摘要
Abstract
Based on the significant geological inducement of rock bursts and mine seismicity caused by the synergistic action of multiple hard main controlling strata,we take the thick and hard main key strata in Shilawusu Coal Mine as the research object.By integrating FLAC numerical simulation,theoretical analysis,and field monitoring data,the synergistic breaking mechanism of the hard roof across goafs is analyzed.The study finds that during the single mining stage,the low-level key strata do not form an obvious stress peak,but the stress continues to rise with face advance.The initial failure of the overlying strata is dominated by shear with a small amount of tension.The plastic zone gradually changes from a semi-"O"shape to a closed"O"shape,and when the face advances to approximately 270 m,it evolves into an"O-X"shaped shear-tension mixed fracture.As the working face approaches an adjacent goaf,stress concentration intensifies significantly;the 5 m coal pillar cannot effectively bear the overlying pressure,and damage in the high-level key strata accumulates continuously,making them prone to disturbance-induced breaking that triggers mine seismicity,while the"O-X"fracture pattern of the plastic zone continues to move forward.With ongoing mining,the main key strata form a giant"O-X"breaking structure as the goaf expands.This structure corresponds to the sub-key strata,resulting in the occurrence of large-scale,high-energy mine seismicity.Numerical simulation further reveals that the subsidence of rock strata increases significantly when the working face approaches the adjacent goaf,and the subsidence is positively correlated with the goaf width.关键词
单一工作面/相邻采空区/关键层/坚硬顶板/"O-X"型破断Key words
single working face/adjacent goaf/key strata/hard roof/"O-X"type fracture分类
矿业与冶金
