WORK PLANS FILE 2 - Laserfiche WebLink

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S E C O R ATTACHMENT 2 FIELD AND LABORATORY PROCEDURES CPT BORINGS AND GROUNDWATER SAMPLING The CPT method consists of advancing a cone-tipped cylindrical probe (1.7 inches-in-diameter) into the ground while simultaneously measuring resistance to the penetration. The CPT method determines soil lithology by comparing the force (cone bearing pressure) required to advance the probe (Qt) to the friction ration (Rf). The Rf equals sleeve friction [Fs] divided by the probe tip load, times the penetration pore pressure [Ud]. Computer generated CPT logs will be plotted in the field that will provide a graphical log of subsurface soil lithology. A CPT test data report, which will include logs of all CPT technique, will be submitted with the final report. CPT testing will be performed in accordance with American Society of Testing and Materials (ASTM) Method D 5778-95 (Reapproved 2000). The CPT will be performed inside a grout collar installed at the ground surface. The grout collar will allow the CPT contractor to backfill the boring as the steel rods are retracted from the hole. Continuous grouting will prevent cross-contamination of water bearing zones that can occur through an open borehole. The boring will be backfilled to surface grade. Grout mix used to backfill the boring will be Portland cement with 5% bentonite. A concrete or asphalt patch will be placed over the borehole where applicable. Immediately adjacent to the CPT borehole a second direct push borehole will be advanced to collect discrete groundwater samples. Groundwater samples will be collected using a hydropunchTM or similar technology by lowering a stainless steel or Teflon® bailer into accumulated groundwater in the borehole, then retrieving and transferring the water into laboratory supplied containers.