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深部岩体在采掘过程中受到的扰动,实质上就是围岩体加卸载过程,此过程岩体所表现出来的性质实际上是它的峰后强度特性。基于MTS815岩石力学实验系统和PCT-2型声发射测试分析系统,对不同围压条件下岩石全应力应变及峰后卸载过程中的声发射特性进行研究。研究表明:在岩石屈服阶段前声发射信号较少,而在屈服阶段后,声发射信号迅速增加;累计振铃计数-时间曲线有个明显的台阶,表明试件破坏前出现相对平静期;试件处于残余阶段,所接收到的声发射信号减少,累计振铃计数曲线斜率减小。在卸围压前,声发射信号相对较少,但在卸围压过程中,声发射信号开始活跃,并且围压越高,声发射累计振铃计数更大,释放能量更高,该现象正好说明在高地应力条件下更容易发生岩爆现象。
The disturbance of deep rock mass during excavation is essentially the loading and unloading process of the surrounding rock mass. The nature of the rock mass in this process is actually its post-peak strength property. Based on the MTS815 rock mechanics experimental system and the PCT-2 acoustic emission test and analysis system, the acoustic emission characteristics under full confinement stress and unloading of rocks under different confining pressures were studied. The results show that there are few acoustic emission signals before the rock yielding stage, and the acoustic emission signals increase rapidly after the yielding stage. The cumulative ringing counting-time curve has a clear step, which shows that there is a relatively quiet period before the specimen failure. Pieces are in a residual phase, the acoustic emission signal received is reduced, and the slope of the cumulative ringing count curve is reduced. Acoustic emission signals are relatively low before unloading confining pressure, but acoustic emission signals start to be active during the unloading confining pressure. The higher the confining pressure is, the more the acoustic emission cumulative ringing counts and the higher the releasing energy. This phenomenon is exactly It shows that rock burst is more likely to occur under high stress conditions.