关键词: 煤层上山, 分级长时加载, 黏弹性, 固帮强顶

Abstract: Based on engineering practice in Wuyang coal mine, the mechanical properties of roof rock has been obtained by the triaxial compression experiment of confining pressures step longtime loading, and the surrounding rock visco-elasticity property of supporting roadway has been analyzed, and controlling principle of surrounding rock has been proposed for controlling deformation of coal rise entry in supporting practice. Four conclusions were drawn: 1) the surrounding rock deformation of roadway is a time course, the deformation tends to be stable after any load being loaded for a certain period of time, and the time span taken by reaching steady increases exponentially with increasing normal loading; 2) the rate of axial strain can be effectively decreased by raising the confining pressure when the axial strain does not tend to be stable; namely, the stability of surrounding rock deformation can be accelerated by raising the confining pressure when roadway displacement does not tend to be stable to avoid the instability of surrounding rocks; 3) roof deformation and the evolution of the plastic zones can be effectively controlled with prestressed anchor cable, but the deformation of coal side and coal seam floor can be aggravated; namely, the stability of slope of roadway sides and floor must be strengthened when the roof is supported with bolting and rope; 4) the appropriate stress transfer can be beneficial to the ultimate stability of surrounding rock, and controlling principles of step loading of one support is highly effective for controlling surrounding rock deformation of the thick coal seam rise entry.

Key words: coal rise entry, longtime step loading, viscoelasticity, reinforcing side and strengthening roof