« 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

Snow is a fascinating material with a complex and evolving microstructure. Snow avalanches, notably slab avalanches, are generally initiated by failure and collapse in the snowpack of a so-called weak layer, whose thickness can be very small (a few mm). This phenomenon, in which the instability of a whole slope is ultimately controlled by rupture mechanisms at the scale of the microstructure of the weak layer, is intrinsically multiscale.

Key points of the PhD:

• Development of an innovative numerical approach
• Applications to natural hazards (snow avalanches)
• Stimulating and multidisciplinary work team

More details in the attached file.

The project CURE (Coupled multiprocess research for reducing landfill emissions) investigates the reduction of the emission potential of landfills by in situ stabilisation measures and will develop predictive tools to forecast the pertaining processes and residual emissions. The objective of the research carried out in this particular PhD project is to quantitatively analyse the spatio-temporal response of landfills to different in-situ stabilisation measures by monitoring the change in quantity and quality of emissions through the water and gas phase as well as the change in the landfills’ structural architecture. This will be achieved by high-resolution measurements of

• Leachate quantity and quality, including stable isotopes and DNA/RNA profiling
• 3D temperature time series and 3D water content time series
• Gas quantity and quality
• Stabilisation-induced consolidation.

I would like to invite applications for a Severo Ochoa PostDoc Researcher Position at the CIMNE-UPC Geomechanics group  in Barcelona. It is an opportunity to join an active research group working in advanced coupled numerical analysis.  The appointment is intended to run for three years. The deadline for applications is June 14th.  More details are provided in the attached file.

Antonio Gens

Context:This PhD will take place within HoTMiX which is a joint French-German academic research project funded for 3 years by the ANR and DFG agencies. It brings together 6 academic labs and is supported by the St Gobain and Safran companies. The aim of the project is to provide a deep understanding of the relationships between the nonlinear mechanical response of oxide materials at very high temperature and their microstructure at the nanoscale. The relationship between microstructure and mechanical properties will be explored by combining two different approaches. In situ measurements at very high temperature or under applied stresses will be carried out using X-ray based advanced techniques at synchrotron radiation beamlines and accurate microstructural modelling based on virtual microstructures submitted to temperature and external stresses evolutions will be developed. More details on the HoTMiX project can be found here: www.bam.de/hotmix

Applications are welcomed for a joint PhD position between GeoRessources laboratory (University of Lorraine), LFCR laboratory (University of Pau) and IRSN. The objective of this thesis is to propose mesoscopic models capable of taking into account Hydromechanical and Electrokinetic couplings when simulating flow and transport in large representative elemental volumes (REVs) typically out of reach of molecular methods.

The candidate must be a highly motivated and autonomous person with a recent university master’s degree (or equivalent) in mechanics, reservoir engineering, applied mathematics, civil engineering or other relevant field. He or she must demonstrate a fundamental knowledge of the principles of fluid mechanics governing the behaviour of porous media. Experience in the development of numerical methods, in particular LBM methods would be an asset. The successful applicant will work under the supervision of

Dr Fabrice Golfier (GeoRessources) and Dr Amael Obliger (LFCR), as well as Dr Anne-Julie Tinet (GeoRessources) and Dr Magdalena Dymitrowska (IRSN).

Candidates are invited to submit their CV, master’s transcripts and cover letter here: https://bit.ly/2W2NFhI

More information in the attachment.