VERIFY THE PREDICTION OF SLOPE FAILURE BY SOIL CREEP WITH LABORATORY EXPERIMENTS

More than a thousand cases of rainfall-induced slope failure occur in Japan every year. Predict the slope failure is social needs. In this paper, we propose and verify a method to predict the instability of the slope surface layer by soil creep combined with the creep theory of metallic materials. To investigate the creep theory affected by soil moisture and deformation and to verify the relationship between creep and soil moisture, and deformation, two kinds of laboratory experiment was conducted to simulate the process of rainfall-induced slope failure, the first one was a multi-layer shear model and the second one was the direct shear test. The soil moisture was controlled by artificial rainfall in the multi-layer shear model, whereas water infiltrates in the direct shear test. The inverse number of velocity calculated by Fukuzono's equation and the surface displacement have been compared; the results show that the tendency of the change of the inverse number of velocity is similar in both model tests. The effect of volumetric water content on the displacement also has been confirmed; when the volumetric water content increased, the displacement trended to start increasing at an accelerated rate. From these results, the prediction of slope failure time can be improved with higher accuracy.