Laserfiche WebLink
r- <br /> Ra <br /> fflD <br /> w <br /> PRE-TARX REPLACEKE11i Site Assessment Work Pion <br /> 6131 Pacific Ave, Stockton, CA <br /> ' Aegis Project No. 90-020 <br /> Page 13 <br /> 4.4 METHODS <br /> 4.1 soil sam._pIinQ <br /> soil borings will be drilled and soil samples collected under the <br /> direction of a State of California registered professional engineer. <br /> The soil boring,• will be advanced to a depth of approximately five <br /> feet below grade by using a hand auger. The sail borings will be <br /> advanced, below five feet to final depth, using a truck--mounted <br /> hollow-stem auger drilling rig. <br /> To reduce the possibility of cross-contamination between boreholes, <br /> all downhole drilling equipment will be steamed cleaned between each <br /> boring. To reduce cross-contamination between samples, the split- <br /> barrel sampler will be washed in a tri-sodium phosphate solution and <br /> double-rinsed between each sampling event. <br /> f �! Soil sampling will be conducted in accordance.-with ASTM 1586-84. Using <br /> this procedure, a two-inch O.D. split-barrel sampler or a two-inch i <br /> I.D. California-type sampler is driven into the soil by a 340-pound <br /> weight falling 30 inches. After an initiL-1 set of 6 inches, the number <br /> of blows required to drive the sampler an additional 12 inches is <br /> known as penetration resistance, or the 'IN" v;Ilue. The N value is used <br /> as an empirical measure of the relative density of cohesionless soils <br /> and the consistency of cohesive soils. <br /> Upon recovery, a portion of the soil sample will be placed into a <br /> glass jar and sealed for later screening with a PID/OVA. Another <br /> portion of the soil sample will be used for classification and <br /> description. That part of the soil sample collected in a brass tube <br /> within the California--type sampler will be stored at approximately 4° <br /> �. C for transport to the laboratory. <br /> L, 4.2 Soil Classification <br /> E <br /> LJE <br /> As the samples are obtained in the field, they are classified in <br /> accordance with the Unified Soil Classification System (USCS) . <br /> Representative portions of the samples are then returned to the <br /> laboratory for further examination and for verification of the field <br /> classification. Logs of the borings indicating the depth and iden <br /> tification of the various soil types, the N value, and pertinent <br /> ►, information regarding the method of maintaining and advancing the <br /> borehole are also made. f <br /> ; i 4.3 soil Sample screening: Portable Photoionization Detector Method <br /> After soil sample jars have been brought to ambient temperature, the <br /> head space of the soil sample jars will be screened with a portable <br /> photoionization detector or organic vapor analyzer equipped with a <br /> 10.2 eV lamp calibrated to benzene for direct reading in ppm. The <br /> j i <br />