Study on Bifurcated Angle Effect of Surrounding Rock Deformation Law of Large-section Hard Rock Bifurcation Roadway

Taking 1160 cross-cut connecting roadway of Daizhuang Coal Mine as engineering project, numerical models for 5 kinds of bifurcated roadway were built, whose bifurcated angle were 30°, 45°, 60°, 75°, 90° respectively. The paper mainly analyzed the surrounding rock deformation laws of large-section hard rock bifurcation roadway with different bifurcated angles from two aspects of stress and strain. As a result, there is a negative relationship between bifurcated angle and the maximum roof subsidence of bifurcation roadway surrounding rock, as well as the distance from the position of the maximum roof subsidence to bifurcated point. Also, the similar linear equation of the latter two was established. Furthermore, the results show that the stress concentration coefficient of surrounding rock is between 1.5 and 3, and it is significantly negative correlated with bifurcated angle below 45°, while the negative correlation become weak gradually with bifurcated angle over 45°. Thus, bifurcated angle should be more than 45°, and the area with serious deformation in bifurcation roadway surrounding rock must be supported emphasisly in the practical engineering.