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A Simple Thermal Conductivity Model for Unsaturated Geomaterials Accounting for Degree of Saturation and Dry Density

Lookup NU author(s): Dr Agostino BrunoORCiD



This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).


© 2020, The Author(s).This paper proposes a simple thermal conductivity model for geomaterials accounting for the combined effect of both degrees of saturation and dry density. The model only requires the determination of the thermal conductivity under dry conditions (i.e., at a degree of saturation equal to zero) and as little as two additional measurements of thermal conductivity performed at different levels of degree of saturation and dry density. The model is a function of only two fitting parameters, namely the moisture factor mf and the density factor md. Despite its simplicity, the model can correctly predict the thermal conductivity of geomaterials and this has been validated against five sets of experimental data obtained on a very broad range of materials ranging from fine (e.g., bentonite) to coarser soils (e.g., a mix of gravel, coarse sand and silt) tested at different levels of degree of saturation and dry density. The paper also shows that the model can be applied to different engineering contexts such as (a) the thermal behaviour of earth materials used for building construction, (b) the thermal performance of bentonites employed for the storage of nuclear waste and (c) the estimation of the heat exchange in shallow geothermal reservoirs. Finally, the proposed model can be easily implemented in a finite element code to perform numerical simulations to study the heat transfer in unsaturated geomaterials.

Publication metadata

Author(s): Bruno AW, Alamoudi D

Publication type: Article

Publication status: Published

Journal: International Journal of Geosynthetics and Ground Engineering

Year: 2020

Volume: 6

Issue: 4

Print publication date: 01/12/2020

Online publication date: 16/10/2020

Acceptance date: 27/09/2020

Date deposited: 06/12/2020

ISSN (print): 2199-9260

ISSN (electronic): 2199-9279

Publisher: Springer Science and Business Media Deutschland GmbH


DOI: 10.1007/s40891-020-00229-8


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Funder referenceFunder name
NE/R018057/1Natural Environment Research Council (NERC)