中文摘要：

水射流割缝卸压增透时存在淹没射流和非淹没射流两种情况,导致煤体上下割缝半径不同,若仅根据一种半径进行钻孔布置,则易出现抽采空白带或增大工程量等问题。为此,提出基于淹没射流和非淹没射流不同破碎半径的钻孔布置新工艺。在分析两种射流速度场分布的基础上,理论计算了两种射流破碎半径,对比分析得出非淹没射流与淹没射流的破碎半径之比是1.48∶1。运用comsol数值模拟软件,建立数值模型,分析了两种射流并存情况下的瓦斯压力变化,并与不考虑淹没射流时抽放数据进行对比分析,结果表明,两种射流并存时抽采范围为不考虑淹没射流的86.5%。根据分析结果,提出应采用交叉割缝的方式,同一行中相邻两割缝终孔间距为7.5 m,相邻两行中,垂直间距相隔5.8 m,且两端割缝中心相错3.75 m的布孔方案,并用comsol进行验证,结果表明,交叉割缝布孔具有较好的抽放效果。

英文摘要：

There exists two kinds of situations,submerged jet and non- submerged jet,when adopting water jet for cutting seam,pressure relief and permeability improvement,which lead to the different cutting radius up and down the coal. If the borehole layout is carried out only according to one diameter,the problems of extraction blanking zone or engineering quantity increase are easy to appear. Therefore,a new technology of borehole layout based on different broken radius of submerged jet and non- submerged jet was put forward. Through analyzing the distribution of velocity field the broken radius for two kinds of jet were calculated theoretically,and with comparison analysis,the ratio of broken radius for non- submerged jet and submerged jet was 1. 48： 1. A numerical model was established using the COMSOL numerical simulation software,the pressure change of gas when two kinds of jet coexisted was analyzed and compared with the extraction data without considering the submerged jet. The results showed that the extraction range when two kinds of jet coexisted was 86. 5% of that without considering the submerged jet. So the borehole layout scheme was suggested that the way of cross cutting should be adopted,and in the same line,the space between two adjacent cutting end holes is 7. 5m,while in two adjacent lines,the vertical space is5. 8m,besides,the space between the cutting center in the ends is 3. 75 m. It was verified by COMSOL,and the results showed that cross cutting borehole layout has a better extraction effect.