新疆伊犁加朗普特黄土滑坡泥石流降雨诱发机理

FAILURE MECHANISM OF LOESS LANDSLIDES DUE TO SATURATEDUNSATURATED SEEPAGE——CASE STUDY OF GALLENTE LANDSLIDE IN ILI,XINJIANG

新疆伊犁谷地黄土广泛分布,黄土滑坡灾害严重,其数量占新疆全区滑坡的80%,其中大型黄土滑坡-泥石流灾害链造成的损失尤为显著。与我国西部典型黄土斜坡相比,伊犁谷地黄土斜坡具有坡体结构复杂和降雨非饱和渗流失稳的特征,黄土滑坡降雨诱发机制复杂。以新源县则克台加朗普特大型滑坡泥石流灾害为例,在建立黄土滑坡坡体结构模型的基础上,基于非饱和渗流理论,计算分析坡体非饱和渗流场变化,研究降雨诱发黄土坡体结构渗流破坏过程与机制,采用渗流-稳定性耦合计算方法,分析非饱和渗透诱发坡体结构失稳过程,揭示新疆伊犁谷地大型黄土滑坡降雨非饱和渗流失稳机理。

Ili valley of Xinjiang in large areas are covered with loess. Loess landslides occur frequently in this region. Its number accounts for 80% of all landslides in Xinjiang province. The loss caused by loess landslide is remarkable. Compared with other typical loess landslides in western China,loess landslides in Ili valley are characterized by complex slope structures and rainfall-induced unsaturated seepage instabilities. Case study of the unsaturated seepage failure mechanism for Gallente landslide is presented in this study. Slope structure model for Gallente landslide is firstly established. Based on unsaturated seepage theory,the two-dimensional unsaturated seepage field in the slope is simulated and analyzed. Then the seepage failure process and mechanism induced byrainfall are examined. The coupling seepage-stability computing method is used to analyze the destabilizing process of slope structure induced by unsaturated seepage. The unsaturated seepage failure mechanism of large-scale loess landslide in Ili valley is eventually revealed.