Rock properties and adaptability of support structures in phosphorus mines: A case study of a phosphorus mine in Guizhou

Over-supporting and under-supporting of the roadway perimeter rock in the mining process will affect the support effect, so the existing roadway perimeter rock support needs to be analysed, and the support structure parameters need to be adjusted accordingly. In order to study the deformation characteristics of the roadway surrounding rock, this article adopts FLAC3D software to simulate the stress distribution and deformation characteristics of the roadway surrounding rock under the existing anchor support, and analyses the test results of the support structure parameters based on mathematical methods. The results show that the existing support situation can improve the surrounding rock stress state, reduce the degree of stress concentration in the surrounding rock, effectively reduce the range of the plastic zone, and reduce the deformation value of the surrounding rock in the roadway, but it cannot effectively reduce the range of its plastic zone. Through orthogonal test, using extreme difference analysis, the primary and secondary order of the influence of the main control factors of the roof roadway on the total deformation of the roadway was obtained as follows: the thickness of the sprayed slurry > the anchor spacing > the length of the anchors = the distance between the rows of anchors. The roof of the roadway is: Spray thickness > Anchor spacing > Anchor length > Anchor row spacing. For the left gang of the roadway, it is: Spray thickness > Anchor spacing > Anchor row spacing > Anchor length, and for the right gang of the roadway, it is: Spray thickness > Anchor row spacing > Anchor length > Anchor spacing. For the total deformation of the roadway in the vein of the ore layer, the primary and secondary order of the influence of the two gangs is: the thickness of the spray slurry > anchor length > anchor spacing > anchor row spacing, and for the top plate of the roadway is: the thickness of the spray slurry > anchor length > anchor row spacing > anchor spacing. When the displacement of the roadway exceeds the permissible amount, the support parameters can be adjusted in the order of the degree of influence of each of the main control factors mentioned above. The results of the study can provide reference significance for the design and optimization of support for similar mines.