On thermodynamically consistent coupling of the Barcelona Basic Model with a hydraulic model for unsaturated soils

The Barcelona Basic Model is a mechanical model for unsaturated soils which uses the net stress and suc-tion as independent stress variables. This paper presents a thorough study of its thermodynamically con-sistent coupling with a hydraulic model. A general framework for poroelastoplasticity formulated in terms of the net stress and suction is developed and then applied to derivation of a consistent hydro-me-chanical coupling for the Barcelona Basic Model. The resulting restrictions for description of the hydraulic behaviour are analysed and they are found to be too strict and not completely physically acceptable. It is demonstrated on a model example that the applicability of the resulting hydro-mechanical model is lim-ited. It is concluded that poromechanical models using the net stress and suction as stress variables gen-erally (at least what poroelasticity concerns) should be developed and utilised carefully with respect to the thermodynamical consistency. Otherwise different types of models should be employed for coupled hydro-mechanical modelling.(c) 2023 Elsevier Ltd. All rights reserved.

Automated summary

This paper investigates the thermodynamic consistency of the Barcelona Basic Model and its coupling with a hydraulic model. A framework for poroelastoplasticity using net stress and suction as stress variables is developed and applied to derive a consistent hydro-mechanical coupling for the Barcelona Basic Model. The resulting restrictions on hydraulic behavior are found to be too strict and not completely physically acceptable. It is concluded that caution should be exercised in developing and utilizing poromechanical models using net stress and suction as stress variables with respect to their thermodynamic consistency, and different types of models should be employed for coupled hydro-mechanical modeling.