三峡库区白家包阶跃型滑坡动态变形特征与机理

三峡库区内许多滑坡受库水位周期性涨落及降雨的影响,其变形时间曲线呈阶梯状,滑坡变形呈现出阶跃型动态变形演化特征。为了深入研究阶跃型滑坡的动态变形机理,评价预测该类型滑坡的稳定性及发展趋势,本文以白家包滑坡为例,根据现场地质调查及勘查资料,充分利用挖掘十多年的监测数据,分析其动态变形特征、变形机理、影响因素和稳定性,预测其动态变形发展趋势。结果表明此类滑坡由于渗透性能较差,当水库退水时,坡体内地下水向水库排水缓慢,形成地下水与库水位的正落差,指向坡体外侧的渗透压力增大,使得坡体稳定性降低。并且库水位下降速率越大,滑坡位移速率就越大。

Characteristics and mechanism of dynamic deformation of Baijiabao lanslide with stepwise in Three Gorges Reservoir area

A stepwise cumulative displacements curve is usually presented for these landslides in the Three Gorges Reservoir, under the condition of reservoir water fluctuation and rainfall, which means the deformation of the landslide in reservoir is a typical stepwise process. In order to understand the dynamic deformation mechanism, stability and deformation trend of stepwise landslides in the Three Gorges Reservoir, taking Baijiabao landslide as an example, this paper used the information of field geological survey and exploration, and monitoring data of more than ten years, analyzed the dynamic deformation characteristics, mechanism, influence factors and stability of Baijiabao landslide in detail, and predicted the deformation trend. The results showed that, due to the poor soil permeability of landslide body, the underground water in landslide could not be discharged in time during the drawdown of reservoir water, so the decline speed of groundwater was much slower than that of reservoir water, and then increasing the seepage force in the landslide body apparently, further reducing landslide stability. In addition, the faster the drawdown rate, the faster the movement of the landslide was.