基于双强度折减策略的边坡稳定性分析方法探讨

基于能耗分析理论,假定黏聚力和内摩擦角按不同折减系数进行强度折减,采用不同边坡综合安全系数定义方式,根据虚功原理推导了各自综合安全系数的目标函数表达式。采用序列二次规划法和内点法编制了非线性规划迭代程序,对综合安全系数目标函数进行优化求解。依据算例结果探讨了双强度折减技术评价方法对边坡安全系数计算的影响规律。研究结果表明,边坡稳定性影响因素众多,抗剪强度参数c与φ的折减系数之间不存在惟一确定的函数关系,现有预先假定黏聚力和内摩擦角按某一比例进行强度折减的处理方法尚难以完全合理解释;通过强度折减的最短路径来定义边坡综合安全系数的方法物理意义更为明确。研究结论可为工程技术人员加深采用强度折减技术进行边坡稳定性分析的认识提供有益参考。

Discussion on slope stability analysis with double strength reduction technique

Based on the analysis of energy consumption theory, the different reduction coefficients of strength on the cohesion and internal friction angle are assumed; different ways to define the comprehensive slope safety factor is used, and the objective function expression of respective comprehensive safety factor is derived from the principle of virtual work. Using sequential quadratic programming method and interior point method, a nonlinear programming iteration procedure for optimization solution of comprehensive safety factor is established. According to the obtained solution, we investigate the effect of double strength reduction technique evaluation method on the calculation of slope safety factor. The results show that due to many factors affecting the stability of slope, the well-determined function relationship between reduction factor of shear strength parameter c and φ does not exist; the current presupposed processing method that the strength reduction of cohesive force and internal friction angle are under a certain proportion is difficult to give full reasonable explanation. Through the shortest path of strength reduction to define the comprehensive safety factor of the slope is of more clear physical meaning, through which it can deepen engineering technicians’ understanding of strength reduction technology used in slope stability analysis.