Development and application of gui equipped 1-d and 2-d debris flow simulator, applied to mixed-size grains

Abstract

Debris flows often cause substantial losses to human life and the economy. The amount of damage can be effectively reduced using numerical simulation models, which can describe the debris-flow process and determine the possible effects of sabo dams or erosion and sediment control dams. Although various models have been developed, many existing debris-flow numerical simulations do not have ef cient graphical user interfaces (GUIs). In addition, actual debris flows are composed of mixed grain-size sediment, which causes sediment sorting, while many simulation models have been developed only for uniform-sized gravel. Here, we report the development of a GUI-equipped one and two-dimensional (1D and 2D, respectively) debris-flow simulation system for mixed-size gravel. The model uses two layers in 1D simulations to account for debris-flow sediment sorting, and can also examine the effect of closed, slit, and grid sabo dams. The model can incorporate multiple dams and combinations of different types of sabo dams. We simulated a debris-flow disaster that occurred on September 6, 2005, in Miyajima, Hiroshima Prefecture. Although two sabo dams were present along the torrent, a large amount of damage was caused in the nearby residential area. We considered these existing dams in our simulation. Our results demonstrated that applying the mixed grain-size sediment model provided a more realistic description of the debris-flow deposition than uniform-sized gravel models. Furthermore, our GUIequipped system enabled the user to input the data easily and to understand the results instinctively from the animated graphical results. Thus, the interface enables users to run high-quality debris-flow simulations easily and leads them to better solutions for sabo engineering.