基于相似材料的岩爆模型实验及其能量释放机制

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.

On the Rockburst Model Experiment Based on Similar Material and the Energy Releasing Mechanism

There is an essential difference between rock mass destruction due to unloading and due to loading. As one of the geological disasters, rockburst is often generated in underground engineering in high geo-stress areas due to the excavation unloading. Aiming at the rock mass under high hydrostatic pressure, taking advantage of the rosin model, the experimental simulation test of the dynamic fragmentation-type "rockburst" due to radial instantaneous unloading was studied. Through the analysis of peak velocity in dynamic fragmentation and unloading acting time, a formula about strain energy and kinetic energy and velocity of spalling fragments was deduced. Rresults show that the formula presented in this paper for calculating peak velocity and kinetic energy is proper, and the kinetic energy is only a small fraction of the recovery strain energy, most of which is dissipated in different ways; the unloading time at different positions apart from the free surface is nearly the same and is much larger than the unloading wave disturbance time. The velocity of the braking wave front is uniform and much less than the velocity of the unloading wave.