Development of two dimensional debris flow model based on quadtree grid structure and its application

The debris flow translated by shallow landslide is one of the main processes changing earth surface and, it is plays critical role in natural hazards. Thus, it is very important to estimate translated and deposited sediment area by the debris flow and, various studies have been performed in many fields. In this study, two-dimensional finite volume debris flow model have developed on rectangular grid with adaptive mesh refinement technique. Shallow water type, vertically integrated governing equation with Voellmy rheological model and simple entrainment model, is implemented to simulate debris flow. Quadtree grid structure was used to support adaptive mesh refinement and the mesh for the simulation is automatically generated as debris flow proceeds. Well-balanced numerical scheme for wet-dry transitions treatment was implemented and implicit discretization for general source term including rheological term was used for numerical stability. The developed model has been verified through the debris flow translated by shallow landslides triggered at Bosung region, 1st July 2018 in Republic of Korea. The debris flow was successfully generated along the area inundated by debris flow adaptively in time and, deposited area was also well matched with the field survey data overall.