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HomeMy WebLinkAbout; Argonauta Way Lot 711; Soils Report Preliminary; 1988-07-25PRELIMINARY SOILS INVESTIGATION PROPOSED SINGLE-FAMILY RESIDENCE LOT #711, ARGONAUTA WAY CARLSBAD, CALIFORNIA JULY 25, 1988 ENGINEERING DEPT. LIBRARY City of Carlsbad 2075 Las Palmas Drive Carfsbad CA920094859 PREPARED FOR: MR. JIM HIGHTOWER 2210 BUENA CREEK ROAD VISTA, CALIFORNIA 92083 f& JOB #1275-88 MV ENGINEERING, INC. 2450 Vineyard Avenue, X102 Escondido, California 92025-l 330 619/743-1214 Job #1275-88 July 25, 1988 Mr. Jim Hightower 2210 Buena Creek Road Vista, California 92083 Preliminary Soils Investigation, Proposed Single-Family Residence, Lot #711, Arqonauta Way, Carlsbad, California 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 engineering 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 questions concerning this us. Reference to our Job your inquiries. Engineering, Inc. If you have any report, please do not hesitate to call #1275-88 will expedite our response to We appreciate this opportunity to be of service to you. , ~~~~ RMV/jm 6 OF c fi,u@ TABLE OF CONTENTS I. II. III. IV. V. VI. General Information .............................. Purpose of Investigation ......................... Field Investigation .............................. A. Surface Conditions ........................... B. Field Work ................................... C. Subsurface Conditions ........................ D. Seismicity ................................... Laboratory Tests and Test Results ................ A. Maximum Dry Density & Optimum Moisture Content ..................... B. In-place Dry Density & Moisture Content ...... C. Expansion Test ............................... D. Direct Shear Test ............................ E. Amount of Materials in Soils Finer Than The #200 Sieve .................... Conclusions & Recommendations .................... Limitations ...................................... Page 1 1 2 2 2 2 3 3 3 3 4 4 4 5 13 APPENDIX Plate Test Pit Location Map............................ 1 Logs of Test Pits (and key)...................... 2-4 APPENDIX "A" Specifications for Construction of Controlled Fills; and Unified Soil Classification Chart. PRELIMINARY SOIL INVESTIGATION PROPOSED SINGLE-FAMILY RESIDENCE LOT #711, ARGONAUTA WAY CARLSBAD, CALIFORNIA I. GENERAL INFORMATION A Preliminary Soil Investigation has been prepared for the above- mentioned site located east of El Camino Real, south of Alga Road, west of Corintia Street, and at the end of Argonauta Way in a residential area of southeast Carlsbad in La Costa (see vicinity map, Plate 1). The site is legally described as Tract 7367, Lot 711, La Costa Meadows #4, in the City of Carlsbad, in the County of San Diego, State of California. The Assessor's Parcel Number is 215-450-08. It is understood that the site will be used for construction of a single-family residence. The proposed location of the residence is indicated on Plate 1. The exact nature of grading and building construction was not known at the time of this investigation. The subject property is located within a mass-graded residential project monitored and certified by Benton Engineering, Inc. The compaction report issued September 10, 1973 indicated only the specific lots listed within their report were graded and tested during the initial site development. It is our understanding, based upon the review of their compaction report, that Lot 711 was not graded, tested and/or certified. 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 - the geologic conditions and obvious geologic hazards; 6 - any construction problems that can be anticipated, and to make appropriate foundation recommendations. MV ENGINEERING, INC. l 2450 VINEYARD AVENUE, X102 l ESCONDIDO, CALIFORNIA 92025-1330 l 619/743-1214 ScmSTESIINO PERC TEST SOILIN”ESTIO*TwNS (IEOTECHNICILlNVESTlDLTlONI PRELIMINARY SOIL INVESTIGATION LOT #711, ARGONAUTA WAY, CARLSBAD PAGE 2 7/25/88 III. FIELD INVESTIGATION A. Surface Conditions The site is an irregularly shaped parcel. The dimensions and orientation are shown on the enclosed Test Pit Location Map, Plate 1. Topographically the site slopes down gently (approximately 15%) to the west. Stockpiles of boulders, brush and debris were observed in the central portion of the site. A concrete brow ditch marks the edge of the eastern property line. Vegetation across the site