利用AG-250kNI电子精密材料试验机,配合自制煤岩三轴蠕变瓦斯渗流装置,对煤岩全应力-应变过程中的瓦斯流动特性进行试验研究,得出煤岩在全应力-应变过程中瓦斯流动特性规律。试验结果表明:应变-瓦斯流动速度曲线与应力-应变曲线变化趋势具有相似性,且表现为少许滞后于应变的特点,这表明煤岩受载过程中的损伤演化决定着瓦斯在其内的流动特性,而瓦斯的吸附-解析过程及瓦斯在煤岩内流动需要时间是其表现出滞后性的主要原因。煤岩所受围压通过侧向压缩煤岩侧壁,导致其内部结构变化而对其所含瓦斯流动起到阻碍作用。进行2种不同粒径煤粉组成的煤岩比较试验,结果表明,其所含瓦斯流动特性差别较大,且颗粒组成较大的煤岩试件受外界条件影响较明显。
The tests on methane flow regularities of complete stress-strain processes of coal samples are performed by AG - 250kNI rock mechanics testing system combined with self-developed coal triaxial creep and gas seepage equipment. The characteristics and principles for gas seepage in complete stress-strain processes of coal samples are obtained. The results show that the strain-gas seepage velocity curves are similar to stress-strain curves of coal samples, but hysteretic nature is found in strain-gas seepage velocity curve, which shows that the character of gas seepage is determined by damage evolution of coal sample during the process of loading. The lasting durations for both the adsorption-desorption processes and seepage processes of gas are the reason of hysteretic nature in strain-gas seepage velocity curve. The confining pressure shows hindering effect on gas seepage through the changes of internal structure caused by compression effect of confining pressure. The results of two kinds of coal samples composed of different particle sizes and powders show that the difference of gas seepage characters is large, and the coal sample composed of larger particle size and powder is more easily to be influenced by external conditions.