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i ; .0 METHON j LI SoiLSRIt1p1Ill8 Soil borings and soil sampling will be performed under the direction of a Delta engineer or geolo3ist. The soil borings will be advanced using a truck-mounted hollow-stem auger drill rig. f i To reduce the possibility of cross-contamination between boreholes,all downhole drilling equipment will be steamed-cleaned between each boring. To reduce cross-contamination between samples,the split-barrel sampler will be washed in a soap solution and doubled-rinsed between each sampling ! 4 event. -1 Soil sampling will be done in accordance with ASTM 1585-84. Using this procedure, a two-inch outside-diameter split-barrel sampler or a 2-inch insidd-diameter.California-type sampler is driven into the soil by a I40-pound weight falling 30 inches. After an initial set of G inches, the number of blows required to drive the sampler an additional 12 inches is known as penetration resistance, or the"N"value. The N value is used as an empirical measure of the relative density of cohesionless soils and the consistency of cohesive soils. z Upon recovery, a portion of the soil sample will be placed into a glass jar and sealed for later r' screening with a photoionization detector. Another portion of the soil sample will be used for classification and description. That part of the soil sample collected in brass tubes within the i California-type sampler will be stored at approximately 4°C for transport to the laboratory. Li LZ—Soil Classl[I_ gILq � ± As the samples are obtained in the field, they will be classified .by the crew chief;geologist in accordance with the Unified Soil Classification System (USCS). Representative portions of the samples will then be returned to the laboratory for further examination and for verification of the ! field classification. bogs of the borings indicating g th a depth and identification of the various strata, the N value, and pertinent information regarding the method of maintaining and advancing the I« borehole will be made. C111121WMIU11[12 ill�lll,-Retec far MethodE i After soil sample jars have been brought to ambient temperature, the head space vapors of the soil f t sample jars will be screened with a portable photoionization detector equipped with a 10.2 eV lamp calibrated to benzene for direct reading in parts per million (ppm). The sample jar lid will be opened and the detector probe immediately placed within the head space-_af the.-jar.--The.. ----- 3, o stsrved reading will be recorded. t r X11 i'