Theoretical Study on the Mechanism of Asymmetrical Large Deformation of Heading Roadway Facing Mining

Abstract

The problem of asymmetric large deformation of surrounding rock of heading roadways is prominent due to the superposition of mining stress in the mining intersection area. Therefore, on the basis of the background of 18,106 tailentry in the Xiegou Coal Mine, this paper establishes a mechanical model of surrounding rock deformation of mining roadways under the effect of advanced abutment pressure. In the model, we deduce the theoretical calculation formula of roadway full-section deformation and discuss the influence factors of roadway surrounding rock deformation. Accordingly, the deformation mechanism of surrounding rock of mining roadways and the engineering suggestions and measures are revealed. The main results and finding are threefold. Firstly, the increase of the stress concentration factor of the coal pillar rib and the increase of the width of the failure zone are the fundamental reasons leading to the aggravation of the surrounding rock deformation on the side of the coal pillar in the heading roadway. Secondly, the deformation of the coal pillar rib increases with the increase of stress concentration factor and decreases with the increase of coal cohesion, internal friction angle, elastic modulus, and roadway rib support resistance. Additionally, the deformation of the roadway roof and floor decreases with the increase of roadway rib support resistance and is inversely proportional to the cubic power of rock beam thickness and elastic modulus. The deformation rate of the roadway roof and floor increases with the increase of vertical stress concentration factor of the coal pillar rib, and the maximum deformation position shifts to the side of the coal pillar. Therefore, increasing the strength and stiffness of the roadway surrounding rock and the supporting resistance of surrounding rock can reduce the deformation of roadway surrounding rock and the influence of advanced abutment pressure on roadway deformation. In the end, the rationality and feasibility of the theoretical analysis is verified through an engineering example. Under the influence of advanced abutment pressure, the deformation of roadway floor heave is the most severe, the asymmetrical deformation on both sides of the roadway is remarkable, and the deformation of coal pillar side is about twice that of solid coal side.