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1 <br /> • <br /> GREGG IN SITU, INC. CONDOR EARTH <br /> April 5, 2002 Canepa's <br /> 02-525tx Stockton, Ca <br />' In situroundwater samples were taken at two locations Groundwater samples were <br /> 9 P P <br /> collected using a Hydropunch® type groundwater sampling system (figure 2) The <br />' groundwater sampler operates by pushing 1 75 inch diameter hollow rods with a <br /> retrievable tip A stainless steel filter screen is attached to the tip At the desired <br /> sampling depth, the rods are retracted exposing the filter screen and allowing for <br />' groundwater infiltration A small diameter bailer is then used to collect groundwater <br /> samples through the hollow rod <br />' Soil samples were taken using a piston type soil sampler (figure 3) The soil samples <br /> were collected in approximately 1 118 inch diameter stainless steel sample rings <br />' 3.0 CONE PENETRATION TEST DATA & INTERPRETATION <br /> The cone penetration test data is presented in graphical form Penetration depths are <br /> referenced to existing ground surface This data includes CPT logs of measured soil <br /> parameters and a computer tabulation of interpreted soil types along with additional <br />' geotechnical parameters and pore pressure dissipation data <br /> The strat€graphic interpretation is based on relationships between cone bearing (qc), <br />' sleeve friction (fs), and penetration pore pressure (U) The friction ratio (Rf), which is <br /> sleeve friction divided by cone bearing, is a calculated parameter which is used to infer <br /> soil behavior type Generally, cohesive soils (clays) have high friction ratios, low cone <br />' bearing and generate large excess pore water pressures Cohesionless soils (sands) <br /> have lower friction ratios, high cone bearing and generate little in the way of excess <br /> pore water pressures <br />' The interpretation of soils encountered on this protect was carried out using recent <br /> correlations developed by Robertson et al, 1988 It should be noted that it is not always <br />' possible to clearly identify a soil type based on qc, fs and U In these situations, <br /> experience and judgement and an assessment of the pore pressure dissipation data <br /> should be used to infer the soil behavior type The soil classification chart (figure 4) <br />' used to interpret soil types based on qc and Rf is provided in the Appendix <br /> 1 <br />