School of Resource and Environmental Engineering, Shandong University of Technology
Xinwen Mining Group Co., Ltd.

以深部煤巷围岩为研究对象,针对冲击地压灾害严重、致冲机理研究尚不完善、防冲工程缺少更具针对性指导依据等问题,采用室内试验、数值模拟、理论分析等方法,从三向应力差异角度揭示深部煤巷围岩冲击致灾机理。基于采掘活动扰乱煤岩体三向等压状态导致围岩破坏的特点,通过 PFC 模拟试验和理论推导研究了不同应力路径下的煤体单元体响应特征,得到单元体失稳的应力差异判据,进一步提出煤巷围岩应力差异梯度 Dg 和应力差异梯度变化率 Dgc 的概念,基于 Drucker-Prager 准则分析了巷道围岩 Dg 演化特征,进而得到巷帮煤体 Dg 集中致冲的作用机理,并结合冲击地压事故案例进行分析验证。结果表明:煤体的应力差异承受能力随着应力路径的不同而存在显著差异;围岩应力演化的目标是 Dg 峰值降至极小值,围岩的破坏和屈服是 Dg 驱动作用的结果;围岩内应力差异梯度 Dg 随埋深增大和煤层冲击倾向性等级升高而增长,体现出明显的 “上升—跌落—下降”梯度性质;Dgc 表征围岩内 Dg 集中程度,Dg 升高区煤体在应力扰动作用下,满足 Dgc0 < D' gc < k1Dgc0 时发生较稳定的变形、位移,满足 k1Dgc0≤D' gc < [Dgc] 时发生较稳定的整体失稳,满足 D' gc≥[Dgc] 时发生冲击地压;巷帮煤体冲击是围岩变形、破坏的一种极端演化形式;防冲机制应以弱化围岩 Dg 水平为核心,以 Dgc 控制为主要着力点。

With the deep coal tunnel surrounding rock as the research object, in view of the serious rock burst hazards, incomplete rock burst mechanism research, and the lack of more targeted guidance on the prevention and control of rockburst engineering, indoor tests, numerical simulation, theoretical analysis and other methods were used to reveal the deepcoal roadway surrounding rock burst mechanism from the three-way stress difference perspective. Based on the understanding that excavation activity disturbs the three-way isobaric state of the coal rock body and causes damage to the surrounding rock, the response characteristics of the coal unit body under the action of different stress paths were studied byPFC simulation. The criterion of unit body instability based on the stress difference was obtained. The concepts of stressdifference gradient and the rate of change of stress difference gradient were proposed. The Dg evolution characteristics ofthe surrounding rock were analyzed based on the Drucker-Prager criterion, and then the mechanism of action of the rockburst caused by the concentration of Dg in the surrounding rock was obtained. Finally, the prevention and control mechanism and rock burst accident cases were analyzed. The results show that the stress differential withstand capacity of the coalbody differs significantly depending on the stress path. The objective of the evolution of the internal stresses in the surrounding rock is to reduce the peak Dg to a very small value, with the failure and yielding of the surrounding rock beingthe result of Dg-driven action. The stress difference gradient grows with the increasing depth of burial and coal seam bursting liability, and reflects the nature of the “rise-fall-fall” gradient. The Dgc characterizes the degree of Dg concentrationwithin the surrounding rock. Under stress perturbation, a more stable deformation and displacement of the coal body in theDg elevation zone occurs when the condition Dgc0 < D' gc < k1Dgc0 is satisfied, a more stable overall instability occurs whenk1Dgc0≤D' gc < [Dgc] is satisfied, and a rock burst occurs when D' gc≥[Dgc] is satisfied. Rock burst of the surrounding rock isan extreme form of evolution of their own deformation and destruction. Rock burst prevention should be centered onweakening the Dg of the surrounding rock, with Dgc control as the main focus.

国家自然科学基金青年基金资助项目(51904178);山东省自然科学基金博士基金资助项目(ZR2018BEE009);中国博士后科学基金面上资助项目(2018M632677)

刘国磊,王泽东,崔嵛,等. 深部煤巷围岩三向应力差异梯度致冲机理[J]. 煤炭学报,2023,48(5):2106−2122.

LIU Guolei,WANG Zedong,CUI Yu,et al. Mechanism of rock burst in deep coal tunnel surroundings due tothree-way stress difference gradient[J]. Journal of China Coal Society,2023,48(5):2106−2122.