HEC-RAS模型在二维溃坝洪水研究中的应用

为准确模拟大坝失事后溃坝洪水的下游演进，运用HEC-RAS二维水动力学模型，修正面板坝溃口发展曲线，设计两种闸门开度的小井沟面板坝漫顶溃坝工况，模拟水库泄洪影响下溃坝洪水的下游演进并生成相应的洪水风险图、最大流速分布图、滞留时间图。研究结果展现了溃坝洪水在中下游平原丘陵地区的泛滥情况、洪水风险的分布差异以及水库泄洪对溃坝洪水的影响。分析得出不同闸门开度下溃坝洪水在中下游平原丘陵地区的淹没水深和范围差异明显，最大流速和洪水滞留时间区别不大, 说明水库全力泄洪能有效降低溃坝洪水对下游人员聚居的平原地区的危害。研究成果对后续的人员疏散和损失估计具有重要参考意义。

Application of HEC-RAS for the research of 2D dam-break flood

In order to accurately simulate the downstream flood routing of the dam-break flood after dam breach, the two-dimensional (2D) hydrodynamic model with HEC-RAS software is used to modify the breach progression curve of the rock-fill dam with face slab and design the working conditions of the overtopping of the Xiaojinggou concrete-faced slab dam with two gate openings. And the model is also used to simulate the downstream flood routing of the dam-break flood under the influences of reservoir flood discharge and generate the corresponding flood risk maps, the maximum velocity distribution maps and the flood detention time maps. The simulation results show that the submerged depth and scope of the dam-break flood in the plain and hilly areas of the middle and lower reaches vary greatly under different gate openings, and the maximum flow velocity and the flood detention time have little difference. From the simulation and analysis results it is found that the reservoir flood discharge can effectively reduce the threats of the dam-break flood to the people's lives and property in the downstream plain areas. The simulated results have important reference values for the evacuation and loss assessment of the dam-break flood.