巷道裂隙围岩稳定性影响因素的数值分析

Numerical analysis of influencing factors in stability of cracked surrounding rock of a laneway

对具有单一裂隙的巷道围岩问题,用边界元分区算法沿裂隙面将围岩分区,对每个子域分别建立边界积分方程。在裂端配置1/4面力奇异单元,对张开或闭合的裂隙,既模拟了裂端位移r的变化规律,又模拟了裂端应力1/r的变化规律。以应力强度因子为指标,依据岩石断裂理论,系统地分析了裂隙几何位置、双向加载侧压比、裂隙面摩擦系数、裂隙长度等因素对围岩稳定性的影响,得出一些有价值的结论。该数值方法适用于分层介质中及复杂几何形状的巷道裂隙围岩稳定性分析。

To analyze the stability of a laneway＇s surrounding rock with single crack, the multi-domain boundary element method is used, The sub-regions are obtained by dividing the whole region along the crack. The boundary integral equation is established in each sub-region. The traction singular quarter-point elements are collocated at the tip of the crack. For the opened or closed crack, not only the characteristic of √r in displacement but also the characteristic of 1/√r in stress near the crack tip are represented. Qua the target, the stress intensity factor is calculated. According to the theory of rock fracture mechanics, the influences of the following factors on the stability of the cracked surrounding rock are analyzed systematically： geometric position of the crack, the ration of dual-pressure, the friction factor of the crack surfaces, the length of the crack. Some valuable conclusions are obtained. This numerical method is suitable for the stability analysis of laneways with complex geometric shape and laneways in layered medium.