关键词: 切顶卸压, 沿空留巷, 动压, 临时支护, 短臂梁

Abstract: According to the problem of the significant influence of dynamic pressure to the gob-side entry retaining formed by roof cutting and pressure relief for a certain period, the basic idea of controlling the deformation of roof by temporary support technology for dynamic pressure bearing was proposed. Based on theoretical calculation and analysis, the action mechanism of temporary support technology for dynamic pressure bearing was discussed. It was concluded that the temporary support had limited effect on the "given deformation" of the upper roof but was very effective in controlling the deformation or separation of the lower roof. The mechanism of temporary support for dynamic pressure bearing was simulated and analyzed by finite difference simulation software FLAC3D. And the following rules were obtained: 1) It was effective to control the deformation of the roof by using temporary support in the gob-side and the middle of the roadway at the same time. 2) The greater the support strength, the better the deformation control effect of the roof. But there was a reasonable range. Within the range, deformation could be easier effected by support strength. While greater or less than the range, the impact imposed by the change of the support strength on deformation would be significantly reduced. 3) If the temporary support was withdrawn before the roof contact with waste rock, the final subsidence amount of the roof was generally large. And the final subsidence amount of the roof would be generally smaller while the temporary support was withdrawn after the roof contact with waste rock. Based on the above analysis, the design idea of temporary support technology for dynamic pressure bearing was proposed and had been successfully applied in the Ningtiaota coal mine. Test data show that the deformation of the roof was generally less than 89mm, and the control effect of the roof was good under the action of the temporary support technology for dynamic pressure.