ABSTRACT
A measurement method is proposed for three-dimensional local displacement and volume in the triaxial compression test in which stereo photogrammetry is applied to digital images. A drained triaxial compression test was performed on Toyoura sand and the three-dimensional deformation of the surface of a cylindrical specimen was measured using 8 digital still cameras. In addition, the local volumetric strain was computed and was compared to the global volumetric strain which was calculated by the volume of water drained from the specimen. As a result, the volumetric strain in the middle layer of the specimen was shown to be more dilative than the global volumetric strain as the global deviator strain increased, and the volumetric strain in the top and bottom layers of the specimen was more contractive than the global volumetric strain.
