Shear Resistance Degrees " " 27 52 " " " 52 " " " 45 *Sample remolded to approximately 90 percent of maximum dry density at near optimum moisture content. - I File No. D-2904-JOl May 25, 1983 TABLE I1 Summary of Laboratory Compaction Test Results ASTM D1557-70 Sample No. Description 1-3 Brown-tan, fine to medium, slightly Clayey SAND 2- 1 Brown, Clayey Silty, fine SAND 2-6 Green-tan, Silty Sandy CLAY Maximum Dry Density Moisture Optimum PCf % Dry Wt. 123.1 11.1 120.2 12.5 111.1 16.6 Sample No. 2-1 2-6 TABLE 111 Summary of Laboratory Expansion Test Results Moisture Content Before Af fer Expansion (+) or Test Test Dry Settlement(-) Surcharge Density x % pcf % psf 12.9 25.2 108.4 + 8.5 150 16.0 30.8 100.8 +14.1 150 i File No. D-2904-JOl - May 25, 1983 RECOMMENDED GRADING SPECIFICATIONS 1. General 1.1 - 1.2 - 1.3 - 2. - 2.1 - 2.2 2.3 - - 2.4 These specifications have been prepared for grading of the Tentative Planned Development, Map 82-23 in Carlsbad, California. They shall be used only in conjunction with the soil report for the project dated May 25, 1983 prepared by Geocon, Incorporated. The contractor shall be responsible for placing, spreading, watering, and compacting the fill in strict conformance with these specifica- tions. All excavation and fill placement should be done under the observation of the Geocon, Incorporated. Geocon, Incorporated, should be .consulted if the contractor or owner wishes to deviate from these specifications. The grading should consist of clearing, grubbing, and removing from the site all material the Soil Engineer designates as "unsuitable"; materials; and all other work necessary to conform with the lines, preparing areas to be filled; properly placing and compacting fill grades, and slopes shown on the approved plans. Preparation of Areas to be Graded All trees and shrubs not to be used for landscaping, structures, weeds, and rubbish should be removed from the site prior to commencing any excavating or filling operations. All buried structures (such as tanks, leach lines, and pipes) not depressions should be properly backfilled and compacted prior to any designated to remain on the site should be removed, and the resulting grading or filling operations. All water wells should be treated in accordance with the requirements of the San Diega County Health Department. The owner shall verify the requirements. All vegetation and soil designated as "unsuitable" by the Soil Engi- neer should be removed under his observation. The exposed surface should then be plowed or scarified to a depth of at least 12 inches until the surface is free from ruts, hummocks, or other uneven fea- tures that would prevent uniform compaction by the equipment used. 1 - f ! ! L" 2.5 Where the slope ratio of the original ground is steeper than 6.0 horizontal to 1.0 vertical, or where recommended by the Soil Engi- neer, the bank should be benched in accordance with the following illustration. NOTES ilNlSEED SLCPE SUEFACE (2) SLOUGHING OR SLIDING DOES NOT KCJR - RWYE AS RECCMVENDED jY S0I.L ENGINEER (NOTE 2) (NOTE I) - 2.6 - 3. 3.1 3.2 3.3 3.4 "B" should be 2 feet wider than the com- paction equipment, and should be a min- inum of 10 feet wide. The outside of the botton key should be below the topsoil or slopewash and at least 3 feet into dense formational ma- terials. After the areas have been plowed or scarified, the surface should be disced or bladed until they are free from large clods; brought to the specified in Section 4 of these specifications. proper moisture content by adding water or aerating; and compacted as Materials Suitable for Use in Compacted Fill Material that is perishable, spongy, contains organic matter, or is used for compacted fill should consist of at least 40 percent fines otherwise unsuitable should not be used in compacted fill. Material smaller than 314-inch diameter. The soil engineer should decide what materials, either imported to the site or excavated from on-site cut areas, are suitable for use in Compacted fills; the Soil Engineer should approve any import material before it is delivered to the site. During grading, the contractor may encounter soil types other than those analyzed for the soil investigation. The Soil Engineer should be consulted to evaluate the suitability of such soils. Any material containing rocks or hard lumps greater than 6 inches in diameter should be placed in accordance with Section 6 of these specifications. The Soil Engineer should perform laboratory tests on representative samples of material to be used in compacted fill. Such tests should of the samples. The tests should be performed in accordance with be perforned to evaluate the maximun dry density and moisture content Materials (ASTM). accepted test methods of the American Society of Testing and - 4.2 4.3 - 4.4 4.5 - 4.6 - 4.7 5. 