Coal stress distribution law in reverse fault area

The in-situ stress and tectonic stress in the reverse fault area are superimposed, and the distribution law of coal body stress is very complex, which affects the safe mining of coal seam in the reverse fault area. In order to obtain the effect of reverse fault structure on the stress distribution of coal mass, the coal-rock mass in F4 reverse fault area of No.1503 mining face of Xinchun Coal Mine in Guizhou Province was collected as the research background. FLAC3D numerical simulation method was used to analyze the stress distribution of coal mass in reverse fault area. The stress analysis theoretical model of coal body in reverse fault area was established, and the expression of coal body vertical stress and horizontal stress were derived. KYKY-2800B scanning electron microscope was used to analyze the microstructure of coal samples at a distance of 70 m, 40 m and 10 m from the reverse fault. The research results show that: ① within 100 m of the reverse fault area, the vertical stress and horizontal stress of the coal body increase and then decrease with the decrease of the distance from the reverse fault. ② the stability of coal body is negatively related to the distance between coal body and reverse fault. The coal body would be destroyed within the range of less than 12.74 m from the reverse fault area. The strength of coal body deteriorates and the stress decreases. ③ there are basically no cracks on the surface of K3 coal samples 70 m away from the reverse fault, and the coal samples are relatively complete. The “X” type cracks are found on the surface of K2 coal samples 40 m away from the reverse fault, and the coal body is still in the elastic deformation stage without damage. The K1 coal sample with a fault of 10 m is broken in structure and mixed with large and small particles. The coal body is damaged and is in the stage of plastic softening or plastic flow. The strength of the coal body is deteriorated and the stress is reduced. ④ The damage of the coal body near the reverse fault leads to the reduction of stress, thus forming a distribution characteristic that the distance from the reverse fault decreases, and the stress of the coal body first increases and then decreases.