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为解决岩石块体在各种复杂条件下的稳定性评价问题,在已有的岩石块体识别的单元重构–聚合方法基础上,进一步提出基于数值分析的块体稳定性评价一般性方法。该方法以含有块体信息的网格模型为出发点,首先引入界面单元,实现块体–围岩结构面滑移和脱开的模拟。其次,提出可动块体的定义和基于数值分析的块体运动形式判别方法。然后,基于结构面强度折减思路,提出块体安全系数定义和加固分析方法,从而实现基于数值分析的块体稳定性评价。该方法相比于刚体极限平衡法,能够考虑初始地应力、围岩变形和非滑面抗剪性能对块体稳定性影响,且在一定条件下,分析结果可与刚体极限平衡法结果基本等同。最后,通过算例验证了该方法的可靠性、有效性,并论证了其与刚体极限平衡法分析结果的关系。算例结果同时表明:该方法可综合考虑块体几何形态、块体埋深和块体出露高度对其稳定性的影响,能够适应复杂条件下工程岩体开挖过程的块体稳定性评价。该方法与已提出的块体识别方法,构成一套有关岩石块体的“识别–可动性判别–运动形式确定–稳定性评价–加固分析”的完整方法体系,总体平行于当前块体力学分析的常用方法(如块体理论),为研究块体在各种复杂条件下的稳定性演化提供了新的实现思路。
In order to solve the problem of rock block stability under various complicated conditions, the general method of block stability evaluation based on numerical analysis is further proposed based on the existing unit reconstruction-aggregation method for rock block identification. This method takes the grid model containing block information as the starting point. First, the interface element is introduced to realize the simulation of the sliding and detachment of the block-surrounding rock structure. Secondly, the definition of movable block and the discriminating method of block motion based on numerical analysis are proposed. Then, based on the idea of reducing the strength of the structural plane, the definition of block safety factor and the reinforcement analysis method are put forward to realize the stability evaluation of block based on numerical analysis. Compared with rigid body limit equilibrium method, this method can consider the influence of initial stress, surrounding rock deformation and non-slip shear resistance on the stability of block, and under certain conditions, the analysis results can be basically the same as those of rigid body limit equilibrium method . Finally, an example is given to verify the reliability and validity of the proposed method, and its relationship with the results of rigid body limit equilibrium analysis is demonstrated. The results also show that this method can comprehensively consider the influence of block geometry, block depth and block height on its stability, and can be used to evaluate the stability of block under the condition of complicated rock excavation . This method and the proposed method of block identification constitute a complete set of method system of “identification - mobility determination - determination of motion form - stability evaluation - reinforcement analysis” of rock blocks, which is generally parallel to the current block The common methods of physical analysis (such as block theory) provide a new idea for the study of the stability evolution of blocks under various complicated conditions.