In situ X-ray CT imaging of transient water retention experiments with cyclic drainage and imbibition
Open Geomechanics, Volume 3 (2022), article no. 5, 33 p.

The water retention curve (WRC) represents a key function in unsaturated soil mechanics as it can be applied for the modeling of the hydro-mechanical behaviour of unsaturated soils. The macroscopic WRC is characterised by different phenomena, such as hysteresis upon cyclic drainage and imbibition. With the help of modern X-ray computed tomography and hydraulic experiments that can be performed in a CT scanning environment, so-called in situ CT experiments, we image cyclic drainage and imbibition in a sand on the pore scale in order to quantitatively measure and study the change of microstructure and capillary state variables, characterising capillary effects in unsaturated granular soils. The measured pore scale data can then be related to the macroscopic WRC. To our knowledge, for the first time very different capillary state variables, such as interfacial areas, contact lines and contact angles, could be extensively measured in high detail for various hydraulic cycles in our experiment. Besides the experimental procedure, the wealth of measured data will be comprehensively presented and discussed and finally shared with the research community.

Published online:
DOI: 10.5802/ogeo.13
Keywords: Unsaturated granular soils, Water retention behaviour, Transient flow experiments, X-ray computed tomography
Milatz, Marius 1; Andò, Edward 2; Viggiani, Gioacchino 3; Mora, Serge 4

1 Hamburg University of Technology (TUHH), Institute of Geotechnical Engineering and Construction Management, Harburger Schloßstraße 36, 21079 Hamburg, Germany
2 École Polytechnique Fédérale de Lausanne (EPFL), EPFL Center for Imaging, Lausanne, Switzerland
3 Univ. Grenoble Alpes, CNRS, Grenoble INP, 3SR, 38000 Grenoble, France
4 Université de Montpellier and CNRS, Laboratoire de Mécanique et Génie Civil, Montpellier, France
License: CC-BY-NC-SA 4.0
Copyrights: The authors retain unrestricted copyrights and publishing rights
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Milatz, Marius; Andò, Edward; Viggiani, Gioacchino; Mora, Serge. In situ X-ray CT imaging of transient water retention experiments with cyclic drainage and imbibition. Open Geomechanics, Volume 3 (2022), article  no. 5, 33 p. doi : 10.5802/ogeo.13.

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