应力加卸载作用下软硬原煤瓦斯渗透规律

河南工程学院 安全工程学院,河南 郑州 451191

应力加卸载; 软煤; 瓦斯渗透特性; 原煤样试件

Gas seepage rule of soft and hard raw coal samples under the action of stress loading and unloading
TIAN Kun-yun

(school of Safety Engineering,Henan University of Engineering,Zhengzhou 451191,China)

stress loading and unloading; soft coal; gas permeation characteristics; raw coal samples

DOI: 10.13800/j.cnki.xakjdxxb.2017.0604

备注

使用自行改装的“瓦斯渗透模拟实验系统”,在不同瓦斯压力条件下,对同一矿井的软硬原煤试件的瓦斯渗透特性进行研究。结果 表明:应力加载阶段,随着应力的增加2种煤样试件的渗透率均呈减小趋势,且加载初期渗透率的降幅最大,当加载围压从0升到4 MPa时,硬煤与软煤的渗透率平均下降69.7%,73.3%; 应力卸载阶段煤样渗透率随着应力的减小而增加,围压完全卸载后2种煤体的渗透率分别恢复到其初始值的22.6%,47.8%; 同样的应力条件下,有效应力的增加对硬煤的影响作用大于煤基质收缩,渗透率随着其内部瓦斯压力的增大而增大,而对软煤则相反。实验结果可为煤体“卸压增透”效果最佳化提供参考,进一步完善低渗透率煤层的瓦斯抽采理论及方法体系。

Research on the gas seepage law of two kinds of raw coal samplesnamely soft and hard coal was carried out using the self designed “simulation experiment system of gas permeability”.Experimental results showed that the permeability of the two kinds samples decreased with the increase of the loading stress in the loading phase,meanwhile,the decrease amplitude was the biggest in the early stage.The permeability decreased by nearly 69.7% and 72.2%,respectively,when the confining pressure increased from 0 to 4 MPa.In the unloading phase,the permeability increased with the decrease of stress,and the permeability was only 22.6% and 47.8% of the initial value averagely.Under the same stress condition,to the primary structure coal,the effect of the increase in effective stresson hard coalwas greater than that of the coal matrix shrinkage,and the permeability reduced with the decrease of the gas pressure.On the contrary,the permeability increased with the decrease of the gas pressureregarding soft coal.The experimental results can provide reference for the optimization of the “pressure relief and permeability” effect of the structure coal,and further improve the theory and method system of gas drainage in low permeability coal seam.