Study on Response Characteristics of Surrounding Rock Rupture Microseismic Events during Coal Roadway Excavation

Abstract

In order to solve the problems such as coal burst and abnormal gas overrun caused by the fracture of surrounding rock in the process of mining in the coal roadway, the ESG microseismic monitoring system is built on the driving face of 8005 transportation roadway of Wuyang Coal Mine to carry out a real-time, continuous, and omnidirectional dynamic state monitoring. In this way, the characteristics of time-frequency evolution and energy distribution of the acquired signals are systematically analyzed, and the location of the roadway microseismic events is studied. The results show the following: (1) influenced by mining activities, the localized microseismic events are mostly distributed in front and on both sides of the working face. Due to mining activities and geological changes, the equilibrium of original stress in coal and rock mass is broken. The stress thus is released accompanied by fracture before reaching a new equilibrium. (2) By comparing the coal and rock fracture signals with the interference signals, it is found that the fracture signals have short duration and large amplitude with obvious abrupt change characteristics. The interference signals have long duration and relatively small amplitude with less obvious change. (3) Fourier transform analysis shows that the main frequency of coal rock fracture signals is 100-200 Hz with large total energy concentrated in the first frequency band, while that of interference signals is mostly less than 100 Hz with small total energy. The research results can effectively identify the coal and rock dynamic disasters, provide technical support for the prediction and early warning of hidden danger, and guide the safe and efficient production.