includes wild grass and brush. The perimeter of the property has been brushed. A large mature eucalyptus tree is located in the southeast corner adjacent to Argonauta Way. B. Field Work Two test pits were excavated with a backhoe on June 28, 1988 in the subject area as shown on Plate 1. The test pits were inspected and logged by our project geologist. Samples of the soils were obtained from the test pit excavations and taken to the laboratory for testing. Earth materials exposed in our excavations were visually classified by field identification procedure in accordance with the Unified Soil Classification System. A simplified version of the Unified Soil Classification System is included in the Appendix of this report. Continuous logs of the soils encountered in the test pits are shown on Plates 3 and 4. C. Subsurface Conditions Geologically the site is underlain by the Santiago Peak Volcanics. Exposures in Test Pit 1 revealed a thin cover of existing fill which is likely a result from the mass grading of the adjacent lots. The fill is in a moderately moist and very loose condition and consists of a sandy clayey rock mixture. The bedrock occurs as a highly fractured, weathered volcanic rock. The upper exposures of the bedrock have a weathered sandy clay with fractured rock zone grading into a more dense and less fractured rock. There is essentially one soil type based on the field descriptions indicated on the logs. The soil is referred to later as Soil Type 1. MV ENGINEERING, INC. l 2450 VINEYARD AVENUE, X102 l ESCONDIDO, CALIFORNIA 92025-1330 l 619/74312,4 so,0115 TESTIN PERC TEIiT *ML ,N”EsT#G*,M”s aEoTEc”w2*L lN”ESl,DArwNS PRELIMINARY SOIL INVESTIGATION LOT #711, ARGONAUTA WAY, CARLSBAD PAGE 3 7125188 SOIL TYPES Soil Type Soil Description 1 Red-brown sandy clay with rock Based upon our observations, no ground water was detected during this investigation. During the course of grading, adverse subsurface conditions may be revealed that were not encountered during this study. Additional laboratory testing and analysis of the test results may be necessary and should be anticipated. D. Seismicity Faults or significant shear zones were not exposed during our field study to the depth explored. 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. IV LABORATORY TESTS AND TEST RESULTS A. Maximum Dry Density and Optimum Moisture Content The maximum dry density and optimum moisture contents of Soil Type 1 were determined in accordance with ASTM D-1557-78 method C using a 10 pound rammer and 18-inch drop. The results are tabulated below. Maximum Dry Opt.Moist. Location Soil Type Soil Description Density (pcf) Content(%) TP l@l 1 Red-brown sandy 126.0 10.9 clay with rock 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. MV ENGINEERING, INC. l 2450 VINEYARD AVENUE, X102 l ESCONDIDO, CALIFORNIA 92025-1330 l 619/743-1214 SOILS TESTING Pew TEST SOILIN”E811GATWNS GEOTECHNIC~ILlNVEFTlDITlONS PRELIMINARY SOIL INVESTIGATION LOT #711, ARGONAUTA WAY, CARLSBAD PAGE 4 7/25/80 C. Expansion Test One expansion test was performed on a representative soil sample of Soil Type 1. The soil was remolded to 90% of the corresponding maximum dry density in a 2f-inch diameter, l-inch high ring mold. The samples were 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 (%I TP l@l 1 10.0 4.3 21.2 7.1 TP = Test Pit w = moisture content (%) D. Direct Shear Test One 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 each soil were prepared by moldinq them in 2&-inch diameter, 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. Wet Angle of Apparent Soil Density Int.Fric. Cohesion Location Type (pcf) 0 (0) c,(psf) TP l@l' 1 124.9 21 716 E. Amount of Materials in Soils Finer Than The #200 Sieve The total amount of materials in soils finer than the #200 sieve was determined in accordance with the ASTM D-1140-71. The test results are tabulated below. Total Dry Total Dry Weight Percent Sample Soil Weight Retained Passing Location Type Before Test(q) After Test (9) #200 Sieve TP l@l' 1 1000 642 36 MV ENGINEERING, INC. l 2450 VINEYARD AVENUE, X102 . ESCONDIDO, CALIFORNIA 92025-I 330 l 6191743-l 214 SOlLS TESTlNG PERC TEST SOILIN”ESTI(IATIONS OEOTEC”NICLLlN”ESIlDITlONS PRELIMINARY SOIL INVESTIGATION LOT #711, ARGONAUTA WAY, CARISBAD PAGE 5 7/25/88 V. CONCLUSIONS AND RECOMMENDATIONS Based upon the foregoing site investigation, the property is suitable for the proposed development provided the recommendations and provisions given herein are incorporated into final plans and implemented during the construction phase. No evidence of adverse qeotechnical conditions were indicated on the property based upon the surface and subsurface exposures observed during our study. 