Permeability experiments of deformation and failure processes of gritstone are carried out in triaxial test instrument. The permeability of gritstone in deformation and failure processes is analyzed. The impact of confining pressure on permeability of gritstone is studied. And the relationship between permeability and volume strain was discussed. It is shown that in the triaxial compression test, the total change law of permeability presents the corresponding stage characteristic of the curve of stress-strain. It is that the permeability reduces slightly with the increase of partial stress in the stages of micro fracture compression and elastic deformation; in the elasto-plastic stage, along with the expansion of new fractures, the permeability increases slowly at first and then sharply reaches the maximum value after peak points at residual flowage stage, the fracture which controls the permeability of gritstone is compressed because the confining pressure and the permeability decreases. During the process of deformation and failure, the permeability decreases because the generation connected fissures is compressed by the confining pressure. The permeability is more sensitive to the change of hoop strain in the deformation and failure processes of rock sample. The greater the confining pressure is, the smaller the peak value and the post-peak residual value of permeability various curve of gritstone are, and the more gentle the curve of permeability-strain is. Lastly, based on the mass conservation equation of the theory of porous media, the relationship between porosity and volume strain is deduced. By using the Kozeny-Carman equation, the relationship between the permeability and volume strain is studied, the results show that the Kozeny-Cannanrnequation has good applicability when pores dominate the flow channel.%利用三轴耦合试验机进行粗砂岩不同围压条件下的变形破坏过程渗透性试验,分析粗砂岩变形及破裂过程中渗透性的变化规律,研究围压对粗砂岩渗透性的影响,探讨试样变形过程中渗透系数与体积应变的关系.研究表明:粗砂岩三轴压缩变形过程中,渗透性变化的总体规律呈现出与偏应力-应变曲线相应的阶段性,即微裂隙压密阶段与弹性变形阶段,渗透性随偏应力增大呈略微降低；弹塑性变形阶段,随新生裂隙的扩展,渗透性先缓慢增大,而后急剧增大,峰值强度后达到极大值;残余流动阶段,产生的贯通性裂隙由于围压作用被压密而导致渗透性下降.在岩样变形破坏过程中,渗透性对环向应变的变化更为敏感.围压越大,粗砂岩渗透性变化曲线的峰值及峰后残余值越小,渗透系数-应变过程曲线越平缓.最后,基于多孔介质理论的质量守恒方程得到孔隙率与体积应变的关系式,采用Kozeny-Carman方程研究粗砂岩变形过程中渗透系数与体积应变的关系,计算结果显示,Kozeny-Carman方程在岩样以孔隙为主要渗流通道阶段适用性较好.
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