ABSTRACT
Triaxial compression tests were performed on diatomaceous mudstone with various effective stress paths. A cap-shaped yield locus was clearly obtained from the triaxial tests. The strain localization of both shear and compaction bands were observed through an image analysis. The image analysis method applying the PTV (Particle Tracking Velocimetry) technique was newly developed for this experiment. A rectangular-shaped prismatic specimen was used to easily measure the displacement of the target on the specimen surface. The distributions of local strain, i.e., shear strain, axial strain, and volumetric strain, were measured on the surface of the specimen to observe the strain localization. After the shear testing, the changes in density of the specimen were measured by an X-ray CT scanner. Some high density regions were found to correspond to the compaction bands observed in the image analysis in the cases of relatively high confining pressure levels.
