Optimization of supporting plans for the quick-return tunnel in an extremely thick and fracture developing coal seam

Deformation control of quick-return tunnel of extremely thick coal seam is one of the key techniques that are related to the effectiveness and productivity of large coal mine in Western China. This study establishes a FLAC3Dcomputational model for Buliangou coal mine, and investigates the control of quick-return tunnel in an extremely thick, fracture developing coal seam. This study investigates the deformation of surrounding rocks in primary and side quick-return tunnels under different supporting plans. The result shows that the surface displacement of roadway increases following a parabolic curve within 30 meters advance distance after placing coal. The deformation of the roof and floor of primary tunnel is clearly stronger than that in the side tunnel. With the same supporting plan for primary and side tunnels, the effectiveness is clearly higher in side quick-return tunnel. It indicates that the advanced stress at the working face is the one of the key factors that affects the tunnel support. Though comparison, the support parameter has great effect on control to deformation of the surrounding rock of the tunnel. The result shows advantages of high-density and high-strength support. Among designed plans, plan 3 is found to well control the deformation of the surrounding rock of the tunnel. © 2014 ejge.