不同类型岩石加载破坏的微震和电荷感应信号特征研究

根据岩石变形破坏过程中有微震信号和电荷感应信号产生,利用岩石变形破裂过程微震和电荷感应监测系统,对不同类型岩石在单轴压缩和加卸载下变形破裂过程进行实时同步监测以获取微震和电荷感应信号特征。试验结果表明:不同类型岩石在变形破裂过程中有微震和电荷感应信号产生,微震和电荷感应信号是低频信号,信号频谱主要集中在40 Hz以下,随着岩石强度的增大,岩石变形破裂过程中的微震和电荷感应信号事件数增大且信号强度也增大;岩石变形破裂过程中微震和电荷的产生机理不同,微震信号是由于岩体裂纹扩展释放弹性应变能而引起的振动波,而电荷主要有微破裂、摩擦作用、压电效应等综合作用产生;对比不同类型岩石变形破裂过程的微震和电荷感应信号并对各信号进行相关性分析,研究发现,岩石在失稳破坏时存在着丰富的微震和电荷感应信号,且各信号具有高相关性,此阶段可作为最危险预警区。

Study on microseismic and charge induction signal characteristics of different types of rock loading failure

According to the generation of microseismic signals and charge induction signals during rock deformation and failure, the monitoring system of microseismic and charge induction for rock deformation and failure process were used to simultaneous monitor the deformation and fracture process for different rock in uniaxial compression loading and unloading and to obtainthe signals characteristics of microseismic and charge induction. The results showed that there were microseismic and charge induction signals in the process of deformation and fracture of different types of rocks, which are with low frequencies, and the signal spectrum are mainly lower than 40Hz. With the increase of rock strength, the signal event number and intensity of microseismic and charge induction signals during rock deformation and fracture process increased. The induced mechanism of microseismic and charge induction signals is different during rock deformation and fracture process. The microseismic signal is due to rock crack propagation release of elastic strain energy in vibration wave form; however, the charge is produced under the comprehensive effect of micro fracture, the friction effect and the piezoelectric effect. The microseismic and charge induction signals are compared during different rock deformation and fracture process, and the correlations of the signals were analyzed. We found that there are abundant microseismic and charge-induced signals with high correlations in rock failure, which can serve as the most dangerous warning zone.