汶川地震灾区帽壳子滑坡形成泥石流的过程和特征  

Processes and Characteristics of Debris Flows Induced by Maoqiaozi Landslide in Wenchuan Earthquake Stricken Area

作　　者：马超[1,2,3] 胡凯衡[1,2] 宋国虎[1,2,3] 田密[1,2,3] 

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 [3]中国科学院大学,北京100049

出　　处：《地球科学与环境学报》2013年第4期98-103,共6页Journal of Earth Sciences and Environment

基　　金：中国科学院知识创新工程重要方向项目(KZCX2-YW-JS305);中国科学院/水利部成都山地灾害与环境研究所青年百人团队项目(110900K235)

摘　　要：实地调查了汶川地震灾区北川县帽壳子滑坡转化为坡面泥石流和沟道泥石流的基本特征和形成过程,并利用能量守恒原理和Takahashi泥石流运动模型对其运动特征进行了分析。结果表明:对于强震诱发的滑坡,其层间碎块石土体强度低,滑坡体内部裂隙发育,在强降雨作用下容易转化为泥石流;滑坡转化为坡面泥石流的过程为岩土体沿基岩面下滑→撞击→强碎屑化→流动→快速停积;滑坡转化为沟道泥石流的过程为滑坡体崩滑→弱碎屑化→水流掺混→掏蚀沟道→流动堆积;滑坡转化为坡面泥石流后,起始速度较快,但没有沟道限制和水力作用,因此运动阻力较大,冲出距离远小于沟道泥石流;利用Takahashi泥石流运动模型计算得到的沟道泥石流冲出距离与实际观察值比较吻合。Basic characteristics and forming processes of Maoqiaozi landslide transformed into slope debris flow and gully debris flow in Beichuan county of Wenchuan Earthquake stricken area were investigated, and the motion features of transformation process were analyzed with energy conservation principle and Takahashi debris flow motion model. The results show that for the landslide induced by strong earthquake, the intensity of interlayer tatter rubble soil body is weak, and fracture in landslide body develops, so that the landslide can be easily transformed into debris flow under the condition of strong rainfall; the process of Maoqiaozi landslide transformed into slope debris flow is sliding-collision-strong fragmentation-fluidization-quick accumulation along the basement surface for rock-soil body; the process of Maoqiaozi landslide transformed into gully debris flow is landslide body collapse-weak fragmentation-water flow mixing-sapping gully-flow accumulation; after landslide transforming into slope debris flow, starting velocity is fast, and there are no hydraulic process and high resistance, so that motion resistance is large and runout distance is much less than that of gully debris flow; the runout distance of gully debris flow calculated by Takahashi debris flow motion model is very close to the field observing value.

关 键 词：泥石流 滑坡 汶川地震 转化过程 运动特征 崩滑 坡面流 

分 类 号：P642.2[天文地球—工程地质学]