1. Grading operations on the project should be tested, inspected and approved by a qualified qeotechnical engineer. Grading should conform to the codes established by the governing agency. Detailed grading recommendations will be provided by this office at the plan review phase when final grading plans are complete. Grading procedures should also be completed in accordance with the enclosed "Specifications for Construction of Controlled Fills", Appendix "A", except where superseded below. 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 qeotechnical engineer or his representative in charge. 3. In order to reduce the potential for differential settlement, it is recommended that if any structures are to be 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, where possible. Footings that straddle a cut/fill interface with more than five feet difference in fill thickness between the undercut portions and the filled ground, are recommended to be provided with additional reinforcement consisting of one additional minimum #4 bar, top and bottom, extending approximately ten feet on either side of the cut/fill line. These precautions will decrease the potential of cracking of the slab along the daylight line. The excavated area must be inspected by the qeotechnical engineer or his representative on site to verify the actual subsurface conditions and exact depths. 4. All underground utility trenches should be compacted to a minimum of 90% of the maximum dry density of the soil unless otherwise specified by the respective agencies. Care should be MV ENGINEERING, INC. l 2450 VINEYARD AVENUE, X102 l ESCONDIDO, CALIFORNIA 92025-1330 l 61917431214 soL*TEwNG PERC TEST 801LIN”ESIIOATWN8 GEOTECHN,C*L,N”ESTI(IIITIONS PRELIMINARY SOIL INVESTIGATION LOT #711, ARGONAUTA WAY, CARLSBAD PAGE 6 7125188 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 flooded with water to achieve compaction. 5. There were no obvious geologic hazards encountered during the field investigation. In our opinion, the main geologic hazard will be from ground shaking during an earthquake. Design in accordance with the latest Uniform Building Code Seismic Zone IV specifications. 6. In their present condition, the upper soils and existing fill are not suitable for the support of structures or fill. It is recommended that the upper soils be excavated down to firm bed- rock material and recompacted to a minimum of 90% of the corresponding maximum dry density. The excavations will be on the order of two to three feet. The exact depths to firm bedrock material cannot always be predicted and will vary throughout the site. The actual depths will be determined during the grading by the qeotechnical engineer or his representative on the site. It can be expected that a rocky soil mixture will be generated during grading. The proper soil to rock ratio of 60% fine soils to 40% rock should be maintained. In the event the qeotechnical engineer or his representative determines the amount of fine qrained soils is below the required levels, import soils may be necessary. Prior to placing any fill or structures, the ground shall be keyed and benched. All keys and benches should be inspected by the soils engineer on site. 7. According to the laboratory test results, the upper soils at the site are highly expansive. We recommend expansive soils not be placed in the upper three feet of the building pads and that select grading be implemented using a granular non-expansive soil import. Foundation and slab alternatives listed below provide options for foundations using a non-expansive import or the on-site expansive.soils. Final foundation designs will depend upon the expansion potential'and soil/rock type of the finished grade materials which can best be determined at the completion of rough grading. An expansion test will be performed on the foundation soils at the completion of rough grading to verify the appropriate foundation recommendations. MV ENGINEERING, INC. l 2450 VINEYARD AVENUE, #IO2 l ESCONDIDO, CALIFORNIA 92025-1330 l 619/743-1214 SOILSTEsTIN(I PEIIC TEST sOll.lN”E*TlaATlONs OEOTEC”NICILIN”E~~TIOITION6 PRELIMINARY SOIL INVESTIGATION PAGE 7 LOT #711, ARGONAUTA WAY, CARLSBAD 7125188 8. Alternative I - Select Grading and Capping of the Building Pad At a minimum of three feet below the proposed pad finish grade, the ground should be prepared in accordance with our above recommendations one through six. 