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25 October 2001 <br /> AGE-NC Project No 97-0301 <br /> ' Page 2 of 7 <br /> Based on CPT lithologic sounding data collected at P-5,P-6, P-7,P-8, P-9 and P-10, depth-discrete <br /> "grab" ground water samples were collected by revisiting locations of the initial CPT soil borings <br /> via an adjacent boring advanced within two feet of the initial boring CPT boring logs are presented <br /> ' in Appendix A, a site plan depicting boring locations is presented in Figure 2 <br /> ' 21 CPT LITHOLOGIC SOUNDINGS <br /> Soil borings P-5,P-6,P-7,P-8,P-9 and P-10 were advanced vertically to total depths of 125 feet bsg <br /> ' utilizing a 25-ton truck-mounted CPT drill rig equipped with 2-inch diameter hollow-stem rods A <br /> hydraulic ram was utilized to advance a cone penetrometer tip to total depth of each CPT boring Soil <br /> parameters such as cone penetrometer tip resistance, sleeve friction, friction ratio (ratio between <br /> ' sleeve friction and tip resistance) and pore water pressure were continuously measured as the cone <br /> penetrometer was advanced to depth A continuous boring log was generated utilizing the <br /> Hogentogler Co CPT computer program The Hogentogler Co computer program utilized the CPT <br /> ' Soil Behavior Classification System (Robertson,P K, Campanella,R G, Gillespie, D and Greig, J , <br /> 1986), to generate a general lithology type and display on a CPT boring log (See Appendix A) <br /> Rinseate generated during drilling activities was containerized in properly labeled DOT-approved <br /> 55-gallon drams, and stored on-site in an area lacking public access All soil borings were backfilled <br /> by inserting hollow steel rods to total depth of each boring and backfilling with a portland cement <br /> ' grout mix <br /> ' 22 STRATIGRAPHY <br /> Based on the findings from CPT soil borings P-5,P-6,P-7, P-8, P-9 and P-10, cross sections D-D', <br /> ' E-E'and F-F'were constructed and depict general lithology beneath the site (Figures 3, 4 and 5) <br /> Cross sections AA', B-B' and GC' were presented in Preliminary Investigation & Evaluation <br /> Report, dated 26 July 1999 Generally, gravelly, fine to coarse sand layers were observed at depths <br /> ' between 55 and 65 feet bsg and 110 and 125 feet bsg, and fine grained, silty clay and clayey silt <br /> layers were observed at depths between 20 and 35 feet bsg, 70 and 80 feet bsg and 105 feet and 110 <br /> feet bsg Variable lithology including silty fine sand, sandy silt and clayey silt to silty clay were <br /> ' observed at all other depths CPT computer-generated boring logs are included in Appendix A <br /> ' 2 3 HYDROGEOLOGIC UNITS <br /> Based on cross sections D-D',E-E'and F-F',AGE informally identified four hydrologic flow units <br /> ' between surface grade and 125 feet bsg (First Water Zone,Second Water Zone, Third Water Zone <br /> and Fourth Water Zone) as having significant intervals of apparently porous, courser grained soil <br /> .advanced GeoEnvironmentai,Inc <br />