确定弹性应变能指标的岩样卸载点的声发射方法

The Acoustic Emission Method to Determine the Unloading Point of Elastic Strain Energy Index

弹性应变能指标方法是岩爆倾向性评判中应用最多的一种方法,但该方法的一个技术难题是在实验中难以确定卸载点。在武夷山隧道工程的岩爆倾向性评价的室内试验中结合岩石的声发射监测技术,试图解决这个难题,并利用弹性应变能指标法对该隧道的岩爆倾向性进行了评价。试验研究结果表明,采用声发射监测技术并利用岩石峰值破坏前声发射突增的特性,可以较好地控制初次加载达到岩石峰值强度的80%以上,且在岩石不发生破坏的情况下及时卸载,从而能很好地满足弹性应变能指标法对岩石加卸载条件的要求,提高了测试结果的可靠性。同时,本实验得出该隧道具有发生中等岩爆的倾向性的结论。

The method of elastic strain energy indices is one of the methods that applied most for rockburst proneness evaluation. However,one technical problem of this method is that it is difficult to determine the unloading point in the experiment. Indoor experiment of rock burst evaluation is conducted combining acoustic emission monitoring techniques in Wuyishan tunnel. The purpose is try to solve the problem and evaluate the rock burst proneness for the tunnel by strain energy index. Experimental results show that when taking advantage of the sudden increase in acoustic emission before rock damage by acoustic emission monitoring system,we can achieve better control of the initial loading of rock reach more than 80% of the peak intensity,and the rock damage does not occur in the case promptly unloading,Which can satisfy the loading and unloading conditions required of elastic strain energy index method to improve the reliability of test results. Meanwhile,the results of this experiment show that rock burst proneness of the tunnel is of medium prone.