Frontier mechanical issues of coal-rock-gas dynamic disasters

Deep coal mining encounters a complex engineering environment characterized by high in-situ stress, high gas pressure, high geothermal temperature, intense mining disturbances, and evident time effect. This multi-physical field coupling fundamentally distinguishes deep mining from a shallow condition and frequently leads to sudden coal-rock-gas dynamic disasters. This paper comprehensively reviews and analyses the static and dynamic mechanical behavior of deep coal-rock masses, the popular discrimination criteria for these dynamic disasters, the underlying mechanisms of their incubation and triggering, the advanced experimental techniques and numerical simulation methods for their reproduction, and the corresponding disaster prevention and control technologies. In addition, this research further systematically elucidates the frontier mechanical issues related to these dynamic disasters under deep mining conditions. It highlights the evolution of research paradigms from static to dynamic and coupled static-dynamic mechanics, emphasizing the central role of addressing mechanical problems in understanding and mitigating these disasters. Critically, it also presents pioneering prevention technologies of our research group, such as in-situ zonal coal seam modification, in-situ gas deflagration and ideas of intelligent control, which transition the disaster mitigation from passive relief to active mechanical regulation. By integrating the latest research from our group with a global perspective, this work provides a comprehensive and frontier mechanical framework and novel technical pathways, offering invaluable scientific support for overcoming the safety challenges in deep coal mining.