Jing Gang, Wang Shuai, Zhao Leilei, Dong Fa, Fan Yi
Key Laboratory of Xinjiang Coal Resources Green Mining, Xinjiang Institute of Engineering, Ministry of Education, Ürümqi, 830023, China.
Xinjiang Key Laboratory of Coal-bearing Resources Exploration and Exploitation, Xinjiang Institute of Engineering, Ürümqi, 830023, China.
Sci Rep. 2025 Jul 2;15(1):22750. doi: 10.1038/s41598-025-08281-y.
Predicting coal bursts in deep mining requires understanding the crack propagation and acoustic emission (AE) characteristics of coal under triaxial stress conditions. This study employs discrete element simulation to investigate the mechanical behavior and AE responses of cylindrical coal specimens under varying confining pressures. The results demonstrate that peak strength increases with loading rate, particularly under low confining pressures, while higher pressures dampen this sensitivity. Volumetric strain-stress curves effectively identify crack initiation and damage thresholds, which increase with confining pressure while reducing the duration of unstable crack propagation. The proportion of tensile cracks gradually decreases while the proportions of shear and mixed-mode cracks increase. Specimens remain stable when β-value < 1 and enter instability when β-value > 1, with β-value remaining unaffected by confining pressure variations., Meanwhile, b-value exhibit a "sharp-drop-plateau" pattern prior to failure. These findings provide a theoretical framework for interpreting AE signals in deep mining environments, enhancing coal burst prediction capabilities through mechanistic insights into confining pressure effects on crack evolution and precursor indicator.
预测深部开采中的煤与瓦斯突出需要了解三轴应力条件下煤体的裂纹扩展和声发射（AE）特性。本研究采用离散元模拟方法，研究了不同围压下圆柱形煤样的力学行为和声发射响应。结果表明，峰值强度随加载速率的增加而增加，特别是在低围压下，而较高的围压会减弱这种敏感性。体积应变-应力曲线有效地识别了裂纹萌生和损伤阈值，这些阈值随围压的增加而增加，同时缩短了不稳定裂纹扩展的持续时间。拉伸裂纹的比例逐渐减小，而剪切裂纹和混合模式裂纹的比例增加。当β值<1时，试件保持稳定；当β值>1时，试件进入失稳状态，β值不受围压变化的影响。同时，b值在破坏前呈现“急剧下降-平稳”模式。这些发现为解释深部开采环境中的声发射信号提供了理论框架，通过对围压对裂纹扩展和前兆指标影响的机理洞察，提高了煤与瓦斯突出的预测能力。
