侧压对巷道岩爆声发射及损伤特性影响试验研究

采用双轴刚性伺服控制系统进行花岗岩岩爆模拟试验，采用美国物理声学公司生产的PCI-2型声发射系统同步采集岩爆过程中的声发射数据，研究了不同水平构造应力对巷道岩爆的影响。研究结果表明:随着侧压的升高，花岗岩峰值强度随之增加，并且孔洞内壁初次弹射岩屑的时间提前;轴向载荷达到峰值荷载的80%～88%时，声发射进入平静期。随着侧压的增大，峰值载荷前的声发射平静期延长，振铃计数率突增点出现的时间提前;随着侧压的增大，岩样出现初始损伤的时间相对滞后。花岗岩孔洞内出现碎片弹射时，声发射b值下降到最低值，这一现象可作为发生岩爆的前兆特征。

Experimental Study of Influence of Lateral Pressure on the Characteristics of Acoustic Emission and Damage during the Rock Burst of Tunnel

An experiment is carried out to simulate granites rock burst with biaxial rigid servo-controlled system. The PCI-2 acoustic emission system produced by American Physical Acoustics Corporation is used to collect the data of acoustic emission in the process of rock burst synchronously. The influence of different horizontal tectonic stress on tunnel rock burst is studied. The result shows that with the increase of lateral pressure, the peak intensity of granites becomes larger and larger and the earlier the inwall of the hole first ejects rock debris. The acoustic emission of granites comes into quiet period when the axial load reaches 80%~88% of the peak load. The higher lateral pressure is, the longer the quiet period is and the earlier the ringing count rate suddenly increases. The initial damage of granites occurs later with the increasing lateral pressure. The acoustic emission b-value decreases to the lowest when the inwall of the hole first ejects rock debris, which can be used as a precursory characteristic of rock burst.