节理岩质边坡的块体元塑性极限分析下限法

结合块体元和塑性极限分析,并利用数学规划的方法,提出了一种新的岩石边坡稳定分析方法-块体元塑性极限分析下限法。针对节理岩体的力学特性,将岩体离散为块体–结构面组成的块体系统,假定块体为刚体;以结构面应力为未知量,根据塑性极限分析下限定理,构造了满足平衡方程、边界条件和屈服条件的静力许可应力场;建立了边坡稳定的下限法数学规划模型,并通过非线性规划方法寻求问题的下限解。最后对三个典型的算例进行分析,结果表明:采用本方法不需要逐个计算可能的滑动形式,而直接得到边坡稳定安全系数,结果同刚体极限平衡法十分接近。

Plastic lower bound limit analysis using block element method for jointed rock slope

A new method to analyze the stability of rock slope was proposed by using block dement method and plastic limit analysis. In view of the mechanical behaviors of rock mass, the rock-structural plane model was used. The block elements were assumed to be rigid, stresses only existed in structural planes, and all discrete block dements were joined by these structural planes. Based on the plastic lower limit theorem, and regarding the stresses of structural plane as unknown variables, the statically admissible stress fields satisfing the equilibrium and boundary conditions and yield criterions were constructed. By using the idea of nonlinear programming, the lower bound limit analysis model of mathematical programming for slope stability was established. The results of three examples indicate that the present method can get the slope safety factor directly without calculating potential sliding patterns one by one and the results of this method is quite close to those from the rigid limit equilibrium method.