02-14-1994 Council Packet - Laserfiche WebLink

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City of Orooo Public Works DqwtmeiU: Project No. CMKX-93-0163 January 28. 1994 Pages D.Methods SoQ Borings and Monitoring Well instiDation The penetration test borings will be pcffcnned with a truck-mounted core and auger drill using 6 1/4-inch auger. All down-hole equipment will be steam cleaned prior use, ai^ clean auger will be used for each bordiole. Sampling for the borings will be conducted in accordance with ASTM D 1586 'Penetration Test and Split-Barrel Sampling of Soils.' Using this method, the bore hole will be advanced with the hollow-stem auger to the desired test depth. Then, a 140-pound hammer falling 30 inches will drive a standard, 2-inch OD, split- barrel sampler a total penetration of 1 1/2 feet below the tip of the lead fl’ght of the hollow- stem auger. The blows for the last foot of penetration will be recorded and are used as an index of soil strength characteristics and for stratigraphic correlation. Samples will be taken at 2 1/2-foot vertical intervals to the termination depth of the borings. The monitoring wells will be constructed of two-inch schedule 40 PVC riser pipe and lO-foot, schedule 40, 0.010-inch slot screens. A six-inch protective casing with locking cover wHI be embedded in the surface seal around each monitoring well for protection. A typical well construction diagram is Included in Appendix B. Soils Classification Soils encountered in the borings will be visually and manually classified in the field by the crew chief in accordance with ASTM D 2487 'Classification of Soils for Engineering Purposes' and ASTM D 2488 'Description and Identification of Soils (Visual and Manual Procedure).' All samples will then returned to the lalK»ratory for review of the field classifications by an environmental geologist. Representative samples will remain in our office for a period of 60 days to be available for examination. Organic Vapor Screening During the field investigation, soil samples will be examined visually by an environmental geologist for staining or other apparent signs of contamination. In addition, soils will be scanned for the presence of organic vapors using a photoionization detector (PID). The PID will be equipped with a 10.2 eV lamp and will be calibrated to a benzene standard. Jar Headspace Procedures Soils rec'^vered from the split-barrel sampler will be additionally analyzed with a PID using jar headspace procedures. The jar headspace procedure consists of placing the soil sample to half-fill a 250 ml clean glass jai. The opening of the jar is subsequently covered with aluminum foil and the cap tightly screw^ on. The jar is vigorously shaken for 15 seconds and allowed to set for at least 10 minutes. Following the 10-minute period, the sample jar is again vigorously shaken for 15 seconds. The cap is then unscrewed and the PID probe is inserted one-halt of the headspace depth. The highest reading observed on the PID is then recorded.