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 import 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 qeotechnical engineer or his representative. 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. These are minimum depths which are measured from the lowest adjacent ground surface, not including the sand/gravel under the slab). B. The 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. All slabs should be a minimum of 3t 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. MV ENGINEERING, INC. l 2450 VINEYARD AVENUE, X102 l ESCONDIDO, CALIFORNIA 92025-1330 l 619/743-1214 601LSTESTINO PERC TEST 801LIN”EsTIOITION* LlEOTECHNlClLINVE~~TIOITIONS PRELIMINARY SOIL INVESTIGATION LOT #711, ARGONAUTA WAY, CARLSBAD PAGE 8 7/25/88 9. Alternative II - Foundation and Slab Recommendations for Buildings Supported Directly on Highly Expansive Soils. Foundation recommendations for the highly expansive (6-10%) Soil Type 1 are given below. A non-monolithic pour or two pour system should be used. Based upon our experience, conventional residential buildings constructed upon expansive soils may be susceptible to some cracking even though deepened foundations are used and footings and floor slabs are provided with additional reinforcement. Ground Preparations Excavate to firm native material as outlined in recommendation #6 and recompact the upper soils to a minimum of 90% of the corresponding maximum dry density at 3% to 5% over the optimum moisture content. Footing and Slab Recommendations A. Footings 1) Excavate the footings to a minimum depth of 24 inches below the lowest adjacent ground surface: minimum depths are measured from the lowest adjacent ground surface not to include the sand/gravel under the slab. Footings should have a minimum width of 12 inches for one-story and two-story structures. 2) Reinforce the interior and exterior footings with a minimum of four #4 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. MV ENGINEERING, INC. l 2450 VINEYARD AVENUE, X102 l ESCONDIDO. CALIFORNIA 02025-l 330 l 6191743-I 214 801LSTESTINO PERC TEST 8011 IN”E811(1ATWNS (IEOTEC”NICILIN”ESTI(I~TIONS PRELIMINARY SOIL INVESTIGATION LOT #711, ARGONAUTA WAY, CARLSBAD PAGE 9 7/25/88 B. Presaturation of the Interior Slab Subqrade 1) Once the concrete for the footings has cured, place 4 inches of pea gravel (a-inch rock) over the slab subgrade. Flood with water to the top of the pea gravel and allow the slab subqrade to soak for approximately seven to ten days, time will vary depending on soils. The required moisture content of the slab subqrade soils is 3% to 5% over the optimum moisture content at a depth of 24 inches. After the slab subqrade soils have soaked for the prescribed period of time, notify this office and schedule a moisture test. The required moisture content of the slab subqrade 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 subqrade has been achieved, place a 6-mil plastic moisture barrier over the pea gravel and place 2 inches of clean sand on top of the plastic. 2) Use a minimum of #3 reinforcing bars spaced 18 inches on center each way placed mid-height in all slabs. All slabs should be a minimum of 4 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 4-inch minimum thick slabs reinforced with minimum 6x6/10x10 welded wire mesh placed mid-height in all slabs. Use 6 inches of clean sand under all slabs. 2) Provide weakened plane joints spaced 6 feet on center each way for all slabs. E. Bearing Capacity and Lateral Load Designs 1) 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 mixtures are specifically known. MV ENGINEERING, INC. l 2450 VINEYARD AVENUE, X102 l ESCONDIDO, CALIFORNIA 9202571330 l 6191743-1214 801LS TESTlNLl PERC TEST SOILIH”E*TKiATwNS DEOTECnNlCILINYEJTI~*TIOHI PRELIMINARY SOIL INVESTIGATION LOT #711, ARGONAUTA WAY, CARLSBAD PAGE 10 7/25/88 2) Granular, non-expansive, and free draining backfill materials should be placed behind the retaining walls within the area of the active zone. 