doi:10.16186/j.cnki.1673-9787.2023020052

Received:2023/02/17

Revised:2023/04/07

Published:2024/01/25

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

LEI Dongji1,2, LIU Ning1, WANG Dengke1,2, LIU Liying1, JIA Ziqiang1

1.Key Laboratory of Gas Geology and Gas Control in Henan Province-State Key Laboratory Cultivation Base，Henan Polytechnic University，Jiaozuo  454000，Henan，China; 2.Collaborative Innovation Center of Central Plains Economic Region for Coalbed Shale Gas，Jiaozuo  454000，Henan，China

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 results 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 magnitude of micro-earthquake events were mostly distributed at -2～0；（2）There is a positive correlation between the tunneling speed and the number and energy of microseismic events.At the same time，the tunneling 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 specific 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 mass fracture is between 90~1 000 Hz， 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.

Key words:coal roadway;microseismic monitoring;spatial distribution;key point;time-frequency characteristic;driving speed;coal rock rupture