围压对圆形巷道岩爆过程中声发射及能量释放规律的影响

利用FLAC模拟了不同围压下圆形巷道围岩岩爆过程中的声发射及能量释放过程。利用8个FISH函数开挖巷道,统计破坏单元数目及破坏单元在应变软化阶段的能量释放总量和能量释放率。模拟分为3步:首先,将静水压力施加在模型上,直到达到静力平衡状态;然后开挖巷道;最后,重新计算,直到达到静力平衡状态或者塑性流动状态。模拟结果表明,当围压较高时,开挖巷道后的围岩的声发射活动呈现间歇式上升特征;而当围压较低时,开挖巷道后的围岩中的声发射活动最终趋于平静;随着围压的增加,能量释放现象出现得早些,声发射累计数、释放的弹性应变能都增加。在开挖巷道后的围岩中,发生剪破坏的单元释放的弹性应变能总量大于发生拉破坏的,最高的剪应变能释放率大于最高的拉应变能释放率。

Influence of Confining Pressures on the Rule of Acoustic Emission Events and Energy Liberation During Rockburst in the surrounding rock of Circular Tunnel

Acoustic emission events and energy liberation during rockburst in the surrounding rock of circular tunnel are simulated by FLAC. Eight FISH functions are used to excavate the circular tunnel and calculate the number of failed elements, the amount and rate of the elastic strain energy liberation in rockburst processes. The simulation is divided into three steps. Firstly, a hydrostatic pressure is applied to the model until the static equilibrium state is reached. Then the tunnel is excavated. Finally, the calculation restarts. Results indicate that active and si- lent acoustic emission events appear alternately at higher confining pressures and dissappear at lower ones after the tunnel is excavated. High- er confining pressure leads to earlier occurrence of the energy liberation, bigger accumulated acoustic emission counts and higher liberated e- lastic shear strain energy. In the excavated model, the liberated elastic strain energy due to shear failure is higher than that due to tensile failure, and the maximum shear strain energy liberation rate is higher than the maximum tensile one.