凹边坡稳定性三维极限平衡法研究与应用

3D limit-equilibrium method for calculating concave slope stability and its application

为揭示拱形约束条件下凹边坡稳定性的三维效应,基于极限平衡理论,从定量认识土体环向侧压力角度出发,提出新的凹边坡稳定性三维计算方法。通过将该方法与经典三维极限平衡法进行对比,验证该方法的准确度。选取典型工程实例,采用该方法与数值模拟相结合,研究平面曲率对凹边坡空间滑坡模式与三维稳定性的影响。结果表明:该方法的精度较高;平面曲率对凹边坡的滑体空间形态、尺寸与稳定性有一定影响,即随平面曲率的减小,滑体走向长度与滑面深度均近线性增大,稳定系数呈指数型规律降低,工程中可通过增大凹边坡的平面曲率改善边坡稳定性和减小滑坡规模。

For the sake of revealing 3D effects of the stability of the concave slope under the arch constrains, a new 3D calculation method for the concave slope was worked out based on the limit equilibrium theory and starting with the quantitative consideration of the circular lateral pressure of the soil, then its precision was verified by the comparison made between the method and the classical 3D limit-equilibrium methods. Through a typical engineering example,using the method and the numerical simulation, the plan curvature＇s influences on the spatial failure mode and the 3D stability of the concave slope were studied. It is shown that the method has high accuracy and that the plan curvature has effects on the space form, size and the stability of the slip mass of the concave slope--the strike length of the sliding body and the depth of the sliding surface increase almost linearly and the slope stability coefficient inclines obeying negative exponent law with decrease in its plan curvature, so the concave slope stability can be improved and the sliding scale can be reduced by increasing its plan curvature.