Research on Support of Anchor Net in Weak Cemented Coal Roadway in Hongqingliang Coal Mine

The roof rock formation of 3-1 coal seam in Hongqingliang Coal Mine in Ordos is poor in cementation, low in strength, and easy to muddy. The 11301 auxiliary roadway has a large amount of deformation of the roof during the early stage of the excavation, and the surface of the roof is cracked at the later stage. In order to strengthen the stability of the roadway, site investigations, laboratory tests and theoretical analysis methods were adopted to analyze the characteristics and control mechanism of the roadway damage, and a support scheme for the top coal retaining nets along the bottom was proposed, and the better effect of the engineering test is obtained. The results show that: the soft mudstone with weak cementation in the roof of 3-1 coal seam has low strength, large area of rock fragmentation and fracture development, and poor active supporting function of anchor net along the top excavation, which leads to the gradual failure and instability of roadway surrounding rocks; the elastic modulus and strength parameters of coal seam are all larger than that of mudstone and sandy mudstone layer, and the top coal can be consistent with the deformation of the overlying strata and provide support force, which is beneficial to the self-bearing capacity of the rock strata; through anchoring, the roof rock integrity is improved, and the soft rock and the top coal are combined to form a composite beam to improve the roof stability.