Abstract: To address the problem of nonlinear large deformation and severe mine pressure caused by the overall external displacement of the anchor solid of the surrounding rock of the roadway side due to the influence of multiple mining dynamic stresses in the section roadway，taking the 15# coal of Xinshun Coal Industry as the research background，the methods of on-site investigation，numerical simulation，mechan⁃ ical modeling and on-site testing were adopted to analyze the overburden fracture structure model of the fully mechanized face of thick coal seams and determine the position of the fracture line. The minimum coal pillar reserved width was solved，and by using FLAC3D the optimal reserved width of the coal pillar in the section was simulated. Research shows that the final width of the coal pillar in the 15102 track chute can be optimized to 22 m，providing theoretical and technical reference for the subsequent section coal width.

Key words: coal pillar width, roadway support, numerical simulation, fracture line