Study of failure mechanisms of rock under compressive–shear loading using real-time laser holography

Failure of rock is quite commonly induced by compressive and shear coupling loading. The knowledge of the mechanism and process of deformation and failure of rock under compressive–shear loading condition is an important basis for the study of stability of rock engineering. Based on the principles of laser holographic interferometry, an experimental system with high precision has been established. Through the experiment, the real-time laser holographic interferential fringes under compressive–shear loading are simultaneously observed and recorded. The active fringes can visually display the distribution, mode, moving path and dynamic evolution of deformation and cracking in rock. On the basis of interpretation and quantitative analysis of the active fringes, the whole process of deformation and failure of rock, including time–spatial evolution law of initiating, propagating, growing and closing of cracks in rock, is quantitatively described. From the experimental results, some conclusions on the mechanism and characters of deformation and failure of rock under compressive–shear loading condition are drawn out.