三峡库区白家包滑坡变形机理及稳定性分析预测

Stability Analysis Prediction and Deformation Mechanism of Baijiabao Landslide in Three Gorges Reservoirs Area

滑坡是三峡库区危害性最大的地质灾害,而水库型滑坡在三峡库区占极大比重,约60%的水库型滑坡发生在库水骤降期,40%发生在水位上升期。以三峡库区白家包滑坡为例,结合多年的专业监测数据,对阶跃型变形退水滞后型滑坡诱发机制进行分析,运用Geo—Studio进行稳定性模拟分析预测。结果表明,退水滞后型滑坡因其坡体渗透性差,库水快速消落时,由于正落差的存在形成了指向坡体外侧的渗透力,不利于坡体稳定,易诱使滑坡失稳;库水消落速率越大,则滑坡的稳定性越差,当以较大消落速率工况2、3、4运行时,白家包滑坡处于欠稳定-不稳定状态。

Landslide is one of the most harmful geological hazards in Three Gorges Reservoir area,and the wading type reservoir bank landslides occupy a great proportion in the three gorges reservoir area.About 60% of the wading type reservoir bank landslides occur in water dropping period and 40% occur in water level rise duration. This paper takes Baijiabao landslide in Three Gorges Reservoir area as an example,combined with years of professional monitoring data,to analyze the induced mechanism of stepwise deformation and lag behind drawdown landslide. Using Geo-Studio simulates and analyses the stability prediction. The results showed that the lag behind drawdown landslide with poor permeability destabilized more easily when reservoir water regressed rapidly that accompanies with Seepage Force that is contrast to the slope direction that is not conducive to the landslide stability; Increasing dailydecreasing range,the stability of lag behind drawdown landslide decrease,the Baijiabao landslide will be in unstable state when it is in working condition 2,3,and 4.