Thermodynamic Model for Sand-Incorporating Morphology

Particle shape, size, and size distribution (gradation) significantly influence the mechanical response of granular soils. This research introduces a thermodynamic model based on granular thermodynamics theory, validated by predicting triaxial shearing tests of packed glass beads and crushed glass assemblies. The model reveals the microscopic mechanisms influencing granular system behavior by incorporating particle shape and size factors into both the elasticity and plasticity. The state-dependent hyperelasticity extended from Hertzian contact theory clarifies how particle morphology affects the mechanical behavior of granular soil, emphasizing how particle shape determines stacking structure. Variations in particle shape significantly affect the mechanical response of granular systems to changes in particle size and size distribution. Irregular particles show heightened particle-size sensitivity of the strength and energy dissipation in a granular system. Elevated confining pressures mitigate the influence of particle size and reduce the kinetic granular fluctuation described by the concept of granular temperature. In conclusion, integrating particle morphology into the thermodynamic framework provides a deeper understanding of granular soil behavior, offering insights for optimizing material design and application in engineering fields.