关键词: 过空巷, 相似模拟, 超前破断, 煤柱失稳

Abstract: Similar simulation experiments were carried out to study the chock sudden closure incident of hydraulic supports when the workface crossed the abandoned roadway or accessed to the removal roadway. The failure characteristics of surrounding rock, the abutment pressure and the working resistance of supports were investigated through the experiments, respectively. Results indicate that the advance fracture appeares before the incident when the workface crosses a large section roadway. The advance fracture leads to an increase of the block length, comparing to that in a normal periodic weighting. Meanwhile, the inferior key stratum brokes and then slides down to the main roof. Once the advance fracture occurrs, conventional supports are unable to prevent the block sliding, which indicates that an incident takes place. Therefore, the most important thing is to prevent the occurrence of advance fracture. To investigate the main causes for the advance fracture, bending moment and deflection of the main roof are calculated by the Winkler foundation beam theory. The calculated results comprehensively explain the failure characteristics of surrounding rock, the abutment pressure and the working resistance of supports. Finally, it is revealed that the failure of coal pillar is the reason for advance fracture of the main roof. Hence, it is significant to improve the strength of coal pillar. At last, a roadway filling strategy is put forward to make uniaxial compression of coal pillar into triaxial compression by Shenghua coal mine. In-situ tests verifies that the strength of coal pillar is successfully increased.

Key words: crossing abandoned roadway, similar simulation, advance fracture, failure of coal pillar