Interpreting temperature effects in soils using thermally-enhanced viscoplastic model

The goal of this work is to show that the thermomechanical behaviour of soils can be interpreted as rate processes that are controlled by temperature-dependent viscous properties. A simple thermally-enhanced viscoplastic model is proposed that combines critical state soil mechanics and overstress viscoplasticity, and includes the dependence of viscosity parameters on environmental temperatures in a way consistent with the well-established Arrhenius law of chemical reactions. This modelling approach is shown to be able to reproduce many well-observed patterns of the temperature effects on the volumetric and distortional characteristics of soils. The application of the thermally-enhanced viscoplastic model in boundary value problems is demonstrated by analysing one-dimensional consolidation of saturated soils subjected to coupled mechanical and thermal loading. The connection between temperature-sensitive viscous properties and experimentally observed transient acceleration of secondary consolidation in soils subjected to heating is highlighted.