Small-strain shear moduli modeling of sand: a non-equilibrium thermodynamic approach, including an application to Leighton Buzzard sand

Abstract

The shear stiffness of soil may decay with strain level by orders of magnitude. This feature of soil plays a critical role in different geotechnical constructions. The constitutive models of small-strain shear moduli used in elasto-plastic and hypoplastic models are mainly based on empirical formulas. In this paper, a constitutive model predicting the small-strain shear moduli of sand is established based on a non-equilibrium thermodynamic approach known as the granular solid hydrodynamics. Using a specific mathematical formulation for the off-diagonal transport coefficient of sand, the proposed model is able to characterize the shear stiffness variation of sand at different strain levels. A calibration procedure for all nine parameters of the model is derived, taking Leighton Buzzard sand as an example. The model predictions of shear moduli for this sand, at different confining pressures or along with different stress paths, are in good agreement with the testing data.