Joint shear displacement-dilation analysis using in-situ opposing profiles

Unrolled digital images of a borehole wall in porphyritic granite are obtained using the borehole scanner system. The roughness profiles of the opposing joint walls are then extracted from these images using image processing techniques. The opposing profiles are analyzed for shear displacement dilation behavior at low normal stresses using a new method that accounts for the interaction of the opposing profiles. The results of the analysis are presented in terms of the joint shear displacement-dilation curve and the ratio of the shear to normal stress as a function of the shear displacement.