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Unformatted text preview: ohms) which changes with length (L) and cross-sectional area (A) of (3-D) medium. (figures from USACOE manual) Calculate resistivity (ohm-cm,ohm-ft)- an intrinsic soil RA ~ property: p = L ELECTRODE ~PACING b. APPARENT RESISTIVITY Typical resistivity values: Wet to moist clay Wet to moist silty clays & silts Moist to dry silts & sands Well fractured to slightly fractured bedrock wI moist soil filled cracks Sand & gravel wlsilt Slightly fractured bedrock wI dry soil filled cracks, Sand & gravel wlsilt layers Massive bedded and hard bedrock, Coarse dry sand and gravel 5-100hm-ft 10-50 ohm-ft 50-500 ohm-ft 500-1,000 ohm-ft 1,000 ohm-ft 1,000-8,000 ohm-ft 8,000+ ohm-ft...
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- Fall '08