In order to solve the influence of bolt length on roadway support under different geological and mining conditions, using FLAC3D numerical simulation software, the numerical simulation research of tunnel support effect of 1.6, 1.8, 2.0, 2.2 and 2.4 m different bolt lengths was carried out. Through five bolt-length support schemes, the stress change and displacement deformation rule of roadway under each scheme were analyzed, and the optimal bolt-length was obtained. The results show that the change of bolt length affects the displacement and deformation of roadway after excavation. When the diameter of the bolt is constant and the length is 2.2 m, the deformation of the roadway surrounding rock is small, and the shear failure in the plastic zone is minimal. Through the comparison of several schemes, it is found that the roadway support effect is best when the length of bolt is 2.2 m.

length of anchor rod  /  support effect  /  numerical simulation  /  stress change  /  plastic zone