机械扩孔有效抽采半径数值模拟及现场应用

Numerical simulation and on-site application of effective extraction radius for mechanical reaming

为研究掘进工作面机械扩孔的卸压增透效果,以扩孔后的抽采有效影响半径为考察指标,借助COMSOL-Multiphysics数值模拟软件建立机械扩孔模型,动态分析机械扩孔后的瓦斯流场,拟合得出扩孔有效影响半径与抽采时间的关系曲线;通过理论分析和现场考察试验,类比同等工况条件下机械扩孔与普通钻孔的预抽效果,定量探讨2种施工工艺条件下瓦斯流量衰减系数。研究表明,机械扩孔的瓦斯抽采流量平均值为0.0222 m^(3)/min,最低瓦斯抽采流量是初始抽采流量的56.9%,下降幅度为43.1%;而普通钻孔的瓦斯抽采流量平均值为0.006826 m^(3)/min,最低瓦斯抽采流量是初始抽采流量的22.6%,下降幅度达77.4%。机械扩孔抽采浓度由72%降到38%,降幅为47.2%,普通钻孔抽采浓度由39%降到17%,降幅达56.4%,说明机械扩孔卸压增透效果显著。

In order to study the pressure relief and permeability enhancement effect of mechanical reaming at the driving face,the effective influence radius of driving after reaming was taken as the investigation index,and the mechanical reaming model was established with the help of COMSOL-Multiphysics numerical simulation software,and the gas flow field after mechanical reaming was dynamically analyzed,and the relationship curves between the effective influence radius of reaming and the extraction time was fitted.Through theoretical analysis and field investigation test,the pre-extraction effect of mechanical drilling and ordinary drilling under the same working conditions was compared,and the attenuation coefficient of gas flow under the conditions of the two construction processes was quantitatively discussed.Research has shown that the average gas extraction flow of mechanical reaming was 0.0222 m^(3)/min,and the lowest gas extraction flow was 56.9%of the initial extraction flow,with a decrease of 43.1%.The average gas extraction flow of ordinary boreholes was 0.006826 m^(3)/min,and the lowest gas extraction flow was 22.6%of the initial extraction flow,a decrease of 77.4%.The concentration of mechanical reaming decreased from 72%to 38%,a decrease of 47.2%,and the concentration of ordinary borehole extraction decreased from 39%to 17%,a decrease of 56.4%.It shows that the mechanical reaming pressure relief and penetration enhancement effect is remarkable.