型煤峰后渗透特性试验研究

摘要

煤层瓦斯渗透率是瓦斯(煤层气)抽采的重要指标之一,通过渗流模拟-吸附解吸试验装置,研究了型煤煤样在不同围压作用下破碎后卸载轴压围压过程中,以及加载至二次破坏过程中煤样渗透率随应力的变化情况.试验表明:型煤峰值强度后的渗透率较初始状态有所增大,峰值强度后卸载围压和轴压,其渗透率均增大.其后,给煤样固定一个围压加载轴压使煤样发生二次破坏,渗透率先减后增,整体呈U型趋势,且煤样发生二次破坏过程中的渗透率整体上要大于初次破坏过程中的渗透率,通过试验研究为矿井瓦斯抽放和煤层气开采提供了一定理论基础.%The gas permeability of coal seam is one of the important indexes of gas drainage.The variation of the permeability of briquette coal samples with the stress under different confining pressure in the processes of unloading confining pressure and axial pressure and loading to the secondary damage process after broken were studied by using the seepage simulation-adsorption and desorption experimental device.The results showed that the permeability of briquette coal after the peak strength increased than the initial state,and both the permeability increased when unloading the confining pressure and axial pressure after the peak strength.Thereafter,the coal sample occurred the secondary damage when the coal sample was fixed to a confining pressure with the loading of axial pressure,the permeability reduced first and then increased,with a u-shaped trend on the whole,and the permeability of coal sample in the secondary damage process was larger than that in the process of damage for the first time on the whole.The experimental research provides a certain theoretical basis for the mine gas drainage and coal bed methane mining.