Abstract: The study of dam break process and dam break flood routing is of great significance for dealing with flood disasters caused by dam break and improving water security. Most models at present could not reflect the interaction between soil and water flow by only simulating dam break process or flood routing, hence resulting in a limited accuracy. In this article, a 2-D numerical model coupling dam break process and flood routing was established in consideration of the finite erosion resistance of soil. The erosion rate expressions of hyperbolic type was employed to describe the rate of dam erosion; simplified Bishop method was adopted to search the critical slip surface for describing slope collapse at breach; and the Mac-Cormack finite volume method with total variation diminishing was adopted to discrete the control equations. A computation example demonstrates that the model could reasonably simulate the process of breach development and the flood routing process with strong stability and good conservativeness in breach transition zone from rapid flow to slow flow. The model can be used as a powerful tool for flood risk assessment and flood disaster forecast.

Key words: dam break process, flood routing, numerical simulation, coupling, conservativeness, finite volume