库水位涨落条件下谭家湾滑坡稳定性演化分析

Stability Evolution Analysis of Tanjiawan Landslide under Reservoir Water Level Fluctuation

以三峡库区谭家湾滑坡为例,采用有限元法,模拟了8种不同库水位升降速率下滑坡体内地下水的暂态渗流场特征,并采用极限平衡计算法对滑坡进行了稳定性分析。结果表明,滑坡体内地下水位随库水位升降而升降,库水位升降对滑坡体内地下水位的影响主要在滑体前缘;库水位上升时,稳定性系数不断增加,且上升速率越大,稳定性系数越大;库水位下降速率小于滑体渗透系数时,稳定性系数不断降低;库水位下降速率大于或接近滑体渗透系数时,稳定性系数先减小后增大。

Taking Tanjiawan Landslide as study example, the transient seepage fields of groundwater in landslide mass are simulated by using finite element method under eight different water level fluctuation rates of reservoir, and the stability of landslide is analyzed by using limit equilibrium method. The research results show that： （a） the groundwater seepage line changes exactly in accordance with the change of reservoir water level, the influence area of reservoir water level fluctuation on groundwater level mainly focuses on the front of landslide; （b） under the condition of the rise of reservoir water level, the safety factor will increase with the rise of water level, and the faster the water level raises, the greater the landslide safety factor; and （c） under the condition of the descend of reservoir water level, the safety factor will decrease with the descend of water level when the water level descent speed is less than the permeability coefficient of landslide mass, and the safety factor will reduce firstly and then increase when the water level descent speed is greater than or close to permeability coefficient.