断层冲击地压失稳过程声发射特征实验研究

Experimental study on acoustic emission characteristics during the unstable sliding of fault rock burst

利用花岗岩双剪滑动模型进行岩石界面滑动实验,以声发射系统作为岩石界面滑动过程信息采集手段,开展断层冲击地压失稳的声发射特征研究。对花岗岩界面滑动过程中声发射振铃计数、声发射能量、声发射主频和声发射事件率进行分析。根据分析结果可知:(1)岩石界面产生滑动时对应的荷载降低量值逐渐增加;岩石界面滑动时刻对应的声发射振铃计数激增,且激增量值呈现逐渐减小的变化趋势;(2)在岩石界面滑动全过程中,岩石界面首次滑动时声发射能量较小,随着加载的进行,岩石界面发生滑动时刻对应声发射能量整体呈现逐渐增大的变化趋势;(3)岩石界面首次滑动后,各主频范围内的声发射事件均减少,在界面滑动时刻的声发射事件减少更为明显;(4)在岩石界面发生滑动前,荷载增长变缓时刻,声发射事件率开始出现下降,此特征可作为断层冲击地压发生的前兆信息。

Experimental study on rock interface sliding is carried out using double shear model of granite. Acoustic emission system is used as a data acquisition method for viscous sliding process of rock interface. Characteristics of acoustic emission in the process of fault slip. The acoustic emission,ringing counts,acoustic emission energy,acoustic emission frequency and AE event rate are analyzed. According to the analysis results： during the experiment,the amount of load reduction corresponding to the rock interface sliding increases gradually,the interface sliding time corresponds to the acoustic emission,the ringing count increases sharply,and the increment value of the excitation decreases gradually; for the first time,the acoustic emission energy is minimum at the interface sliding,as the loading goes on,the interface slip at the rock interface occurs at the moment,and the acoustic emission energy increases gradually as a whole; when the rock interface slides for the first time,the acoustic emission events in each frequency range are smaller,and the events are less obvious at the sliding time; before the rock interface slides,the load increases slowly,and the AE event rate begins to decrease. At this moment,it can be used as precursor information of fault slip.