新疆伊宁县皮里青河滑坡成灾机理分析

Analysis of formation mechanism of Piliqinghe landslide in Yining County,Xinjiang Province

2017年3月24日,受冰雪消融影响,新疆伊犁哈萨克自治州伊宁县喀拉亚尕奇乡喀拉亚尕奇村发生滑坡灾害,滑坡堵塞皮里青河,形成堰塞湖,未造成人员伤亡。通过现场调查分析和数值模拟,结果表明:(1)皮里青河滑坡成灾过程为:河流冲刷坡脚,前缘局部滑动→发生蠕滑-拉裂,坡体强烈变形→在冰雪融水入渗作用下发生整体滑动→堵塞河道,形成堰塞湖→堰塞体溃决;(2)因气温升高,冰雪消融入渗是滑坡形成的直接诱因,雪水入渗后并转化为地下水,黄土含水达到饱和,孔隙水压力增高,滑坡稳定性系数降低,在重力作用下发生整体高速下滑;(3)分析了新疆地区冰雪消融引起滑坡灾害链的成灾模式,为进一步科学地指导防灾减灾提供技术支撑。

On March, 24,2017, affected by ice and snow melting, a landslide occurred in Kalayagaqi village Kalayagaqi town in Kazak Autonomous Prefecture of Yi in Xinjiang , which blocked the Piliqing River and formationed danmmed lake. At the same time, the landslide causd no casualties. On the basis of field investigation and simulation calculation, the conclusions are as follows ： （ 1 ） The developing process of disaster on piliqinghe landslide involved of the following steps. First, the leading edge of landslide slipped because of the scour of the river. Second, sliding body wriggled. Third, what the trailing of landslide was ripped caused deformation of the slope. Fourth, the slope occurred the total motion under the infiltration of ice and snow melt water. Final, the landslide occurred and the burst of water pooled. （2） With the temperatures rising, Ice and snow melting and infiltration are the direct causes of landslide formation. At the same time, snow water infiltrated and converted into groundwater. So the water content of loess was saturated and pore water pressure increases. At the last, The stability coefficient of landslide decreases, and the landslide occurred at high speed under the action of gravity. （3）This paper analyses the hazard mode of collapses and landslide disaster chain caused by the effect of the seasonal snowpack melt in Xinjiang, and further guides disaster prevention and reduction scientifically by providing technical support.