In the soil mechanical field, the team is actively involved in fundamental and applied research to better understand, analyze and model the thermo-hydro-chemo-mechanical coupling, aging effects and multi-scale analysis of soils and geotechnical structures. We have, in particular, strong experiences in the coupled multiphysics problems in soil mechanical, geotechnical and geo-environmental engineering. The competences are recognized in the fields of laboratory modelling and characterisation, numerical and computational methods. The team is well-supported by governemental and private research grants through collaborative applied research, high-level consulting and testing services.

Research in the group falls within three broad thematic areas: (i) Soil stabilization and improvement for barrier systems in fine grained soils, embankments, … (ii) Geotechnical engineering applied to enhanced geothermal system and geothermal ground strucures, (iii) Swelling, shrinkage, cracking and post rupture behavior of clayey soils.

Topics

• Soil Stabilization and Soil Improvement

This field of research is focused on the thermo-hydro-chemo-mechanical behaviour of soils. Several topics are considered, lime stabilization, long term repository of nuclear wastes, as well as the use of non traditional additives for soil treatment. An emphasis is put on study of the very long term behaviour of soils submitted to cyclic wetting and drying, cyclic thermal stress, or a permanent circulation of fluids. Dedicated experimental devices were developed to characterize the behaviour of stabilized soils, both at the macro- and micro-scale. Constitutive relationships with an explicit coupling between physico-chemical processes and the hydromechanical behaviour of stabilized soils are also developped. 

• Energy Geo-structures

To study geo-exchange systems in ground structures (piles, embankments, retaining structures,…), the complex interactions between temperature variations and induced stresses/deformations must be considered. The cyclic variation of the temperature may affect long-term building performance.

Different geotechnical laboratory and small scale tests are carried out to assess the impact of cyclic temperature variations which cover the maximal variations of the soil temperature induced by current implementations of thermal structures. These tests provide necessary parameters for numerical modelings based on coupled thermo-hydro-mechanical behavior of soil-structure interaction. This approach is essential to better understand the physical phenomena and be able to predict the long-term behavior of thermal ground structures at the conception phase.

• Swelling, Shrinkage and Cracking of soils

This topic deals with the multiscale swelling behaviour of expansive soils submitted to a modification of their humidity. Innovative experimental procedures to characterize the thermo-hydromecahnial behaviour of these soils are developed. The main objective is the understanding of the impact of swelling, shrinkage and crackings on geotechnical structures.

Present models face limitations in the case of extensive drying, mainly because of apparition of shrinkage cracks beyond the shrinkage limit. Our studies are focused on the experimental characterization as well as constitutive and numercial modeling of crakcs apparition in expansive soils.

Applications 

• Soil treatment, reinforcement and improvement: road embankments and subgrades, backfilling of quarries and radioactive waste storage galeries, stone columns, etc.
• Energy geo-structures, thermal ground structures: piles, slabs, retaining walls, tunnels, embankments, etc.
• Shrinkage, swelling, cracking: individual houses, waste storage facilities, dykes, embankments, etc.

National and International Relations

• ANDRA, BRGM, IFSTTAR,
• Solétanche-Bachy – Bouygues Construction – Eurovia
• University of Exeter (Royaume Uni),
• Luléa University of Technology (Suède),
• Université of Monash (Australie),
• Université of Andes (Colombie)
• Università degli Studi di Napoli Federico II (Italie)
• Universidade Federal do Rio Grande do Sul (Brésil)
• École Polytechnique de Montréal (Canada)
• EGE University (Turquie)