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HomeMy WebLinkAbout; La Costa Meadows Unit 1 Lots 92,185; Soils Report; 1972-06-28. ,, - - - - - -. - PHlLlP H(ENKING BENTON PrlESI0El.T ClllL CNGINELR BENTON ENGINEERING. INC. APPLIED SOIL MECHANICS ~~~~ FO”NDAIIONS 6741 EL CAJON BOULEY*PD SAN DIEGO. C*LIFORNI* 92115 June 28, 1972 La Costa Land Company Costa Del Mar Road Rancha La Costa, California 92008 Subiect: Proiect No. 70-lo-28D (Grading Permit L 3785) Final Report on Cojnpacti~.Fille&GW~~~d F 6k92and 185of ’ Lta33 do. I ‘.-~~~~;“““.~~~.~,, Gentlemen: This is ta report the final resulk of tesk and abseervations made in order ta inspect the compaction of filled ground placed on certain areas of Lok 92 and 185 in La Costa Meadows Unit No. 1. The msulk of tests and observations made b=t th=paction of filled ground placed during the major grading of this subdivision and special recommendations for construction on expansive soils were included in our interim report on this project dated October 12, 1971. This report includes the resulk of test Nos. 1377 ta 1380, inclusive, taken in compacted filled ground placed on Lok 92 and 185. These fills were placed on April 24, 1972 and June 13, 1972. This report includes all test data and information not previously reported and completes our final report on La Costa Meadows Unit No. 1. The approximate areas and depths of filled ground placed under our inspection in accordance with the approved specifications are shown on the attached Drawing No. 1, entitled “Location of Compacted Filled Ground.” The grading plan used for the placement of filled ground was pre- pared by Rick Engineering Company and last revised January 29, 1971. The approximate locations at which test Nos. 1377 ta 1380, inclusive, were taken and the final test resulk were presented on page T-44, under the “Table of Test Results.” Test Nos. 1 ta 1376, inclusive, were presented on pages T-l ta T-43, inclusive, of our previous report. The laboratory determinations of the maximum dry densities and optimum moisture contenk of the major fill materials placed during this recent grading period are presented on page L-l under the “Labora- taty Test Resul k.” Test Nos. 1377 ta 1380, inclusive, reported hemin, were t&en on the dates indicated below: Test Number Date i 377 and 1378 April 24, 1972 1379 and 1380 June 13, 1972 SlOlO .17.82 Project No. 70-lo-28D LaCosta Meadows Unit No. 1 -2- June 28, 1972 The final resul k of tesk and observations indicate that the compacted filled ground has been placed at 90 percent of maximum dry density or greater. It has been determined that the fill materials, compacted to 90 percent of the maximum dry density, have a safe bearing value of 1930 pounds per square faot for one foot wide continuous footings founded at a minimum depth and placed 5 feet or mom inside the tap of the compacted filled ground slopes. If footings am placed closer to the exposed slopes than 5 feet inside the top of compacted filled ground slopes, these should be deepened one foot below a 1 l/2 horizontal ta 1 vertical line projected outward and downward from a point 5 feet horizontally inside the top of compacted filled ground slopes. Task indicate that the compacted filled ground is adequate to support the proposed wood frame dwellings without detrimental settlemenk. - Critically expansive soils exist in the upper three feet below finished grade on Lok 92 and 185. Themfom the special design and pmcautions presented for Type “A” lak in our previous IntK report dated October 12, 1971 are recommended for buildings constructed on these two lok. Respectfully submitted, - BENTON ENGINEERING, INC. - - - - - - BY z&? R. C. Remer Reviewed by Philip H. Benton, Civil Engineer Distr: (4) Addressee (1) La Costa Land Company Attention: Mr. Burton 1. Kramer (1) Rick Engineering Company (2) San Diego County Building Inspectton, Vista Office (1) San Diego County Engineering Department Attention: Mr. Joe Savella RCR/PHB/ew BENTON ENGINEERING. INC. Project No. i&10-28D La Costa Meadows Unit No. .l -. - - - - - .- .- - - - Test No. Approx- lmote Location Lot No. Depth of Fill at Test in Feet 1377 185 30.0 1378 185 32.5 l 1379 92 1 .o 1380 92 2.3 l * Finished grade T-44 June 28, 1972 TABLE OF TEST RESULTS Field DV M&turn Density %drywt Ib/cu ft 14.5 102.3 14.6 104. I 14.3 103.6 14.4 107.7 Maximum DV Density Percent Ib/cu ft Compact Ion 111.3 92.0 111.3 93.5 115.0 90.1 117.4 91.8 BENTON EkGlNEERING. INC.