潮州至惠州高速公路煤系地层边坡滑动机理研究

Study on Slope Sliding Mechanism of Certain Coal System Layer on Chaozhou-Huizhou Expressway

分析了广东省潮惠(潮州—惠州)高速公路沿线一煤系地层滑坡的地质结构特征及滑坡类型。运用饱和-非饱和渗流及强度理论,对煤系地层边坡在降雨条件下的变形特征及滑动机理进行了有限元分析。该边坡的滑动机理为:降雨引起边坡中的地下水位从坡脚开始上升,坡脚处的煤系地层遇水易软化,强度迅速降低,导致坡脚失稳,牵引上部边坡产生张拉裂缝;持续降雨沿张拉裂缝入渗,在煤系地层接触面上汇流并沿着岩层向坡脚贯通,形成了煤系地层软化的滑动带,促使其发生滑动。

In the paper,the characteristics of the geological structure and the type of landslide of coal system layer on Chaozhou-Huizhou Expressway in Guangdong were analyzed.Based on the saturated unsaturated seepage strength theory,a finite element analysis was conducted to understand the deformation characteristics and sliding mechanism of the coal system layer slope under rainfall.The groundwater level began to rise from the toe of side slope due to the rainfall.The coal system layer at the toe of side slope was subject to softening because of water,resulting in sudden lower strength and instability.The tension cracks in upper slope occurred.With the increasing penetration of rainfall through the tension cracks,water converged at the contact surface of the coal system layer and further flew along the layer till the toe of side slope.Therefore,a softening sliding belt in the coal system layer existed and slope sliding may be activated.