Multi-factor coupling analysis of large-energy events in a kilometer deep mine

Based on the research background of Shandong Lilou Coal Mine, this paper used methods such as on-site investigation, engineering comparison, and on-site monitoring to research on the high-energy events that have occurred in Lilou Coal Mine since 2020, and drew the following conclusions: ①Systematically analyzed the relationship between four influencing factors and high-energy microseismic events including the distribution of abutment pressure, working face “square”, crossing faults, and mining speed, and searched the causes of large energy events. The mining influence range of No.1302 (top) working face is about 30 m behind the face to 170 m in front, and the advanced stress peak is about 70 m in front. The lateral microseismic events are mainly distributed along the gob-side entry, and the whole is offset to the side of the goaf. The distribution of microseismic events at No.1303 working face in the advancing direction of the working face ranges from 15 m behind the face to 200 m in front of the face, and the advanced stress peak is about 80 m in front of the face. The microseismic event at the No.1303 working face is bimodal in the lateral distribution pattern, shifting to the belt grooves. Affected by the wide coal pillar, the stress concentration on the belt grooves is higher than that on the track tunnel. The frequency and energy of microseismic events gradually increased before the “square” of the work face, and stabilized after the “square”. Before crossing the fault, the microseismic events gradually increased, decreased sharply during the crossing, and gradually stabilized after crossing the fault. The peak position of the event was about 40 m in front of the “square” or before the fault. When the mining speed of 1302 (top) working face is 50 m/month and the 1303 working face is 60 m/month, the frequency and energy are the largest. ②By analyzing the inducing factors and locations of large-energy events, large-energy events can be divided into three categories: “energy accumulation type” high-energy events, “fault activation type” high-energy events, and “island structure type” high-energy events, and put forward specific prevention and control measures for different types. The research in this article will provide reference for surrounding mines with similar geological factors and mining technical conditions.