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HomeMy WebLinkAbout; 7327 El Fuerte St Single Family Res; Soils Report; 1988-09-19PRELIMINARY SOIL INVESTIGATION PROPOSED SINGLE-FAMILY RESIDENCE 7321 EL FUERTE STREET LA COSTA, CALIFORNIA SEPTEMBER 19, 1988 PREPARED FOR: MR. IRAJ KHADEM 11084 PINZON WAY SAN DIEGO, CALIFORNIA 92127 JOB #1391-88 MV ENGINEERING, INC. 2450 Vineyard Avenue, X102 Escondido, California 92025-l 330 619/743-1214 Job #1391-88 September 19, 1988 Mr. Iraj Khadem 11084 Pinzon Way San Diego, California 92127 Preliminary Soil Investigation, Proposed Single- Family Residence, 7327 El Fuerte Street, La Costa Pursuant to your request, MV Engineering, Inc. has performed an investigation of the surface and subsurface soil conditions at the subject site. The enclosed report has been prepared to present the results of our preliminary soil investigation. This report includes the results of our field investigation, laboratory analyses, and our summary of findings and recommendations for site development as understood. From a geotechnical standpoint, it is our opinion that the site is suitable for the proposed development provided the recommendations presented in this report are incorporated into the design and construction of the project. Thank you for choosing MV Engineering, Inc. If you have any questions concerning this report, please do not hesitate to call us. Reference to our Job #1391-88 will expedite our response to your inquiries. We appreciate this opportunity to be of service to you. Ralph M. Vinj\e GE #863 RMVf kmh TABLE OF CONTENTS I. General Information. ............... II. Purpose of Investigation ............. III. Field Investigation. ............... A. Surface Conditions. .............. B. Field Work. .................. C. Subsurface Conditions ............. D. Seismicity. .................. IV. Laboratory Tests and Tests Results ........ A. Maximum Dry Density & Optimum Moisture Content. ........... B. In-Place Dry Density & Moisture Content. ............... C. Expansion Test. ................ D. Direct Shear Tests. .............. V. Conclusions and Recommendations. ......... VI. Limitations. ................... Page 1 1 1 1 2 2 2 3 3 3 3 4 4 13 APPENDIX "A" Plate Test Pit Location Map. . . . . . . . . . . . . . . 1 Logs of Test Pits and Borings (including Key). . . 2-4 APPENDIX "E" Specifications for Construction of Controlled Fills; and Unified Soil Classification Chart. MV ENGINEERING, INC. . 2450 VINEYARD AVENUE, #IO2 . ESCONDIDO, CALIFORNIA 920251330 l 619/743-1214 SOILSTESTING PERCTEST *OILIN”ESII(IATwNs ~EOTECHNICILIN”E*TIO*TION* PRELIMINARY SOIL INVESTIGATION PROPOSED SINGLE-FAMILY RESIDENCE 7327 EL FUERTE STREET LA COSTA, CALIFORNIA I. GENERAL INFORMATION A Preliminary Soil Investigation has been prepared for the above-mentioned site (see Vicinity Map, Plate 1). The site is legally described as Tract 8302, Lot 73, Carlsbad Tract #75-4 in the County of San Diego, State of California. The Assessor's Parcel Number is 215-492-13. A site development plan with proposed finish grade elevations was submitted to this office and a draft of this is enclosed with this report as Plate 1. It is understood that the proposed development will consist of a single family residence to be located as shown on Plate 1. No other plans pertinent to this development were available for our review at the time of this investigation. II. PURPOSE OF INVESTIGATION The purpose of this investigation is to determine the following: 1 - the existing soil conditions; 2 - the presence and effect of any expansive soil; 3 - the allowable soil bearing pressures; 4 - the presence of existing fill or ground water; 5 - any grading and construction problems that can be anticipated, and to make appropriate foundation recommendations. III. FIELD INVESTIGATION A. Surface Conditions The site is a rectangularly shaped parcel. The dimensions and orientation are shown on the enclosed Test Pit Location Map, Plate 1. The site is bounded by residential developments to the east, north and south and El Fuerte Street to the west. Topographically the site consists of hillside terrain which MV ENGINEERING, INC. . 2450 VINEYARD AVENUE, #lo2 l ESCONDIDO,CALlFORNlA 920251330 l 6191743.1214 801LJTEST,NO PEW TEST 801LIN”EJTIOA,WNS ~EOTECHNICILlNVESTlOITlONS PRELIMINARY SOIL INVESTIGATION PAGE TWO EL FUERTE, LA COSTA SEPTEMBER 19, 1988 slopes generally to the south at approximately 15%. The property is in a natural state and is marked by numerous rock outcrops as indicated on Plate 1. Vegetation across the site consists of weeds, brush, and wild grasses. ,- B. Field Work The subsurface investigation included two test pits excavated using a rubber-tired backhoe. The test pits were logged by our geologist and backfilled. The test pits were approximately located in the area of the proposed residence. The trench locations and logs are enclosed as Plates 1 and 3 through 4 respectively. C. Subsurface Conditions The site is underlain by volcanic bedrock. The test pit exposures revealed a thin cover of colluvium consisting of a silty sand to sandy clay soil overlying the bedrock. The colluvium occurs in a dry, blocky, and stiff condition overall. The upper exposures of the bedrock occur as a weathered highly fractured rock which grades into a dense rock fabric with depth. The depth of the overlying soils to the bedrock is irregular and varies throughout the site; however, for estimating purposes the indicated depths on the attached test pit logs can be used. There are essentially three soil and rock types based on the field descriptions indicated on the logs. The soil types are referred to later as Soil Types 1, 2, and 3. Soil Types Soil Type Soil Description brown sandy clay brown silty sand light colored-tan volcanic rock D. Seismicity As with most areas of southern California, the study property lies within a seismically active zone. Distant faults including the