不同应力路径下含瓦斯煤渗透特性的实验研究

通过对含瓦斯煤渗透特性的实验研究,系统分析了不同应力路径下含瓦斯煤的渗透率变化规律,建立了含瓦斯煤渗透率与轴向压力、围压及瓦斯压力等之间的定性与定量关系,探讨了不同应力路径下含瓦斯煤渗透性的控制机制和变化规律。结果表明应力路径对含瓦斯煤的渗透率有着重要影响:1)含瓦斯煤渗透率随着轴向压力和围压的增加而减小,随瓦斯压力的增加而增加。2)含瓦斯煤渗透率与轴向压力、围压和瓦斯压力呈指数关系变化。3)三轴压缩下全应力-应变实验过程中,含瓦斯煤的渗透率呈"V"字型走势;渗透率随煤样的应变先减小后增大,然后达到最大值,而且渗透率的增加速率小于其减小速率。

Seepage Property of Coal Containing Gas Under Different Paths in Laboratory

According to experimental investigation on seepage property of coal containing gas,the change rule of permeability of coal containing gas is analyzed systematically under different stress paths.The quantitative and qualitative relations between the permeability of coal containing gas and ax-ial pressure,confining pressure and gas pressure were established respectively.The controlling mecha-nism and changing law of permeability of coal containing gas under different stress paths are discussed.The results showed that stress path has an important impact on the permeability of coal containing gas,and the details are: 1) The permeability of coal containing gas decreases with increasing of axial pres-sure and confining pressure,and increases with increasing of gas pressure.2) The relationship between permeability of coal containing gas and axial pressure,confining pressure and gas pressure obeys ap-proximately an exponential law.3) During the whole stress-strain process under the condition of triaxial compression,the change trend of permeability of coal containing gas versus strain curve displays nearly a shape of letter "V".The permeability of coal sample decreases with strain first,then increases,and reaches its maximum finally.The rate of permeability at increasing stage is less mildly than that at de-creasing stage.