ARCHIVED REPORTS XR0003352 - Laserfiche WebLink

Home Browse Search

Collected depth discrete soil and groundwater samples from separate borings situated immediately adjacent to each CPT boring location Prior to implementation of field activities, drilling permits were obtained from SJCEHD and an encroachment permit was obtained from the City of Stockton Drilling locations were marked 48 hours prior to fieldwork Underground Service Alert, SJ'CEHD, the City of Stockton, ExxonMobil, and ETIC Engineering, Inc , the consultant currently representing Exxon/Mobil, were notified 48 hours prior to beginning work activities Field practices and procedures utilized during this investigation are described in Appendix A All work was conducted under the direct supervision of a State of California Professional Geologist Copies of the drilling permits and encroachment permit are provided in Appendix B Field Activities CPT Testing and Direct Push Sampling A Stratus geologist was on-site to oversee Gregg In Situ, Inc (C-57 #656407) of Martinez, California, complete the CPT testing and direct push sampling between September 6 and 12, 2005 The CPT method consists of advancing a cone-tipped cylindrical probe (1 7 inches in diameter) into the ground while simultaneously measuring the resistance to penetration The CPT method estimates soil lithology by comparing the force (cone bearing pressure) required to advance the probe (Qt) to the friction ratio (Rf) [(Rf equals sleeve friction (FS) divided by the probe tip load times the penetration pore pressure (Ud)] A graphical diagram illustrating CPT interpretations of soil types is included in Appendix C Computer generated CPT logs were plotted in the field to provide a graphical log of subsurface soil lithology The CPT test data report, which includes logs of all CPT data, graphical geologic logs, and additional information on the CPT technique, is presented in Appendix C CPT tests were performed in accordance with American Society of Testing and Materials (ASTM) Method D3441 The approximate locations of borings CPT-1 through CPT-7 are included on Figures 2 and 3 Following advancement to total depth, each borehole was backfilled with neat cement to surface grade Groundwater samples were collected ftom a separate boring, directly adjacent to the CPT boring, using the HydropunchTM technique Water samples were collected by pushing the HydropunchT sampler, with 2-inch diameter steel rods, to the bottom of the borehole The CPT operator subsequently pulled up on the steel rods, exposing a 4-foot long PVC screen at the desired sampling interval Samples were collected by lowering a metal bailer within the steel rods Groundwater was collected in the bailer and placed in glass sample containers containing a hydrochloric acid preservative Following collection, the samples were placed in an ice-chilled cooler Each sample was appropriately labeled and identified on a chain-of-custody form A diagram illustrating the HydropunchT sampler utilized by Gregg In Situ, Inc is included in Appendix C Soil samples were collected from the same boring as the groundwater samples Soil samples were collected by driving a 1 7-inch diameter piston sampler, equipped with two pre-cleaned 1 25-inch diameter by 6-inch long brass sleeves, into undisturbed soil Additional sleeves of soil collected at each sampling interval were field screened for volatile organic compounds (VOCs) using a photwomzation detector (PID) The soil samples were also classified using the Unified K\USA Gasolme1Q835\Reports\nsa835 scm-assessment-report doc Page 6 5TRA WS