Abstract: In order to investigate the reason of the failure of stage backfill stope during one mine, the deformation characteristics, failure mode of backfill roof and pillar and the surface displacement law of roadway have been studied by similar material simulation, numerical modeling and field monitoring based on the field engineering condition and investigation results. The results indicate that mining action has a significant influence on the stability of the stope and rock surrounding and the engineering on the perimeter zone, and it also poses a different impact on the maximum displacement of stope roof at different sublevel. The incremental quantity of roof displacement reaches the most when mining activity processes at second sublevel. And when mining at the third sublevel exacerbates the stress concentration of pillar, the splitting failure begins to appear along the pillar and the roadway in a structural plane of approximately 60°, and at the same time, the side walls nearby the goaf inside the pillar begin to collapse. Compared to the results obtained from the numerical simulation and field monitoring, the conclusions obtained by similar model test are testified. The research conclusions propose a comprehensive understanding of the reason of the collapse accident, and clarify the potential hazards of backfill stop, which can provide security references for other similar mines.

Key words: dynamic disturbance, stage backfill, stope, catastrophe mechanism