基于降雨、库水位联合作用的滑坡渗透稳定性分析

为了进一步研究库水位与降雨联合情况下滑坡体渗流特性以及稳定性的规律,根据非饱和渗流原理,利用Geostudio 2007软件,对某滑坡体库水位骤降与降雨联合作用工况进行了渗流特性以及稳定性分析。结果表明:库水位下降速率越大,降雨强度越大,降雨持时越长,滑坡体稳定系数越小;距离岸坡较远的滑坡体内部孔压变化存在一个"滞后"现象,距离岸坡越近,孔压变化幅度越大。库水位骤降对不同监测点的孔压有一个影响时间,上部、中部和下部监测点影响时间分别为360 d、150 d和100 d。降雨影响了滑坡体内部瞬时孔压变化,而对整体的孔压变化影响较小。降雨发生在库水位骤降过程中而非库水位下降开始时刻或结束时刻时容易导致滑坡体失稳。研究成果为研究在库水位和降雨联合作用下的滑坡机理提供一定的参考。

Joint effect of rainfall and reservoir water level-based analysis on landslide seepage stability

In order to further study the law of the seepage characteristics and stability of landslide body under the joint effect ofboth rainfall and reservoir water level， the analysis on the seepage characteristics and stability is made for the operation conditionunder the joint effect of sudden drawdown of reservoir water level and rainfall on a landslide with the software of Geostudio 2007in accordance with the principle of unsaturated seepage. The result shows that the larger the rate of the drawdown of the reservoirwater level， the larger the rainfall intensity and the longer the rainfall duration are， the smaller the stability coefficient of thelandslide is to be， and moreover， a“lag”phenomenon is there for the change of the internal pore pressure of the landslide bodythat is far away from the bank-slope， for which the nearer to the bank-slope is， the larger the amplitude of the change of the porepressure is to be. An influence time is there from the sudden drawdown of reservoir water level for the pore pressures of variousmonitoring points， i. e. the influence time for the upper， medium and lower monitoring points are 360 d， 150 d and 100 d respec-tively. Ｒainfall influences the instantaneous change of the internal pore pressure， but has less influence on the whole changinglaw of the pore pressure. If rainfall occurs at the moment during the sudden drawdown of reservoir water level instead of the mo-ments of the beginning or the end of the drawdown of reservoir water level， the instability of landslide body is prone to be caused.The study result provides a certain reference for study the mechanism of the landslide under the joint effect of both reservoir waterlevel and rainfall.