动力扰动下含瓦斯高储能煤体失稳破坏机理研究

Abstract: When underground coal mining is extending to deep levels, coal and gas outbursts frequently take place, which are associated with underground high stress conditions. Underground coal and rock are subjected to the combined effects between high stress and gas pressure. During mining activities, they are frequently subjected to dynamic disturbance such as instantaneous excavation unloading, mining stress redistribution, blast loading from adjacent underground openings and periodic roof caving, etc. In this project, the coal and gas outburst is considered as a complex dynamic problem combining coupled static-dynamic loading and stress-fluid flow. The micro-structure damage and strength deterioration of gas-containing coal subjected to coupled static stress and gas pressure will be investigated at first. Then a damage mechanical model for gas-saturated coal under static stress conditions will be developed. The modified triaxial coupled static-dynamic loading SHPB test system will be employed to investigate dynamic properties of coal samples saturated with methane. Based on the former experiment results, the impact disturbance factor will be introduced from rock dynamics and structural instability theory, which quantitatively illustrates the necessary involvement of dynamic disturbance in triggering coal and gas outbursts. The failure mechanism of coal subjected to coupled static stress, gas pressure and dynamic disturbance will be proposed. In addition, the rule how impact disturbance hazards influence the coal and gas outbursts intensity will be illustrated and clarified by the self-developed multe-field coupling simulation test equipment for dynamic hazards in coal mines, which guides underground coal mining activities and disaster control.

随着煤炭开采走向深部，煤岩体经常处于高应力及瓦斯压力共同作用状态，煤岩体采掘工程中的动力扰动，如强卸荷、开采应力重分布、工程爆破荷载和顶板周期垮落等，都容易诱发煤与瓦斯动力灾害。项目将煤与瓦斯突出作为动静组合荷载与固气耦合共同作用的复杂动力学过程进行研究，首先研究静力载荷与瓦斯压力共同作用下煤样的细观结构损伤演化及强度劣化规律，建立静力载荷下含瓦斯煤体的损伤力学模型；然后借助改进的三轴动静组合载荷SHPB试验系统，研究含瓦斯煤体的动载强度规律与冲击动力学特性，获得含瓦斯煤岩的动态本构关系；在此基础上，结合岩石动力学和结构失稳理论，量化表征冲击载荷扰动因子，提出“静态应力+瓦斯压力+动力荷载”组合应力环境下的煤体破坏机理；最后，利用自主研制的多场耦合煤矿动力灾害大型模拟试验系统，验证并阐明动力扰动对煤与瓦斯突出强度的影响规律，为深部煤炭开采的动力灾害控制提供参考依据。

随着煤炭开采走向深部，煤岩体经常处于高应力及瓦斯压力共同作用状态，煤岩体采掘工程中的动力扰动，如强卸荷、开采应力重分布、工程爆破荷载和顶板周期垮落等，都容易诱发煤与瓦斯动力灾害。项目将煤与瓦斯突出作为动静组合荷载与固气耦合共同作用的复杂动力学过程进行研究。首先研究静力载荷与瓦斯压力共同作用下煤样的细观结构损伤演化及强度劣化规律，建立静力载荷下含瓦斯煤体的损伤力学模型；然后基于能量守恒原理建立的煤与瓦斯突出能量判据，并基于试验结果渗透率随有效应力的演化规律，建立的瓦斯运移致灾关键结构，最终基于瓦斯运移致灾关键结构建立了煤与瓦斯突出力学判据，验证并阐明动力扰动对煤与瓦斯突出强度的影响规律，为深部煤炭开采的动力灾害控制提供参考依据。