Combined test research on coal-rock pillar width setting of district sublevel for fully-mechanized face with large mining height

摘要

Reasonable width of district sublevel coal-rock pillar is the premise of scientific mining for a safe and high efficient mine.they all indicate that,the setting width of forty meters coal pillar is obviously large in Ningdong test mine now,by the analysis of FLAC3D numerical simulation based on ideal elastoplastic theory and engineering practice results of many mines.The in situ test under the mine involves real-time monitoring of sixteen hollow inclusions' 3-D strain,dynamic monitoring of surrounding rock stress and deformation in test roadways with different coal pillar width (10m & 20 m) before and after the mining-induced influence by the workface.Combination of the above theoretical calculations,simulation and underground test results are considered to determine a reasonable width scope of district sublevel coal pillar design from 8.9 meters to 11.9 meters in the test mine under specific geological condition,which provides some guiding role for width design method of district sublevel coal-rock pillar under similar mining conditions.