煤体应变对渗透率的影响分析

The Influence Analysis of Coal Strain on Permeability

煤的渗透率受到骨架应力与孔隙压力的共同作用,并与煤的吸附变形有关。通过实验方法研究了煤体渗透率与变形之间的关系,结果表明:相同气体组分相同围压条件下,应变与渗透率的变化关系呈"V"字形曲线,应变有一临界范围,大于这一范围随应变的增大渗透率变化不大,而小于这一值时,渗透率变化很大;气体组分不同时,高应变条件下,CO2的渗透率略微大于N2的渗透率,这与孔隙压力与渗透率的变化关系是有区别的。

The permeability of coal is influenced by frame stress and pore pressure,as well as influenced by the adsorption deformation of the coal.In this paper,the relationship between permeability and the coal deformation can be obtained through the experimental study.The test results show that if the gas component and the confining pressure are the same,the relationship between strain and permeability submits to the shape of the V curve.The strain has a critical range,when the strain is larger then this range;the permeability changes little with the augment of strain,while the strain is less then this range,the permeability changes obviously.While the gas component is not same,in high strain conditions,permeability of carbon dioxide is slightly more than the nitrogen permeability,and this is different from the relationship of pore pressure and permeability change.