NUMERICAL MODELING OF ANHUI DEBRIS FLOW

A mathematical model is formulated to simulate dam-break transient deb ris flows, in which the debris and water mixture is assumed to be isot ropic and continuous. In terms of its viscoelastoplasticity, a three-d imensional (3D) rheologic model for Bingham body is used to describe t he relationship between the stress tensor and the rate of strain. Only the deformation caused by the deviatoric stress tensor is taken into account. Under the prior considerations, the governing equations for t wo-dimensional (2D) depth-averaged transient debris flows are obtained by integrating the equation of continuity and equations of motion ove r depth for 3D Rows. To deal with the transient and high-speed feature s of dam-break debris flows, the derived governing equations are discr etized and solved using the method of characteristics. The model is ap plied to simulate the dam-break debris Bow of April 30, 1986, for the Jinshan debris reservoir in Anhui, China. The debris and water mixture s reach as far as 900 m downstream from the initial tailings dam site, with a depth of 1.7 m near the tailings dam and 1.0 m at 900 m downst ream. These model results are in good agreement with the available obs ervations.