Dynamic deformation of granite under multiaxial compression

Granite is a typical anisotropic and brittle rock, which may experience uniaxial, biaxial, or triaxial stress states in geological structures. It may be subject to extreme dynamic loads, such as earthquakes, planetary impacts, and underground explosions. However, the deformation and damage of granite associated with high strain rate loading need more quantitative mechanism-based evidence. In this work, we conduct dynamic compressive experiments on Westerly granite under uniaxial, biaxial (lateral confinement), and triaxial (radial confinement) stress states using a Kolsky (split-Hopkinson) bar at strain rates up to 10^3/s. We utilize advanced diagnostic techniques, including high-speed digital image correlation (DIC) and X-ray computed tomography (XCT), that enable high-resolution measurements of stress-strain behaviors and their damage and microstructures when applicable. The associated damage is characterized by XCT to map the size, shape, and distribution of defects. The experimental continuum data and corresponding microstructure will be analyzed to establish a correlation between the resulting damage and stress states. This study will enhance a critical understanding of the structural integrity of geomaterials and relevant brittle solids under extreme conditions.