基于极限平衡理论的局部最小安全系数法

Local minimum factor-of-safety method based on limit equilibrium theory

根据极限平衡原理和Mohr Coulomb破坏准则 ,应用最优控制理论思想 ,并充分考虑运动许可条件 ,建立了能同时确定边坡临界滑动面和计算最小安全系数的局部最小安全系数法。该法既满足条块力和力矩的平衡 ,又符合边坡稳定问题的物理本质 ;既能保证所求解是运动许可的 ,又能保证不出现数值计算上的困难 ;不但可以确定临界滑动面和计算对应的最小安全系数 ,又可以确定条底及条块界面上法向力的作用点 ,从而消除了以往利用极限平衡法进行边坡稳定分析时对临界滑动面的形状以及条底和条块界面上法向力的作用点的人为假定。算例计算比较表明 ,本文所给方法是合理可靠的。

Local minimum factor of safety method is developed in this paper based on the principle of limit equilibrium and Mohr Coulomb failure criterion, using the idea of optimal control theory and considering kinematic admission conditions sufficiently. This new method satisfies force and moment equilibrium conditions of slices and is consistent with the mechanical and physical aspects of the slope stability problem. It ensures that solutions are kinematically admissible and that difficulties about numerical computation do not appear. It can determine critical slip surface and compute the minimum safety factor and can determine the positions of normal forces acting on base and interface of slices,and then it eliminates some relevant man made assumptions that are used now in the limit equilibrium method of slope stability analysis. The computation and comparison of examples in literature indicate that the method in the paper is logical and reliable.