四川凉山州美姑县quot;6#183;1quot;泥石流灾害研究.pdfVIP

Journal of Engineering Geology 工程地质学报 1004 - 9665/ 2006/ 14 （02 ）-0 152-07 四川凉山州美姑县“6 ·1”泥石流灾害研究! 刘希林 倪化勇 赵 源 苏鹏程 （中国科学院成都山地灾害与环境研究所 成都 61004 1） 摘 要 四川凉山州美姑县“6 ·1”泥石流灾害实例研究表明，该泥石流约为20 年一遇的中小规模的泥石流。流域上游短历 时强降雨和冰雹天气过程是这次泥石流暴发的诱因，流域内退化的生态环境和中下两岸不稳定边坡以及沟道内大量的松散 堆积物为这次泥石流提供了丰富的固体物质来源。泥石流堆积物具有典型的多峰型粒度特征，且有较高的粘粒含量。巨大 的泥石流漂砾、石背石现象、龟裂现象、侧积堤和龙头堆积证实了这次泥石流为粘性泥石流。危险度评价表明，采莫洛沟属于 高度危险的泥石流沟，危险度为0 . 67 ；乃托沟属于中度危险的泥石流沟，危险度为0 . 58 。风险评估结果可知，两沟都属于泥石 流高风险区风险度分别为0 . 52 和0 . 45 。高风险区的泥石流灾害给当地的经济社会造成了严重影响并直接造成了较大的人 员伤亡和财产损失。 关键词 泥石流 灾害过程 美姑县 中图分类号：P642 . 23 文献标识码：A RESEARCH ON THE “6 ·1”DEBRIS FLOW HAZARDS IN EI U COUN- TY OF LIAN SHAN STATE，SICHUAN LIU Xilin NI Huayong ZHAO Yuan SU Pengcheng （Institute of Mountain Hazards and Enuironment ，Chinese Academy of Sciences ，Chengdu 61004 1） Abstra t Studies on the 6 . 1 debris flows in Meigu county of Liangshan state ，Sichuan show that the return pe- riods of the debris flows are approximately 20 years and are small/ moderate magenitude debris flows. The rainstorm and hail with short duration and high density in the upper reaches of the drainage basins are the triggering factors for the debris flows. The degenerate ecological environment in the drainage basin ，unstable slopes in the low - middle reaches and a lot of unconsolidated materials in the channels of the gullies ，provide enough materials for the debris flows. The debris flows are typically of the grain curve characteristics with multiple peaks. The deposits of the deb- ris flows have a high content of clay. The large boulders ，the boulder piling up boulder ，mud crack ，lateral accu- mulation mound and surge deposits demonstrate the debris flows are viscous. Hazardousness assessment indicates ， the Caimoluo gully is a high hazardous debris flow gully and has the hazard degree of 0 . 67 ；the Naituo gully is a moderate hazardous debris flow gully and has the hazard