A novel thermodynamic constitutive model of coarse-grained soils considering the particle breakage

Abstract

The granular thermodynamics was extended to the solid–liquid system, developing a constitutive model for coarse-grained soils (CGS). The model combined the physical conservation equation, thermodynamic differential equation and entropy increase equation to construct a new elastic potential energy density function (EDF). The dissipation energy caused by particle breakage and deformation was associated with macroscopic mechanical behavior using dissipation system, migration coefficients, and particle breakage function. The particle breakage function was applied to convey the change in particle gradation, as well as the critical-state stress ratio. The model integrated the concept of critical-state line drift, revealing the attenuation of shear stiffness/strength due to dilatancy/shrinkage. Test results of Toyoura sand (TS), crushed cambric slate (CCS), and calcareous sand (CS) were selected to validate the proposed model, manifesting a great advantage and high prediction accuracy.