Abstract:To address the issue of the excessive width of coal pillars in roadway section affected by multiple mining under the condition of thick hard roof, based on the engineering background of Dongtai Xinyuan Coal Mine 10109 transport channel, theoretical calculation and analysis, Flac3D simulation and engineering practice were adopted to carry out top cutting and pressure relieving for thick hard roof. It is determined that the reasonable remaining width of coal pillar in roadway section affected by two dynamic pressures is 16.5m. The findings indicate that the cutting height is set at 27 meters with an angle of 0°. The numerical simulation demonstrates that when the coal pillar width is below 16 meters, the coal pillar has high stress concentration and serious plastic failure after being affected by two mining movements. When the width of coal pillar is higher than 16m, the elastic core area within the coal pillar exceeds 50%, ensuring the stability of the surrounding rock in the roadway. Therefore, a support plan utilizing a “Strengthen the side to protect the top” has been suggested. The maximum surface displacement of the top and bottom plate of 10109 transport trough under the influence of one mining is 165mm, and the maximum surface displacement of the two sides is 118mm. The coal pillar in the 16.5m wide section, along with the combined support technology, can effectively manage the deformation of the roadway's surrounding rock under dynamic pressure.
