ARCHIVED REPORTS XR0001837 - Laserfiche WebLink

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GREGG IN SITU, INC DANA BOOTH January 27, 1995 Lerner Texaco site Lodi, Ca The cones were pushed using GREGG IN SITU's CPT rig, having a down pressure capacity of approximately 20 tons 14 CPT soundings were performed The penetration tests were carred to depths of approximately 55 feet below ground surface In situ groundwater samples were taken at 10 locations Groundwater samples were collected using the Hydropunch groundwater sampling system The Hydropunch operates by pushing 1 75 or 1 5 inch diameter hollow rods with a retrievable tip A stainless steel filter screen is attached to the tip At the desired sampling depth, the rods are retracted exposing the filter screen and allowing for groundwater infiltration A small diameter baler is then used to collect groundwater samples through the hollow rod The CPT/Hydropunch holes were grouted using our support rig The grouting procedure consists of pushing a hollow CPT rod with a "knock out" plug back down the hole to the test hole termination depth Grout is then pumped under pressure as the tremae pipe is pulled from the hole 3.0 CODE PENETRATION TEST DATA & INTERPRETATION The cone penetration test data is presented in graphical form in the attached Appendix Penetration depths are referenced to existing ground surface This data includes CPT logs of measured soil parameters and a computer tabulation of interpreted soil types along with additional geotechnical parameters and pore pressure dissipation data. The stratigraphic interpretation is based on relationships between cone bearing (Qc), sleeve friction (Fs), and penetration pore pressure (Ut) The friction ratio (Rf), which is sleeve friction divided by cone bearing, is a calculated parameter which is used to infer soil behavior type Generally, cohesive soils (clays) have high friction ratios, low cone bearing and generate large excess pore water pressures Cohesionless soils (sands) have lower friction ratios, high cone bearing and generate little in the way of excess pore water pressures Pore Pressure Dissipation Tests (PPDT's) were attempted at various intervals in order to measure hydrostatic water pressures and approximate depth to groundwater table In addition, the PPDT data can be used to estimate the horizontal permeability (kj of the soil The correlation to permeability is based on the time required for 50 percent Of the measured dynamic pore pressure to dissipate (t,5o) A summary of the PPDT