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井下断层活动的定量监测及其对冲击地压的影响研究

Research on quantitative monitoring of underground fault activity and its influence on rock burst

  • 摘要: 为建立断层活动与冲击地压之间的定量关系,实现煤矿冲击地压有效防控。通过理论分析义马矿区地质构造环境,以及耿村煤矿13200工作面与断层影响带的相对位置关系,研究了断裂构造对冲击地压的宏观控制作用。计算了井田构造应力并进行了构造应力区划分,分析了构造应力分区对冲击地压的控制作用。提出了井下断层活动性的定量监测方法,构建了“震源区煤岩体与动力核区尺度等量,震源能量随传递距离逐渐衰减”的模型,建立了大能量微震事件与断层活动的关系,确定了断层活动性对冲击地压的影响。研究结果表明:义马煤田内相对复杂的逆冲推覆构造体系,构成了义马矿区冲击地压的地质构造背景条件。F16断层的影响带范围为7 000~7 600 m,13200工作面全部处于F16断层的影响带内,在开采活动的影响下进一步增大了冲击地压的发生危险。Ⅰ-2断裂、Ⅲ-4断裂和Ⅳ-7断裂等控制的区域是冲击地压和大能量微震事件显现的主要区域,且冲击地压和大能量微震事件大多位于应力梯度区范围内。在大能量微震事件孕育和发生期间,F16断层位移分别增长50 mm和45 mm;大能量微震事件发生前,断层活动拉力的增幅均相对最高,分别为2.58 kN和2.93 kN,断层位移量的快速增加和较高的应力增幅构成了大能量微震事件的主要能量来源。表明大能量微震事件和冲击地压的发生均与断层的活动联系紧密。井下断层的实际定量监测方法可以广泛应用于矿井冲击地压预测与防控的指导工作中。

     

    Abstract: In order to establish a quantitative relationship between fault activity and rock burst, realize the effective prevention and control of rockburst. We analyzed the geological structure environment of rockburst in Yima mining area theoretically, and analyzed the relative position relationship between panel 13200 and fault influence zone in Gengcun coal mine by taking the evaluation method of geo-dynamic conditions of rockburst. We further discussed the macro-control effect of the fault structure on rock burst. On this basis, we calculated the tectonic stress in the minefield and divided the tectonic stress into different zones, and analyzed the control effect of tectonic stress on rockburst. We designed the actual quantitative monitoring method of underground fault, monitored the activity of F16 fault in Gengcun mine field directly, analyzed the changes of fault displacement and stress increase during the preparation and occurrence of high-energy microseismic events quantitatively. We constructed a model of “the scale of coal and rock mass in the focal area is equal to that of the dynamic core area, and the energy of the focal area gradually attenuates with the transmission distance,” which provides an important tool for establishing the relationship between large-energy microseismic events and fault activities, establishes the relationship between high-energy microseismic events and fault activities, and determines the influence of fault activity on rock burst. The research results show that in Yima coalfield, the complex thrust nappe structure system constitutes the geological tectonic background of rockburst in Yima mining area. The width of F16 fault influence zone is 7 000 to 7 600 m, and the whole panel 13200 is within the influence zone of F16 fault, which further increases the risk of rockburst under the influence of mining activities. The areas controlled by Ⅰ-2 fault, Ⅲ-4 fault and Ⅳ-7 fault are the main areas for the occurrence of rockburst and large energy microseismic events in Gengcun Coal Mine. Most of the rockburst and large energy microseismic events are located in stress gradient areas. During the preparation and occurrence of large energy microseismic events, the displacement of F16 fault increased by 50 mm and 45 mm respectively. Before the two large energy microseismic events occur, the increase of fault activity tension are relatively the highest, which are 2.58 kN and 2.93 kN. The rapid increase of fault displacement and higher stress increase constitute the main energy source of large energy microseismic events. The occurrence of large energy microseismic events and rockburst are closely related to the activity of faults. The actual quantitative monitoring method of underground faults can be widely used in the guidance of mine rockburst prediction and prevention and control.

     

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