Experimental Study on Fluid Permeation Evolution in Whole Failure Process of Tuff

Based on the test results of fluid permeation in the whole 3D stress-stain process of tuff under compression with variable parameters,the permeation evolution of tuff was investigated in the deformation/failure process to analyze empirically the relationship between volumetric strain,permeability and ambient pressure.The results indicated that the permeability of tuff closely relates to stress level.After the strength peak,the peak value of permeability occurs till the internal microcracks have been permeated through the rock specimen,with such inflection points as the peaks of stress and volumetric strain corresponding well to the permeability peak.This conclusion will be of great significance to the more reasonable mathematic model for predicting the fluid permeation evolution in the failure process of rock.