增大库水位日降幅联合降雨条件下张家祠堂滑坡稳定性分析

Stability Analysis of Zhangjiacitang Landslide under Increased Daily Drawdown Rate of the Reservoir Level and Rainfall

库水位下降对滑坡的稳定性变化有重要影响。以张家祠堂滑坡为例,利用Geo-studio软件的Seep/W模块和Slope/W模块分别对滑坡渗流场和稳定性进行数值模拟计算,分析降雨和不同库水位下降速率对该滑坡稳定性的影响规律,并结合滑坡变形的调查情况和数值模拟计算结果对该滑坡进行稳定性预测与评价。结果表明:张家祠堂滑坡为降雨型滑坡,相对于降雨,增大库水位日降幅对滑坡稳定性影响非常有限;预测在非汛期增大库水位日降幅条件下,滑坡整体基本稳定;滑坡在中前部虽有变形,但滑坡整体并未形成连续贯通的软弱面,因此该滑坡目前为基本稳定;滑坡在最危险工况(库水位日降幅1.2m/d+降雨)下的稳定性系数为1.154,滑坡处于基本稳定状态。

Reservoir level fluctuation has a major impact on the stability of the landslide.This paper takes Zhangjiacitang landslide as a case study,and uses the Seep/W module and Slope/W modules of the Geo-studio software to calculate the seepage field and stability of the landslide.Then the paper analyzes the law of the landslide stability with the influence of rainfall and different reservoir drawdown rates,and evaluates the stability of the landslide combined with the investigation into the landslide deformation and the calculation results.The results suggest that the type of Zhangjiacitang landslide is the rainfall type.Compared with the rainfall,the effect of increasing the drawdown rate of the water level on the stability of landslide is very limited.The overall landslide is presumed to be basically stable when the drawdown rate of the reservoir level increases in non-flood season.Although the deformation appears in the middle and front of the landslide,a continuous penetrating weak surface doesn＇t form in the overall landslide,so currently the landslide is basically stable;the stability coefficient calculation result of the landslide in the most dangerous working conditions（rainfall at daily drawdown rate of 1.2m/d）is 1.154,and the landslide is basically in the stable state.