Elsinore Fault to the northeast and unnamed offshore faults will periodically affect the property. MV ENGINEERING, INC. l 2450 VINEYARD AVENUE, Xl02 l ESCONDIDO, CALIFORNIA 92025-l 330 l 6191743-l 214 SOILSTEST1N.3 PEW TEST SOIL INYE*TIGATwNs DEOTECHNlCILIN”ESTIO/\TIONS PRELIMINARY SOIL INVESTIGATION PAGE THREE EL FUERTE, LA COSTA SEPTEMBER 19, 1988 IV. LABORATORY TESTS AND TESTS RESULTS A. Maximum Dry Density and Optimum Moisture Content The maximum dry density and optimum moisture content of Soil Type 1 were determined in accordance with ASTM D-1551-78. The results are tabulated below. Optimum Soil Maximum Dry Moisture Location TyPe Density (pcf) Content (%) TP 1@2' 1 116.5 15.0 TP = Test Pit These results may be used during the grading where applicable. B. In-Place Dry Density and Moisture Content In-place dry densities and moisture contents of representative chunk soil samples were determined using the water displacement method. The test results are presented on the logs at the corresponding locations. The percent ratio of the in-place dry densities to the corresponding laboratory maximum dry densities are also determined and included on the excavation logs. C. Expansion Test An expansion test was performed on a representative sample of Soil Type 1. The soil sample was remolded to 90% of the corresponding maximum dry density in a 2&-inch diameter, l-inch high ring mold. The sample was instrumented, loaded with 1 psi and submerged in water. The ratio of the change in height from the air dry to the saturated condition is defined as the percent expansion. The results are presented below. Soil Initial Air Dry Saturated Expansion Location Type W W W (%) TP 1@2' 1 14.4 9.7 30.6 19.4 W = moisture content (%) MV ENGINEERING, INC. l 2450 VINEYARD AVENUE, X102 l ESCONDIDO, CALIFORNIA 92025-I 330 l 6191743-l 214 SOlLSTEST,ND PERCTEJT SOILIN”ESTIOATION6 (1EOTEC”NICAL IN”EsmITIONS PRELIMINARY SOIL INVESTIGATION PAGE FOUR EL FUERTE, LA COSTA SEPTEMBER 19, 1988 D. Direct Shear Test A direct shear test was performed on a representative sample of Soil Type 1 for strength parameters in the lateral load and bearing capacity calculations. Three specimens of the soil were prepared by molding them in 2$-inch diameters, l-inch high rings to 90% of the corresponding maximum dry density and optimum moisture content and soaked overnight. The specimens were loaded with normal loads of 1, 2, and 4 KSF respectively and sheared to failure in an undrained shear. The results are presented below. : Angle of Apparent Soil Density Int. Fric. Cohesion Location Type (pcf) 0 ("1 c, (psf) TP 1@2' 1 119.1 5 459 IV. CONCLUSIONS AND RECOMMENDATIONS The following conclusions and recommendations are based upon exposures developed beneath the site to the depths explored, laboratory testing, engineering analysis of the test results, and our experience in the field of geotechnical engineering. Based upon the foregoing site investigation the property is suitable for the proposed development provided the recommendations given herein are incorporated into the final plans and implemented during the construction phase. Adverse geotechnical conditions were not indicated on the property based upon the surface and subsurface exposures observed during our study. However, the hard volcanic bedrock and the critically expansive soil can present grading/construction problems. The proposed design grades for the residence will likely be achieved with heavy ripping. In areas of deeper cuts (approximately six feet for the retaining wall located in the northern portion of the property), blasting may be needed to achieve design grades and should be anticipated. In order to minimize the effects of expansive soils, it is preferred and recommended to provide the building pad areas with a non-expansive soil cap. As requested, three options for grading and foundations are given in the following sections. MV ENGINEERING, INC. l 2450 VINEYARD AVENUE, X102 l ESCONDIDO, CALIFORNIA 92025-1330 l 6191743-1214 SOILSTESTINO PERCIEJT SOlLlN”ESTlBlTwN* DEOTECHNlCILIN”ESTIO*TION* PRELIMINARY SOIL INVESTIGATION PAGE FIVE EL FUERTE, LA COSTA SEPTEMBER 19, 1988 General Grading Recommendations Grading operation on the project should be tested, inspected, and approved by a qualified geotechnical engineer. Grading should conform to the codes established by the governing agency. Grading procedures should also be completed in accordance with the enclosed "Specifications for Construction of Controlled Fills," Appendix "B", except where superseded below. It is recommended that a pre-grading meeting be held between the owner, grading contractor, and a representative of this firm to discuss the operation and to arrange a testing schedule. This office should be notified a minimum of 24 hours prior to any grading operations or any fill placement. Testing and inspections are required any time fill is placed which exceeds 12 inches or more in depth under any conditions. In addition, testing and inspections are required, but not limited to, the following items: building pads, street improvements, sidewalks, curbs and gutters, trenches, undercuts, wall backfills, subgrade and basegrade, foundation trenches and reinforcement, and any operations not included herein which require our testing, supervision, and inspection for certification to the appropriate agencies. 1. The fill soils generated at the site from grading excavations will likely include rock debris which may present disposal and compaction problems. Rocks may be incorporated into on-site fills provided individual rock sizes are less than six inches in maximum diameter and are suitably dispersed throughout the fill. The rock soil mixture should maintain a minimum of 60% (by weight) finer than No. 4 sieve materials. In the event insufficient quantities of finer soil material are not generated during the grading operations, import soils will be required. Additional recommendations for proper compaction and disposal will be given by the geotechnical engineer during the rough grading if necessary. 