Research on support technology of right angle trapezoidal roadway in generally inclined coal seam

The form of deformation and failure of roadway in gently inclined coal seam under the action of dip angle and various geological conditions is complicated,which results in many problems to the stability control of roadway surrounding rock. The deformation and failure of roadway presents asymmetrical characteristics,lacking strong support measures. In order to mine gently inclined coal seam safely and economically,taking the actual project at the Shitanjing No.2 Mine of Ningmei Coal Group as an example,this paper uses numerical simulation,laboratorial similar model's test and field monitoring to study the distribution law and support technology of roadway surrounding rock in gently inclined coal seam. The results show that the stress distribution of the roadway surrounding rock presents an asymmetrical feature. The stress concentration and range of the roadway low side are obviously larger than that of the roadway high side,and the distance from the low side stress concentration area to the side of the roadway is greater than that from the high side. The larger the dip angle,the more obvious the difference of stress concentration between the two sides,and the distance between the low side stress concentration areas and the two sides of roadway is larger than that of the high side. The top corner of high side and bottom corner of low side are compressive stress zones,while the other two side corners are tensile stress zones. Under the action of asymmetric stress,the surrounding rock of the roadway exhibits asymmetric deformation and failure characteristics. According to the asymmetric stress-deformation characteristics of roadway in gently inclined coal seam,the principle of support design is put forward,and the support scheme of roadway surrounding rock is designed. After the roadway support,the vertical and horizontal asymmetric stress distribution characteristics of the surrounding rock of the roadway are obviously improved,and the vertical stress is obviously directed to the roadway. In the middle transfer,the difference in stress concentration at each corner is significantly reduced. The maximum settlement of the roof is reduced from 217 mm to 65.3 mm before and after the support,and the convergence of the two sides of the roadway is reduced from 194.5 mm to 74.4 mm before and after the support. Through the actual verification of the project,the stability of the surrounding rock is effectively controlled. The author studies the stress distribution and support technology of the surrounding rock in the right angle trapezoidal roadway in gently inclined coal seam,and draws some conclusions. However,the analysis of the failure mechanism and control technology of roadway in the gently inclined coal seam with different roadway sections and different dip angles is also not comprehensive and sufficient,the future study will be systematic and in-depth research.