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 superhigh 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.%为提高顺层瓦斯抽采钻孔密封性,确保瓦斯抽采效果,基于传统的“两堵一注”带压注浆封孔工艺,结合超高压水力割缝技术,提出封隔一体化封孔工艺,即在封孔段采用割缝的方式进行辅助封孔.通过钻孔应力及漏气形式分析,研究了钻孔周边煤体应力分布特征及卸压范围,确定了3类漏气通道;阐述了封隔一体化封孔工艺原理并确定了相关工艺参数.现场试验结果表明:采用封隔一体化封孔的抽采钻孔取得了较好的封孔效果,其抽采瓦斯浓度比同等条件下的常规封孔方法提高25％～30％,减缓了抽采瓦斯浓度衰减速率,为顺层瓦斯抽采钻孔提供了一种良好的封孔方法.
展开▼
