抄録
Hillside landslides frequently occur in many parts of Japan during the period of heavy rains every year. In making a hillside landslides model and investigating the stability of a mountain slope throgh this model, the results of numerical experiments will be considerably influenced by values of specific characteristics of the soil.
In this study, to comprehend the vertical characteristics of soils on the mountain slope, an investigation into mountain soils was performed. As the result of this investigation, it was confirmed that the mountain slope soil consists of Two layers and that the boundary line exists approximately 50 cm under the surface of the mountain slope. Further, to improve accuracy for predicting hillside landslides through a numerical simulation model, the Two layer hillside landslides model, that considers the surface soil layer on a montain slope as a Two soil layer structure, was proposed. This Two layer model was prepared through improvement of an earlier One layer model that had been proposed. This Two layer model was applied to the basin where many hillside landslides occurred and the following matters were confirmed: a) The Two layer model is available to study in detail the behavior of groundwater level and slope stability and the time when hillside landslides occur, on a specific slope. b) On the other hand, the One layer model is available to study generally the site of hillside landslides and the final distribution of hillside landslides.
