Application of strong pier column in crossing large cross-section empty roadway of large mining height working face under close distance goaf

Based on the engineering background of the large cross-section empty roadway in the fully mechanized mining face with large mining height under the goaf of shallow buried close-distance coal seam, the law of mine pressure behavior during the mining of the fully mechanized mining face with large mining height under the goaf of close-distance coal seam is analyzed by numerical simulation. The roof load of the empty roadway is calculated theoretically, and the large-scale uniaxial compression experiment of the strong pier column is carried out. The experiment shows that the maximum bearing capacity of the 1000 mm strong pier column is 10500 kN, the residual strength is 6000 kN, and the longitudinal total deformation is 250 mm. In the large mining height working face of 2⁻² coal seam, the width of the empty roadway is 6 m and the height is 4 m. The high water material strong pier column is adopted to support, the diameter of the pier column is 1000 mm, and the water cement ratio of the high water material is 1∶1. The pier columns in the empty roadway are arranged in 2 columns, with an interval of 3000 mm × 2600 mm. The field industrial application shows that during the working face passing through the empty roadway, the maximum stress of the pier column is 7680 kN, the shape of the pier column is intact, and there is no dumping or splitting. The whole empty roadway is stable, and there is no serious deformation and roof leakage.