岩质块体渐进破坏的稳定分析方法

岩桥的破裂贯通是一种非连续变形现象。强度折减技术虽然是渐进破坏过程模拟的主流技术，但其不具备描述非连续变形现象的能力。提出连通率折减法和刚度折减法来模拟含非贯通结构面岩块的渐进破坏过程，并建立考虑渐进破坏过程的块体稳定分析方法。首先，引入Goodman单元来描述共面非贯通结构面的岩桥部分和裂隙面部分，建立静力平衡方程来求解滑裂面内岩桥单元和裂隙面单元的应力。其次，岩桥单元采用Griffith准则来判别破坏，利用连通率折减法来描述其破裂；裂隙面单元采用MC准则来判别破坏，用刚度折减法来描述其屈服；通过循环迭代，模拟岩桥单元的破裂过程和裂隙面单元的应力调整过程，实现整个滑裂面的渐进破坏过程模拟。然后，定义考虑渐进破坏过程的滑裂面极限状态；通过自重超载方式将滑裂面推送至极限状态；基于极限状态设计的理论框架，计算度量块体稳定性的安全系数指标。工程实例分析结果表明，渐进破坏过程模拟结果与现场调查结果是一致的。渐进破坏过程的模拟实现，有助于岩质边坡变形破坏机制分析从定性分析阶段扩展至定量分析阶段。

Simulation of progressive failure process and stability analysis method for rock block

The fracture of the rock bridge is a discontinuous deformation phenomenon. Strength reduction method, although it is the mainstream approach for progressive failure process simulation, it can not describe the discontinuous deformation phenomenon. The connectivity rate reduction method and the stiffness reduction method are proposed to simulate the progressive failure process of the rock block bounded by the coplanar non-persistent joints, and a block stability analysis method considering the progressive failure process is established. Firstly, the Goodman element is introduced to describe the rock bridge part and the fracture part of the coplanar non-persistent joint. The stress of the rock bridge element and the fracture element in the slip surface is solved by the equation of static equilibrium. Secondly, Griffith criterion is used to judge the failure for rock bridge element, and the connectivity rate reduction method is used to describe its rupture. The MC criterion is used the to judge the failure for fracture element, and the stiffness reduction method is used to describe its yield. By cyclic iteration, rupture process of the rock bridge element and the stress redistribution process of the fracture element to realize the simulation of the progressive failure process of the whole slip surface. Then, the limit state of the slip surface is redefined considering the progressive failure process, and the slip surface is pushed to the limit state by the weight overload method. Based on the theoretical framework of the limit state design, the safety factor of the block stability is calculated. The results of the engineering examples show that the simulation results of the progressive failure process are consistent with the field survey results. The simulation of the progressive failure process is helpful to the analysis of the deformation mechanism of the rock slope from the qualitative analysis stage to the quantitative analysis stage.