Abstract:Gucheng Coal Mine is a high gas mine. In order to realize Y-shaped ventilation and improve the recovery rate of coal resources, the technology of gob-side entry retaining was studied in the auxiliary transportation roadway of N1303 working face. The floor of the roadway is a weak coal seam or sandy mudstone, and the concrete roadside filling method is determined. FLAC3D numerical simulation software is used to simulate the deformation of roadway under different strength and different width. The concrete strength is C30 and the width is 1.5 m. Combined with the field situation, the reinforcement measures of roadway roof and two sides are put forward. Aiming at the problem of large deformation of weak floor, the method of floor cutting and concrete pouring is adopted. The mine pressure observation after the mining of the working face shows that the deformation of the roadway is small and can meet the requirements of secondary mining.