Analytical and numerical modelling of air trapping during wetting of unsaturated soils

Scarfone, R. and Wheeler, S. J. (2022) Analytical and numerical modelling of air trapping during wetting of unsaturated soils. Acta Geotechnica, 17(8), pp. 3499-3513. (doi: 10.1007/s11440-022-01470-3)

Abstract

At high values of degree of saturation, the apparent soil water retention curve (SWRC) measured in a wetting test in the laboratory may differ from the true SWRC, because of the occurrence of air trapping, meaning that gas pressure in the trapped air is greater than the externally applied gas pressure. Physical arguments indicate that the true SWRC will reach full saturation at a positive value of suction. Analytical and numerical modelling of the phenomenon of gas trapping during wetting shows that, once air trapping occurs, the apparent SWRC depends upon many aspects of the wetting test conditions and is not a fundamental representation of the soil behaviour. The only correct way to represent the occurrence and influence of air trapping during wetting within numerical modelling of boundary value problems is to use the true SWRC in combination with a gas conductivity expression that goes to zero at the air-discontinuity point.

• Item Type: Articles
• Additional Information: This work was supported by 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 Wheeler, Professor Simon
• Authors: Scarfone, R., and Wheeler, S. J.
• College/School: College of Science and Engineering > School of Engineering; College of Science and Engineering > School of Engineering > Infrastructure and Environment
• Journal Name: Acta Geotechnica
• Publisher: Springer
• ISSN: 1861-1125
• ISSN (Online): 1861-1133
• Published Online: 27 January 2022
• Copyright Holders: Copyright © 2022 The Authors
• First Published: First published in Acta Geotechnica 17(8): 3499-3513
• Publisher Policy: Reproduced in accordance with the publisher copyright policy
• Data DOI: 10.5525/gla.researchdata.1237

Project Code	Award No	Project Name	Principal Investigator	Funder's Name	Funder Ref	Lead Dept
172964	675762	TERRE	Simon Wheeler	European Commission (EC)	Wheeler, Professor Simon	ENG - Infrastructure & Environment