WP0039799 - Laserfiche WebLink

Home Browse Search

R-1292 Geotechnical Boring Work Plan Task: Field Investigation The proposed field investigation includes a site reconnaissance to perform Pre-Dig Verification of the utility clearances including contracting a private utility locator and verifying utility clearance through USA, drilling, sampling and logging of exploratory borings, and staging of the drummed cuttings. A detailed description of our proposed field exploration program is presented as follows: • In accordance with PG&E Gas Contractor Safety requirements, a Pre-Dig Verification will be performed prior to excavation work.This will be attended by Kleinfelder staff, the private utility locator, the excavation subcontractor, and the PG&E Standby Inspector. We propose to perform the Pre-Dig Verification for all boring locations at the beginning of the drilling mobilization. If the Pre-Dig Verification process is required to be performed on a separate day in advance of the fieldwork, additional fees will apply. • Subsurface conditions will be explored by drilling two exploratory borings with a truck-mounted drill rig using hollow stem auger and mud rotary drilling methods to maximum depths of 80 feet below the ground surface. Drilling is constrained to what can be completed in two days in the field and one mobilization/demobilization of the drill crew. We expect the site will be accessible by truck-mounted drilling equipment. • The borings will be performed as close to practical as the proposed pipeline alignment.These locations will be adjusted as needed in the field due to site constraints or to avoid conflicts with underground utilities and/or overhead lines. • The borings will be hand augured in the upper 5 feet to clear the borings with regard to underground obstructions, per typical PG&E procedures. It is assumed that the boring locations will take no more than 30 minutes per boring to clear. • Soil samples will be obtained near the ground surface and at vertical intervals of approximately every 5 feet. Soils will be sampled using the hand auger in the upper five feet. Samples will be obtained for the remainder of the boring using either a 2-inch outside diameter, standard penetration test (SPT) barrel sampler in general accordance with ASTM D1586 or a 3-inch outside diameter, split-barrel "California- type" sampler in general accordance with ASTM D3550. The SPT and California-type samples will be obtained by driving a 140-pound automatic hammer with a free fall distance of 30 inches, in general accordance with ASTM D1586. Groundwater, if encountered, will be noted on the boring logs.