Application of a thermo-elastoplastic constitutive model for numerical modeling of thermal triaxial tests on saturated clays

In the present study, the behavior of saturated clays while they are mechanically loaded under constant temperatures has been investigated by simulating thermal triaxial test. A critical state-based thermo-mechanical constitutive model has been added to the ABAQUS finite element (FE) software through a user subroutine to define the stress-strain, volume change and pore pressure behavior of saturated clays. In order to have better predictions by the numerical implemented model, it has been changed by defining a new plastic potential function similar to its yield surface. The model has been integrated via an explicit integration scheme. Verification of the discretized axisymmetric numerical model has been carried out by three different series of triaxial tests for both drained and undrained conditions, and the experimental results were compared with numerical simulations. According to these comparisons, the adopted numerical model is able to predict the results of thermal triaxial tests on saturated normally consolidated and overconsolidated clays in a good manner. The presented methodology is general and can be used for application of any other critical state-based thermal constitutive model in a FE program. Based on the results, it can be suggested to be implemented in similar thermal boundary value problems of geotechnical engineering.