A simple constitutive model for history-dependent cyclic loading response of sand

Abstract

The cyclic loading response of sand is of particular importance for many branches of engineering practices including earthquake engineering. This work presents a simple constitutive model that considers the key mechanical characteristics of cyclically loaded sand, including the dependence on initial stress level and void ratio, as well as past stress history. For this purpose, a two-surface modeling scheme is adopted by combining a rotating yield surface and an expanding bounding surface. The latter evolves with plastic deformations and memorizes past stress history. Both hardening rule and plastic flow rule are functions of state parameters to account for the dependence of strength and dilatancy on void ratio and confining stresses. The enhanced contraction and stiffness degradation following plastic dilation are considered. The model performance is evaluated against laboratory tests of this study and reported in the literature. We also utilize the model to explore the effects of past stress history on the monotonic and cyclic loading response of sand.