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 soils with a friction angle of at least 30 degrees. The provided soil lateral pressures are determined based upon the anticipated characteristics of granular non-expansive soils and assume drained and level backfill conditions. The lateral design soil pressures should be re- evaluated at the time when the characteristics of the backfill materials are specifically known. Revised recommendations may be necessary and should be anticipated. Expansive clayey soils should not be used for backfilling of any retaining structure. A coefficient of friction of 0.25 for concrete on soil may also be considered. 10. As an alternative, buildings constructed on expansive soils may be provided with mat foundations consisting of a post- tensioned slab-on-grade designed by a qualified structural engineer. Adhere to the previously mentioned ground preparation recommendations 1-6. A soil bearing capacity of 1000 psf may be used for preliminary estimates. Additional soil parameters associated with the design of post-tensioned slabs will be provided upon request. 11. If the option of minimum grading using stem wall construction is planned, the following recommendations should be adhered to. A. It is recommended that all footings penetrate the upper loose/compressible soils and are embedded a minimum of 12 inches for one-story and 18 inches for two-story structures into dense undisturbed native material. Footings should be 12 inches wide for a single-story building and/or 15 inches wide for a two-story building (UBC Requirements). Interior and exterior footings should be reinforced with a minimum of two #4 bars, one bar placed 3 inches below the top of the footing, and one bar placed 3 inches above the bottom of the footing. The depths to dense native material (measured from the present adjacent ground surface) will be on the order of 2 to 3 feet. The footings should be inspected by a representative from this office to verify the conditions of the footing trenches and reinforcement prior to pouring the foundations. Additional engineering recommendations will be given at that time, if necessary. MV ENGINEERING, INC. l 2450 VINEYARD AVENUE, #IO2 l ESCONDIDO, CALIFORNIA 92025.1330 l 619/743-1214 SOIL*TESTIN(I PERC TEST SOIL IN”E*TIm,,ON6 (IEOTECHNIC*L,N”E~TIG*TION* PRELIMINARY SOIL INVESTIGATION LOT #711, ARGONAUTA WAY, CARLSBAD PAGE 11 7/25/88 B. An allowable soil bearing pressure of 2000 psf may be used for footings suppor~ted entirely on dense, undisturbed bedrock. 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. C. Any structures such as slabs, driveways, paved roads and improvements which are planned to be supported directly upon existing native grades should adhere to the ground preparations outlined in recommendations 1 through 6. 12. During the grading it is probable that the on-site soils will be mixed, therefore, further laboratory testing and additional engineering will be necessary. Revised foundation recommendations should be anticipated. If any import soil is needed to complete grading, the soil should be granular and non-expansive. The soil must be examined and approved by the soils engineer or his rep- resentative prior to the delivery to the site. 13. This office should be notified to inspect all footing trenches and foundation reinforcement prior to pouring of the concrete to include all retaining wall structures. Specific drainage provisions behind the retaining walls should be verified by this office. 14. Caution should be used during the grading and trench excavations so that the existing adjacent structures/improvements are not distressed by the removals. Appropriate setbacks will be required and should be anticipated. All existing utilities on or in the vicinity of the property should be located prior to any grading or trenching operations. 15. This office should be notified a minimum of 24 hours prior to any grading or backfilling operations. 16. During the grading a rocky soil mixture may be generated by the excavations. It is recommended that the soil is mixed well and extra water is used. Compact the soil to a minimum of 90% of the corresponding maximum dry density as specified by ASTM D-1557-78. 17. 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 MV ENGINEERING, INC. l 2450 VINEYARD AVENUE, #IO2 l ESCONDIDO, CALIFORNIA 92025-I 330 . 