The coal-rock combination body is prone to rock burst and surface subsidence under loading, and adopting effective monitoring methods are valuable. In this paper, cyclic loading and unloading (CLU) tests were conducted to investigate the response and precursor of pressure stimulated currents (PSCs) in coal-rock combination samples. The results indicate that the PSCs of the coal-rock combination samples have good response characteristics to stress. Furthermore, the PSCs between the two components are significantly larger and more stable than those of the coal body, which can clearly reflect the failure under a progressive failure mechanism and are related to the difference in the resistivities and microstructures of the components. During the CLU tests, the PSCs of each cycle are well fitted by the Gaussian distribution and have a memory effect. During the loading or unloading process of each cycle, the variation in PSCs with stress conforms to the power function relationship with exponent . As the cycle number increases, the rates of increase in PSC under stress are gradually weakened, and the indexes of PSCs including exponent increase or decrease sharply first and then remain stable or even decrease, which is due to the loading history. The stable state of these indexes with obvious inflection points in later cycles of CLU tests can be considered a precursor of coal-rock failure. The PSC flow direction between the two components is exactly opposite to that in the coal body. The results provide new ideas for the monitoring and prediction of coal-rock combination body failure, which is helpful for the prevention of geological disasters in mines.

中文翻译：

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循环应力下组合煤岩压力激流响应及前兆实验研究


煤岩结合体在荷载作用下容易发生岩爆和地表沉陷，采取有效的监测方法具有重要意义。本文通过循环加载和卸载（CLU）试验来研究煤岩组合样品中压力刺激电流（PSC）的响应和前兆。结果表明，煤岩组合样品的PSC具有良好的应力响应特性。此外，两个构件之间的PSC明显比煤体更大且更稳定，这可以清楚地反映渐进破坏机制下的破坏，并且与构件的电阻率和微观结构的差异有关。在CLU测试过程中，每个周期的PSC都很好地符合高斯分布，并且具有记忆效应。在每个循环的加载或卸载过程中，PSC随应力的变化符合指数 的幂函数关系。随着循环次数的增加，PSC在应力作用下的增加速率逐渐减弱，PSC的各项指标包括指数先急剧上升或下降，然后保持稳定甚至下降，这是由于加载历史所致。这些指标在以后的CLU试验循环中处于稳定状态并出现明显的拐点，可以认为是煤岩破坏的前兆。两个组分之间的PSC流动方向与煤体中的流动方向正好相反。研究结果为煤岩结合体破坏监测与预测提供了新思路，有助于矿山地质灾害的防治。