Abstract: The full field three-dimensional digital image correlation (3D-DIC) system is introduced, the system comprises three groups of the 3D acquisition units setting around the cylindrical specimen to cover the maximum surface area as much as possible. The speckle images are collected during test and used to analyze the deformation of the specimen. For verifying the reliability of measured results of the 3D-DIC system, the constant strain rate and alternative strain rate tests are conducted with Emochi andesite in uniaxial compression, the results are coincident with each other by comparing the measured results of 3D-DIC and strain gage, which indicates that the 3D-DIC system can meet the requirements of non-contact and visual deformation measurement of rock mechanics test. Moreover, taking Tage tuff as object, the evolutions of displacements and strain fields are obtained by images analysis, the non-linear and localized deformation of specimen are observed at the same time. The results indicate that it is more effective to study the rock deformation by using 3D-DIC method than that by using conventional methods. The 3D-DIC system provides a new and advanced test method for investigation of rock mechanics.

Key words: 3D-DIC, rock mechanics, non-contact, heterogeneous deformation, full-field strain