Mechanical behavior and stability control of regenerated roof in long wall stratified mining of thick steeply dipping coal seam

This study focused on the stability control of roof in long wall stratified mining of large dip angle thick coal seam. Taking Panbei Coal Mine in Huainan as an example, the effect mechanism of water content, compression ratio and grain size grading on the compression characteristics of gangue is analyzed by comprehensive application of gangue lateral compression test, 3D imaging borehole detection test, physical simulation and numerical simulation method. In addition, the effect of these factors on the stability of the reclaimed roof were also analyzed, the structural characteristics and stress state of the reclaimed roof were obtained, the dynamic behavior of the reclaimed roof was revealed, the stability control measures of the reclaimed roof were formulated, and the control effect of the reclaimed roof stability was evaluated. The research results indicate that the clay minerals of goaf mudstone and sandy mudstone are beneficial for the secondary cementation of gangue. The contact state and stress state of