卸压边界区径向瓦斯渗流特性试验研究

以淮北青东煤矿8号突出煤层煤样为研究对象，利用自行研制的径向瓦斯渗流实验系统，结合保护层卸压边界区地应力及瓦斯压力分布特征，进行变轴压、变瓦斯压力、变钻孔孔径条件下突出煤样径向瓦斯渗流试验。试验结果表明：相同轴压下，径向瓦斯渗流量随瓦斯压力增加而增加，成二次多项式关系，渗透率随瓦斯压力增加，在0~0.6 MPa内迅速降低，随后缓慢下降，并趋于稳定；相同瓦斯压力下，渗透率随覆压增加呈线性递减趋势；受钻孔卸压影响，在低轴压阶段，大孔径松软低强度试样渗透率显著高于小孔径试样的渗透率，随轴压增加，两者渗透率逐渐趋于一致。

Experimental study of radial gas seepage characteristics in stress-relief boundary area

Based on the coal samples of the outburst coal seam No.8 of Qingdong Mine in Huaibei，with the distribution characteristics of ground stress and gas pressure in stress-relief boundary area，the experiment of outburst coal’s radial gas seepage was carried out under variable axial pressure，gas pressure and hole diameter by a self-developed test system of radial gas seepage.The experimental results show that the gas seepage flow increases with the increase of gas pressure under fixed axial pressure，and the relationship between gas seepage velocity and gas pressure can be described as quadratic polynomial function，the permeability of coal samples decreases rapidly with the increase of gas pressure in the range of 0-0.6 MPa，then decreases slowly with the developing of gas pressure and tends to be stable；the permeability of coal samples decreases linearly with the increase of axial pressure under fixed gas pressure；Affected by the borehole pressure relief，the permeability of soft and low strength coal samples with large diameter borehole is significantly higher than the coal samples with small diameter borehole in low axial pressure stage，both permeability gradually tends to be the same with the increase axial pressure.