2010 年 6 巻 1 号 p. 7-11
A large number of the shotcrete slopes constructed during Japan’s post-war economic boom are now more than 30 years old, and their structural deterioration is an ongoing problem. Therefore, it is necessary to accurately assess the stability and durability of these existing slopes. In this paper, we propose a technique to evaluate rock weathering and groundwater fluctuation behind the slope using a conversion analysis of seismic velocity and resistivity to porosity and water saturation of rocks. In the conversion analysis, porosity and water saturation of rocks are estimated with a non-linear optimization method based on the empirical relations of seismic velocity and resistivity to porosity and water saturation. This proposed technique was applied to a shotcrete slope along a road and verified with boring data. The porosity and water saturation estimated with the conversion analysis of seismic P-wave velocity and resistivity measured at the slope were interpreted to evaluate the rock grade and groundwater distribution of the rock behind the shotcrete slope. The interpretation was verified with the boring data to clarify the applicability of the proposed technique.
