Category of Microseismic Signals and Time-space Analysis of Microseismic Event in Liyazhuang Coal Mine

In order to provide a theoretical basis for predicting the risk of rockburst, SOS microseismic monitoring system was used to monitor the microseismic signal of coal and rock mass near 2-610 working face in Liyazhuang Coal Mine for two months. Based on the information of microseismic signal energy, epicenter location and vertical elevation of the source comprehensively, the types of microseismic signal on working face were analyzed, the temporal and spatial distribution of microseismic events were also studied. The results show that the energy level of fault activation microseismic signal of the 2-610 working face is 10⁵ J, and the main frequency is from 30 Hz to 55 Hz; the energy level of microseismic signals of basic roof fracture in goaf and roof fracture at open-off cuts is 10⁴ J, the former main frequency is from 25 Hz to 35 Hz, the latter is from 45 Hz to 70 Hz; the energy level of the microseismic signal of immediate roof caving in goaf is 10³ J, and the main frequency is from 25 Hz to 45 Hz, microseismic events mainly focus on three regions in which position have little change in the determined production space; microseismic frequency is mainly influenced by production time, and increases gradually with the increase of production time after change shifts, and there is a certain lag time.