含瓦斯煤体渗透率与煤体结构关系的实验

Experiments on the relationship between permeability of gas-bearing coal and coal body structure

为了研究不同结构煤的渗透率差异,以焦作煤田为例,对Ⅰ～Ⅴ类结构煤进行了渗透率测试,结果表明:渗透率与不同煤体结构关系曲线近似呈正态分布,先是呈级数增大,随后呈级数减小,Ⅱ类渗透率最大,V类煤体渗透率最小,Ⅰ、Ⅳ、Ⅴ类煤体渗透率差别不大。引入渗透率变异系数、渗透率级差概念,评价得出二1煤层的非均质性、各向异性较强,而单个类型煤体均质性较好。对饱含瓦斯煤体瓦斯分布的分区分带、矿井瓦斯涌出、煤与瓦斯突出作用机理进行了解释,渗透率变化是孔裂隙的发展过程,是控制瓦斯分布、涌出、煤与瓦斯突出的主控因素。

Permeability tests of type I to V coal from Jiaozuo coalfield are carried out to study the gas permeability difference of coals with different structures.The experimental results show that the relation curve of permeability to different coal structures show normal distribution,and the value of permeability first increases quickly and then decreases sharply.Type II coal’s permeability is the maximum and that of type V is the minimum.There is little difference of perm abilities of type I,type IV and type V.The concepts of variation coefficient of permeability and permeability ratio are brought in to evaluate the heterogeneity and anisotropy of No.21 coal seam.It found both of them are high,however,the homogeneity of a single type structure coal is good.Mechanisms of gas sub region and banding,gas emission,gas outburst of gas-bearing coal are explained by the permeability differences.Permeability changes are the direct result of pore-fracture development and the major controlling factor of gas distribution,gas emission and coal and gas outburst.