扰动作用下矿柱滑移失稳的理论分析

动力扰动作用下，处于高静载状态的岩石极易沿已有裂缝产生滑移，造成滑移型岩爆等动力灾害。通过能量分析和变分原理对动力扰动诱发高应力矿柱断裂滑移失稳（滑移型岩爆）的力学机理进行分析，得出了动力扰动条件下矿柱失稳的充要条件。通过开展动静组合荷载作用下的矿柱滑移失稳试验，验证了理论分析的正确性。研究表明：矿柱的动力滑移失稳只会发生在峰后阶段，对于处在峰前稳定平衡状态的矿柱，若要发生动力滑移失稳，需要爆破振动、巷道断裂等人工或者自然活动所产生的动力扰动达到一定量值，同时还需满足加载刚度k1小于峰后的滑移刚度k2。因此，对矿柱断裂滑移型岩爆量级的预测则须准确地确定过剪应力的量值。

Theoretical Analysis on Slip Stability of Ore Pillar Under Dynamic Perturbation

With the action of dynamic disturbance, the rock under high geo-stress is easy to slip along the existing cracks, resulting in sliding rockburst and other dynamic disasters. The mechanical mechanism of shearing stability of ore pillar under high geo-stress with disturbance is analyzed in this paper. The sufficient and necessary condition for the stability of ore pillar was derived from energy analysis and variation principle. The correctness of the theoretical analysis was verified by the sliding test of the ore pillar under the combined dynamic and static loading. The results indicate that the dynamic slip instability (or slip rock burst) only occurs in the post-peak stage; for the ore pillar under pre-peak stable equilibrium state, certain extra energy from dynamic disturbance (such as blasting vibration, fracture of tunnels and natural activities) is needed to trigger dynamic slip instability; simultaneously, the value of loading stiffness k1 must be smaller than that of post-peak stage k2.The accurate prediction of intensity of slip rock burst of ore pillar should be performed by determining the value of excess shear stress.