Outburst flood of landslide dams induces catastrophic disasters. It's necessary to investigate into process of overtopping erosion and sediment transport to estimate at downstream disasters by overtopping erosion of landslide dam. The numerical simulation model concerning the overtopping erosion of a landslide dam has been proposed so far by Satofuka et al. and the applicability has been shown about the hydrograph and the peak discharge rate. However, the side bank erosion rate was given experienced constant, and there was a problem that the way to give the constant was difficult. The erosion of the bed progresses by overtopping and the phenomenon of the side bank collapses along with it is confirmed by the hydraulic model experiment. On the other hands, it has been proposed two]layer flow model applied to the two]dimensional numerical simulation by Takahama et al. So in this study, we applied slope collapse model proposed by Sekine to the model. As a result, The process which the erosion of the bed by overtopping, and the phenomenon of the side bank collapses along with it was able to be reproduced by considering the slope collapse of the side bank in the numerical simulation.


Key wordsFlandslide dam, numerical simulation, two layer flow model, slope collapse, overtopping erosion