极端条件下堆石坝溃坝风险及应急预案

Dam-break risk and emergency plan of a rockfill dam under extreme conditions

考虑洪水漫顶条件下的溃决模式,拟定汛限水位、校核洪水位与校核洪水流量、多年平均入库流量的极端组合方式,采用DB-IWHR模型计算堆石坝溃坝洪水过程;利用MIKE 21模拟洪水演进过程,取支流历史最大洪水过程并使其与干支流洪峰遭遇,评估洪水对下游的淹没风险。以涔天河大坝为例,根据库容、堆石材料参数等确定不同入库洪水组合方式及坝体侵蚀特性,结果表明:构建的溃坝及洪水演进模型能较好模拟溃坝过程及溃坝洪水对下游的淹没风险特征。最后提出库坝安全运行建议,并制定避洪转移预案。

Taking a rockfill dam as a research object,the collapse modes of flood overtopping were considered.The flood process of rockfill dam break was calculated by DB-IWHR model under extreme conditions of the combination for flood limit water level,checked flood water level,checked flood discharge and multi-year average inflow.Flood evolution process was simulated using MIKE 21 to assess the downstream risk of flood inundation by taking the maximum discharge processes of historical floods of tributaries encountered with the flood peak of the main stream.The Centianhe Dam was selected as an example,in which different combinations of inflow floods and dam erosion features were determined according to the reservoir capacity and rockfill material parameters.The results show that the proposed dam break and flood routing models can effectively simulate the process of dam break and the characteristic of flood inundation risk in the downstream region.Finally,suggestions for safe operation of the dam are put forward and plans for flood avoidance and personnel transfer are correspondingly formulated.