Study on borehole sealing technique with sealing andisolation integration to gas drainage borehole along seam

In order to improve the sealing performances of the gas drainage borehole along the seam and to ensure the gas drainage effect,based on the conventional pressurized grouting and sealing technique with “two sealing and one grouting”,in combination with the super-high pressure hydraulic slotting technology,a sealing and isolation borehole sealing technique was provided.Thus a slotting method was applied at the borehole sealing section for the auxiliary borehole sealing.With the analysis on the stress and air leakage mode of the borehole,the stress distribution features of the coal around the borehole and the pressure released scope were studied and three type air leakage channels were determined.The paper stated the principle the “sealing and isolation integration” sealing technique and determined the relevant technical parameters were determined.The site test results showed that the gas drainage borehole with the “sealing and isolation integration” obtained good borehole sealing effect.The volume fraction of the drained gas was 25%～30% higher than conventional borehole sealing method under the same condition,could reduce the decay rate of the drained gas concentration and could provide a good borehole sealing method of the gas drainage borehole along the seam.