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Additional Soil and Groundwater Investigation Re r po t Canepa s Car Wash(Park Street) July 12,2004 Page 3 . 3 0 FIELD AND ANALYTICAL METHODOLOGY This section includes a description of the site preparation, CPT boring procedures, direct push (hydropunch) groundwater sampling and soil sampling procedures, and laboratory analytical methodology 3 1 SITE PREPARATION Appropriate permits were obtained from the SJCEHD, the City of Stockton, and Caltrans prior to conducting the fieldwork The boring locations were marked with white paint, and Underground Services Alert (USA) was notified at least 48-hours in advance of the fieldwork to locate and identify I underground utilities in the vicinity of the work area The SJCEHD, City of Stockton, and Caltrans were notified of the fieldwork schedule at least 48 hours in advance of field activities 3 2 CONE PENETROMETER AND DIRECT PUSH PROCEDURES Prior to conducting investigation activities, an on site tailgate safety meeting was held with all drilling and Condor field personnel in attendance A site-specific Health and Safety Plan was discussed with and presented to all personnel for their signatures Fugro Geosciences, Inc (Fugro) of Oakland, California installed five CPT/hydropunch boring pairs and a single soil boring at one of the CPT locations CPT borings CPT3 through CPT7 were hydraulically advanced from the ground surface to the target depth of approximately 150 feet CPT drilling refusal was met at depths between approximately 102 and 107 feet bgs in three of the five CPT borings Measurements of the soil response to cone bearing pressure, sleeve friction, and dynamic pore water pressure were recorded at approximately two-inch intervals to provide a nearly continuous interpretive stratigraphic log of subsurface soil conditions based on soil behavior type classification charts The CPT borings were abandoned following completion by grouting with a tremie pipe from the bottom of the boring to the ground surface Groundwater samples were obtained by hydraulically advancing the hydropunch sampler with a disposable point and PVC screen near the CPT boring At the desired sampling depth, the sampler push rods were pulled back, allowing the point to drop off and exposing approximately four feet of sampler inlet screen to the formation The groundwater flowed hydrostatically into the inlet screen and samples were collected using a stainless steel bailer lowered through the push rods into the sample screen Following sample collection, the push rods were retrieved, the push rods and stainless steel bailer were steam cleaned to prevent sample cross-contamination, a new disposable push-point and screen were placed over the end of the hydropunch sampler, and the sampler was hydraulically advanced through the same bore hole to the next desired sample depth Hydropunch sampler refusal was met between 102 and 109 feet in four of the five hydropunch borings The hydropunch borings were grouted with a tremie pipe from the bottom of the boring to the ground surface upon completion of sampling One soil boring, B2, was advanced using direct-push sampling techniques The soil boring was sampled using a piston type soil sampler that was advanced to the desired sample depth, a retrievable tool was lowered down the rods to disengage the latching mechanism on the piston, the piston pulled back allowing the sampler to opening, and the sampler advanced one foot to retrieve the sample After sample retrieval, the sampler was reinserted in the down-hole rods and advanced to the next sample location The push rods and other down-hole equipment were decontaminated between sampling events by steam • cleaning to prevent cross-contamination �� CONDOR