库水位波动及降雨作用下巫峡干井子滑坡流-固耦合特征及稳定性分析

Flow-solid coupling characteristics and stability analysis of Ganjingzi Landslide in the Wu Gorge under reservoir water level fluctuation and rainfall

三峡库区巫峡段高陡峡谷区地质环境脆弱,库岸滑坡分布密集,受库水位和降雨影响变形明显。以巫峡段干井子滑坡为例,基于有限元方法和非饱和土力学理论建立滑坡流-固耦合计算模型,考虑滑坡瞬态渗流引起的土骨架变形和渗透系数变化,将非饱和土强度理论和孔隙水压力分布应用到极限平衡法中,分析滑坡在库水位波动和降雨条件下的渗流、应力应变和稳定性变化规律。结果表明,干井子滑坡地下水位和稳定性受库水位波动的影响较大。降雨受斜坡地形因素控制很难直接入渗至滑体深部,在强降雨条件下滑坡整体稳定性变化较小,滑坡中后部易发生浅表层变形,模拟结果与野外实际调查情况一致。研究对库区地质灾害监测预警和防治工作有一定指导作用。

The geological environment of the high-steep gorge area of Wu Gorge in the Three-Gorges Reservoir(TGR) region is vulnerable,and the bank landslides distributed densely.Taking Ganjingzi landslide in the Wu gorge for example.The landslide fluid-solid coupling calculation models were established based on the finite element method and unsaturated soil mechanics.The unsaturated soil strength theory and pore water pressure distribution were applied to the limit equilibrium method considering the deformation of soil skeleton and permeability coefficient changing caused by the landslide transient seepage.The seepage,stress-strain and stability were carried out to Ganjingzi landslide under the reservoir water level fluctuating and rainfall.The consequences indicate that groundwater level and stability of the Ganjingzi landslide are greatly affected by the fluctuation of the reservoir water level.Due to the special topographic,the precipitation infiltrate into the deep part of the slope hardly,the slope is relatively stable under the heavy rainfall conditions,shallow sliding tending to occur in the rear part.The simulation results are consistent with the actual investigation in the field.The conclusions are useful for guiding the monitoring,early warning and prevention of geological disasters in the TGR area.