Research On Surrounding Rock Control Technology Of Large Height Near-goaf-roadway In Jinhuagong Mine

According to the special geological conditions of "two hard" and large mining height working face at Jinhuagong mine which forms from the hard roof and hard coal seam, for solving the technical problems of airport roadway surrounding rock seriously unstable caused by lateral concentrated stress that the goaf basic roof to entry protection coal-pillar, overlying coal pillar vertical stress, the bending moment made by the lateral roof cantilever beam and mining stress superposition, comprehensive method has been used with the combination of theoretical analysis, numerical calculations, engineering tests. The results show that roadway deformation of roof and floor and two are severe, at the same time the deformation of roof and floor is more than two sides. The maximum roof and floor convergence value is 1.4 meters, the maximum two sides convergence value is 1.0 meters. The biggest heaving floor is up to 1.4 meters. Adjacent goaf coal pillar is side-blasting, and the depth is up to 1.2～2.5 meters, and side-blasting is about 45 meters. The paper reveals airport roadway’s overlying strata subsequently mechanism in the "two hard" working face with large mining height, and set up "two hard" working face with large mining height pre-split relief control design model and computational formula of the coal pillar load bearing under the condition of cantilever beam. The calculated actual coal pillar load bearing is 56.81～56.81 MPa named σp, which is greater than the compressive strength of coal pillar. Based on this, we established a technology system for airport roadway lateral roof with "presplit relief" as the main technical mean, "structural motion parameters precontrol" and support reinforcement for the auxiliary, which ensures the safe and efficient production of working face.