Three-dimensional numerical simulation of debris flows and its applications

A numerical program designed for field application is developed in this paper. We use the generalized Julien & Lan (1991) rheological model to simulate debris flows. A scale analysis is performed to prove that a strong thin shear layer near the bottom (the boundary layer) and a thick weak stress layer (the plug layer) can be separated mathematically. Therefore, we can first solve the plug flow layer solution and then correct the solution with the boundary layer solution. A numerical scheme with upwind method and central difference in space and Adam-Bashforth 3(rd) order scheme in time is used for both layers. The scheme is tested against analytical solutions and laboratory experiments with very good results. Application to the field, Shen Mu village which has more complicated geometry, also achieves good agreement compared with in-situ measurements.