Experimental research on permeability and acoustic emission characteristics during whole failure process of fine sandstone

In order to discuss the permeability and acoustic emission characteristics of fine sandstone during the deformation and failure process, a series of tests for characteristics of permeability and acoustic emission were performed under triaxial conditions by using MTS 815 rock mechanical test system and PAC PIC-2 acoustic emission test station. The variation of permeability, the relationship between permeability and strain and the acoustic emission characteristics were studied. The results show that the permeability during the process of deformation and failure changes in accord with the stress-strain curves, and the rules under different confining pressures are similar. The permeability decreases with confining pressure increasing. The changes of permeability and lateral strain ε3 with axial strain ε1 have a good corresponding relationship. The point where ε3 increases sharply is corresponding to where permeability increases, so ε3 reflects the variation of permeability better. The acoustic emission characteristics in the whole process reflect the development of the cracks, and the acoustic emission correlates well with the stress-strain and permeability. The energy rate, one of the parameters of acoustic emission, increases with confining pressure increasing. The characteristics of acoustic emission can reveal the emergence and development of fractures in rocks, which can develop a deeper understanding of the variation of permeability during the deformation and failure process. ©, 2015, Academia Sinica. All right reserved.