汶川地震大型崩滑堆积体转化为泥石流机理研究

Abstract：The wenchuan earthquake induced many landslides and rockfills, which causes a large deposits of loose granular materials with an amount of about 7.5 billion cubic meters in the disaster area. The surface runoff can easily induce erosion and debris flow in the loose granular deposits. In August 2010, in the disaster area of Sichuan province, a huge debris happened two years after the earthquake. This research will be focused on experimental and theoretical study of the initiation mechanism of this erosion-induced debris flow. First, the physical and mechanical behavior of the loose deposits will be studied. Second,flume test,centrifuge tests and in situ tests will be carried out to study the initiation mechanism of the debris flow. The relationships between the erosion rate and theinfluencing factors will be studied and a new erosion function will be raised. The influencing factors include the density, the grading, the initial water content,the clay content of the deposits, the runoff and the slope. The rainfall intensity and the runoff, the previous accumulative rainfall and the intial water content will be linked. Based on the experimental results and the erosion function, a new early warning model will be raised with the creterias of previous accumulative rainfall and rainfall intensity.

汶川地震引发的大量滑坡、崩塌灾害在地震极重灾区形成了约75 亿立方的松 散崩滑堆积体。这些松散崩滑堆积体在地表径流冲刷作用下很容易产生底蚀和侧蚀而形成大 型泥石流。2010 年8 月四川省地震极重灾区，在暴雨后集中爆发了震后大型泥石流灾害（8.13 特大泥石流灾害）。本研究将针对这种震后大型"侵蚀"性泥石流启动机理进行试验和理论 研究。本项目拟首先研究汶川地震大型崩滑堆积体物理力学特性。然后通过室内水槽泥石流启动试验、离心机泥石流启动试验和现场试验研究泥石流爆发的内因（松散崩滑体的密度、级配、初始含水量、粘粒含量）和外因（地表径流量、坡度）与泥石流启动模式和侵蚀率之间的关系，建立"侵蚀方程"。将雨强和地表径流量；前期累计（有效）降雨量与松散堆积体内部的初始含水率联系起来。基于"侵蚀方程"将雨强和前期累计（有效）降雨量为预警判据，建立震后大型泥石流预警模型。

汶川地震引发的大量滑坡、崩塌灾害在地震极重灾区形成了约75 亿立方的松散崩滑堆积体。这些松散崩滑堆积体在地表径流冲刷作用下很容易产生底蚀和侧蚀而形成大.型泥石流。2010 年8 月四川省地震极重灾区，在暴雨后集中爆发了震后大型泥石流灾害（8.13特大泥石流灾害）。本研究将针对这种震后大型“侵蚀”性泥石流启动机理进行试验和理论研究。本项目拟首先研究汶川地震大型崩滑堆积体物理力学特性。然后通过室内水槽泥石流启动试验、离心机泥石流启动试验和现场试验研究泥石流爆发的内因（松散崩滑体的密度、级配、初始含水量、粘粒含量）和外因（地表径流量、坡度）与泥石流启动模式和侵蚀率之间的关系，建立“侵蚀方程”。将雨强和地表径流量；前期累计（有效）降雨量与松散堆积体内部的初始含水率联系起来。基于“侵蚀方程”将雨强和前期累计（有效）降雨量为预警判据，建立震后大型泥石流预警模型。