Modelling of avalanche-obstacle interaction using the depth-averaged continuum approach

摘要

The present paper adopts the dimensionless depth-averaged continuum model for avalanches to study interactions between an avalanche and obstacle. Three approaches are used to represent the effect of an obstacle on an avalanche. The first is to include the obstacle as the terrain, the second is to exclude the obstacle from the computation domain, and the third is to define the avalanche-obstacle interaction force with a new mathematical expression proposed in this paper. Combined with the three obstacle treatment approaches, we simulate the flow process of an avalanche bypassing different heights of obstacles placed either in the inclined plane or deposit zone. Hydrodynamic model and S-H theory are comparatively studied in the simulation of an avalanche bypassing a high dam in the inclined plane. In the simulation of avalanche striking a low dam in the inclined plane, the first and third obstacle treatment approaches are systematically compared. The effect of the coefficient of friction acting between the side walls and avalanche and the effect of the angle of basal friction are investigated by fixing a cuboid in the deposit zone. Graphic abstractComputed deposit configuration (a); computed sequences at four time points represented by different colors (b); grains overtopping a dam as captured adopting the third approach of obstacle treatment (c); the evolution of avalanche depths with different drag coefficients during the flow process at two positions (d)