To study the rock mechanical behaviors and damage process mechanism of granite samples under triaxial stress, conventional triaxial compression tests were carried out on an RMT-150B rock mechanics testing machine and acoustic emission detector. The test results show that the strength of the granite sample has a good linear relationship with the confining pressure, the cohesion force of the granite samples is 29.37 MPa, and the internal friction angle is 54.23° by calculation based on the Mohr-Coulomb strength criterion. The larger the initial confining pressure of the rock sample is, the larger the crack initiation stress () and dilatancy stress () of the granite specimen are, the larger the energy values at the crack initiation point and dilatancy point are, and the larger the peak energy storage and energy release rate at the failure are. In the case of a small initial confining pressure, the AE ringdowning counts and the cumulative AE ringing counts increase to their maximum instantaneously at the peak stress point, and the damage of the sample develops rapidly. While the initial confining pressure is high, the AE ringing counts and the cumulative AE ringing counts of the granite specimens increase evenly, and the deformation damage of the granite specimens is slow. Before the crack initiation point, AE signals are mainly low-energy and low-frequency friction-type AE events, while after the dilatation point, AE signals of samples are mainly high-frequency and high-energy fracture-type AE events. The failure mode of granite samples judged by acoustic emission parameters according to the distribution of characteristic values of AE parameters RA and AF is consistent with the reality. The AE value of the granite sample is large when the confining pressure is low, and there will be a sudden drop, the decrease time is late, and the decrease rate is large. Under the same stress level, the larger the confining pressure is, the larger the damage variable is.

中文翻译：

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三轴压缩下花岗岩力学行为及声发射特性研究

为研究三轴应力作用下花岗岩试样的岩石力学行为及损伤过程机制，在RMT-150B岩石力学试验机和声发射探测器上进行常规三轴压缩试验。试验结果表明，花岗岩试样的强度与围压具有良好的线性关系，根据莫尔-库仑强度准则计算，花岗岩试样的内聚力为29.37 MPa，内摩擦角为54.23° . 岩样初始围压越大，裂纹萌生应力（）和剪胀应力（）越大花岗岩试件的裂纹萌生点和剪胀点的能量值越大，破坏时的峰值储能和能量释放率越大。在初始围压较小的情况下，AE 振铃计数和累积 AE 振铃计数在峰值应力点瞬间增加到最大值，样品损伤迅速发展。在初始围压较高的情况下，花岗岩试件的AE振铃次数和累积AE振铃次数均匀增加，花岗岩试件的变形破坏速度较慢。在裂纹萌生点之前，声发射信号主要是低能量、低频摩擦型声发射事件，而在膨胀点之后，样品的声发射信号主要是高频、高能量的裂缝型声发射事件。根据声发射参数RA和AF的特征值分布，通过声发射参数判断花岗岩样品的失效模式与实际相符。AE围压低时花岗岩试样的值大，会出现突然下降，下降时间晚，下降率大。在相同应力水平下，围压越大，损伤变量越大。