考虑岩桥破坏的块体稳定性分析方法

经典块体理论在进行块体可移动性分析和稳定性计算时是分步独立进行的，默认不可移动块体是稳定的，对不可移动块体不再进行稳定性分析。实际工程中，某些阻碍岩石块体运动的“岩桥”可能发生破坏，使得不可移动块体发生滑动。当块体的规模比较大时，在重力作用下破坏局部岩桥的可能性会增高。文中提出一种考虑岩桥破坏的块体稳定性分析方法，不再默认不可移动块体绝对稳定，计算块体稳定系数时，将阻碍块体移动的岩桥的抗剪切力纳入到块体的抗滑力中。该方法首先找出块体所有可能的滑动面和裂隙交线，识别块体沿每一个方向运动时需要破坏的岩桥，基于摩尔-库仑强度准则计算出块体沿每个方向运动时的稳定系数，然后，选取最小的稳定系数作为块体的实际稳定系数，最小稳定系数对应的方向即为块体最有可能的运动方向。

Stability analysis method of block considering cracking of rock bridge

The removability and stability analysis of rock block are carried out independently in the classical block theory which tacitly approves the nonremovable block being absolutely stable and thus skips the stability analysis. However, in the practical engineering project, the “rock bridge” preventing the movement of rock block may crack, resulting the sliding of the nonremovable blocks. The likelihood of the cracking under gravity would increase with the size of block. This paper proposes a stability analysis method considering the cracking of the rock bridge. The nonremovable blocks are no longer assumed to be absolutely stable. When calculating the block stability factor, this method integrates the shear resistance of the rock bridges into the anti-sliding force of the block. Firstly every possible sliding surface and the intersection line of fractures are listed. Then the rock bridges damaged along each possible moving direction are determined. Afterward, the stability factor along each direction is calculated based on the Mohr-Coulomb yield criterion. The minimum stability factor is selected as the actual stability factor of the block and the associated moving direction is considered to be the most possible moving direction of the block.