Analysis of permeability variation during the stress-strain process of rocks

Considering the relation between permeability-strain curve and rock failure process, the relationship among permeability, strain and stress of rock is analyzed based on the permeability-strain curve and permeability-stress curve under complete stress-strain path. It is proposed that rock system gets its instability condition, when stress reaches the critical value. The experimental results verify the reasonableness of the analysis. The results show that the lowest rock permeability corresponds to the rock expansion point. The stress-strain path can be divided to three stages, which are compaction stage, expansion stage of pre-peak and post-peak stage. It is proposed that the change of rock permeability is caused by the interaction of the smaller micro-scale level burst, which resulted in the formation of permeable channel.