6191743-l 214 SOILSTESTING PEW2 TEST *OILIN”E*~lGAT,ONs (IEOTEC”NICILlN”ESTlDITlONS PRELIMINARY SOIL INVESTIGATION PAGE 12 LOT #711, ARGONAUTA WAY, CARLSBAD 7/25/88 the initial development or grading should be reviewed by this firm prior to construction. 18. Footings located on or adjacent to the top of slopes should be extended to a sufficient depth to provide a minimum horizontal distance of 5 feet or one-half of the slope height, whichever is greater (need not exceed 10 feet maximum) between the bottom edge of the footing and the face of the slope unless otherwise recommended by the geotechnical engineer or his representative on site. 19. Use cut and fill ratios of 2:l (horizontal to vertical) for overall gross slope stability. It is recommended that the fill slopes be overbuilt and cut back to the design configuration. 20. Structural sections for roadway and parkway designs will be determined at the completion of grading with the appropriate sampling and laboratory testing. 21. During the course of our investigation two test pits were excavated to depths of 3f and 9 feet. After logging and sampling of the test pits, they were backfilled, rolled and tamped. 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. 22. 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 land- scaping is fully established, plastic sheeting should be kept accessible to protect the slopes from periods of prolonged and/or heavy rainfall. 23. In order to maintain future site performance, it is recommended that all pad drainage should 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 should MV ENGINEERING, INC. l 2450 VINEYARD AVENUE, Xl02 l ESCONDIDO, CALIFORNIA 92025-1330 . 619/743-1214 soIL8TES11NO PERC TEST 801LIN”ESTIOATwNs DEOTEC”NlCILlN”ESTlDITlONJ PRELIMINARY SOIL INVESTIGATION LOT #711, ARGONAUTA WAY, CARLSBAD PAGE 13 7/25/88 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. 24. 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. 25. Finalised development plans should incorporate these recommendations and be reviewed and approved by this office. If the finalised 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. 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 notified immediately so that an inspection can be made and additional recommendations issued, if required. 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 almost 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. MV ENGINEERING, INC. l 2450 VINEYARD AVENUE, X102 l ESCONDIDO, CALIFORNIA 92025.1330 l 819/743-1214 sons TESTING PERC TEST SOn.lN”ESTlalTlONS BEOTEC”NlCLL,N”ESII(I~TIONS PRELIMINARY SOIL INVESTIGATION LOT #711, ARGONAUTA WAY, CARLSBAD PAGE 14 7/25/88 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 make 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 #1275-88 will expedite response to your inquiries. We appreciate this opportunity to be of service to you. GE #863 RMV/jm MV ENGINEERING, INC. l 2450 VINEYARD AVENUE, X102 l ESCONDIDO, CALIFORNIA 92025-l 330 l 619/743-l 214 *on.s TE8TIW PERC TEST SDlL lNYE*T,GAllONS ~EOTECHNIC)IL,N”ES~,~~~~~~ TEST PIT LOCATION MAP PROPOSED SINGLE-FAMILY RESIDENCE LOT 711, ARGONAUTA WAY CARLSBAD, CALIFORNIA SCALE 1”=60’ APPROXIMATE AREA APPROXIMATE AREA Gf Gf VICINITY MAP EXPLANATION I TP Test pit approximate location I / NO SCALE PLATE 1 JOB NO. 1275-88 PRIMARY DIVISIONS I I GROUP SECONDARY DIVISIONS GRAVELS CLEAN -- ~./ELS SYMBOL GW 1 Well graded pravels. gravel-sand mlxture8. ttttte w no tines. MORE THAN HALF OF COARSE FRACTION IS LARGER THAN NO. 4 SIEVE -.-.._ SANDS GP ( poorly graded gravels or gravel-sand mixtures. Sttte M no riles. GM silty Q,Wd% Qravet-sa”d+.ttt “,txt”~~B, “0”@,sttc tt,Wa. GC _..- SW CtW3y QW&. grnvnt~snnd-ctny mt”tWB., pt”“ttC ttW8. Welt Qraded ssnds. gravelly sands. little 0, “0 fines. MORE THAN HALF OF COARSE FRACTION IS SMALLER THAN SP ( Poorly graded sand8 07 QWetty sanda. little 0, “0 tt”es SM 1 Sltty sands. eand-sttt mtxtures. non-ptasttc tines NO. 4 SIEVE FINES SILTS AND CLAYS SC 1 Clayey sands. sandetay mixtures. plastic tines. ML tnOrQaniC silts and very fine sands. rock Itour. silty or clayey tine Sands or clayey sit19 with slight plasticity. LIOUID LIMIT IS LESS THAN 50% SILTS AND CLAYS LIQUID LIMIT IS GREATER THAN 50% CL OL MH CH OH Inorganic clays of tow to medium plasticity, gravelly clays. Sandy clays. silty ctays. tean ctay.9 olQW,tC Sit19 and O,Qa”tC Silty clays Ot t0W pb$ticttY. t”O,Qa”tC 9ilt9. micaceo”s or diatomaceous tine sandy or Silty soils. elastic silts. Inorganic clays of high plasticity. tat clays. OQ9”iC clays 0, medium t0 high ptW‘tkity. 