加卸载作用下构造煤峰值前渗透率变化特征试验研究

1.河南工程学院 安全工程学院,河南 郑州 451191; 2.河南省煤矿安全重点实验室培养基地,河南 郑州 451191

构造煤; 加卸载; 渗流特性; 有效应力; 渗透率

Experimental study on pre-peak permeability of coalsamples under axial stress loading and unloading
SUN Guang-zhong1,2, JING Yong-bin1,2

(1.School of Safety Engineering,Henan Institute Engineering,Zhengzhou 451191,China; 2.Key Laboratory of Coal Mine Safety Training Base in Henan Province,Zhengzhou 451191,China)

tectonic coal; loading-unloading; seepage characteristics; effective stress; permeability

DOI: 10.13800/j.cnki.xakjdxxb.2016.0208

备注

利用自行研制改造的含瓦斯煤热流固耦合三轴渗流实验装置,以典型豫西“三软”构造煤原煤样为研究对象,进行三轴压缩下构造煤样渗透率测试,分析了轴向应变-渗透率变化关系; 研究了轴向应力加卸载作用下含瓦斯构造煤渗透率的影响。结果 表明:三轴压缩作用下含瓦斯煤的渗透率与轴向应变的关系呈斜“V”字型走势; 渗透率在轴向应力加载过程中减小,卸载过程中有所恢复,且煤样渗透率与轴向应力在加卸载过程中符合负指数函数分布,并给出了数据拟合参数; 在加载过程中,有效应力大,渗透率无因次量降低速率大; 卸载过程中,有效应力大,使得渗透率无因次量变化幅度减小,变化速率趋近于0.渗透率无因次量与有效应力在加卸载过程中服从负指数函数分布。

To study the permeability characteristics of tectonic coal using fluid-solid-heat coupling triaxial servo-controlled seepage system of coal containing gas that was developed in house,Based on the Henan western “three soft” tectonic coal as the research object,carried out the triaxial compression seepage test and analyzed the relationship between the axial strain permeability; Studied the tectonic coal permeability characteristics under the axial cyclic loading-unloading; The test results show that: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 oblique shape of letter “V”; In the process of axial stress loading,the permeability decreases,and recovered in the process of unloading,Permeability of coal samples and axial stress distribution accords with negative exponential function in the process of loading and unloading,and the fitting parameters is given.In the process of loading,the bigger effective stress,reduce the rate of large amount of dimensionless permeability; In the process of Unloading,the great effective stress has made the amplitude of dimensionless permeability decrease,and its change rate converge to zero.Dimensionless permeability and effective stress in the process of loading and unloading obey negative exponential distribution function.