Abstract: To study the failure mechanism and support measures of roadway surrounding rock in deep thick coal seam, based on geological conditions analysis, the borehole TV and geological radar were used to survey the failure modes and rules of roadway surrounding rock in this paper, and the failure mechanism of surrounding rock was obtained through numerical simulation. On this basis, the targeted optimization support program and specific parameters of pretension bolt network coupled with yieldable cable beams were proposed. The results show that the failure degree decreases successively from the surface of surrounding rock to the interior, and forms 3 to 4 failure zones, while the external two failure zones are the traditional relaxation zones. The relaxation zone distributes in coal seam and bottom mud, while the average thickness of relaxation zone in the top is 3m, and is easy to cause separation. The roadway is more unstable in thick coal seam, while the failure mechanism is that the roof bolts locates in the relaxation zone of thick seam, and easily produces slippage of anchor end and overall falling. In-site support test shows that the proposed optimization support program is effective to control the stability of thick coal seam roadway.

Key words: deep roadway, thick coal seam, rock relaxation zone, failure mechanism, support optimization