Deformation and failure law and control technology of roadway surrounding rock in island working face based on distribution characteristics of deviatoric stress invariant

Abstract

In view of the severe problem of mine pressure behavior under the influence of mining stress superposition on both sides of the working face, this paper takes the isolated working face of Shanxi Yangquan H-N Coal Mine as the research object, and uses FLAC3D numerical simulation software to study the evolution of the plastic zone of the mining roadway in the isolated working face, the distribution of the second invariant field of the partial stress and the distribution of the third invariant field of the partial stress. The results show that there is a large-scale non-uniform failure in the roadway within 15 m of the advanced working face, and the plastic zone of the negative side and the floor appears through the phenomenon. The plastic zone at the roof extends to the positive side, and the shape is ' eagle beak '. The distribution pattern of J2 is basically consistent with the distribution pattern of plastic zone; According to the distribution pattern of J3, within 15 m from the working face, large compressive strain appears in the deep part of both sides of the roadway, and a certain range of tensile strain appears in the shallow part of the roadway. The J2 distribution of roof and floor of mining roadway is ' inverted trapezoid ' distribution, and both sides of roof and floor are more prone to large damage. The J3 distribution of floor of mining roadway is ' trapezoid ' distribution, both sides of floor are in compressive strain state, the middle part of roadway is in tensile strain state, and the J2 distribution of roadway side is ' inverted V ' distribution. With the closer to the working face, the vertex of ' inverted V ' is farther from the roadway, and the vertex value of ' inverted V ' is larger, that is, the greater the damage; the distribution of J3 in the side of the mining roadway is ' V-shaped '. On the positive side, only the coal in the middle of the coal pillar is in compressive strain, and the rest is tensile strain. On the negative side, only the shallow part of the roadway is in tensile strain, and the rest is compressive strain. According to the shape of plastic zone, J2 and J3 distribution, the roof roadway is reinforced and the angle of anchoring hole is adjusted. According to the observation results of surface displacement on site, the optimization of support parameters has a good effect on controlling the deformation of surrounding rock of mining roadway in island working face.