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' 19 July 2004 <br />AGE -NC Project No 95-0121 <br />Page 4 of 9 <br />' ; • Hydrologic Unit S (HUS) - Located between 53 and 100 feet bsg Generally characterized <br />by low to high pore pressures and comprised primarily of less permeable, semi -confining to <br />confining, stiff fine grained, silt, clay and localized silty sand This unit may be generally <br />subdivided with additionaltinvestigation and monitoring, based on the laterally discontinuous <br />sand layers, encountered <br />24 PORE PRESSURE DISSIPATION TESTING <br />} i <br />' Pore pressure dissipation tests were conducted at various hydrologic Intervals (Appendix B) to <br />measure hydrostatic water pressures and approximate depth to ground water (Appendix B) The _ <br />approximate depth to ground water was calculated using the equation <br />Dw = Dcone - Hwater <br />- where Dw= Depth to Ground Water (ft) <br />Done = Depth of CPT Tip <br />'. Hwater = Hydrostatic Water Head (1 psi = 2 31 ft) <br />Pore pressure dissipation testing was conducted in the following Informal hydrogeologic units <br />"4 ' <br />• CPT -1/30 ft (HU2) - Pore pressure appeared to stabilize at approximately 4 31 psi after 590 <br />seconds, depth to ground water was calculated at 20 31 feet bsg <br />'0 6PT-1142 ft (HU4) - Pore pressure appeared to stabilize at approximately 8 36 psi after <br />1,200 seconds, depth to ground water was calculated at 22 85 feet bsg <br />' CPT -1/80 ft (HU5) -Pore pressure appeared to stabilize at approximately 25 2 psi after 645 <br />i seconds, depth to ground water was calculated at 22 15 feet bsg " <br />' CPT -2/46 ft (HU4) - Pore pressure appeared to stabilize at approximately 10 82 psi after 845 ; <br />seconds, depth to ground water was calculated at 2143 feet bsg <br />• CPT -2147 ft (HU4) Pore pressure appeared to stabilize at approximately 11 psi after 470 <br />seconds, depth to ground water was calculated at 22 36 feet bsg <br />• CPT -4151 ft (HU4) - Pore pressure appeared to stabilize at, approximately 13 1 psi after 385 <br />seconds, depth to ground water was calculated at 21 09 feet bsg <br />I t <br />i Advanced GeoEnvironmentai, Inc <br />i <br />r <br />