0,Qa”ic Sib I I HIGHLY ORGANIC SOILS 1 PT I Peat and other highly Organic soit9. - GRAIN’SIZES U.S. STANDARD SERIES StEVE CLEAR SOUARE SIEVE OPENINQS 200 40 IO 4 314” 3” 12” SAND GRAVEL SILTS AND CLAYS FtNE MEDttJM COARSE FlNE COARSE RELATIVE DENSITY CONSISTENCY JNDS, GRAVELS AND #ON-PLASTIC SILTS BLOWS/FOOT VERY LOOSE o-4 LOOSE 4-10 MEDIUM DENSE IO-30 DENSE 30.50 VERY DENSE OVER 50 CLAYS AND PLASTIC SILTS VERY SOFT SOFT FIRM STIFF VERY STIFF HARD I STRENGTH 0.X ‘A % ‘A 1 1.2 2.4 OVER 4 E i 3LOWS/FOOT O-2 2-4 4.8 6.16 16-32 OVER 32 1, Blow count, 140 pound hammer falling 30 inches on 2 inch O.D. split spoon sampler (ASTM D-l 588) 2. Unconfined compressive strength per SOILTEST pocket penetromeler CL-700 A = unmurbed chunk sample 1 ‘4S = with blow counls per 6 inches Standard Penetration Test (SPT) (ASTM D-l 586) 0 = disturbed sample II ‘4S = California Sampler with blow counts per 6 inches MV ENGINEERING, INC. I KEY TO EXPLORATORY BORING LOGS Unified Soil Classification Svstem [ASTM D-2487) I Jim Hightower Lot 711, Argonauta Way, Carlsbad 31LL RIG BACKHOE SURFACE ELEVATION ---- LOGGEO BY RW r I IPTt = SE hw 0% 0 1 2 3 4 5 6 7 0 9 IO 11 12 13 14 -IT01 -_ - ; - - GROUND WATER N/E BORING DIAMETER 2 4 ” -.... DESCRIPTION AND CLASSIFICATION Red-brown sandy clay with rock. FILL 40-45% rock. Angular volcanic rock, pebble to small boulder size. Very loose, moderately moist. 2" thick sand layer @ 2' Soil Type 1 Red-brown sandy clay with rock. NATIVE Gray-brown volcanic bedrock, highly fractured, weathered to sandy clay. 40-45% rock, less clay with depth. Continued highly fractured, 85 to 90% rock. Dense Bottom @ 9' Soil Type 1 I = = = EXPLORATORY BORING LOG )RII = $ I - - J/r - 8. Jr - - MV ENGINEERING, INC. 2450 Vineyard Ave.. Suite 102 Escondido. CA 92025.1330 Phone: 6191743~1214 Jim Hightower Lot 711, Argonauta Way, Carlsbad PROJECT NO. PLATE -...-- 1776-RR 7 TP 1 c 9[ x! - hlLL RIG BACKHOE i 1 SURFACE ELEVATION ---- iPTt - ;& 0% 0 I 2 3 4 6 6 7 8 9 10 11 12 13 14 1 TO ( - 3ROUND WATER N/E BORING DIAMETER 24” .-. DESCRIPTION AND CLASSIFICATION Red-brown sandy clay w/rock. Loose dry topsoil to 1 foot. 45 to 50% rocks upper 1 foot, grades to decomposed volcanic bedrock. Fractured, very dense, slow digging. 90% rock from 2 feet. Moderately dry. Slow diqging, less fractured. Soil Type 1 Bottom of trench @ 34'. LOGGED BY RW DA =z= =Lu PO 25 ti? 6C DIL tRI1 6 i/8 zz-= 1 - --- -- =-- EXPLORATORY BORING LOG MV ENGINEERING, INC. 2450 Vineyard Ave.. Suke 102 Escondldo, CA 920251330 Dhnn.. C10,7”1_17,” Jim Hightower Lot 711, Argonauta Way, Carlsbad PROJECT NO. PLATE -...-- 177=,-RR n TP 2 - APPENDIX "A" 7108 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 Geotechnical 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. B. C. D. E. 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. 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. AW 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. 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. No fill shall be placed until the prepared native ground has been approved by the geotechnical engineer or his representative on site. F. G. H. I. 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-1557-78. Expansive soils may require special compaction specifications as directed in the preliminary soil investigation by the geotechnical engineer. The cut portions of transition pads require excavation and recompaction for density compatibility with the filled portion of the graded pads as directed by the geotechnical engineer. 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. E. F. 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. 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. 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 Group Identifying Criteria Symbol I. COARSE GRAINED (more than 50% larger than #200 sieve) Gravels (more than 50% larger than #4 sieve GW but-smaller than 3") Non-plastic 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 than 50 III. HIGHLY ORGANIC SOILS CH OH PT Silt, organic, silts and organic silt-clays of low plasticity. Silt, inorganic silts micaceous or dictomaceous fine, sandy or silty soils, elastic silts. Clay, inorganic, clays of medium to high plasticity, fat clays. Clay, organic, clays of medium to high plasticity. Peat, other highly organic swamp soils.