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岩体的卸载破坏和加载破坏有本质区别,岩爆是高地应力区地下工程开挖卸载产生的地质灾害现象。针对处于高静水压力状态下的岩体,采用松香模型实验研究径向瞬时卸载引起动力破碎型“岩爆”;通过分析动力破碎过程中的速度峰值、卸载波作用时间特征,推导了应变能及剥落(破碎)块体动能及速度计算公式。结果表明:文中给出的速度峰值和动能计算方法是可行的,剥落(破碎)块体动能仅占可恢复应变能很小部分,大部分能量最终以不同形式耗散掉;距自由面不同距离处的卸载波作用时间大致相等,远大于卸载波的扰动时间;破碎波阵面在介质中推进速度大致为匀速,也远小于卸载波扰动速度。
There is an essential difference between unloading failure and loading failure of rock mass. Rock burst is the geological disasters caused by the unloading of underground engineering in high stress area. Aiming at the rock mass under the condition of high hydrostatic pressure, the dynamic crushing type “rockburst” caused by radial instantaneous unloading is induced by the rosin model experiment. By analyzing the velocity peak during unloading and the time characteristic of unloading wave, the strain Can spalling (broken) block kinetic energy and speed formula. The results show that the calculation methods of velocity peak and kinetic energy are feasible. The kinetic energy of exfoliated (fragmented) blocks accounts for only a small part of the recoverable strain energy, and most of the energy eventually dissipates in different forms. At different distances from the free surface The unloading waves have roughly equal acting time, which is much larger than the unloading wave disturbance time. The breaking wave front propagating in the medium is almost uniform and far less than the unloading wave disturbance rate.