WP0039973 - Laserfiche WebLink

Home Browse Search

Geosyntec° C011Sttitattt, If Shelby tube samples of clays and silts have low or no recovery, samples using a Modified California (ModCal) sampler (3-inch outside diameter, 2.5-inch inside diameter) sampler with brass liners will be driven immediately below the depth of the last Shelby tube sample. When encountering cohesionless soils such as sands and non-plastic silts, especially below the groundwater level, a standard penetration test (SPT) sampling without liners in the barrel will be used(i.e.split spoon samplers)in accordance with ASTM D1586. To drive the split spoon samplers, a 140-pound above-ground slide hammer falling 30 inches will be used. If available, a 300-pound hammer will be used. The sampler, blows per 6-inch intervals,and hammer type will be recorded on the boring log. If the sand sample is lost, a sand catcher will be used; the use of the sand catcher will be noted in the boring log. Blow counts will be recorded every 6 inches of penetration on the boring log; the sampler will be driven a maximum of 18 inches at a time(i.e., overdriving of the sampler will not be performed). While the SPT sampler will be driven without liners, the ModCal sampler with liners will be used instead of the SPT sampler if gravels are encountered. All the SPT samples will be contained in double-bagged plastic bags and each 6-inch ModCal liner capped on both ends. The samples will be labeled with the boring number, the interval sampled, and the sampler used. The energy correction calibration of the sampling setup will be measured for the various samplers used or expected to be used(i.e., SPT and ModCal), starting at 5 feet bgs and every 5 feet thereafter at various depths using the rods that will be used throughout the sampling program. Geosyntec will contract with an energy measurement subcontractor to measure the energy at one borehole. Energy measurement is needed for performing a liquefaction evaluation. Geosyntec will store the samples in the shade and covered so that they do not dry out. The tubes will be packed vertically and boxed with the top of the tube up; bubble wrap may be used so that the samples do not bang against each other during handling and shipment. ModCal tubes also need to be stored vertically to minimize disturbance. Plastic bags and ModCal tubes will be placed in boxes for transportation. Geosyntec will assign the geotechnical tests as shown in Table 1. The tests will be performed by an independent geotechnical soil laboratory contracted by Geosyntec. The Shelby tubes and ModCal brass tubes will be stored vertically. Each Shelby and brass tube collected will be capped and labeled with the boring number and the depth interval. The top of each tube will also be marked and the end caps will be taped or hot waxed so that loss of moisture is minimal. Information recorded on labels will be written legibly with ink in a clear and precise manner for proper identification in the field and subsequent tracking. 3.3 Post-Sampling Activities Industrial derived waste (IDW) generated during the proposed investigation is anticipated to include, but may not be limited to: drill mud, decontamination water, disposable sampling implements, personal protective equipment (e.g., disposable gloves), plastic bags, and Pre-Design Data Collection Work Plan 5 July 22,2019