ARCHIVED REPORTS XR0009635 - Laserfiche WebLink

Home Browse Search

i City of Stockton A68104 01A October 25, 1995 Page A-2 It is then driven 12 inches deeper by repeatedly dropping a 140-pound weight from a height of 30 inches The number of blows required to advance the sampler 12 inches is recorded on the boring logs as "blows per foot" This information is used in estimating soil density Soil samples are examined for the purpose of preparing lithologic logs Soils are logged consistent with the Unified Soil Classification System (USCS) The soil boring logs note soil types encountered at depth including consistency, soil moisture, particle size, color, and other distinguishing features The soil samples are field screened for evidence of volatile organic chemicals (VOCs) and/or other contaminates The field screening consist of, visual observation for straining or free fluids, unusual odor, and head space analysis using a photoionization detector (PID) or drager tube The procedure for performing head space analysis are describe in a subsequent paragraph (if pertinent to this investigation) Generally, soil samples selected for analyses typically represent those which the field screening indicated will be most likely to contain the contaminate of concern In most instances the deepest two samples and/or and sample collected from just above groundwater are selected for analyses Samples intended for chemical analyses are sealed with Teflon tape and plastic end caps, labeled, placed on ice, and delivered to a laboratory, along with chain-of-custody documentation The soil borings may be completed as groundwater monitoring wells, or abandoned by grouting with a 6-sack cement slurry Abandonment procedures depend upon the boring depth, depth to groundwater, project objectives, and regulatory requirements For borings greater than 15 feet deep, grout is emplaced through the hollow augers or a tremae pipe which will extend to within 15 feet of the bottom of the boring The slurry is pumped through the annulus in the hollow-stem augers or the tremae pipe Backfill is placed in one continuous operation from the bottom to the top of the borehole When the annulus/borehole fills with the slurry, auger flights or tremae pipe sections are removed (no more than 10 feet at a time) from the borehole, allowing the slurry to uniformly fill the borehole to the surface SOPs for groundwater monitoring well installation are described in a subsequent paragraph (if pertinent to this investigation) Soil cuttings generated during drilling are containerized in properly labeled, United States Department of Transportation (DOT)-approved drums, or placed on and covered with plastic sheeting, and stored on site in an area inaccessible to the general public Typically, the stockpiled soil is characterized by collecting and analyzing composite samples from the stockpile Twining can recommend an appropriate method for disposition of the cuttings based on the analytical results Disposal will be the responsibility of the client A-2 Standard Operating Procedures for Groundwater Monitoring Well Installation Twining is a C-57 licensed water well drilling contractor (Contractor's License No 506159) The groundwater monitoring wells are installed under the direction of a California