基于水分影响的加-卸载围压条件下含瓦斯煤渗流特性研究

Seepage characteristics of coal mass containing gas considering moisture effect in loading-unloading confining pressure test

利用自行研制的"受载含瓦斯煤温控三轴加载渗流实验装置",以河南方山煤矿煤样为研究对象,进行了不同含水率条件下2次加-卸载围压的三轴渗流实验,系统研究了水分和加-卸载围压对含瓦斯煤渗透特性的影响规律。研究结果表明:1)围压及煤样的含水率对型煤煤样渗透率控制性较强,型煤渗透率与水分及围压大小都呈负相关关系;2)2次加载过程相比,第2次加载过程中渗透率变化明显较第1次平缓,且两者渗透率与围压的关系曲线路径不同;3)2次卸载过程中,渗透率都有一定程度升高,但均恢复不到初始值,且随着煤样含水率越高其恢复程度越小;4)同一次加载或卸载过程中,含水率越高的煤样渗透率变化曲线越平缓。第1次加载后,进行第1次卸载及2次加卸载过程中,水分对煤体渗透率的控制性要显著高于围压对其控制性。实验结论对处于反复加-卸载情况下,煤层瓦斯渗透率主要控制因素选择有一定意义。

In this paper, taking coal samples in Fangshan Coal Mine, Henan as research object, the self developed ＂Loaded coal containing gas triaxial loading seepage experiment device＂ was used to conduct the loading-unloading confining pressure triaxial seepage experiments under the condition of different moisture contents, and to analyze the influence law of moisture and loading-unloading confining pressure on the seepage characteristics of coal mass containing gas. The results show that： 1） Confining pressure and moisture content of coal sample have strongly control ability to the permeability of briquette, while the permeability is correlated negatively with the moisture and confining pressure. 2） In the two loading processes, the permeability variation in the second loading process is gentler, and the relation between permeability and confining pressure curve path is different. 3） During the two unloading processes, the permeabilities increase to some extent, but can＇t recover to the initial value. The higher the moisture content is, the smaller the recovery degree is. 4） During the same loading or unloading process, the permeability of coal sample with higher moisture content changes more gently. After the first loading, during the first unloading and the second loading-unloading processes, the control ability of moisture content in the permeability of coal sample is much higher than that of the confining pressure. Experimental conclusions can provide reference to the choice of the main control factors to gas permeability in coal seam under the repeated loading-unloading conditions.