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目的研究不同层状岩体渐进破裂直至岩爆临界状态前的孕育过程及其微破裂前兆规律.方法在完整岩体、水平层状岩体、及急倾斜层状岩体中建立隧洞开挖三个数值模型,运用RFPA2D对隧洞开挖诱发岩爆机理进行数值试验研究.结果 RFPA2D模拟隧洞卸载失稳是可行的,同时表明结构面对隧洞围岩的破坏失稳模式有显著影响,不同性质的结构面使得隧洞最后破坏状态完全不一样.结论隧洞开挖卸载岩爆破坏程度在水平层状岩体中表现最为强烈,倾斜层状岩体中次之,完整岩体中相对最弱.隧洞破坏在水平层状岩体与完整岩体中具有对称性,倾斜层状岩体中具有明显的非对称特征.围岩卸荷破坏具有明显的脆性特征,岩体破坏时表现出沿卸荷方向强烈扩容破坏特征,洞周围岩产生明显的侧向膨胀,致使洞室断面缩小.
Aim To study the inoculation process and the rupture law of micro-rupture before progressive rupture of different stratigraphic rock mass until the rock burst state.METHODS Three tunnel excavation methods were established in intact rock mass, horizontal stratiform rock mass and steeply inclined stratigraphic rock mass Numerical model was established and the numerical experiment on the rock burst mechanism induced by tunnel excavation was carried out by using RFPA2D.Results The unloading instability of RFPA2D tunnel is feasible and it shows that the structural plane has a significant influence on the failure instability mode of tunnel surrounding rock, The structural plane makes the final failure state of the tunnel completely different.Conclusion The degree of unloading rock burst in tunnel excavation is the strongest in the horizontal layered rock mass, followed by the inclined layered rock mass and the weakest in the intact rock mass. It has symmetry in horizontal layered rock mass and complete rock mass, and has obvious asymmetric characteristics in inclined layered rock mass. The unloading failure of rock mass has obvious brittle characteristics. When the rock mass is destroyed, it shows strong tendency along unloading direction Dilatancy characteristics of destruction, the rock around the hole to produce significant lateral expansion, resulting in cave section reduced.