12. Imaging/Interpretation Frontiers
Monitoring of Groundwater Behavior on a Rock Slope by Combination Geophysical Prospecting
Makoto Nakamura(1) and Harushige Kusumi(2)
(1) NEWJEC Inc., Japan. (2) Kansai University, Japan.
Abstract
The characteristic of the groundwater flow in a rock slope primarily depends on rock joint sets. In particular, the groundwater flow in a rock slope which has random joint sets is very complicated, and the specific methods which to monitor this flow have not been developed. In our past research, the systematization of geological evaluation technique that converted from seismic velocity and electric resistivity to porosity and saturation was proposed. The outline of proposed evaluation method is shown in the following. Though the seismic velocity and electric resistivity are different physical quantity, these physical quantities can relate the porosity and the saturation of rock masses as a parameter. In this method, the evaluation of the seismic velocity adopts the Wyllie¡Çs equation in 1956, and the evaluation of the electric resistivity adopts the Archie's equation in 1941. These formula are shown respectively as the uniting equation about one which converts porosity and saturation for the ground element (cell which divides into a small section). Therefore, if the resistivity and seismic velocity of the ground are already-known, an unknown porosity and saturation can be obtained from the these formula by the back-analysis (optimization technique). In this paper, using this proposed technique, we tried to monitor the groundwater flow behavior during rainfall in rock slope site by changing of saturation in a rock slope.
Last modified: Tue May 23 14:22:28 2006