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603284-001 <br />being incrementally advanced. The ModCal sampler has an outside diameter <br />(OD) of 3.0 inches and is lined with 12 1-inch-high by 2.41-inch inside diameter <br />(ID) sampling rings and one 6-inch-high by 2.41-inch ID barrel. Six rings were <br />chosen from the twelve containing the relatively undisturbed sample and were <br />placed in PVC containers, labeled and transported to our geotechnical <br />laboratory. <br />The SPT samples were obtained by driving a Standard Penetration Test sampler <br />into the bottom of the boring as it was being incrementally advanced. The SPTs <br />were performed in general accordance with ASTM D1586. The sampler did not <br />include a liner. Samples of the materials obtained from the SPT sampler were <br />placed in plastic bags, labeled, and transported to our laboratory. <br />Both the ModCal and SPT samplers were generally driven a total of 18 inches <br />unless practical refusal was encountered, or other conditions precluded driving <br />the sampler farther. The number of blows under a 30-inch drop of the 140-pound <br />automatic hammer to achieve a 6-inch penetration was recorded. The blow <br />counts provide a measure of the density or consistency of the soils. The number <br />of blows to achieve each 6 inches of penetration is indicated on the boring logs. <br />The borings were logged by a certified engineering geologist, who also <br />coordinated drilling operations and collected the soil samples.Visual <br />observations were made of the materials at each sampling depths. The earth <br />materials were classified visually, in general accordance with the Unified <br />Classification System (USCS). Stratification lines on the logs represent the <br />approximate boundaries between predominant types of materials. Stratification <br />may contain differing materials, with transitions generally occurring gradually. <br />Task 3 - Field Percolation Tests <br />Two borings designated for field percolation testing, B-8 PERC-1 and B-9 PERC- <br />2 (Appendix B), were converted to test wells upon completion of drilling and <br />sampling activities. The wells were then soaked overnight prior to percolation <br />testing. The details of percolation testing performed in the field are as follows: <br />• Boring B-8 PERC-1 and B-9 PERC-2 were drilled to depths of approximately <br />10 and 5 feet below existing grade, respectively (Figure 2). A 2-inch diameter <br />Schedule 40 polyvinyl chloride (PVC) section of 0.020-inch slotted pipe was <br />installed to the bottom of the borings. A filter pack consisting of %-inch clean, <br />-3- <br />Leighton