摘要
堰塞坝冲刷溃决及溃决洪水演进过程十分复杂,其溃决洪水对下游人民生命财产构成巨大威胁。利用数值分析方法对大型滑坡堰塞坝的溃决演进过程进行模拟和重演,对堰塞湖下游的避险与防灾减灾具有重要指导意义。以2018年金沙江“10·11”白格滑坡堰塞湖为例,基于无人机获取的地形数据,建立白格滑坡堰塞坝的三维数值模型,采用Flow-3D软件对堰塞坝的自然泄流冲刷溃决过程进行模拟,分析泄流槽内的流速、冲淤变化特征以及下游溃口处的洪峰流量演变过程。模拟结果表明:堰塞坝漫顶冲刷可以划分为溃决冲刷前、溃口快速拓展阶段、洪峰时刻、溃口稳定发展阶段4个时间段;溃决泄流过程中,泄流槽斜坡道上的水流流速较大,冲刷深度最大,堰塞坝下游出现明显淤积;白格堰塞湖溃决过程中出现了明显的溯源侵蚀现象,在泄流槽不断下切的过程中,泄流槽跌坎不断向上游移动。模拟结果有助于进一步深化对金沙江“10·11”白格滑坡堰塞坝冲刷溃决过程和机理的认识,对于堰塞湖应急处置措施和科学避险方案的制定具有一定的参考价值。
Outburst flood of the landslide dam poses a great threat to the life and property of the people downstream.Also,the processes of dam erosion and flood evolution are very complicated.Thus,using numerical methods simulate and repeat the typical landslide dam breaching has a great significance for disaster prevention and mitigation in the downstream.This study focuses on the“10·11”Baige landslide dam on the Jinsha River in 2018.A three-dimensional numerical model of the Baige landslide dam is established with the terrain data acquired by UAV,and the processes of dam discharge,scour and breaching are simulated using the Flow-3D software.The velocity and sediment scour in the natural spillway are analyzed,and the peak discharge process at the downstream is measured.The results show that overtopping and scouring of the Baige landslide dam can be divided into four phases,i.e.before the outburst,rapid expansion phase,peak discharge phase and breach steadily-developing phase.The velocity of flow on the ramp of spillway was large during the releasing period,which led to a maximum scour depth,while deposition occurred at the downstream of the dam body.There was an obvious headward erosion in the breaching process,the spillway bed was incised continuously which led channel bed drop-off moving to the upstream.This study is significant for understanding the process and mechanism of the“10·11”Baige landslide dammed breaching,which could provide references to the emergency treatment and rescue plan formulation.
作者
谢忱
陈骎
侯奇东
胡宇翔
周家文
范刚
XIE Chen;CHEN Qin;HOU Qidong;HU Yuxiang;ZHOU Jiawen;FAN Gang(College of Water Resource and Hydropower,Sichuan University,Chengdu 610065,China;State Key Laboratory of Hydraulics and Mountain River Engineering,Sichuan University,Chengdu 610065,China)
出处
《人民长江》
北大核心
2021年第8期22-29,共8页
Yangtze River
基金
国家重点研发计划项目(2018YFC1508601)。
关键词
堰塞坝
冲刷溃决
洪峰流量
溃口演变
数值模拟
白格堰塞湖
landslide dam
erosion and breaching
peak discharge
breach evolution
numerical simulation
Baige landslide dammed lake
