Roof stability analysis in No.3 coal seam of Panxie peripheral

In view of problems of poor accuracy and weak maneuverability existed in roof stability evaluation methods, the extension theory was applied to stability analysis of coal seam roof. For problem of roof stability of No.3 coal seam of Panxie peripheral, fault fractal value, hard-rock ratio, strength coefficient of immediate roof and number of layers in the statistical thickness were used as evaluation factors. And classification standard of each factor was determined by quartering and mathematical statistics analysis. Finally, the grey relation method and the extension matter-element model were used to evaluate roof stability. The evaluation results show that stable region has a large area in Panxie peripheral, mid-stable zone is scattered, unstable and extreme unstable areas are located in the central of peripheral and the vicinity of F66 fault and magmatic intrusive area; the overall roof stability in the south is better, while roof stability in the northern and southern parts is poor, which mainly related to magmatic erosion; from northwest to southeast, the influence of F66 fault on roof stability of nearby coal seam decreases gradually.