Rock burst is a serious nonlinear dynamic geological hazard in underground engineering construction. In this paper, a true triaxial unloading rock burst experiment and numerical simulation are carried out on Tianhu granite to investigate the rock burst tendency and crack development characteristics of surrounding rock after excavation. The experiment and numerical simulation process monitored the rock burst stress path to determine the rock burst stress. According to the evolution law of the frequency and amplitude of rock burst acoustic emission monitoring, the shape characteristics of rock burst fragments are analyzed. The rock burst numerical simulation analysis is carried out by the PFC software, and the temporal and spatial evolution law of cracks is obtained. The research results show that the laboratory experiment and numerical simulation of Tianhu granite have rock burst strengths of 163.4 MPa and 161 MPa, respectively, and the average rock burst stress ratio is 8.38, that is, the Tianhu granite has a low rock burst tendency. During the rock burst, the development of tensile cracks will produce flaky debris, and the development of shear cracks will produce lumpy debris. Rock burst will happen when the crack growth rate to be exceeded the unloading crack growth rate; therefore, it can be used as a precursor signal for the occurrence of rock burst.

中文翻译：

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天湖花岗岩岩爆趋势及裂缝发育特征的试验与数值分析

岩爆是地下工程建设中严重的非线性动态地质灾害。本文对天湖花岗岩进行了真实的三轴卸荷岩爆试验和数值模拟，研究了开挖后围岩的岩爆趋势和裂缝发展特征。实验和数值模拟过程监控了岩爆应力路径，以确定岩爆应力。根据岩爆声发射监测频率和幅度的演化规律，分析了岩爆碎片的形状特征。利用PFC软件对岩爆进行了数值模拟分析，得出了裂纹的时空演化规律。研究结果表明，天湖花岗岩的室内试验和数值模拟分别具有163.4 MPa和161 MPa的岩爆强度，平均岩爆应力比为8.38，即天湖花岗岩具有较低的岩爆趋势。在岩石破裂期间，拉伸裂纹的发展将产生片状碎屑，而剪切裂纹的发展将产生块状碎屑。当裂纹扩展速率超过卸载裂纹扩展速率时，将发生岩石破裂。因此，它可以用作发生岩爆的前兆信号。拉伸裂纹的发展将产生片状碎屑，而剪切裂纹的发展将产生块状碎屑。当裂纹扩展速率超过卸载裂纹扩展速率时，将发生岩石破裂。因此，它可以用作发生岩爆的前兆信号。拉伸裂纹的发展将产生片状碎屑，而剪切裂纹的发展将产生块状碎屑。当裂纹扩展速率超过卸载裂纹扩展速率时，将发生岩石破裂。因此，它可以用作发生岩爆的前兆信号。