Experimental and numerical study on the fragmentation mechanism of a single calcareous sand particle under normal compression

The rate-dependent mechanical properties of a specific geomaterial play a crucial role in engineering design and application. However, there have been very few studies involving rate-dependent mechanical properties of calcareous sand particles. This present investigation aims to study the rate-dependent breakage behavior of calcareous sand particles experimentally and numerically. Experimental tests were conducted under various loading rates. Moreover, the discrete element method was utilized in particle crushing tests to assess the breakage sub-processes. The experimental results reveal that the particle crushing strengths conform to the Weibull distribution. As the loading rates increase, the fragmentation mode changes from primary splitting and successive breaking to severe disintegration, corresponding to the three types of axial force-displacement curves, namely, the quasi-hardening, the slight quasi-softening, and the obvious quasi-softening. The simulation results show that the fractures initiate in the vicinity of contact point between the particle and loading walls, eventually penetrating through the particle along the vertical section of the sample. A higher loading rate may lead to a greater extent of particle breakage. The findings presented in this study may advance the understanding of the rate-dependent mechanical properties of calcareous sands.