松软构造煤负压抽采下瓦斯渗流特性实验研究

Experiment Research on Gas Permeability of Soft Tectonic Coal Under the Condition of Negative Pressure Extraction

利用自行设计改装的煤岩体三轴渗流仪以低渗透性松软构造原煤体试件为研究对象进行实验,研究了抽采负压作用下松软构造煤体中瓦斯渗流规律。实验结果表明:静态加载过程中围压、轴压、进口瓦斯压力保持恒定的条件下瓦斯渗透率随着抽采负压的增大而增大,负压较高时,煤体瓦斯渗透率增幅较小,负压为30 kPa时,渗透率的增幅已趋于0;改变加载轴压、围压及瓦斯进气口压力,比较不同组别之间的差异性发现,随着加载轴压和围压的增大,构造煤瓦斯渗透率一直在降低,提高进气口瓦斯压力及出口抽采负压则有利于提高渗透率,但总体增幅较小。

Using the self-designed and modified coal rock mass trlaxial stress seepage experiment device, taking low permeabilityand soft tectonic coal as the test sample, we carry out the triaxial stress seepage experiment, and study the permeability law of softtectonic coal under the condition of negative pressure extraction. The experiment result shows that the permeability of coal gasincreases with the increase of negative pressure under the condition of constant confining pressure, axial pressure and inlet gaspressure in the process of static loading; when the negative pressure is higher, the increment of gas permeability is relativelysmall, and the increment of permeability is zero when the negative pressure is 30 kPa; by changing the axial pressure, confiningpressure and inlet gas pressure and comparing the difference among different groups, we find that the gas permeability of tectoniccoal decreases with the increase of axial pressure and confining pressure, and improving gas pressure is beneficial to theimprovment of pemleability, however, the permeability increases slightly in general.