2. It is recommended that any septic tanks or large buried objects detected during the grading be removed. The voids should be filled with compacted soil and tested by the geotechnical engineer or his representative in charge. 3. Use cut and fill ratios of 2:1 (horizontal to vertical) for overall gross stability. It is recommended that the fill slopes be overbuilt and cut back to the design configuration. 4. All underground utility trenches should be compacted to a minimum of 90% of the maximum dry density of the soil unless MV ENGINEERING, INC. . 2450 VINEYARD AVENUE, #IO2 . ESCDNDIDO, CALIFORNIA 92025-1330 . 619/743-1214 *OIL*TEFIIN(I PERC TEST sOILIN”E*TIOA,,0Ns ~EOTECHNIC~LINYESTIO~,,ONS PRELIMINARY SOIL INVESTIGATION PAGE SIX EL FUERTE, LA COSTA SEPTEMBER 19, 1988 otherwise specified by the respective agencies. Care should be taken not to crush the utilities or pipes during the compaction of the soil. All utility trenches under slabs in expansive soils (2% or greater) should be backfilled with sand (S.E. 30 or greater) and properly compacted to achieve at least the minimum compaction requirements. 5. If any import soil is used to complete the grading it should be granular and non-expansive. The import soil should be inspected and approved by a representative from this office prior to the delivery of the soil to the site. Revised foundation recommendations may be required based on the specific characteristics of the import soil. 6. During the course of our investigation, two test pits were excavated to various depths. After logging and sampling of the test pits, they were backfilled, tamped, and rolled. The backfilled materials are not suitable for the support of structures or pavement; therefore, during the grading of the site the test pits should be re-excavated and backfilled to not less than 90% of the corresponding maximum dry density. The approximate locations of the test pits are shown on the Test Pit Location Map, Plate 1. Grading/Foundation Option 1 - Capping the Building Pad With Three Feet of Non-Expansive Soil A three foot cap of granular non-expansive soil will minimise the anticipated rock and expansive soil problems at the site. Grading The recommendations given in the above "General Grading Recommendations: and in "Appendix "B" should be followed except when superseded by the following recommendations. In areas of the proposed structure, removal and recompaction of all loose topsoils is required to a minimum of three feet below the proposed pad finish grade to a distance of ten feet outside the building perimeter. The upper loose topsoils should be excavated down to firm bedrock and recompacted to a minimum of 90% of the corresponding maximum dry density at 5% to 8% above the optimum moisture content. In the cut areas there should be at least one foot of compacted, non-expansive capping soils under all footings. MV’ENGINEERING, INC. l 2450VlNEYARDAVENUE, #IO2 . ESCONDIDO, CALIFORNIA 92025-1330 l 819/743-1214 801L6 TEJTING PERC TEST sOIL1N”E*II(IATtON* LIEOTEC”NIC~LlN”ESTlBlTlONS PRELIMINARY SOIL INVESTIGATION PAGE SEVEN EL FUERTE, LA COSTA SEPTEMBER 19, 1988 After approval by our field representative, the building pad should be capped with the minimum three feet thick granular non-expansive soil compacted to a minimum of 90% of the maximum dry density and optimum moisture content per ASTM D-1557-78. The capping soil must be approved prior to and during placement as fill. At the discretion of the geotechnical engineer or his representative, this aspect of the grading operation can be terminated if the soil becomes unsatisfactory or is deemed unsuitable as a capping soil. The three-foot cap is only a minimum allowance and is subject to change by the geotechnical engineer or his representative. Foundations A. It is recommended that conventional continuous and/or isolated footings be used in accordance with the latest Uniform Building Code design (i.e., 12 inches wide by 12 inches deep and 15 inches wide by 18 inches deep for one- and two-story structures respectively; minimum depths are measured from the lowest adjacent ground surface not including the sand/gravel under the slab B. All interior and exterior footings should be reinforced with two #4 reinforcing bars, one bar placed three inches below the top and the other bar placed three inches above the bottom of the footing. C. Use minimum 6x6/10x10 welded wire mesh placed mid-height in all slabs and a minimum of four inches of clean sand under all slabs. Special attention should be given to the re-entrant corners (?270° corners) and curing practices during and after concrete pour. All slabs should be a minimum of 3;-inches in thickness. A plastic moisture barrier should be provided for the interior slabs and should be placed mid-height in the sand. Provide weakened plane joints spaced 12 feet on center each way for all slabs. D. An allowable soil bearing pressure of 1500 psf may be used for footings supported entirely on properly compacted, non-expansive fill. The allowable soil bearing pressure provided herein is for dead plus live loads and may be increased by one-third for wind and seismic loading. This value should be verified at the completion of rough grading. The allowable soil bearing pressures provided herein are determined for footings having a minimum width of 12 inches and a minimum depth of 12 inches below the adjacent ground surface. These values may be increased per Uniform Building Code, Table 29-B for additional depths and widths if needed. MV ENGINEERING, INC. l 2450 VINEYARD AVENUE, #IO2 . ESCONDIDO, CALIFORNIA 92025.1330 . 