Study on progressive failure of a landslide dam
Shoki TAKAYAMA, Masamitsu FUJIMOTO and Yoshifumi SATOFUKA
Landslide dam outburst floods can cause catastrophic damage to downstream areas. Therefore, it is necessary to predict the area affected by such flooding when large-scale landslide dams are found. There are three types of a process leading to landslide dam outburst : erosion due to overtopping, instantaneous slip failure, and progressive failure. Numerical simulation models of erosion due to overtopping and instantaneous slip failure have been previously developed. However, few studies have been conducted on a numerical simulation model of progressive failure. In this study, we conducted small-scale flume experiments on progressive failure of a landslide dam and investigate the process of dam deformation. The results showed that a partial collapse proceeded upward rapidly when groundwater level was high. Furthermore, the large-scale slip of a landslide dam increased the peak discharge rate. Based on the results of these experiments, we developed a numerical simulation model of landslide dam progressive failure. We then verified the model by comparing its results with the experimental results ; the model reasonably reproduced the dam deformation process and outflow hydrograph.
Landslide dam, progressive failure, flume experiment, numerical simulation, sensitivity analysis