RESEARCH ON THE STABILITY OF MULTI KEY LAYER STRUCTURES AND ANTI IMPACT AND VIBRATION REDUCTION TECHNOLOGIES IN DEEP BURIED ROCKBURST MINES

In order to create favorable conditions for the safe production of multi key layer mines with deep buried impact ground pressure, a study on the stability of multi key layer structures was carried out based on the Vlasov plate theory. It is found that the maximum tensile stress inside thick hard rock layers is greatly affected by the short side of the goaf, and the maximum tensile stress in thick hard rock layers decreases with the increase of the thickness of the thick overlying rock layer. In addition, research suggests that the key layer one (thickness 5~22 m) of the 3100 working face will break when the width of the goaf reaches about 20-25 m; key layer two (thickness 33~53 m) will break when the width of the goaf reaches about 90~100 m. Then, through on-site practical research methods, anti impact and shock absorption measures were proposed for different layers of thick and hard roof, including low-level roof blasting pressure relief and high-level directional hydraulic fracturing pressure relief. Finally, a comparative analysis was conducted on the pressure relief effects of the 3100 and 3102 working faces in the same mining area of Menkeqing coal mine. It was found that the 3100 face, which adopted multiple key layer pressure relief measures, had a 9.5% reduction in microseismic frequency per meter and an 86.2% reduction in microseismic energy per meter compared to the 3102 face, which did not adopt multiple key layer pressure relief measures. The research results have been applied to the Menkeqing mine and achieved good results.