高位顺层钻孔瓦斯抽放数值模拟

针对八连城煤矿19号煤层62.1%~71.6%的瓦斯来源于采空区的问题,提出高位顺层钻孔抽放采空区瓦斯的治理方案.基于关键层理论和＂O＂形圈理论,分析了采空区上覆岩层裂隙形态,对瓦斯在其中的运移规律进行了研究,认为在上覆岩层采动裂隙中瓦斯流动符合达西定律.利用商业软件COMSOL-Multiphysics对瓦斯抽放进行了数值模拟,直观展示了瓦斯抽采时的瓦斯分布状态.模拟结果表明瓦斯抽放有效降低了瓦斯压力,给现场瓦斯抽放提供了理论依据,具有重要的实践意义.

Numerical Simulation of Gas Drainage with High-Position Boreholes Along Coal Seam

In the coal seam 19 of Baliancheng Coal Mine,the 62.1%～71.6% of gas emission was from goaf.A gas drainage procedure with high-position boreholes along seam in goaf was proposed in order to control the gas disaster.Based on the key stratum theory and the O shape circle theory,fissure pattern in the overburden rock strata above the goaf was analyzed.Through the study of the gas migration in overburden rock fissure,it is regarded that the gas flow follows the Darcy’s law.A numerical simulation was done with the commercial software COMSOL-Multiphysics for gas drainage.It clearly illustrated the gas migration during the flow drainage.The results showed that the gas drainage reduces the gas pressure effectively.This study may provide theoretical basis for site gas drainage and is of important practical significance.