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Home My WebLink AboutCT 73-29; Carrillo Estates; Earthpackage Investigation; 1981-07-29." 4 - -c / r, ~' , r <. " ,- 3467 Kuflz Streel San Diego. California 921 10 Telex 697-841 714-224-291 I July 29, 1981 Project No. 51142W-EP01 Ponderosa Homes, Inc. San Diego, California 92121 11300 Sorrento Valley Road Attention: Mr. Ken Cook EARTHPACKAGE INVES ATION CARRILLO EST- e CARLSBAD, CALIFORNI Woodward-Clyde Consultants Gentlemen: dated June 8, 1981, we are pleased to present the results of In' accordance with your request and our authorized proposal our earthpackage investigation for the subject site. The purpose of this study is to estimate the quantities of various soils requiring special handling during grading, including compressible soils, expansive soils, and hard rock requiring blasting. In addition, we will address the availability of and requirement for finish grade soils on the site and the need for canyon subdrains. Our studies included reviewing the following: 0 "Soil Investigation for the Proposed Carrillo Woodward-Gizienski & Associates, dated September 6, Estates, Carlsbad, California," prepared by - 1973. 0 "Update Soil and Geologic Investigation, Carrillo Woodward-Clyde Consultants, dated May 5, 1981. "Grading Plans for Carlsbad Tract No. 73-29 by Rick Engineering Company. (Carrillo Estates Unit No. 2) ," undated, prepared - Estates Unit 2, Carlsbad, California," prepared by 0 - ~~ ~. ~ .. .. ~ .. . - .~ ~~~ ~ ~ ~~ ~~~ Consullmg Engineers. Geologm and Envwonmental Sclenllsts Ollces In Olher Prlncval Ctkes Ponderosa Homes, Inc. July 29, 1981 Project NO. 51142W-EP01 Woodward-Clyde Consultants SOILS REQUIRING SPECIAL HANDLING DURING GRADING Compressible Soils Our investigation indicates the presence of loose compressible alluvial soils in the drainage along the proposed extension of El Fuerte Street. We recommend that these soils be excavated, watered as required, and recompacted prior to placing additional fill or structures. We estimate that the depth of excavation and compaction will range from 3 to 5 feet; however, we recommend that the actual depth be evaluated in the field at the time of grading. We estimate that the volume of alluvial material requiring excavation and compaction will be 10,000 cubic yards. Additional compressible soils exist in areas of end-dumped and spread uncompacted fill soils and debris which are scattered throughout the eastern three-quarters of the site. In our opinion, these fill soils may be utilized in struc- tural fil'ls once all deleterious debris and oversize mate- rial is removed. . We estimate that the volume of compressible fill soils on the site will be 9,000 cubic yards. Natural surfaces and the surfaces of existing fills are dried and loose to shallow depth. Normal scarifying. watering and compacting should be done on these surfaces. No volume for this operation was calculated. Expansive Soils The natural residual and topsoil clays that are present along daylight lines and other areas of shallow cut and fill are classed as.highly expansive. We recommend that these below finish grade and be replaced with properly compacted, soils be undercut where encountered a minimum of 2 feet nonexpansive or slightly to moderately expansive soil available on the site. We expect that undercut for topsoil clay will be required on portions of Lots 147, 148, 153 to 155, 178, 182 to 185, 189, 192, 193, 204, 205, 209 to 211, and 226. We estimate that the volume of expansive soil requiring undercutting and replacement on these lots will be 1ess.than 2,000 cubic yards. Hard Rock Excavation Excavation of the hard rock areas generally depends on weathering and decomposition of the materials, natural fracture patterns, condition of the excavating equipment, and operator technique. Our field investigations indicate Ponderosa Homes, Inc. July 29, 1981 Project No. 51142W-EP01 Page 3 Woodward-Clyde Consultants that the hard rock areas along the alignment of El Fuerte Street can generally be excavated with heavy-duty excavating equipment to depths on the order of 5 to 10 feet. Deeper We estimate that the volume of hard rock requiring blasting cuts will generally require blasting for efficient excavation. to achieve proposed finish grade will be 4,000 cubic yards. FINISH GRADE SOILS Amounts Available and Required The finish grade soils necessary to cap lots will be derived from cut areas on the site, below any expansive overburden soils. Our soils investigation revealed that most of the cut material generated will be nonexpansive, silty sand and will be suitable for use at finish grade. CANYON SUBDRAINS Due to the meandering nature of the drainage with respect to the planned grading along the proposed extension of El Fuerte Street and the steep gradient of the drainage bottoms in we do not anticipate the need for canyon subdrains in this areas of proposed canyon-side fills within the subdivision, project. LIMITATIONS The earthwork volumes presented herein are approximate and intended for preliminary budgeting purposes only and not for should be made in the field at the time of grading. The "pay" quantities. Actual evaluations of soil quantities cantractor may move significantly more soil than that indicated depending on equipment and procedures. If you have any questions, please give us a call. Very truly yours, WOODWARD-CLYDE CONSULTANTS Richard P. While R.E. 21992 (4)