采动煤岩动静荷载组合作用力学机制及损伤演化特征

As the coal resource exhausted increasingly in shallow mining area, the deep mining will turn into a normal state in the future. The complex mechanical environment in the deep mining leads to the low efficiency of gas extraction in high-outburst coal mines. Developing the accurate mechanical model of deep mining is the key to realize ultra-low ecological damage mining. The mechanical essence of coal and rock during the mining process will be proposed. It breaks through the traditional quasi-static method research framework that ignores the cover depth effect and engineering disturbance. The mechanical model considering coupled dynamic and static loads for deep coal mining should be developed. Namely, the static loads result from the high-stress state of gravitational and the tectonic effect and the dynamic loads result from the mining effect. Based on self-researched international advanced real-triaxial loading CT system, the innovative test loading paths that reproduces the real mining process will be proposed. The mechanical characteristics and failure law under the static-dynamic loading and load-unloading test will be deeply explored. The difference between the mechanical characteristics of static-dynamic loading and conventional quasi-static loading will be studied. Besides, the evolution of fracture network and seepage characteristics under static-dynamic loading will obtain a scientific understanding. Combining the different coal mines with different mining depth, the coal rock mechanics behavior will be discussed from the aspect in which the relationship between the gas flow law and buried depth and mining intensity considered. The micro-damage and permeability-enhanced characteristics under the static-dynamic loading and load-unloading test will be quantitatively studied which can provide the theoretical foundation for the simultaneous exploitation of coal and gas in the deep high-outburst coal seams.

浅部资源开采殆尽，未来走向深部将成为常态。深部复杂力学环境导致高突矿井瓦斯抽采效率低下。准确建立深部采动力学模型是实现低生态损害开采的关键。提出煤岩体采动过程的力学本质，突破传统或忽略深度影响及工程扰动的准静态研究框架，构建深部煤炭开采动静荷载组合力学模型，即煤层采前赋存于自重及构造作用的高应力状态，采动则叠加了循环动荷载。基于自主研发的真三轴加载式CT系统和环境模拟装置，创新试验加载路径，再现真实深部采动过程，探索动静荷载组合及循环加卸载作用下煤岩力学特性及破坏规律，揭示采动煤岩的损伤演化、破坏规律与常规准静态加载方式的差异，科学认识深部采动煤岩体裂隙网络演化规律及渗透特性。结合不同开采深度矿井，工程尺度探索采动煤岩体力学行为，揭示瓦斯流动规律与埋深及开采强度的关联机制。定量表征深部煤岩在动静荷载及循环加卸载作用下的微观损伤及增透效果，为深部高突煤层的煤与瓦斯共采奠定理论基础。

千米深井煤炭开采逐渐成为资源开发新常态，然而随着深度的延伸，岩体材料的非线性行为更加凸显，不同工程活动方式诱发的高应力和高量级的灾害更加凸显。究其原因发现传统建立在经验和经典线性力学基础上的现行开采理论与技术没有考虑开采深度与开采方式的扰动，而深部煤炭开采实质上是典型的动静荷载组合扰动问题。因此项目以不同动静荷载组合作用下煤岩力学行为响应-煤岩裂隙损伤演化规律-煤岩渗透特征为研究主线，依托大型煤矿生产基地平煤矿区，从室内到工程尺度上开展了动静组合荷载作用下煤岩力学行为、力学行为加载率效应、动静荷载下煤岩裂隙网络演化特征和渗流行为等方面研究。探明了煤岩开采动静扰动应力环境演化规律，构建了深部煤炭开采过程的动静荷载组合作用力学模型，揭示了动静荷载组合作用下煤岩静态、动态力学行为及损伤演化特征和渗流行为演化规律；从而从理论研究、室内试验到现场监测等多方面揭示了工程实践中动静组合荷载扰动影响下煤岩力学机制及损伤演化特征。共发表论文27篇，其中SCI/EI收录25篇，出版专著1部，申请专利18项，获得软件著作权2项，获2019年教育部技术发明一等奖等省部级奖励三项。通过对动静组合荷载作用下煤岩力学行为、裂隙网络演化特征以及渗流特性等多方面系统研究，研究成果有助于提升对深部煤岩采动力学行为的有益认知以及指导对平煤集团埋深超千米矿井的瓦斯抽采方案设置，对增强深部资源的获取能力和效率具有重要意义，经济社会效益显著。