基于物理模型的唐家山堰塞湖溃决过程模拟

Physically based simulation of the breaching of the Tangjiashan Quake Lake

针对水动力条件复杂变化、水土耦合作用强烈的堰塞湖溃决过程,采用修正HLL(Harten-Lax-van Leer)格式离散水流演进方程,基于颗粒流的方法来描述强非恒定流下的泥沙选择性输移和床面形态变化,发展了基于物理机制的溃决过程模拟模型。模型应用于唐家山堰塞湖溃决过程的模拟,很好再现了溃决洪水流量过程线、溃口展宽和下切过程,验证了模型合理性和应用潜力。

Dam breaching is a complicated process involving rapidly changing flows and intense sediment transport over complex topographical boundaries.This paper presents a physically based numerical model to simulate the dam breaching process.The model features not only an improved HLL（Harten-Lax-van Leer） scheme to characterize the dam-break flow over rapidly varying topography with steep slopes and sudden expansions and contractions,but also a particle-based method to quantify selective sediment transport and bed form evolution for strongly unsteady flows.Simulation of the breaching of the Tangjiashan Quake Lake showed that the model reasonably reproduces the dam-break hydrograph,breach widening and breach progression process and is applicable to quake lakes.