Study On Optimization Of Mining Roadway Section In Three Soft Coal Seam And Mechanical Property Of Flattened U Shape Support

Under the condition of three soft coal seam, the mechanical property of mining roadway surrounding rock is bad. The difficulty of maintaining roadway surrounding rock will increase if the roadway section is not chosen properly. Based on the condition of 3204 working face in Zouzhuang coal mine, theoretical analysis(complex variable function method), numerical analysis(finite element method) and on-site observation were fully used to systematically studied the distribution laws of stress and displacement in the surrounding rock of roadway with different section shape, the mechanical property of U-type steel support with different geometry shape under multiple kinds of load, and main research results as follows:1) According to the stress distribution of roadway surrounding rock, the surrounding rock stress condition of direct wall semicircle arch roadway is better than that of flattened U shape roadway, and the surrounding rock stress condition of rectangular roadway is the worst of all. According to the displacement distribution of roadway surrounding rock, the surrounding rock displacement condition of direct wall semicircle arch roadway and flattened U shape roadway are at the same level, but both better than that of rectangular roadway;2) Comprehensive consideration of the distribution laws of stress and displacement suggests that, direct wall semicircle arch roadway and flattened U shape roadway should been chosen under the condition of three soft coal seam, but rectangular roadway is not suitable for three soft coal seam;3) According to the distribution laws of plastic zone and displacement of U-type steel support, the bearing capacity of flattened U shape support and that of direct wall semicircle arch support are at the same level;4) The stress and displacement distribution laws of roadway surrounding rock, the mechanical property of U-type steel support and the advanced support technique of mining roadway in 3204 working face were considered comprehensively, and the flattened U shape roadway section was chosen finally. The on-site observation indicates that, the displacement magnitude of mining roadway surrounding rock is under control, the stable requirement of mining roadway surrounding rock is fulfilled; the increase of substituting shed efficiency ensures the safe and fast advancement of working face.This thesis contains 49 figures, 8 tables and 90 references.