919,743.1214 BOILSTESTING PERC TEST SOILINYE6TIBATIONS DEOTEC”NlCILIN”ESTIOITION6 PRELIMINARY SOIL INVESTIGATION PAGE EIGHT EL FUERTE, LA COSTA SEPTEMBER 19, 1988 Grading/Foundation Option 2 - Minimum Grading Using Stem Wall Foundations Minimum grading using stem wall construction may be considered. Existing fill soils on the site would require extended footings penetrating all fill soils into the dense bedrock. Grading The recommendations given in the above, "General Grading Recommendations," and in Appendix "B" should be followed except when superseded by the following recommendations. Removal and recompaction of the upper loose soils under all slabs and driveways will be required. In cut portions of the site, a minimum undercut and recompaction of two feet is required. The upper loose topsoils and all fill soils should be excavated down to firm bedrock and recompacted to a minimum of 90% of the corresponding maximum dry density at 5% to 8% above the optimum moisture content. The excavations will be on the order of two feet. The exact depths will be determined during the grading by the geotechnical engineer or his representative on the site. Foundations 1. In order to reduce the potential for differential settlement between cut and filled ground using minimum grading, all building foundations may be supported on the bedrock. The foundations should penetrate the upper soft compressible soils and be embedded at least 12 inches (12 inches wide) into dense bedrock for one-story buildings and 18 inches (15 inches wide) into dense bedrock for two-story buildings. The footings should be reinforced with minimum two #4 bars, one bar placed three inches below the top and one bar placed three inches above the bottom. The indicated reinforcement is provided for the portion of the footing embedded into the bedrock. Reinforcement requirements for stem wall portions of the foundations should be designed by the project structural engineer. 2. Final design for the slab-on-grade type floorings will depend on the expansion potential and soil-rock mixture of the finished grade materials which can be best determined at the completion of rough grading. Ground and subgrade soils preparations beneath the floor slabs should be performed as specified in the "Grading" portion of the transmittal (also see "General Grading" and MV ENGINEERING, INC. l 2450 VINEYARD AVENUE, #102 . ESCONDIDO, CALIFORNIA 92025.1330 l 6191743.1214 solLSTE*TlNG PERC TEST SOIL INYESTIGITWNS PEOTECHNlCILIN”E~TI(I~TIONS PRELIMINARY SOIL INVESTIGATION PAGE NINE EL FUERTE, LA COSTA SEPTEMBER 19, 1988 Appendix tlBtt). There should be at least two feet of properly compacted fills beneath all slabs. Additional #3 bars, 18 inches on center both ways extending at least five feet either side of the daylight line, should be provided in the floor slabs if the above option is utilized. An allowable soil bearing pressure of 2000 psf may be used for foundations supported on dense bedrock. Grading/Foundation Recommendation 3 - Cut/Fill Grading and Construction on Expansive Soils Typical cut/fill grading techniques is another option for construction on the site. It is anticipated that a rocky soil mixture will result from the excavations during grading. Expansion potential of soil-rock mixture will be determined at completion of rough grading by appropriate testing. For estimating purposes only, the following foundation recommendations for the anticipated rocky soils may be used. These recommendations should be confirmed at the completion of grading. Gradinq The recommendations given in the above "General Grading Recommendations" and in Appendix "B" should be followed except when superseded by the following recommendations. Removal and recompaction of the upper loose topsoils will be required to a distance of ten feet outside the building perimeter. In cut portions of the site, a minimum undercut and recompaction of three feet to a distance of ten feet outside the building perimeter will also be necessary to reduce the potential of differential settlement. The upper loose topsoils should be excavated down to firm bedrock and recompacted to a minimum of 90% of the corresponding maximum dry density at 5% to 8% above the optimum moisture content. The excavations will be on the order of two feet. The exact depths will be determined during the grading by the geotechnical engineer or his representative on the site. MV ENGINEERING, INC. . 2450 VINEYARD AVENUE, Xl02 l ESCONDIDO, CALIFORNIA 92025.1330 l 61917431214 SOIL6TESTINO PERC TEST SOILIN”E*TIOA,,ONs (IEOTEC”N,CILIH”EST,(I*TIONS PRELIMINARY SOIL INVESTIGATION PAGE TEN EL FUERTE, LA COSTA SEPTEMBER 19, 1988 Foundations Foundation recommendations for critically expansive (lo%+) soils are given below. A non-monolithic pour or two pour system should be used. Footing and Slab Recommendations A. Footings (1) Excavate the footings to a minimum depth of 30 inches below the lowest adjacent ground surface; minimum depths are measured from the lowest adjacent ground surface not including the sand/gravel under the slab. Footings should have a minimum width of 12 inches for one- and two-story structures. (2) Reinforce all interior and exterior footings with four #5 reinforcing bars in both interior and exterior footings, two bars placed three inches below the top and two bars placed three inches above the bottom of the footing. (3) Dowel the slab to the footings using #4 reinforcing bars spaced 18 inches on center extending 18 inches into the footing and 18 inches into the slab. The dowels should be placed mid-height in the slab. Alternate the dowels each way for all interior footings. (4) After the footings have been excavated and cleaned, place the reinforcing steel and dowels and pour the footings. (5) The perimeter foundations should enclose the entire building perimeter. B. Presaturation of the Interior Slab Subgrade (1) Once the concrete for the footings has cured, place four inches of pea gravel (3/a-inch crushed rock) over the slab subgrade. Flood the slab subgrade area with water to the top of the pea gravel and allow the slab subgrade to soak for approximately