关键词: 特厚煤层, 综放开采, 防冲煤柱, 强冲击倾向性

Abstract: In order to study the reasonable coal pillar width of fully mechanized caving face in extra thick seam with strong bursting liability, some outburst phenomenon frequently occurring along the coal pillar of the 250102 working face in Huating coal mine was analyzed. It is found that 20 m coal pillar of 250102 working face is under the stress conditions which can easily induce coal pillar type rock burst. By means of numerical simulation and theoretical calculation, the reasonable width of coal pillar in 2501 mining area was studied. The results show that: the stress concentration coefficient, when the coal pillar width is 5 m, is the lowest and it is 1.14, which indicates the low rock burst risk. When the coal pillar width is 20 m, the stress concentration coefficient reaches the highest and it is up to 3.40, and the corresponding rock burst risk reaches the highest. When the coal pillar width is more than 25 m, the stress curve in the pillar changes from a single peak to a double peak, and the coal pillar is in the bearing stage of a wide coal pillar instead of the yield stage of a narrow pillar. Moreover, the rock burst risk is increasingly decreased with the increasing of pillar width. The theoretical width of coal pillar 2501 mining area is 5.64 m and it is well consistent with the numerical simulation results. 6 m coal pillar was adopted in subsequent working face in 2501 mining area and it has a good effect on the prevention and control of rock burst risk based on the field monitoring. The study results are of significance for the prevention and control of rock burst in other coal mines with similar geological conditions.