堵塞坝溃决对上游来流及堵塞模式的响应  

The response of upstream flow and blockage patterns to the failure of landslide dam

作　　者：陈华勇[1,2] 崔鹏[1,2] 唐金波[1,2] 周公旦[1,2] 

机构地区：[1]中国科学院山地灾害与地表过程重点实验室,四川成都610041 [2]中国科学院水利部成都山地灾害与环境研究所,四川成都610041

出　　处：《水利学报》2013年第10期1148-1157,共10页Journal of Hydraulic Engineering

基　　金：国家自然科学基金重点项目(41030742);中国科学院重点部署项目(KZZD-EW-05-01);中科院山地所青年基金(SDS-QN-1302)

摘　　要："5·12"汶川地震诱发了大量山体滑坡,导致山区沟道内形成大量松散堵塞坝,其在山洪作用下可能发生溃决,而上游来流及堵塞坝形态对堵塞坝的溃决模式具有重要影响。通过水槽实验研究了不同上游来流条件及堵塞坝形态条件下堵塞坝的溃决过程,将堵塞坝的溃决模式概括为4种:正常溢流、洪水过坝冲刷、无爬高侧蚀以及爬高和侧蚀。研究了不同溃决模式下,堵塞坝的坝体溃决过程和机理,分析了不同溃决模式下溃口流量、溃决历时及溃口发展规律之间的差异。在前人研究成果的基础上,分析了正常溢流模式和无爬高侧蚀模式的溃口发展数值计算模型,借助于Meyer-Peter与Müller泥沙输移公式,计算了洪水过坝冲刷模式下,坝体溃决过程中单宽冲刷率的变化规律,并与实测值比较吻合良好。由于水流与堵塞坝相互作用的复杂性,目前对单个堵塞坝的溃决机制及沟道内多个堵塞坝级联溃决机制等问题的研究仍然不够深入,需要开展大量的研究工作。Enormous landslides were triggered by ＂5＂ 12 Wenchuan Earthquake. A large amount of loose debris distributed randomly in a gully would form landslide dams when the flash flood occurred due to in tense rainfall. The scale of a flash flood and blockage patterns of landslide dams have great effects on the failure of landslide dams. Experimental tests were conducted to record the process of landslide dam failure under the conditions of different discharges of flash flood, semiblockage and fullblockage of landslide dam. Four models of landslide dam failure were defined, including： （1） erosive beach due to overtopping; （2） upstream scour and downstream erosion; （3） sidederosion without climbing up; and （4） climbing up and sidederosion. According to interaction of water flow and landslide dams, the reasons which led to fail ure of the dams were explained by shear failure and impact failure of water flow. The discharge of debris flow, duration of dambreaking, and the development of dam breach in different patterns were analyzed. Ac cording to MeyerPeter, Muller bedload formulas, sedimenttransport per unit width in the upstream scour and downstream erosion pattern was calculated, and the results are in good agreement with the experimen tal ones. Study on the failure of a single landslide dam and cascade failure of dams is not deep enough due to the complex interaction between water flow and landslide dams. Much more research is required to better understand the mechanism of this interaction in the future.

关 键 词：堵塞坝 堵塞坝形态 溃决模式 单宽输沙率 动水压力 

分 类 号：P642.23[天文地球—工程地质学]