基于局部矿井刚度理论的冲击地压机理研究

Coal bursts involve the sudden, violent ejection of coal or rock into the mine workings without warnings. They are one of the most safety important issues faced by Chinese coal mine industry. Existing mechanisms of coal bump are basically elaborated from the perspective of stress or energy. This project aims to propose a new mechanism of coal bump from the perspective of stiffness. The research will be performed using a combined method of laboratory test, physical modeling, numerical modeling and theoretical analysis, based on the principles of rock mechanics, geology and geophysics. The influence of low-stiffness loading on the energy evolution mechanism of coal during unstable failure process, factors controlling the post-peak characteristic curve of coal, the temporal and spatial evolution of local mine stiffness and the influence of coal mechanical properties on the evolution of local mine stiffness will be systematically studied. The objective of this project is to promote and expand the theoretical study of coal bump, provide further insight into the coal bump mechanisms and scientific measures for the warning and prevention of coal bump hazards in China.

冲击地压是煤岩体突然抛出的动力现象,是我国煤炭资源开采所必须面对的重要问题之一，问题的根本解决需要从最基础的机理研究做起。现有的冲击地压机理基本上都是从应力或能量的角度来阐述的。本项目针对煤矿冲击地压机理问题，基于岩石力学、地质学、地球物理学等，综合采用实验室试验、相似模拟、数值模拟、理论分析等研究方法，以局部矿井刚度时空变化为核心，系统研究低刚度加载诱发煤岩不稳定性破坏能量演化机理、煤体峰后特征曲线影响因素、局部矿井刚度随采掘过程发展的时空演化规律、煤体力学特征对局部矿井刚度演化的影响规律等一系列研究工作，以此推动、拓展煤矿冲击地压的理论研究，为我国煤矿巷道掘进冲击地压的预警与防治提供一定的理论参考与科学对策。

本项目针对煤矿冲击地压机理问题，以局部矿井刚度时空变化为核心，系统研究低刚度加载诱发煤岩不稳定性破坏能量演化机理、煤体峰后特征曲线影响因素、局部矿井刚度随采掘过程发展的时空演化规律、煤体力学特征对局部矿井刚度演化的影响规律等。通过不同弹性模量的细砂岩、粉砂岩开展了不同刚度加载垫块组合下的煤样单轴压缩试验，分析了不同刚度加载垫块下煤样的变形与冲击破坏过程，得到了低刚度加载下煤样的不稳定破坏模式，揭示了低刚度加载诱发煤岩不稳定破坏的能量传递与演化机制；研发了基于局部矿井刚度理论的冲击地压模拟试验系统并开展了不同加载刚度条件下中心煤柱冲击试验，阐明了局部矿井刚度随采掘推进的时空演化规律及诱冲机理；探究了基质力学性质、结构弱面特征、测试煤样尺寸及加载条件对煤样峰后特征影响，对单一显著影响因素及多因素交互作用进行敏感性分析,并采用大直径钻孔卸压技术在煤矿现场进行了工业性试验及理论验证；以红庆河煤矿地质条件为工程背景构建了FLAC 3D数值模型，系统分析了煤柱变形、载荷、弹性能量密度及局部矿井刚度随采掘作业演化过程，并与现场实测地音及微震数据进行对比分析，揭示局部矿井刚度随采掘推进的时空演化规律及其诱冲机理。本项目研究成果从局部矿井刚度随采掘作业演化角度揭示深埋矿井冲击频发原因，为煤矿冲击地压防治与机理研究提供新思路。