Elastoviscoplastic modelling with distorted isotaches and swelling for constant strain rate and incremental loading

Abstract

A novel elastoviscoplastic model is proposed to improve the modelling of the one-dimensional unloading response of soils. Creep is modelled as an isotache process, but with the possibility to incorporate distortion of the isotaches after unloading. Upon unloading, swelling develops as a transient superimposed process that enables the sequential occurrence of swelling and creep as observed in experiments. The model features a flexible reference isotache to improve the fit to real laboratory tests. The model is implemented with full hydro-mechanical coupling and enables simulation of both load-controlled and strain rate-controlled stress paths. The model is calibrated with a laboratory test with a complex stress path including constant rate of strain, incremental loading and relaxation stages.