Study on overlying rock fissure and energy evolution law of high intensity mining working face adjacent to gob

The high-intensity mining in the western mining area has led to severe damage to the overlying rock structure and surface of the working face, resulting in the deterioration of the surface ecological environment. Taking Daliuta Mine as the engineering background, the study investigated the overlying rock fractures and energy evolution laws of high-intensity mining adjacent to the working face through on-site monitoring and theoretical analysis; using FLAC3D numerical simulation analysis, the vertical stress, range of overlying rock failure, and energy accumulation characteristics of the 12203 working face and the evolution law of key layer energy in different mining stages were obtained. The results showed that after the initial compaction, the surface cracked and collapsed, with visible depths ranging from 0.1 m to 0.7 m. The periodic compaction step distance was 7-17 m, with an average step distance of 12 m; the range of overlying rock damage on the 12203 working faces increases with the increase of mining speed. The development range of overlying rock fractures and the range of surface damage are positively correlated with the advancing speed of the working face. The mining speed has a significant impact on the range of overlying rock damage on adjacent working faces; the stress of the coal pillar in the section increases with the increase of the mining speed, and 50 m in front of the working face is still subjected to high static stress, and the roadway is prone to impact instability; the energy density value and energy accumulation area at the adjacent goaf end of the 12 lower 201 working face are strongly disturbed by the surrounding rock of the mining area, and the energy accumulation of the overlying rock cannot be released in time, which can easily cause instability of the roof surrounding rock due to impact.