WORK PLANS - Laserfiche WebLink

Home Browse Search

29 January 2024 AdvancedGeo Project No. 23-7523 An Employee-Owned Company Page 2 of 8 2.0. PROCEDURES Prior to conducting the subsurface investigation, the work area was marked with white paint and Dig Alert - North was subsequently notified for the marking of subsurface utility lines (Dig Alert Ticket No. 2024010301230-000). 2.1. SOIL SAMPLING PROCEDURES On 08 January 2024, four (4) soil borings (V7 through V10) were advanced to 30 feet below surface grade (bsg) for collection of soil samples. Borings V7 through V10 were advanced on the exterior of the building using a GeoProbe 7700 direct-push drilling rig equipped with a 2.25-inch diameter Geoprobe macro core soil sampling assembly loaded with a five-foot-long acetate liner. With the exception of V10, soil samples were collected continuously from all borings from near surface grade to 30 feet bsg. Initially, borings were advanced to five feet bsg using a hand auger. During hand clearing, soil samples were collected at depths of 2 and 5 feet bsg by hand-packing soil into six- inch sections of acetate liners; soil samples were not collected from boring V10 between surface and 15 feet bsg. Upon collection, the ends of each liner were covered with Teflon sheets, capped, and sealed with tape. Each sample liner was labeled with soil boring location, depth, time, date, and sampler's initials and then placed in a chilled container. Soil samples were transported under chain-of-custody to McCampbell Analytical, Inc. (MAI) a California Environmental Laboratory Accreditation Program (ELAP)-certified laboratory. Selected soil samples were analyzed for volatile organic compounds (VOCs) in accordance with EPA Method 8260B. 2.2. SOIL-VAPOR POINT INSTALLATION AND SAMPLING Borings V7, V8 and V9 were converted to triple completed soil-vapor wells with sampling points installed at 5, 15 and 30 feet bsg (V7-A, -C, -D; V8-A, -C, -D; and V9-A, -C, -D). Additionally, boring V10-D was converted to a single-completed soil vapor well with a sampling point installed at 30 feet bsg. For the installation of the triple completed soil-vapor wells (V7 through V9), approximately three (3) inches of #2/12 sand was placed at the bottom of the borehole, from approximately 29.75 to 30 feet bsg, for the vapor implant to be placed upon. Once the sand pack at the base of the borehole was in place, a 1/4-inch diameter, 2-inch-long polyethylene soil-vapor implant and approximately 32 feet of inch Teflon® tubing were lowered to the bottom of the boring. Once the sand, tubing and vapor implant were in place, filter pack of #2/12 sand was added from the bottom of the borehole to approximately 28 feet bsg. Following placement of the filter pack, approximately one foot of dry-granulated bentonite was placed atop of