seven to ten days; the actual soaking time may vary. The required moisture content of the slab subgrade soils is 5% to 8% over the optimum moisture content at a depth of 30 inches. After the slab subgrade soils have soaked for the prescribed period of time, notify this office and schedule a MV ENGINEERING, INC. l 2450 VINEYARD AVENUE, Xl 02 l ESCONDIDO, CALIFORNIA 92025-1330 l 619/7431214 SOlLSTESTlNG PERC TEST *OlLlN”ESTlalTlONS GEOIECHNIC*LlNYEST,GI,,ONS PRELIMINARY SOIL INVESTIGATION PAGE ELEVEN EL FUERTE, LA COSTA SEPTEMBER 19, 1988 moisture test. The required moisture content of the slab subgrade must be verified by this office prior to pouring the interior slab. C. Interior Slab Reinforcing (1) When the required moisture content for the slab subgrade has been achieved, place a six-mil plastic moisture barrier over the pea gravel and place two inches of clean sand on top of the plastic. (2) Use minimum #3 reinforcing bars spaced 18 inches on center each way placed mid-height in all slabs. All slabs should be a minimum of five inches in thickness. (3) Provide weakened plane joints spaced 12 feet on center each way for all slabs. D. Exterior Slabs (patios, sidewalks and driveways) (1) Use four inch minimum thick slabs reinforced with minimum 6x6/10x10 welded wire mesh placed mid-height in all slabs. Use six inches of clean sand under all slabs. (2) Provide weakened plane joints spaced six feet on center each way for all slabs. E. Bearing Capacity (7) An allowable bearing capacity of 1000 psf for continuous and isolated footings may be used. The recommended soil bearing value should be re-evaluated at the completion of rough finished grades when the characteristics of the foundation soil mixture are specifically known. Earth Pressures/Retaining Walls 1. Expansive clayey soils should not be used for backfilling of any retaining structure. All retaining structures should be designed by the project structural engineer. Specific drainage provisions behind retaining wall structures should be verified by this office. MV ENGINEERING, INC. . 2450 VINEYARD AVENUE, #IO2 l ESCONDIDO, CALIFORNIA 92025-1330 l 6191743-1214 SOlLSTEJTlNG PERC TEST *OILIN”ESTI(IATIONs GEOTECnNlCILINYEJTIG*TIONS PRELIMINARY SOIL INVESTIGATION PAGE TWELVE EL FUERTE, LA COSTA SEPTEMBER 19, 1988 2. The lateral soil pressures of 40, 60, and 360 pcf equivalent fluid pressures may be used for active, at rest, and passive conditions respectively for backfill soils with a friction angle of at least 30°. The provided soil lateral pressures are determined based upon characteristics of a granular, non-expansive soil and assume drained and level backfill surface conditions. Lateral soil pressures provided herein do not include hydrostatic pressures and should be re-evaluated at the time when the nature of the backfill materials is specifically known. Revised recommendations may be necessary and should be anticipated. Because large movements must take place before maximum passive resistance can be developed, the earth pressures given for passive conditions should be reduced by an appropriate factor of safety. 3. A coefficient of friction of 0.10 may be considered for concrete on on-site upper soils. This value should be verified at the completion of grading when the engineering properties of the bearing soils are specifically known. 4. The passive and frictional lateral resistance may be combined provided either one of the two is reduced by one-third. General Recommendations 1. Finalized development plans should incorporate these recommendations and be reviewed and approved by this office. If the finalized development plans significantly change.or if they were not available at the time of this investigation, further investigation and engineering by this firm will be required. 2. Structural sections for roadway and parkway designs will be determined at the completion of grading with the appropriate sampling and laboratory testing. 3. In order to maintain future site performance, it is recommended that all pad drainage be collected and directed away from proposed structures. A minimum of two percent gradient should be maintained. Roof gutters and downspouts should drain away from the foundations and slabs. Installation of area drains in the yards should also be considered. In no case should water be allowed to pond or flow over slopes. The property owner(s) should be made aware that altering drainage patterns, landscaping, the addition of patios, planters, and other improvements, as well as excessive irrigation, and variations in seasonal rainfall, all affect subsurface moisture conditions, which in turn affect structural performance. MV ENGINEERING, INC. l 2450 VINEYARD AVENUE, X1 02 l ESCONDIDO, CALIFORNIA 92025.1330 l 6191743-1214 SOIL8 TEJTING PERC TEST *OILIN”E6TIPATIOIIS OEOTEC”N,CILIN”ESTIOITION~ PRELIMINARY SOIL INVESTIGATION PAGE THIRTEEN EL FUERTE, LA COSTA SEPTEMBER 19, 1988 4. All slopes within the development should be planted with appropriate ground cover vegetation to protect the slopes from erosion. Deep-rooted types of ground cover will assist in the prevention of surficial slumping. Excessive watering of the planted slopes should be avoided. An irrigation system should be installed in accordance with the governing agencies. Water should not be allowed to flow over the slopes. Until the landscaping is fully established, plastic sheeting should be kept accessible to protect the slopes from periods of prolonged and/or heavy rainfall. 5. Any future structures placed on the subject property may affect the on-site drainage pattern or impact the structural integrity of the existing fill or structures. Construction of any additional future improvements not included/indicated in the initial development or grading should be reviewed by this firm prior to construction. 