动水压力型滑坡对库水位升降作用的响应--以三峡库区树坪滑坡为例

摘要

Numerous wading landslides formed in Three Gorges Reservoir.Water level cyclical fluctuations causes the changes of properties of the rock-soil bank landslides,also make the changes of seepage field and the stability of the landslides.This paper studies the response of the wading landslide's stability induced by water level fluctuation. It analyses the hydrodynamic pressure landslide using the classification of significant wading landslide in Three Gorges Reservoir.It takes the Zigui Shuping Landslide as a case study.The SEEP and SLOPE modules Geo-studio software are used to model the process of seepage field and calculate the stability,analyzes the law of effect hydrodynamic pressure landslide under different permeability coefficients of the landslide and the water level rate. The results show that the groundwater level has a concave phenomenon and the stability coefficient increases when the reservoir water level rises.The groundwater level has a convex phenomenon and the stability coefficient obvious decreases when the reservoir water level reduces for hydrodynamic pressure landslide.The reservoir water level fluctuation has the larger rate,and the permeability coefficient is smaller.The reservoir water level fluctuation has more obvious effect on the seepage and stability of the landslide.%三峡库区涉水型滑坡众多，库水位周期性涨落引起库岸滑坡岩土体物理性质的改变，还使得滑体内渗流场发生变化，进而影响滑坡体稳定性。为研究库水位升降作用对涉水边坡稳定性的影响，基于三峡库区重大涉水滑坡分类，对动水压力型滑坡进行分析。以三峡库区秭归县树坪滑坡为例，利用Geo-Studio软件的SEEP模块及SLOPE分别对滑坡渗流场与稳定性进行计算，分析不同滑体渗透系数及不同库水位升降速率对动水压力型滑坡的影响规律。结果表明：对于动水压力型滑坡，库水位上升过程中，地下水位线有下凹趋势，稳定性系数有所增大；库水位下降过程中，地下水位线有上凸现象，且稳定性系数明显减小；库水位升降速率越大，滑体渗透系数越小，库水位变动对滑坡渗流及稳定性影响越明显。