Implementation and validation of advanced constitutive models for the analysis of hydro-thermo-mechanical interactions in geo-environmental engineering problems

Aim of this work is the implementation and the numerical validation of advanced constitutive models for isothermal and non-isothermal water saturated or unsaturated soils in the finite element code COMES-GEO developed at University of Padua. In this code soils are modelled as non-isothermal multiphase porous media, where interstitial voids of the deforming solid matrix may be filled with liquid water, water vapour and dry air or other gas (e.g. methane). To handle this multiphase system, an analytical multi-scale approach has been used by the general frame of averaging theories in deriving the governing balance equations. The following advanced constitutive models for soils have been implemented : 1. ACMEG-T model for water saturated clays in non isothermal conditions; 2. ACMEG-TS model for water saturated and partially saturated clays in non isothermal condition; 3. Pastor-Zienkiewicz model for water saturated sands in isothermal conditions; 4. Bolzon-Schrefler-Zienkiewicz model for partially saturated sands in isothermal conditions; 5. Bolzon-Schrefler model for partially saturated sands in non isothermal conditions]. Validation of the models implementation was performed by comparison between the F.E.M. results and the results obtained by experimental tests or by the model driver. In particular, three different tests were simulated: isotropic compression test, oedometric compression test and triaxial compression test in different conditions of confining pressure, temperature and suction and for different kind of soils.