6. The homeowner(s) should be made aware of the possibility of shrinkage cracks in concrete and stucco materials. The American Concrete Institute indicates that most concrete will shrink approximately l/8-inch within a 20-foot section. Some separation between construction and cold joints may occur and should be expected. VI. LIMITATIONS The conclusions and recommendations provided herein have been based on all available data obtained from our field investigation and laboratory analyses, as well as our experience with the soils and formational materials located in the general area. The materials encountered on the project site and utilised in our laboratory testing are believed representative of the total area; however, earth materials may vary in characteristics between excavations. Of necessity we must assume a certain degree of continuity between exploratory excavations and/or natural exposures. It is necessary, therefore, that all observations, conclusions, and recommendations be verified during the grading operation. In the event discrepancies are noted, we should be contacted immediately so that an inspection can be made and additional recommendations issued if required. MV ENGINEERING, INC. l 2450 VINEYARD AVENUE, #lo2 l ESCONDIDO, CALIFORNIA 92025-1330 l 8191743.1214 soILSTESTIN(I PERC TEST *OIIIN”EsTtG*T,ONS (IEOTECHNIC*L,N”E*TIOITIOH6 PRELIMINARY SOIL INVESTIGATION PAGE FOURTEEN EL FUERTE, LA COSTA SEPTEMBER 19, 1988 The recommendations made in this report are applicable to the site at the time this report was prepared. It is the responsibility of the owner/developer to insure that these recommendations are carried out in the field. It is a.lmost impossible to predict with certainty the future performance of a property. The future behavior of the site is also dependent on numerous unpredictable variables, such as earthquakes, rainfall, and on-site drainage patterns. The firm of MV Engineering, Inc. shall not be held responsible for changes to the physical conditions of the property such as addition of fill soils or changing drainage patterns which occur subsequent to issuance of this report. This report should be considered valid for a period of one year and is subject to review by our firm following that time. If significant modifications are made to your tentative development plan, especially with respect to the height and location of cut and fill slopes, this report must be presented to us for review and possible revision. This firm has prepared this report in accordance with generally accepted engineering practice and makes no other warranties, either expressed or implied, as to the professional advice provided under the terms of the agreement and included in this report. Once again, should any questions arise concerning this report, please do not hesitate to contact this office. Reference to our Job #1391-88 will expedite response to your inquiries. We appreciate this opportunity to be of service to you. MV ENGINEERINg, INC. f A RMV/kmh cc: Ken Ash, Schuss, Clark & ASSOC iates MV ENGINEERING, INC. . 2450 VINEYARD AVENUE, Xl 02 l ESCONDIDO, CALIFORNIA 92025-1330 l 6191743-1214 soILSTESTIN(I PERC TEST 801LIN”EsTIO*T,ONS GEOTEC”NlCILIN”ESTI(I/IIION* APPENDIX "A" SECONDARY DIVISIONS MORE THAN HALF OF COARSE FRACTION IS LARGER THAN MORE THAN HALF OF COARSE FRACTION IS SMALLER THAN NO. 4 SIEVE clays, silty clays. lea” clays. SILTS AND CLAYS LIQUID LIMIT IS GREATERTHAN 50% 200 40 10 4 314” 3” 12” SAND SILTS AND CLAYS GRAVEL COBBLES BOULDERS FINE MEDIUM COARSE FINE COARSE RELATIVE DENSITY CONSISTENCY SANDS, GRAVELS AND BLOWS/FOOT CLAYS AND NON-PLASTIC SILTS PLASTIC SILTS STRENGTH BLOWS/FOOT VERY LOOSE O-4 VERY SOFT 0-Y. o-2 SOFT ‘/, % LOOSE 4.10 2-4 FlRM % f MEDIUM DENSE 10-30 4-a DENSE 30. so STIFF 1-2 6- 16 VERY DENSE OVER 50 VERY STIFF 2.4 16-X HARD OVER 4 OVER 32 1. Blow count, 140 pound hammer falling 30 inches on 2 inch O.D. split spoon sampler [ASTM D-l 586) 2. Unconfined compressive strength per SOILTEST pocket penetrometer CL-700 A = undisturbed chunk sample 1 *de = Standard Penetration Test (SPT) (ASTM D-l 586) 0 = disturbed sample with blow counts per 6 inches 11 2‘tg = Callforma Sampler with blow counts per 6 inches 7327 EL FUERTE LA COSTA MV ENGINEERING, INC. 3RILL RIG BACKHOE 510B SURFACE ELEVATION i 273 LOGGED BY S . M . 3EPTH TO GROUND WATER N/E BORING DIAMETER 2 ft. x 6 ft. DATEDRILLED B/31/88 DESCRIPTION AND CLASSIFICATION $ f!glll 6 EF $iZZ Lj BEi $5 :: ok 2 &E pg z”: ZjG 52 u, $4 $$JE 5 z;g ggg igg 0 - Brown sandy clay. Dry, blocky, fractured rock throughout, 1 - stiff. ALI 2 SOIL TYPE 1 CL 2 2 4.3 Light colored to tan volcanic rock. Highly fractured, dry, BEDROCK. '3 - with pockets of sandy clay throughout, \ dense. L13 0.7 158.6 Slow diqqinq at 3 feet. 4 - Bottom at 3 feet. 5 - 6 - 7 - 6 - 9 - 10 - 11 - 12 - 13 - 14 - 7321 EL FUERTE LA COSTA TEST PIT 1 DRILL RIG BACKHOE 510B 1 SURFACE ELEVATION k 276 LOGGED BY S . M . I I IEPTt I GROUND WATER N/E = 1 BORING DIAMETER 2 ft. I 6 f D 8 DRIL DESCRIPTION AND CLASSIFICATION -5 z g 5 In 63 5; ;g- : 0 5 $ - ?LL?- Brown silty sand, dry, porous, loose, fractured rocks throughout. 1 2 3 SOIL TYPE 3 ;M 3.5 - Light colored to tan volcanic rock. BEDROCK. 4 Highly fractured, dense, dry with 3 3 0.9 pockets of soil throuqhout. Slbw digging at 3 feet.- ottom at three feet. 5 6 7 6 l/8 63. - MV ENGINEERING, INC. 2450 Vineyard Ave.. Suite 102 Escondido. CA 920251330 Phone: 619/743-,214 EXPLORATORY BORING LOG KHADEM 1327 EL FVERTE, LA COSTA PROJECT NO. PLATE 1391-88 4 TEST PIT 2 APPENDIX "B" 0188 SPECIFICATIONS FOR CONSTRUCTION OF CONTROLLED FILLS GENERAL DESCRIPTION 1 - The following grading specifications have been prepared for the subject site and are consistent with the Preliminary Investigation report performed by this firm. 2 - The grading contractor shall be responsible to perform ground preparation and compaction of fills in strict compliance with the specifications outlined herein. All earthwork including ground preparations, placing, watering, spreading and compacting of fills should be done under the supervision of a state registered geotechnical engineer. The project geotechnical engineer should be consulted if any deviations from the grading requirements provided herein are desired by the owner/contractor. 