王恩元, 冯俊军, 张奇明, 孔祥国, 刘晓斐. 冲击地压应力波作用机理[J]. 煤炭学报, 2020, 45(1): 100-110. DOI: 10.13225/j.cnki.jccs.YG19.1603
引用本文: 王恩元, 冯俊军, 张奇明, 孔祥国, 刘晓斐. 冲击地压应力波作用机理[J]. 煤炭学报, 2020, 45(1): 100-110. DOI: 10.13225/j.cnki.jccs.YG19.1603
WANG Enyuan, FENG Junjun, ZHANG Qiming, KONG Xiangguo, LIU Xiaofei. Mechanism of rockburst under stress wave in mining space[J]. Journal of China Coal Society, 2020, 45(1): 100-110. DOI: 10.13225/j.cnki.jccs.YG19.1603
Citation: WANG Enyuan, FENG Junjun, ZHANG Qiming, KONG Xiangguo, LIU Xiaofei. Mechanism of rockburst under stress wave in mining space[J]. Journal of China Coal Society, 2020, 45(1): 100-110. DOI: 10.13225/j.cnki.jccs.YG19.1603

冲击地压应力波作用机理

Mechanism of rockburst under stress wave in mining space

  • 摘要: 针对动载扰动下大型冲击地压的发生及演化过程难题,分析了采场动载应力波的产生机制,研究了动载应力波与静载耦合作用下煤岩体冲击破坏规律,从应力波的产生、传播与致灾过程详细解释了大型冲击地压演化机理。研究结果表明,采场高位坚硬顶板断裂与深部应力集中区煤体破断所产生的动载应力波幅值随着煤岩体强度增大而升高,应力波持续时间随着破断尺度增大而增大,说明在煤矿开采过程中,顶板或煤体强度越高、破断尺度越大,越容易产生大能量的动载应力波;动静载耦合冲击破坏实验结果证实,高静载、高动载应力波、静载与应力波耦合加载条件均能使煤岩体发生冲击破坏,且随着轴向静载的增大,试样发生冲击破坏所需的临界动载应力波强度先增大后减小,其上升段与下降段的分界点约为单轴抗压强度50%。当静载达到该临界点时,煤体发生冲击破坏所需的动载应力波强度急剧减小,说明高地应力环境煤岩体受到动载应力波的影响更为显著;现场大尺度模拟分析表明,动载应力波作用下,采场煤岩体塑性破坏区范围逐渐增加并主要集中在巷道两侧,且随着应力波幅值和持续时间增加,塑性破坏区范围不断扩大;研究提出了冲击地压应力波作用机理:动载扰动下冲击地压是静载、动载应力波与煤岩体结构耦合作用的结果,采场煤岩体大尺度破断产生高能量动载应力波,应力波与地应力耦合作用导致采掘空间围岩发生大范围破坏,最终形成冲击地压灾害。

     

    Abstract: Aiming at the problem of occurrence and evolution of large-scale rockburst under dynamic impact,the gen- eration mechanism of dynamic stress wave in mining space was analyzed,the law of impact failure of coal under the coupling of dynamic stress wave and static load was studied,and the evolution mechanism of large-scale rockburst was finally interpreted from the perspective of the generation,propagation,and impact of dynamic stress wave. The results show that the amplitude of the dynamic stress waves generated by hard roof fall and coal fracture in stress concentra- tion zone increases with the coal and rock strength,and the duration of the stress wave increases with the fracture scale,which indicates that coal and rock with higher strength fracture in large scale would cause stronger dynamic stress wave in underground coal mining. The results of coupling loading experiments of dynamic stress wave and static stress show that high static stress,high dynamic stress wave,or the coupling of static stress and dynamic stress wave all could result in impact failure of coal,and the required critical dynamic stress wave first increases and then decreases with the increment of static stress,and the turning point is about 50% of the uniaxial compressive strength of coal. When the static stress reaches the critical point,the required dynamic stress wave decreases significantly,which indi- cates that the coal and rock mass under high geo-stress condition is more significantly affected by the dynamic stress wave. The results of large-scale simulation show that the failure area of coal mass under dynamic stress wave increases gradually and concentrates on both sides of the roadway,and the failure area increases with the increment of amplitude and duration of dynamic stress wave. The mechanism of rockburst under stress wave was finally proposed,which dem- onstrates that the rockburst under dynamic impact is resulted by the coupling of static stress,dynamic stress wave and the coal-rock structure,the large-scale fracture of the coal and rock in mining space generates strong dynamic stress wave,then the coupling of static geo-stress and dynamic stress wave causes a large-scale failure of surrounding rock, thereby results in a rockburst.

     

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