Missions

The soil mechanics of LEMTA is seeking a full-time postdoctoral researcher (12 months) with research interests in the thermo-hydro-mechanical-chemical behaviour of clay-based materials. In the context of deep nuclear wastes storage deep galleries will be backfilled with clay-based materials. The backfill must have specific hydromechanical properties to prevent water circulation along the repository after its closure. The backfill material will be partly made from the excavated material, i.e. Callovo-Oxfordian argillite that would have been stored at the surface during the exploitation period, and mixed with sand or expansive clay to reach the target design properties. The hydromechanical properties of the backfill must remain stable over time. It is thus necessary to determine the relative impact of several factors such as the setting conditions, nature and dosage of treatment product, etc. on the properties of the backfill. The contribution of LEMTA is focused on the understanding of the cross relationship between macroscopic hydro-mechanical properties, the impact of the swelling of clay particles upon hydration, as well as the alteration processes associated to the circulation of alkaline water, with two main actions.

Activities

1- Analysis of the thermo-hydro-mechanical-chemical behaviour of bentonite/sand/crushed_argillite-based mixtures to improve understanding of physical and chemical mechanisms governing the material properties. 2. Long term behaviour of bentonite/sand/crushed argillite mixtures. The phenomenon known as alkaline plume triggers the dissolution and modification of clay minerals in the backfill material,altering its structure and, in turn, its performance. The impact of this process will be investigated, considering its impact on the compressibility and transfer properties of the mixtures.

Skills

Expertise inTHMC behaviour of compacted soils - geomechanics - soil mechanics

Work Context

Successful candidate will engage in interdisciplinary research and will contribute to the research work of LEMTA. The work will be of experimental and/or numerical nature, relying on state-of-the art laboratory equipment and numerical modelling resources of LEMTA.

The position is located in a sector under the protection of scientific and technical potential (PPST), and therefore requires, in accordance with the regulations, that your arrival is authorized by the competent authority of the MESR.

Constraints and risks

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