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values, when properly evaluated, indicate the relative density or consistency of the materials. Depths at <br />which the samples were taken and the penetration resistance values are shown on the logs of the <br />exploratory test holes in Figure #3. The associated Legend and Notes are shown in Figure #4. <br />After the drilling was completed, temporary PVC casing was installed in three of the test holes so that the <br />groundwater levels and limited slope movement observations could be made. The casing consists of 2 -inch <br />diameter slotted and solid PVC pipe with slotted pipe placed in the lower portions of the test holes and <br />solid pipe placed in the upper portion of the test hole and extending 1 '/z to 2 feet above the existing ground <br />surface. Clean sands were used to backfill the annulus between the slotted casing and edge of test hole; <br />whereas the on -site clays were used to backfill the annulus between solid casing and edge of the test hole. <br />Laboratory Investigation <br />Samples obtained from the exploratory test holes were examined and classified in the laboratory by the <br />NWCC's project engineer. Laboratory testing included standard property tests, such as natural moisture <br />contents, dry unit weights, grain size analyses and liquid and plastic limits. Unconfined- compressive <br />strength tests were also conducted on samples of the soils and bedrock to evaluate the strength values of <br />these materials. <br />The laboratory test results are discussed later in this report and are summarized in the attached Table 1. All <br />laboratory testing was conducted in general accordance with applicable ASTM specifications. <br />Subsurface Conditions <br />The subsurface conditions encountered in the test holes were variable and generally consisted of a layer of <br />man -made fill materials overlying natural sands, weathered claystone and claystone bedrock that extended <br />to the maximum depth investigated in each of the test holes. Graphic logs of the test holes are shown in <br />Figure #3 and the associated Legend and Notes are presented in Figure #4. <br />A layer of man -made fill materials was encountered at the ground surface in all test holes and extended to <br />depths ranging from 5 V2 to 12 feet beneath the existing ground surface (bgs). The fill materials consisted <br />of clays and sands with cobble to boulder sized bedrock fragments. These materials were low to moderately <br />plastic, fine to coarse grained, soft to very stiff, moist to very moist and brown to dark brown in color. <br />Samples of the fill materials classified as SC -CL and CL soils in accordance with the Unified Soil <br />Classification System. <br />Natural sands were encountered beneath the fill materials in Test Holes 1 through 5. The sands extended to <br />depths ranging from 9 to 19 feet bgs in these test holes and were slightly silty to very silty, very low to non <br />plastic, fine to coarse grained with occasional gravels, loose to medium dense, moist to wet and brown in <br />Jab Number 11 -8970 <br />TT\XJCr T Pa 3 <br />