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

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.