A hysteretic hydraulic constitutive model for unsaturated soils and application to capillary barrier systems

Scarfone, R. , Wheeler, S. J. and Lloret-Cabot, M. (2022) A hysteretic hydraulic constitutive model for unsaturated soils and application to capillary barrier systems. Geomechanics for Energy and the Environment, 30, 100224. (doi: 10.1016/j.gete.2020.100224)

Abstract

Unsaturated soils exhibit water retention hysteresis, with different water retention behaviour during drying and wetting paths. Water retention hysteresis has often been modelled using expressions for the main drying and main wetting water retention curves that are unsatisfactory at low values of degree of saturation. In addition, the effect of retention hysteresis on the unsaturated hydraulic conductivity behaviour has typically not been explicitly considered. This paper presents a new hysteretic hydraulic constitutive model for the water retention and hydraulic conductivity behaviour of unsaturated soils, which is effective and easy to apply. The model includes: (i) main wetting and main drying water retention curves modelled with a modified version of the van Genuchten model, improved at low degree of saturation; (ii) hysteretic scanning water retention curves modelled using a bounding surface approach; (iii) the effect of hydraulic hysteresis on a soil hydraulic conductivity curve (SHCC) model improved at low degree of saturation and including the effect of liquid film conductivity. The new hysteretic hydraulic model is then validated against experimental data. After implementation in the finite element software Code_Bright, the new hydraulic constitutive model is applied in a numerical study of the impact of hydraulic hysteresis on the behaviour of capillary barrier systems (CBSs). Water retention hysteresis, which has typically been neglected in the modelling of the hydraulic behaviour of CBSs, is shown to have a significant impact on: (i) movement and redistribution of water within the finer layer of a CBS; (ii) the phenomenon of water breakthrough across the interface between the finer and coarser layers of a CBS and the subsequent restoration of the CBS after infiltration at the ground surface ceases; (iii) the prediction of evaporation from a CBS into the atmosphere.

• Item Type: Articles
• Additional Information: The authors wish to acknowledge the support of the European Commission via the Marie Skłodowska-Curie Innovative Training Networks (ITN-ETN) project TERRE ‘Training Engineers and Researchers to Rethink geotechnical Engineering for a low carbon future’ (H2020-MSCA-ITN-2015-675762).
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Scarfone, Riccardo and Lloret-Cabot, Dr Marti and Wheeler, Professor Simon

Creator Roles

Scarfone, R.: Conceptualization, Methodology, Software, Validation, Data curation, Writing – original draft, Visualization
Wheeler, S. J.: Conceptualization, Methodology, Writing – review and editing, Supervision, Project administration
Lloret-Cabot, M.: Writing – review and editing, Supervision

• Authors: Scarfone, R., Wheeler, S. J., and Lloret-Cabot, M.
• College/School: College of Science and Engineering > School of Engineering > Infrastructure and Environment
• Journal Name: Geomechanics for Energy and the Environment
• Publisher: Elsevier
• ISSN: 2352-3808
• ISSN (Online): 2352-3808
• Published Online: 06 October 2020
• Copyright Holders: Copyright © 2020 Elsevier Ltd.
• First Published: First published in Geomechanics for Energy and the Environment 30: 100224
• Publisher Policy: Reproduced in accordance with the publisher copyright policy
• Data DOI: 10.5525/gla.researchdata.1073