To study the influence of the loading rate on the failure process of coal, uniaxial compression tests were performed with various axial strain rates of 0.83 × 10 –5 to 6.66 × 10 –5 s −1 on coal samples, which were collected from the Shamushu Coal Mine in Sichuan Province. The parameters of stress, strain, and acoustic emission during the failure process were collected and recorded. The peak stress, axial strain stiffness, energy dissipation, and acoustic emission characteristics of coal samples with different axial strain rates were analysed. The results demonstrate that (1) as axial strain rates increase, the peak strength and degree of fragmentation of the coal sample after failure also increase, and they exhibit good dependence on the axial strain rate; (2) the axial strain rate has little influence on the change trend in strain stiffness during the process of failure, but as the axial strain rate increases, the strain stiffness value of the horizontal section of the axial strain stiffness curve increases, and the initial stress level of this stage has a forward trend; (3) as the axial strain rate increases, the total energy absorbed by the coal sample increases gradually, and the proportion of elastic strain energy decreases when the peak stress is reached, while the proportion of dissipated energy increases gradually; (4) as the axial strain rate increases, the AE signal’s activity increases in the process of sample failure, the threshold value of the strain level decreases corresponding to AE active and intense periods, and higher amplitude AE signals are produced in the violent period. The research results can provide reference for monitoring and controlling geological hazards, such as pillar instability and failure in underground mining.

中文翻译：

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基于单轴压缩试验的煤破坏过程加载速率相关性研究

为了研究加载速率对煤破坏过程的影响，对采自沙木树的煤样进行了单轴压缩试验，轴向应变速率为 0.83 × 10 –5 至 6.66 × 10 –5 s -1四川省煤矿。收集并记录破坏过程中的应力、应变和声发射参数。分析了不同轴向应变速率下煤样的峰值应力、轴向应变刚度、能量耗散和声发射特性。结果表明：（1）随着轴向应变率的增加，破坏后煤样的峰值强度和破碎程度也随之增加，且对轴向应变率表现出良好的依赖性；(2) 轴向应变率对破坏过程中应变刚度的变化趋势影响不大，但随着轴向应变率的增大，轴向应变刚度曲线水平截面的应变刚度值增大，初始此阶段压力水平有前移趋势；(3)随着轴向应变率的增加，煤样吸收的总能量逐渐增加，达到峰值应力时弹性应变能的比例减小，耗散能的比例逐渐增加；(4)随着轴向应变率的增加，样品失效过程中声发射信号的活动性增加，声发射活动和强烈期对应的应变水平阈值降低，在剧烈期产生更高幅度的声发射信号。