A Visco-Hypoplastic Model with Solid Hardness Degradation for Granular Soil

In order to investigate creep failure behaviour of granular soil, a visco-hypoplastic constitutive model accounting for the solid hardness degradation and time-dependent behaviour is proposed. The visco-hypoplastic constitutive model is divided into inviscid part and viscous part, respectively. The inviscid component, incorporating the solid hardness degradation, is validated by comparing with experimental results of various void ratio and confining pressure. The viscous component is assumed to be the rate form of the power law equation related to the strain acceleration. Comparison between numerical and experimental results illustrates that the model is capable of simulating creep behaviour of granular soils. Moreover, the creep deformation mechanism between inviscid and viscous stresses is explained in view of proposed visco-hypoplastic model.