中文摘要：

为提高预抽煤层瓦斯消突效果,文章提出了一种变孔径的钻孔卸压增透技术,并在下山揭煤钻孔中进行了试验研究。通过对已施工好的下向穿层钻孔实施掏穴扩孔后,实际钻进出煤量相应增加,钻孔的卸压影响范围增大,钻孔周围的煤体变形和透气性增大,抽采瓦斯效果显著提高,值得在低透气性高瓦斯突出煤层消突实践中推广应用。

英文摘要：

In order to improve the gas outburst elimination effect of the gas pre-drained seam,a borehole pressure releasing and permeability improvement technology with the varied diameter borehole was provided and an experiment study was conducted on the boreholes applied to the seam opening in the downward gateway.With the downward borehole passed through strata applied to the cut shot and borehole reaming,the actual coal production from the drilling would be relatively increased and the pressure releasing influence scope of the borehole would be increased.The coal deformation and permeability around the borehole would be increased and the gas drainage effect would be obviously improved.It would be a value of the promotion and application to the outburst elimination practices in the low permeability and high gassy outburst seam.