With the steady increase in the size, intensification, and modernization of coal production enterprises, the deep coal resources in large coal bases are gradually entering the mining stage. When the coal mining reaches the deep zone, the interactions between various underground dynamic hazards begin to occur. These interactions are affected by the engineering geological environment and can lead to the occurrence of severe compound hazards. When coal and gas outbursts occur and destabilize the mining area, the high geostress causes the multiphysical coupling effect of the laminated overburden system to become more pronounced. Therefore, we analyzed the development path of a coal-rock system under instability conditions from the perspective of coal–rock coupling, constructed a model of the coal-rock combination system’s structure, and proposed three directions (i.e., strain softening, limit equilibrium, and dynamic instability) for the development of coal-rock system instability. Then, we established a model for the critical conditions of the system’s failure process and elucidated that the release of the rock’s elastic energy promoted the instability of the coal. Furthermore, we verified the established critical conditions through laboratory tests on a coal-rock combination structure and obtained the patterns of the rock energy transferring into the coal seam during the instability failure process of the coal–rock combination structure. When the coal–rock combination structure failed, the rock strain reached its maximum value and the strain rebound phenomenon occurred. The stored elastic strain energy released by the rock into the combination system accounted for 26% to 53% of the accumulated energy in the rock itself, and the released elastic energy and the new surface area of the crushed coal sample followed a logarithmic relationship. The findings of this study provide theoretical support for the identification and quantitative analysis of instability due to the dynamic hazards of coal-rock gas in deep mines.

中文翻译：

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深部煤岩组合系统破坏过程的临界条件和能量传递特性

随着煤炭生产企业规模的不断壮大，集约化和现代化程度的提高，大型煤炭基地的深层煤炭资源正逐步进入开采阶段。当煤矿开采到达深部区域时，各种地下动力灾害之间便开始发生相互作用。这些相互作用受工程地质环境的影响，并可能导致严重的复合危害的发生。当发生煤与瓦斯突出并破坏采矿区的稳定性时，高地应力会导致层状覆盖系统的多物理场耦合效应变得更加明显。因此，我们从煤岩耦合的角度分析了不稳定条件下煤岩系统的发展路径，构建了煤岩组合系统结构模型，并提出了煤岩系统失稳发展的三个方向（即应变软化，极限平衡和动力失稳）。然后，我们为系统失效过程的关键条件建立了一个模型，并阐明了岩石弹性能量的释放促进了煤的不稳定性。此外，我们通过对煤岩组合结构进行实验室测试，验证了已建立的临界条件，并获得了在煤岩组合结构失稳破坏过程中岩石能量转移到煤层中的模式。当煤岩组合结构破坏时，岩石应变达到最大值，并发生应变回弹现象。岩石释放到组合系统中的储能弹性应变能占岩石本身储能的26％至53％，并且释放的弹性能与碎煤样品的新表面积呈对数关系。本研究结果为深部煤层气动态危害引起的失稳的识别和定量分析提供了理论支持。