煤矿地下水库下压煤层开采中层间岩体裂隙网络的拓扑演化分析OA

During the mining of lower coal seams beneath underground reservoirs,the interlayer rock mass undergoes deformation and failure due to mining-induced disturbances.Crack propagation and in-terconnection pose significant threat to reservoir safety.Taking the working faces of 2-2 and 5-2 coal seams in Shenhua Daliuta Mine as prototypes,this study conducted physical similarity simulation exper-iments to analyze stress and crack evolution patterns in interlayer rock masses during lower seam extrac-tion.We classified fractures into trace lines and segment lines to investigate the evolution of their topol-ogical and geometric characteristics.A three-phase diagram of fractures was established based on aver-age connection numbers to quantitatively evaluate connectivity.Results indicate that as mining ad-vanced,the interlayer rock mass experienced a nonlinear increase in pressure,followed by sudden pressure relief and stress fluctuations.Cracks continued to expand until reaching a maximum aperture before closing.The number of nodes in trace lines and segment lines increased with mining advance-ment,with the longest trace line typically being a horizontal bedding separation fracture.During evolu-tion,fracture networks predominantly propagated as connected clusters while maintaining spatial conti-nuity.This study provides a method for calculating the safety distance of coal seam mining beneath un-derground reservoirs and evaluating the safety of interlayer rock masses in coal mines.