3 - The construction of controlled fills shall consist of clearing and removal of existing structures and foundations, preparation of land to be filled, excavation of earth and rock from cut area, compaction and control of the fill, and all other work necessary to complete the grading of the filled areas to conform with the lines, grades, and slopes as shown on the accepted plans. CLEARING AND PREPARATION OF AREAS TO BE FILLED A. All fill control projects shall have a preliminary soil investigation or a visual examination (depending upon requirements of the governing agency and the nature of the job) by a qualified geotechnical engineer prior to grading. B. All timber, trees, brush, vegetation, and other rubbish shall be removed, piled, and burned, or otherwise disposed of to leave the prepared areas with a finished appearance, free from unsightly debris. C. Any soft, swampy or otherwise unsuitable areas shall be corrected by drainage or removal of compressible material, or both, to the depths indicated on the plans and as directed by the geotechnical engineer. D. The natural ground which is determined to be satisfactory for the support of the proposed fill shall then be plowed or scarified to a depth of at least six inches (6") or deeper as specified by the geotechnical engineer. The surface should be free from ruts, hummocks, or other uneven features which would tend to prevent uniform compaction by the equipment to be used. E. F. G. H. I. J. NO fill shall be placed until the prepared native ground has been approved by the geotechnical engineer or his representative on site. Where fills are made on hillsides with slopes greater than 5:l (horizontal to vertical), horizontal benches shall be cut into firm, undisturbed, natural ground. A minimum two-foot deep keyway, one blade width should be cut. The geotechnical engineer shall determine the width and frequency of all succeeding benches which will vary with the soil conditions and the steepness of slope. After the natural ground has been prepared, it shall be brought to the proper moisture content and compacted to not less than 90% of maximum density per ASTM D-1557-70. Expansive soils may require special compaction specifications as directed in the preliminary soil investigation by the geotechnical engineer. In order to reduce the potential for differential settlement for structures placed on a transition area of the lot, the cut portion should be undercut a minimum depth of three feet below the proposed pad grade or to a minimum depth of twelve inches below the bottom of the footing, whichever is greater, and replaced as structural fill. The undercut should extend a minimum horizontal distance of ten feet outside the building perimeter. The excavated area must be inspected by the geotechnical engineer or his representative on site to verify the actual subsurface conditions and depths. Caution should be used during the grading and trench excavations so that existing adjacent or underground structures/improvements are not distressed by the removals. Appropriate setbacks will be required and should be anticipated. ~11 existing utilities on or in the vicinity of the property should be located prior to any grading or trenching operations. These precautions are the responsibility of the owner/contractor. MV Engineering, Inc. will not be held responsible for any damage or distress. MATERIALS The fill soils shall consist of select materials, graded so that at least 40 percent of the material passes the #4 sieve. The material may be obtained from the excavation, a borrow pit, or by mixing soils from one or more sources. The materials used shall be free from vegetable matter and other deleterious substances. Oversized rocks greater than two feet in maximum diameter should not be included in fills. Rocks greater than 12 inches (12") in diameter should be properly buried ten feet or more below grade, measured vertically. Rocks should be placed per project geotechnical engineer or his representative to assure filling of all voids with compacted soils. Rocks greater than six inches (6") in diameter should not be allowed within the upper three feet of all graded pads. Rock fills require a special inspection and testing program under direct supervision of the project geotechnical engineer or his representative. If excessive vegetation, rocks, or soils with unacceptable physical characteristics are encountered, these materials shall be disposed of in waste areas designated on the plans or as directed by the geotechnical engineer. No material of a perishable, spongy or otherwise unstable nature shall be used in the fills. If soils are encountered during the grading operation which were not reported in the preliminary soil investigation, further testing will be required to ascertain their engineering properties. Any special treatment recommended in the preliminary or subsequent soil reports not covered herein shall become an addendum to these specifications. Laboratory tests should be performed on representative soil samples to be used as compacted fills in accordance with appropriate testing procedures specified by ASTM in order to determine maximum dry density and optimum moisture content of the fill soils. PLACING, SPREADING AND COMPACTION OF FILL MATERIAL A. B. C. D. The selected fill material shall be placed in layers which shall not exceed six inches (6") when compacted. Each layer shall be spread evenly and shall be thoroughly blade-mixed during the spreading to insure uniformity of material and moisture in each layer. When the moisture content of the fill material is below that specified by the geotechnical engineer, water shall be added until the moisture