低渗透突出煤破坏过程中瓦斯运移规律研究

Study on Gas Migration Law for Low Permeability Outburst Coal in the Process of Destruction

利用自主研制的煤与瓦斯突出模拟实验装置,结合数值模型的建立,基于实验和数值模拟的基础上,分析研究了低渗透性突出煤层在煤与瓦斯突出过程中瓦斯的运移规律,研究结果表明:低渗透性突出煤层在受地应力或移动支承压力的反复作用下,煤体渗透性增加,吸附态瓦斯解吸,内部瓦斯压力升高,并呈初期增长速率较快,之后逐渐变小,最后变缓的趋势;同时,游离态瓦斯向气体压力低的采掘空间方向运移,当大量的游离瓦斯不能及时扩散、运移到外界,导致煤体内部瓦斯压力持续升高并积聚到一定程度时,就会与地应力共同作用而造成煤与瓦斯的突出,因此,降低游离瓦斯压力是低渗透性突出煤层防突技术的关键。

Based on the experiment and numerical simulation,the paper analyzes and studies the gas migration law of low permeability coal seams during coal and gas outburst process by using self-developed coal and gas outburst simulation experiment device and the numerical model.The results show that,under the repeated action of the in-situ stress or moving abutment pressure,the permeability of the coal body in the low permeability coal seams increased,the absorption gas desorbed,the internal gas pressure increased,and the initial growth rate was faster,gradually became smaller,and finally became slower.At the same time,the free gas moves toward the mining space with low gas pressure.When a large amount of free gas can not be diffused and transported to the outside in time,the gas pressure inside the coal body continues to rise and accumulate to a certain extent.It will jointly with the in-situ stress effect to cause coal and gas outburst.Therefore,reducing free gas pressure is the key technology of low permeability outbust coal seam.