Investigation of a fractional derivative creep model of clay and its numerical implementation

Abstract

The fractional calculus has been successfully applied to characterize the rheological property of elastic viscoplastic materials. However, soils were seldom involved in fractional derivative constitutive models, and the topic of triaxial creep tests is rarely discussed through fractional calculus. This study presents a fractional derivative model that describes the time-dependent behavior of Shanghai marine clay. The fractional derivative Merchant (FDM) model is established by introducing fractional element into the Merchant model. The comparison of the calculated values of the FDM model and the Merchant model shows that the FDM model can better describe the instant elastic deformation, attenuation creep and steady-state creep stages of the clay. The FDM model was implemented into a finite-element code in ABAQUS, which is used to simulate the creep tests. The simulations demonstrate that the development model has good ability to predict the time-dependent behavior of clay.