滑坡堰塞坝漫顶溃决对外部动力条件的响应机制

Study on the response mechanism of landslide dam failure to external dynamic condition

堰塞湖库容、入库流量等外部动力条件对堰塞坝漫顶溃决过程具有重要影响。本文通过水槽试验,系统研究了不同库容和入库流量条件下漫顶溃决各阶段冲蚀特性变化,以揭示溃决历时和溃口峰值流量对外部动力条件的响应机制。研究结果表明:库容和入库流量通过控制溃决初始阶段堰塞湖水位变化速率,影响溯源冲刷效率,对初始阶段溃决历时产生显著影响;库容和入库流量通过控制溃口侧向侵蚀速率、影响加速冲蚀阶段溃口侧向展宽效率,对溃决峰值流量产生影响;加速冲蚀阶段溃口垂向侵蚀和侧向侵蚀对外部动力条件变化响应不一致,垂向侵蚀过程受到显著抑制。研究成果有助于深入认识堰塞坝漫顶溃决机制,并为相关防洪减灾工作提供参考。

The external dynamic conditions,such as reservoir capacity and inflow rate,significantly impact the overtopping breach process of the landslide dam.This paper systematically investigates changes in erosion characteristics at different stages of the overtopping breach process under various reservoir capacities and inflow rates through flume experiments,with the aim of revealing the response mechanisms of breach duration and peak discharge to external dynamic conditions.The research results indicate that reservoir capacity and inflow rate significantly influence backward erosion efficiency by controlling the rate of water level change during the initial breaching stage of the landslide dam,which affects breach duration.Reservoir capacity and inflow rate affect the peak discharge by controlling the lateral erosion rate of the breach,thus influencing the lateral widening efficiency during the accelerated erosion stage.There is an inconsistent response between vertical and lateral erosion to changes in external dynamic conditions during the accelerated erosion stage,with vertical erosion being significantly more suppressed.These findings contribute to a deeper understanding of the overtopping breach mechanism of landslide dams and provide valuable insights for flood control and disaster mitigation efforts.