不同层理方向裂隙煤体承压过程瓦斯渗透规律实验研究

Experimental study on gas permeation laws of fractured coal with different bedding directions during pressure bearing process

为获取应力加卸载过程中3种不同层理方向裂隙煤体的瓦斯渗透规律,采用应力瓦斯渗透模拟实验装置对加卸载过程平行、斜交及垂直层理方向的原煤试件进行了实验。研究结果表明:加载过程中,3个煤样试件的渗透率与所施加的有效应力成正比,当有效应力最大时平行层理裂隙煤样试件的渗透率的降幅最大,不同层理方向最大渗透率比值为7.2∶1;卸载过程中,渗透率与有效应力之间存在反比关系,在应力卸载初始阶段渗透率增幅不大,当有效应力卸荷到一定程度时,渗透率的增幅陡然增加,相同的卸载条件下,斜交层理试件的渗透率恢复比最大。研究结果可为煤体抽放钻孔布置提供一定参考,以使瓦斯抽采效果最大化。

In order to obtain the gas permeation laws of fractured coal with three different bedding directions during the process of stress loading and unloading,the experiments on the raw coal samples with the parallel,oblique and vertical bedding directions during the loading and unloading process were carried out by using the stress gas permeation simulation experimental device. The results showed that during the loading process,the permeability of three coal samples were directly proportional to the applied effective stress,when the effective stress was the maximum,the decreasing amplitude of the permeability of the fractured coal sample with the parallel bedding was the largest,and the maximum permeability ratio with different bedding directions was 7. 2 ∶ 1. During the unloading process,the permeability were inversely proportional to the effective stress,the increasing amplitude of the permeability at the initial stage of stress unloading was not significant,while increased sharply when the effective stress was unloaded to a certain degree,and under the same unloading conditions,the permeability recovery ratio of the coal sample with the oblique bedding was the largest. The results can provide certain reference for the drainage borehole layout of coal,so as to maximize the gas drainage effect.