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Md Work Plan—Additional Soil and Groundwater Investigation CSUS—Multi-Campus Regional Center October 5,2001 Page-3- proposed CPT boring locations are shown in Figure 3, Appendix A. It is possible that the borings will be terminated at refusal before the boring reaches a depth of 75 feet. The borings will be advanced in pairs, for a total of six borings. The first boring of each pair will be used to log the geology of the site at that location. An electric piezocone will be pushed downward into the subsurface by the CPT rig. Measurements of cone bearing, sleeve friction, and dynamic pore water pressure will be measured at approximately two-inch intervals to provide a nearly continuous hydrogeologic log of the subsurface. The second boring, located within one foot of the first, will be used to collect discrete interval groundwater samples. Sample intervals will be selected based on the data produced by the first boring. Groundwater samples will be collected using a push-type groundwater sampler. The sampler has a sealed, retrievable stainless steel screen. The sampler will be pushed in a closed position to the desired sampling interval. The sampler push rod will then be retracted exposing the inlet screen. Groundwater will flow hydrostatically from the formation into the inlet screen. The groundwater sample will be collected by lowering a stainless steel bailer through the hollow push rods and into the sample screen. The groundwater will be gently emptied from the bailer into the appropriate laboratory supplied containers. The sample containers will be sealed, labeled, placed in a cooler chilled with Blue Ice®, and delivered under chain-of-custody procedures to a California certified laboratory for analyses. t... The piezocone and associated push rods will be thoroughly cleaned before each boring is advanced using laboratory-grade, non-phosphate detergent and de-ionized water and double rinsed with de-ionized water. Upon completion of the boring and sampling, the borings will be grouted with neat cement. The cement will be tremied into the borehole to avoid bridging. 3.3 DIRECT PUSH BORING PROCEDURES Prior to commencement of fieldwork, a tailgate safety meeting will be held and a site-specific Health and Safety Plan will be discussed with, and presented to, all field personnel for their signatures. Four direct push borings will be advanced to an approximate depth of 75 feet bgs. The proposed direct push boring locations are shown in Figure 3, Appendix A. It is possible that the borings will be terminated at refusal before the boring reaches a depth of 75 feet. Three soil samples from each of the four borings will be selected for laboratory analyses based on field observations and field screening with a photoionization detector(PID). The direct push borings will be hydraulically advanced using a 2-inch diameter conical bit. The bit and '—' associated push rods will be thoroughly cleaned before each boring is advanced using laboratory-grade, non-phosphate detergent and de-ionized water and double rinsed with de-ionized water. Upon completion of the boring and sampling, the borings will be grouted with neat cement. The cement will be tremied into the borehole to avoid bridging. Soil samples will be collected from each boring with a 1.75-inch O.D., 4-foot long, core barrel, fitted 6W with a clean, single use, polyethylene liner. The soil sampling equipment will be cleaned prior to collecting each sample using laboratory-grade, non-phosphate detergent and de-ionized water and double rinsed with de-ionized water. V During the sampling, the core barrel will be driven in 4-foot intervals. The sample liner will be extracted from the core barrel and used for geological logging and field observations. The soil samples will be r.+ logged according to the Unified Soil Classification System (USCS). Geological logs will be prepared containing field observations including soil type, estimated moisture content, PID measurements, and the presence of staining or odor. n L1v CONDOR 1.1