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k' ■ K L E I N F E L DER This proposal may be used only by the client and only for the purposes stated, within a reasonable time from its issuance. Land use, site conditions (both on-site and off-site) or other factors may change over time, and additional work may be required with the passage of time. .. IV. GEOTECHNICAL ENGINEERING SERVICES 1. Field Exploration Initially, we will submit required drilling permits and fees to the San Joaquin County Environmental Health Department (SJCEHD). In addition, we will contact Underground Service Alert (USA) to verify the presence or absence of public utility right-of ways at the site. Also, one week prior to our field exploration we will locate and post flags at each of the exploration locations in order to obtain the property owners approval. Once approval is obtained, we propose to explore the subsurface conditions at the site by drilling eleven borings to depths of about 20 feet below the present ground surface. In addition, we will drill six to eight borings along street alignments to depths ranging from about 5 to 10 feet. Also, we will perform six cone penetration tests (CPT's) to depths of about 20 to 30 feet below the present ground surface. Although the site is located in UBC Seismic Zone 3, it is located very close to UBC Seismic Zone 4 (Alameda County line) and the Great Valley fault system. In similar situations, San Joaquin County and other agencies have required that developments meet the requirements for Seismic Zone 4. In order to reduce the chance for approval delays from a ` geotechnical standpoint, we proposed to perform two additional CPT's to a depth of at least 40 feet in order to evaluate the potential for seismic liquefaction. Finally, we will drill two borings in the proposed lake/detention basin area to evaluate the subsurface conditions and perform percolation testing to estimate the infiltration characteristics of the native soils. Since the subsurface conditions should be relatively consistent at the site, the intent of our proposed field services is to perform at least one exploration for about every 9 to 10 acres of the development. The borings will be drilled using a truck mounted drill rig equipped with continuous flight auger. ` During drilling operations, penetration tests will be performed at regular intervals to evaluate the soil consistency, obtain information regarding the engineering properties of the subsoils, and to retain soil samples for laboratory testing. Pocket penetration tests will also be performed on soil samples retrieved to evaluate the consistency of fine grained (clay and silt) soils encountered. The soils encountered will be continuously examined and visually classified in accordance with the Unified Soil Classification System by an engineer with our firm. Upon completion, the borings will be backfilled with lean cement or a cement-bentonite grout under the observation of SJCEHD personnel. The CPT's will be performed by hydraulically pushing a 1.4-inch diameter Dutch Cone Penetrometer into the subsurface soils using an enclosed truck-mounted 20-ton ram system. During penetration the cone or tip resistance and sleeve friction resistance will be recorded on a L 02001PROP.GEO/ST02P093 August 21,2002 ©2002 Kleinfelder,Inc. Page 7 of 11