5.1 5.2 Placing, Spreading, and Compacting Fill Material Unless otherwise specified, fill material should be compacted while at a moisture content near the optimum moisture content and to a relative compaction of at least 90 percent as determined by accepted ASTM test methods. Fill materials should be placed in layers that, when compacted, have a relative compaction in conformance with the project specifications. Each layer should be spread evenly and mixed thoroughly to provide uniformity of materials in each layer. When the moisture content of the fill material is less than that reconmended by the Soil Engineer, water should be added until the moisture content is as recommended. When the moisture content of the fill material is more than that recommended by the Soil Engineer, the fill material should be aerated by blading, mixing, or other methods until the moisture content is as recommended. After each layer is placed, nixed, and spread evenly, it should be thoroughly compacted to the recommended minimum relative Compaction. The fill should be compacted by sheepsfoot rollers, multiple-wheel pheumatic-tired rollers, or other types of compacting rollers that content. Each layer should be rolled continuously over its entire are capable of compacting the fill at the recommended moisture area until the recornended minimum relative compaction is achieved throughout the fill. The fill operation should be continued in layers, as specified above, until the fill has been brought to the finished slopes and grades shown on the approved plans. Fill slopes should be compacted by sheepsfoot rollers, by track- walking with a dozer, or by other suitable equipment. , Conpaction operations should continue until the slopes are properly compacted least 90 percent at a horizontal distance of 2 feet from the slope (that is, in-place density tests indicate a relative compaction of at face). Observation of Grading Operations The Soil Engineer should make field observations and perform field and laboratory tests during the filling and compaction operations, so that he can express his opinion whether or not the grading has been performed in substantial compliance with project recommendations. The Soil Engineer should perform in-place density tests in accordance with accepted ASTH test methods; such density tests should be made in the Compacted materials below the disturbed surface. When results of’ that recommended, that layer or portion thereof should be reworked tests taken within any layer indicate a relative compaction below until the recommended relative compaction is obtained. -j .? 6. 6.1 6.2 6.3 6.4 7. 7.1 7.2 Oversize Rock Placenent 'v "Oversize" rock is defined as material that is greater than 6 inches maximum dimension shou1d:not be used in fills; such material should and less than 4 feet in maximum dimension. Material over 4 feet in be exported from the site, broken into acceptably sized pieces, used for landscaping purposes, or placed in areas designated by the Soil Engineer andfor approved by appropriate governing agencies. The Soil Engineer should continuously observe the placement of over- size rock. Oversize rock should be placed in lifts not exceeding the maximum dimension of the rock, and should be placed in a manner that will not resulc in "nesting" of the rocks. Voids between rocks should be completely filled with properly compacted (minimum relative com- paction of 90 percent), fine granular material. Oversize rock should not be placed within 5 feet of finish pad grade, within 10 feet of street subgrade, or within 2 feet of the bottom of the proposed utility lines, whichever is deeper. Protection of Work During construction, the contractor should grade the site to provide positive drainage away from structures and to prevent water from age adjacent properties or finished work on the site. Positive ponding adjacent to structures. Water should not be allowed to dam- drainage should be maintained by the contractor until permanent with project plans. drainage and erosion control facilities are installed in accordance No additional grading shall be done, except under the observation of the Soil Engineer. I'