content is near optimum as determined by the geotechnical engineer to assure thorough bonding during the compaction process. This is to take place even if the proper density has been achieved without proper moisture. When the moisture content of the fill material is above that specified by the geotechnical engineer, the fill material shall be aerated by blading and scarifying or other satisfactory methods until the moisture content is near optimum as determined by the geotechnical engineer. After each layer has been placed, mixed and spread'evenly, it shall be thoroughly compacted to not less than the recommended minimum compaction requirements per specified maximum density in accordance with ASTM D-1557-78. Compaction shall be by means of tamping or sheepsfoot rollers, multiple-wheel pneumatic-tired rollers, or other types of rollers. Rollers shall be of such design that they will be able to compact the fill to the specified density. Rolling each layer shall be continuous over its entire area and the rollers shall make sufficient passes to obtain the desired density. The entire area to be filled shall be compacted to the specified density. E. Fill slopes shall be compacted by means of sheepsfoot rollers or other suitable equipment. Compacting of the slopes shall be accomplished by backrolling the slopes in increments of three to five feet (3'-5') in elevation gain or by overfilling and cutting back to the design configuration or other methods producing satisfactory results. If the method of achieving the required slope compaction selected by the contractor fails to produce the necessary results, the contractor shall rework or rebuild such slopes until the required degree of compaction is obtained. F. Field density tests shall be made in accordance with ASTM Method D-1556-82 by the geotechnical engineer for approximately each foot in elevation gain after compaction, but not to exceed two feet (2') in vertical height between tests. The geotechnical engineer shall be notified to test the fill at regular intervals. If the tests have not been made after three feet of compacted fill has been placed, the contractor shall stop work on the fill until tests are made. The location of the tests shall be spaced to give the best possible coverage and shall be taken no farther than 100 feet apart. Tests shall be taken on corner and terrace lots for each two feet (2') in elevation gain. The geotechnical engineer may take additional tests as considered necessary to check on the uniformity of compaction. Where sheepsfoot rollers are used, the test shall be taken in the compacted material below the disturbed surface. NO additional layers of fill shall be spread until the field density tests indicate that the specified density has been obtained. G. The fill operation shall be continued in six inch (6") compacted layers,, as specified above, until the fill has been brought to the finished slopes and grades as shown on the accepted plans. SUPERVISION Supervision by the geotechnical engineer or his representative shall be made during the filling and compacting operation in order to verify that the fill was constructed in accordance with the preliminary soil report or agency requirements. The specifications and soil testing of subgrade and basegrade material for roads or other public property shall be done in accordance with specifications of the governing agency unless otherwise directed. It should be understood that the contractor shall supervise and direct the work and shall be responsible for all construction means, methods, techniques, sequences and procedures. The contractor will be solely and completely responsible for conditions at the job site, including safety of all persons and property during the performance of the work. Intermittent or continuous inspection by the geotechnical engineer is not intended to include review of the adequacy of the contractor's safety measures in, on, or near the construction site. SEASONAL LIMITS No fill material shall be placed, spread, or rolled during unfavorable weather conditions. When the work is interrupted by heavy rain, grading shall not be resumed until field tests by the geotechnical engineer indicate that the moisture content and density of the fill are as previously specified. In the event that, in the opinion of the. engineer, soils unsatisfactory as foundation material are encountered, they shall not be incorporated in the grading; disposition will be made at the engineer's discretion. UNIFIED SOIL CLASSIFICATION Identifying Criteria Group Symbol I. COARSE GRAINED (more than 50% larger than #200 sieve) Gravels (more than 50% larger than #4 sieve but smaller than 3") Non-plastic GW GP GM GC Sands (more than 50% smaller than #4 sieve) Non-plastic SW SP SM SC II. FINE GRAINED (more than 50% smaller than #200 sieve) Liquid Limit less than 50 ML CL Soil Description Gravel, well-graded gravel- sand mixture, little or no fines. Gravel, poorly graded, gravel- sand mixture, little or no fines. Gravel, silty, poorly graded, gravel-sand-silt mixtures. Gravel, clayey, poorly graded, gravel-sand-clay mixtures. Sand, well-graded, gravelly sands, little or no fines. Sand, poorly graded gravelly sands, little or no fines. Sand, silty, poorly graded, sand-silt mixtures. Sand, clayey, poorly graded, sand-clay mixtures. Silt, inorganic silt and fine sand, sandy silt or clayey-silt-sand mixtures with slight plasticity. Clay, inorganic clays of low to medium plasticity, gravelly clays, sandy clays, silty clays, lean clays. II. FINE GRAINED - continued Liquid Limit greater OL Silt, organic, silts and than 50 organic silt-clays of low plasticity. MH Silt, inorganic silts micaceous or dictomaceous fine, sandy or silty soils, elastic silts. CH Clay, inorganic, clays of medium to high plasticity, fat clays. OH Clay, organic, clays of medium to high plasticity. III. HIGHLY ORGANIC SOILS PT Peat, other highly organic swamp soils.