Abstract: To study the instability fracture evolution process of roadway surrounding rock in deep thick coal seam, taking some coal mine as the engineering background, based on the discrete element, this paper has used the random distribution of triangle model unit blocks to analyze the failure process during roadway excavation process. According to the displacement and stress evolution laws of instability fracture process of surrounding rock in deep thick coal seam, the horizontal stress release has been found to be more intense in two side coal-walls than that in roof and floor of the roadway, while the vertical stress is the opposite because the main vertical stress release part is in the middle of the roadway. Numerical simulation results have shown two mains instability fracture evolution characters of surrounding rock with thick coal seam roadway. Firstly, there exists "spire" catastrophic collapse in roadway roof, and the middle of roadway is key position of surrounding rock instability. Secondly, roof and floor of the roadway delaminate seriously. The failure mechanisms corresponding with the test results have also been analyzed including factors such as the soft and broken features of roof and floor coal petrography, poor stability, the radial stress relatively intense release in roof and floor of roadway, poorbearing capacity in roof and floor of roadway with rectangular cross section, all of which have caused roof and floor of surrounding rock delamination deformation. Based on the failure mechanism of deep buried roadway with thick coal seam, a supporting method consisting of anchor cables has also been given, which can be applied in roadway support, and simulation results have shown that the supporting method can effectively control deformation of thick coal seam roadway.

Key words: roadway with thick coal seam, deformation failure mechanism, instability fracture evolution, discrete element simulation, bolts and anchor cables supporting method