Study on microseismic events of coal rock rupture during coal roadway driving

LEI Dongji; LIU Ning; WANG Dengke; LIU Liying; JIA Ziqiang

doi:10.16186/j.cnki.1673-9787.2023020052

Abstract：Objective In order to monitor and forewarn the danger that may occur in front of the coal mine roadway,Methods the microseismic monitoring technology is used to carry out real-time monitoring of the roadway.Through the data information captured by the monitoring system,the spatial distribution law,the occurrence time,the frequency and the energy key points of the microseismic events under the influence of tunneling are studied,finally,the time-frequency characteristics of typical micro-seismic signals of coal and rock fracture are studied by using the Short-time Fourier transform and s-transform methods.Results The re-sults showed that:(1)The microseismic events are mainly distributed in the area of 50～100 m in front of the heading direction of the roadway,and most of them are medium and low energy microseismic events.Only a few high-intensity coal and rock fracture events occurred in front of the heading face,and the magni-tude of micro-earthquake events were mostly distributed at-2～0;(2)There is a positive correlation be-tween the tunneling speed and the number and energy of microseismic events.At the same time,the tunnel-ing speed also affects the occurrence of coal-rock dynamic disasters;(3)The roadway excavation will cause the instability of coal and rock mass,in which the signal frequency of rock mass fracture is high,the spe-cific gravity value is big,the signal frequency is between 0～2 000 Hz,the main frequency is about 700 Hz,the signal frequency of micro-seismic event of coal and rock fracture is between 90～1 000 Hz,the signal fre-quency of micro-seismic event of coal and rock mass fracture is between 90～1 000 Hz,the signal frequency of micro-seismic event is between 0～2 000 Hz,the signal frequency of micro-seismic event is between 0～200 The main frequency is about 250 Hz,and the supporting force drops after the rock mass breaks,and the pressure transfers to the coal body,which results in the coal body breaking.The signal frequency of the micro-seismic event of coal body breaking is between 90～1 000 Hz,and the main frequency is about 350 Hz.Conclusion It can be seen that the micro-seismic events can comprehensively reflect the degree of failure of coal and rock mass,identify the types of coal and rock fracture during excavation,and provide a theoretical basis for early warning of coal and rock dynamic disasters in mine production.