Laserfiche WebLink
i <br /> ~ METHODS <br /> Soil Sam iln <br /> Site investigations, including boring and soil sampling, are performed under the direction <br /> of a professional engineer or registered geologist registered with the State of California. <br /> After auguring by hand to a depth of approximately five feet below surface, <br /> the borings <br /> are drilled to total depth using a truck-mounted hollow-stem auger drilling rig. The soil <br /> sampling is done in accordance with ASTM 1586-84. Using this procedure, a two-inch <br /> w O.D. split-barrel sampler or a two-inch LD, California-type sampler is driven into the soil <br /> by a 140-pound weight falling 30 inches. After an initial set of B inches, the number of <br /> blows required to drive the sampler an additional 12 inches is recorded. This number, <br /> "N", is called the penetration <br /> resistance. The N value is used as an empirical measure <br /> of the relative density of cohesionless soils and the consistency of cohesive soils. <br /> To reduce crass-contamination between samples, the split-barrel sampler is washed in <br /> a tri-sodium phosphate solution and double-rinsed between each sampling event. Upon <br /> recovery, a portion of the soil sample is placed in a capped brass tube for later screening <br /> ortion of the soil sample is used <br /> with a portable photcionization detector (PID). Another p <br /> for classification and description. The portion of the sample held within the brass tube <br /> is stored at approximately 40 C for transport to the laboratory. <br /> Soil Classification <br /> As the samples are collected, they are classified by the field engineer or geologist using <br /> the Unified Soil Classification System. Boring logs are maintained during the sampling. <br /> The logs indicate the depths of the sc mples and the various strata encountered by the <br /> boring. The also include pertinent information relating to the drilling operation. When a <br /> well is installed, the logs will include details of the well completion. <br /> Soil Sam le Screenin by Portable Photoionization Detector <br /> After a soil sample is sealed within a brass tube, it is brought to ambient temperature and <br /> the head space within tube is measured for concentrations of organic vapors using a PID. <br /> The PID is equipped with a 10.2 Ev lamp calibrated to Isobutylene for direct reading in <br /> est observed reading is recorded on the boring log. <br /> parts-per-million. The high <br />