« Impact of climatic conditions on long term performances of treated soils »

A fully funded PhD scholarship for 3 years at the Université de Lorraine (F) is available to start in October 2020. This work will be accomplished in cooperation with the company Ginger-CEPBTP.

Waste-geomaterials generated by construction and mining activities represent more than 50% of the total waste generated in Europe, corresponding to 1.5 billion tons of excavated geomaterials that are landfilled while at the same time virgin soil and rock resources are extracted and used by the same infrastructure projects. The fundamental goal of this thesis is to contribute to the development of strategies and tools for the valorisation of waste-geomaterials, and thus to turn a waste into a valued durable construction material. Although frequently used, this technique is limited to certain materials and applications due to a lack of knowledge on the coupling between the physical and chemical actions of the binder and the geotechnical behaviour of the treated material. The challenge is to determine how the site materials can be reused in a variety of contexts (backfill, dykes, canals, retaining walls, dams, etc.).

 In this context, the main objective of the thesis is to understand the evolution of the hydromechanical characteristics of soils treated with lime and/or cement as a function of environmental stress (hydric cycle and prolonged exposure to water). For this purpose, the research work will focus on reference soils and on treated materials taken in situ, just after the treatment or on old structures, several years after the commissioning of the structure. The thesis work will combine an experimental approach and a modelling approach using the resources of the project partners. The thesis should lead to the development of an approach to take into account the alteration of the mechanical characteristics of a treated soil in the dimensioning of a geotechnical structure.

Contact : Olivier.Cuisinier@univ-lorraine.fr and Farimah.Masrouri@univ-lorraine.fr

Extended description in attachment.

PhD Advisors : Prof. Charles Aubourg (UPPA, France, charles.aubourg@univ-pau.fr),  Dr. Nicolas Beaudoin (UPPA, France, nicolas.beaudoin@univ-pau.fr), Dr. Elma Charalampidou (Heriot-Watt, Ecosse, ec10@hw.ac.uk)

PhD location: Université de Pau et des Pays de l’Adour, Heriot Watt University (Edinburgh, Scotland).

This PhD thesis explores deformation bands observed in two different areas located in the southern foreland of the Pyrenees: the Boixols overlap area (Tremp basin) and the Cotiella thrust area (Armena Valley). These sites provide access to two types of host rock lithologies: Cotiella cement-limestone calcarenites and Boixols sandstones. The goals of this PhD thesis are: a) to characterise the petrophysics of these bands focusing on their textural characteristics; and  b) to evaluate the impact of the observed bands on the structural integrity of the rock mass. The PhD thesis will develop along 4 axis; work will focus on a) the (micro)structural characterisation of the terrain (geological interpretation); b) the characterisation of grain texture by 3D imaging (XR CT, petrophysical investigation); c) the understanding of the bands’ formation (including deformation and fluids the circulated history) by  reconstructing the temperature conditions using isotopic approaches;  and d) the mechanical response of samples with pre-existing  deformation bands (whose grain distribution has been previously characterised by 3D X-ray CT) accompanied by a numerical modelling of fluid flow along the samples’ volume. The first three parts will be mainly carried out at the host university (UPPA, Pau, France), and the last part will require a stay at Heriot-Watt University (Edinburgh, Scotland).

Two new experimentalist positions are available in the Geomechanics and Porous Media research group at University Pau & Pays Adour, Basque Coast Campus, Anglet, France. The positions are:

Research Engineer Assistant in experimental porous media. Starting date: September 1st, 2020 (16 months). Details may be found at (in French): https://perso.crans.org/gregoire/positions@G2MP/Offre-AI-G2MP.pdf

Research Engineer in experimental porous media. Starting date: September 1st, 2020 (16 months). Details may be found at (in French): https://perso.crans.org/gregoire/positions@G2MP/Offre-IR-Newpores.pdf

Thierry Faug and Itai Einav are having a new PhD position available, arranged as a cotutelle agreement between INRAE at University of Grenoble Alpes, France, and SciGEM at the University of Sydney, Australia.

You will find more details in the attached file.

In support of the research programme related to the safe disposal of nuclear waste, KU Leuven and SCK CEN are looking for a PhD candidate for following topic:

Diffusion of gases in desaturated clay-based materials

The main aim of the PhD is to investigate how desaturation influences the diffusive properties of the samples for gases. This will be accomplished by performing diffusion experiments on different clay-rich materials (e.g. Boom Clay, Opalinus Clay, bentonite, sand-bentonite mixtures, …) at different degrees of saturation (but still highly saturated to avoid a continuous gas pathway), using different gases (He, Ne, CH₄, C₂H₆). Different methods to perform transport experiments under desaturated conditions exist (e.g. osmosis method, saturated salt method …), but none of them has been used to measure diffusivity of dissolved gases. Diffusivity data will be complemented with a full petrophysical characterisation of all samples in order to assess the effect of changing petrophysical properties on diffusivity, and to compare the observations to those of fully saturated samples. The PhD will be executed in the international context of the EC-EURAD project, with close collaboration between SCK-CEN and the Paul Scherrer Institute (PSI, CH) and other partners involved in EURAD. More information on the topic & how to apply can be found on http://academy.sckcen.be/en/Your_thesis_internship/AllTopics/Diffusion-of-gases-in-desaturated-clay-based-materials-2242

For further details, please contact Dr. Elke Jacops (elke.jacops@sckcen.be)

Deadline for application is September 4th, 2020