Modelling creep in clay using the framework of hyper-viscoplasticity

Abstract

This paper addresses the derivation of creep models using the framework of hyper-viscoplasticity. It demonstrates that the formulations widely used already can easily be obtained using the hyper-viscoplastic formalism. This means that existing formulations (i.e. of the flow potential) are thermodynamically sound. The key assumptions are that the free energy is only a function of elastic strains and that there is no dissipation under pure volumetric swelling (tension). The presented derivations, using the framework of hyper-viscoplasticity, allows for further model development along the same lines, as presented here, with only minor modifications.