Numerical Modelling of Water Breakthrough in Coarse Soils Initially at Very Low Degree of Saturation

Scarfone, R., Lloret-Cabot, M. and Wheeler, S. J. (2018) Numerical Modelling of Water Breakthrough in Coarse Soils Initially at Very Low Degree of Saturation. In: The 7th International Conference on Unsaturated Soils (UNSAT2018), Hong Kong, China, 3-5 Aug 2018, (Accepted for Publication)

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Abstract

Conventional constitutive models describing the water retention and hydraulic conductivity behaviour of soils under unsaturated conditions (e.g. the Van Genuchten-Mualem model) have some shortcomings when applied in numerical modelling of problems where the initial degree of saturation is very low. The reason is that they assume that the hydraulic conductivity only tends to zero as suction tends to infinity (this is physically unreasonable, because continuity of liquid water will be lost at a finite value of suction). This shortcoming becomes particularly evident when modelling the breakthrough of water from the finer layer to the coarser layer of a capillary barrier system (CBS), where the coarser layer is initially at very low degree of saturation. Numerical results obtained using CODE_BRIGHT suggest that a model having the hydraulic conductivity tending to zero at a finite value of suction is able to simulate the phenomenon of breakthrough better than the Mualem model. The results presented in the paper demonstrate the importance of describing realistically the hydraulic behaviour of coarse soils at low degrees of saturation.

Item Type:Conference Proceedings
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:Accepted for Publication
Refereed:Yes
Glasgow Author(s) Enlighten ID:Scarfone, Riccardo and Wheeler, Professor Simon and Lloret-Cabot, Dr Marti
Authors: Scarfone, R., Lloret-Cabot, M., and Wheeler, S. J.
Subjects:T Technology > TA Engineering (General). Civil engineering (General)
College/School:College of Science and Engineering > School of Engineering > Infrastructure and Environment
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