中文摘要：

泥石流运动数值模拟是确定泥石流泛滥范围、进行危险性分区、辅助减灾工程设计与检验的重要方法。以西藏波密古乡沟为实例，从泥石流的二维运动方程出发，使用一种新的数值方法对古乡沟50α一遇泥石流在堆积扇上的运动过程进行了数值模拟，获得了其最大流速、流深、动量和动能的空间分布，并据此确定了受泥石流危害较小的川藏公路穿越堆积扇方案。将泥石流数值模拟结果与游勇等1997年做的模型试验结果进行了比较，具有较好的相似性。

英文摘要：

Numerical simulationof debris flow is an important method for predicting debris flow inundation region, making debris flow risk zoning and aiding the design of debris flow control works. Debris flow is assumed as a single-phase flow and it follows Navier-Stokes equation. The vertical velocity can be neglected in the simulation because it is very small comparing the horizontal velocity. So the two-dimension movement of debris flow can be described with Saint-Venant equation. In order to check the velocity of debris flow numerical simulation result, Guxiang Valley, a typical debris flow valley located in Bomi, Tibet along the highway from Chengdu to Lhasa, is selected as a case study to develop numerical simulation. The numerical simulation of the debris flow with 50 years returning period is developed with the two-dimension model of debris flow movement in Guxiang Valley. The results of debris flow numerical simulation and the model testing carried out by Yong You et al （1997） in Guxiang Valley are compared. The conclusion is make out as following： the result of debris flow numerical simulation is similar to that of model testing, and debris flow numerical simulation is a good method to check or replace debris flow model testing. In addition, a modified route scheme across the fan has been made based on the numerical simulation.