Agmt12 Infrastructure Engineering Corporation

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TASK 11— GEOTECHNICAL INVESTIGATION Services under this task will be performed by Cornerstone Earth Group and will consist of a supplemental geotechnical investigation to provide a basis for final design level geotechnical recommendations for the alternative civil site layout and retaining wall system. File Review Review select information available in our files pertinent to the site conditions near the project site prior to site explorations. Field Exploration Geologic Reconnaissance: Perform a reconnaissance of the site and the nearby site vicinity to evaluate the potential presence of geologic hazards, including fault rupture, slope instability, springs, expansive soils, and other features indicative of potential geologic hazards. Utility Clearance: Mark the boring locations at least two working days prior to beginning our explorations as required by law, and notify the regional utility notification center — Underground Service Alert (USA) so that public and private utilities can be identified and marked at the ground surface. Where practical, mark the locations in white paint, or otherwise designate the exploration locations, as required by USA. Contract with a private utility locator to reduce the risk of damaging unidentified underground utilities during drilling. Exploratory Borings: Drill, log and sample two exploratory borings at the site using track -mounted hollow -stem auger drilling equipment. Conventional borings will extend to depths of approximately 15 to 30 feet, depending on the depth and consistency of the bedrock encountered. Collect soil samples from our borings for visual classification and laboratory testing. The final location and depth of all explorations may be modified in the field, as needed. Permits, Site Access and Disposal of Drill Spoils: Explorations will be permitted and backfilled with cement grout in accordance with San Mateo County Environmental Health guidelines. Drill spoils generated during drilling will be left near the explorations. Exploration equipment is typically heavy, and drilling is a destructive process that disturbs surface soils and other improvements. Site restoration, as defined herein, is limited to backfilling of the excavations and general clean-up and does not include the restoration of the site to the exact conditions existing prior to the work. Laboratory Testing To evaluate the engineering properties of site soils, the following laboratory tests are anticipated: • In-situ Moisture/Density tests, American Society for Testing and Materials (ASTM) D2937 Test Procedure • Atterberg Limit tests, ASTM D4318 • Consolidated -Undrained Triaxial Shear tests with pore pressure measurements, ASTM D4767 Engineering Analvsis and Report Preparation The engineering analysis phase of work will focus on developing site grading recommendations and geotechnical design parameters for foundations, retaining structures and pavement areas. The data obtained from the field investigation and the laboratory testing program will be utilized in the engineering analysis. Page 7 of 23 REV: 08-16-17 PR ATTY/AGR.Amendment No. 1/Infrastructure Engineering Corporation - CA Tank