Theoretical model and simulation study of uniform strength beam support in deep coal mine roadway

In this paper, the stress characteristics of the rectangle roadway roof is analyzed.The distribution law of the bending normal stress and shear force of the roof is obtained.The bolt parameters to ensure the stability of the roadway roof are deduced.Furthermore, the sensitivity analysis of the factors influencing the length selection of bolt is carried out.The primary and secondary relations of each factor to the influence degree of bolt length selection are determined.Thus, the roadway surrounding rock with different lengths of bolt support can meet the stability requirement. The uniform strength beam support concept of deep roadway is put forward according to the bending normal stress distribution characteristic of the roof.High strength long bolt is adopted locally in the region with large bending normal stress.The length of bolt can be appropriately decreased in the area where the bending normal stress is gradually reduced. The same maximum normal stress can be achieved under different lengths of bolt support in the roadway roof.The construction technology of uniform strength beam support is preliminarily established.Finite difference software FLAC3D is applied to simulate the roof stress and displacement distribution of traditional bolt support and uniform strength beamsupport, respectively. Numerical results indicate that the uniform strength beam support can significantly optimize the stress distribution of roadway.And the local stress of roof reaches to the uniform distribution.The surrounding rock deformation also decreases. The results indicate that the uniform strength beam support technology is feasible for deep mining.