Effects of Shear Path and Consolidation History on the Mechanical and Breakage Behaviors of Coral Sand: A Comprehensive Triaxial Test Study

Stress path dependency, as a crucial property of geomaterials, influences not only mechanical behavior but also particle breakage behavior of coral sand.However, current research in this area remains incomplete, particularly lacking investigation under triaxial extension stress states. In this study, 163 triaxial compression and extension tests were conducted for this purpose on three coral sands with different gradations. Different shear and consolidation stress paths, combined with other conditions such as relative density, confining pressure and drainage condition, were planned for experimental investigation. After testing, the particle size distributions of coral sand were measured and analyzed to explore the effect of stress path on particle breakage. The test results showed that consolidation history (or consolidation stress path) and shear path exhibited different effects on the mechanical and breakage behaviors of coral sands under compression and extension stress states. However, regardless of consolidation history, shear path or other test conditions, the effective stress ratios of coral sands had trends of convergence toward a common value under both compression and extension stress states, with approximate values of 1.5 and 1.1 respectively. Furthermore, input energy E could effectively characterize the particle breakage evolution of coral sands under different consolidation histories and shear paths.