HYDRAULIC EXPERIMENTS ON THE FAILURE MECHANISMS OF LANDSLIDE DAM DUE TO OVERFLOW UNDER DIFFERENT INFILTRATION CONDITIONS

Abstract

 When a landslide dam collapses due to flooding, severe damage occurs at the downstream. For this reason, the measures for collapse of landslide dam are being implemented immediately. However, the difference of the destruction phenomena caused by the infiltration situation of the reservoir water impregnated upstream of the dam into the soil mass of the landslide dam has not been clarified. In the Hidakahoronai river, the largest landslide dam at the 2018 Hokkaido Eastern Iburi Earthquake was formed, and a detailed investigation was conducted by the Hokkaido Development Bureau. In this study, hydraulic experiments, in which the experimental conditions, were set based on the result of this investigation were conducted and the influence of the infiltration condition into landslide dam on the erosion phenomena of landslide dams due to overflows was discussed. As a result, it was confirmed that the situation of collapse changes greatly due to the difference of penetration, and the progress speed of the phenomenon also changes greatly depending on the way of collapse.