Abstract: In order to effectively solve the problem of hole plugging and hole collapse in the gas drainage hole in the soft coal seam of holsingh coal mine,a kind of maintenance device for the stability of the gas drainage hole is developed,which is mainly composed of the coal seam gas collection system,the rotatable screen cleaning system,the gas drainage power system and the stable system,which can realize the stability maintenance of the gas drainage holes with different diameters,and has been successfully carried out Field measurement and application.The results show that after the support treatment of the maintenance device,the borehole deformation is significantly reduced.According to the given expression of the borehole deformation maintenance efficiency,the borehole maintenance efficiency is about 30%.After the maintenance treatment,the borehole gas emission speed,the total amount of emission and the effective drainage time are increased.Compared with the non maintenance treatment,the total amount of gas emission is increased by more than 20%,and the effective drainage time is increased about four days.

Key words: soft coal seam, gas, gas drainage, borehole deformation