基于滑体渗透性与库水变动的滑坡变形滞后规律研究

三峡水库运行过程中库岸滑坡的变形演化往往滞后于库水位的变化, 表现出时间滞后效应, 而且随渗透系数和库水位波动速率的不同, 滞后效应亦不同。以三峡库区白家包滑坡为例, 通过现场调查、监测数据分析以及数值模拟的方法, 研究了滑坡在不同渗透系数k和不同库水位下降速率v条件下的变形滞后时间变化规律。研究表明: 滑体渗透系数一定时, 库水位下降速率越大, 地下水滞后越明显; 库水位下降速率一定时, 滑体渗透系数越大, 地下水下降越快。当滑体渗透系数一定时, 库水位下降速率越大, 滑坡的变形滞后时间越短; 滑体渗透系数k=0.85 m/d时不同库水位下降速率作用下滑坡的变形滞后时间为3.74~9 d, 当0.47＜v/k＜1.18时, 0.24＜相对变形滞后时间＜1;当1.18＜v/k＜2.38时, 0＜相对变形滞后时间＜0.24。当库水位下降速率一定时, 滑体渗透系数越大, 滑坡变形滞后时间越短, 不同库水位下降速率下滑坡变形滞后时间随渗透系数的变化规律大致相同; 库水位下降速率v=1.8 m/d时不同滑体渗透系数下滑坡的变形滞后时间为1.7~8 d, 当0.52＜v/k＜0.84时, 0＜相对变形滞后时间＜0.16;当0.84＜v/k＜2.12时, 0.16＜相对变形滞后时间＜0.43;当2.12＜v/k＜9时, 0.43＜相对变形滞后时间＜1。研究成果对水库滑坡预测预警具有较强的应用价值。 

Landslide deformation hysteresis regularity based on permeability of landslide and reservoir water change

The deformation evolution of reservoir landslides of ten lags behind the variation in the reservoir water level during the operation of the Three Gorges Project, showing a deformation hysteresis effect, and the hysteresis effect is different with the difference in the permeability coefficient and fluctuation rate of reservoir water. Taking the Baijiabao landslide in the Three Gorges Reservoir area as an example, the variation law of the deformation lag time under different permeability coefficients k and reservoir water level decline rates v is studied by field investigation, monitoring data analysis and numerical simulation. The results show that when the permeability coefficient of the landslide is constant, the higher the decreasing rate of reservoir water level is, the more obvious the groundwater lag. When the reservoir water level drops at a certain rate, the greater the permeability coefficient of the sliding body is, the faster the groundwater drop.When the permeability coefficient of the sliding body is 0.85 m/d, the higher the rate of reservoir water level decline is, the shorter the deformation lag time of the landslide.The corresponding lag time is 3.74-9 d under different decline rates of the reservoir water level.When 0.47 < v/k < 1.18, 0.24 < relative deformation lag time < 1; when 1.18 < v/k < 2.38, 0 < relative deformation lag time < 0.24. When the reservoir water level decline rate is constant, the larger the landslide permeability coefficient is, the shorter the landslide deformation lag time is. Under different reservoir water level decline rates, the change rule of the relative deformation lag time with increasing v/k value is roughly the same, v=1.8 m/d, and the corresponding lag time of different permeability coefficients is 1.7-8 d. When 0.52 < v/k < 0.84, 0 < relative deformation lag time < 0.16; when 0.84 < v/k < 2.12, 0.16 < relative deformation lag time < 0.43; when 2.12 < v/k < 9, 0.43 < relative deformation lag time < 1. The research results have strong application value for the prediction and warning of reservoir landslides.