Literature survey and application of a full-field 3D-DIC technique to determine the damage characteristic of rock under triaxial compression

Digital-image correlation (DIC) is a deformation-measurement technique used to determine rock and soil mechanics. We review DIC tests of rock and soil, with data categorized according to specimen shape, test type, and DIC method. A new three-dimensional-DIC system integrates a transparent triaxial-compression servo-control test system for rocks. The confining pressure cell is transparent and three groups of image-acquisition units, which can be controlled with loading cell at the same time, are adopted to obtain the maximum observed fields. The average magnification factors caused by the transparent cell and oil are 1.4430 and 1.0331 for the measured horizontal and vertical distances, respectively. A triaxial compressive test of rock is performed and the specimen’s surface-strain fields and crack propagation are discussed.