Chorafas Foundation Award 2009 - Nuth Mathieu

"Dr. Nuth has developed an innovative theory to describe the mechanical behavior of soils and to allow a sustainability-oriented design of geo-structures, accounting for future climatic scenarios, and contributing to natural risk management.

Constitutive modelling of unsaturated soils with hydro-geomechanical couplings.

The climatic changes, as well as the global densification of population, address new issues to urban and industrial planners, provided that an increasing number of infrastructures, earth dams and houses have to be built in arid zones or closer to landslides that are sensitive to rain.
This thesis is dedicated to the improvement of the modelling of unsaturated soils, in which the key problem to address is the effect of the groundwater on the bearing capacity and resistance of the ground.
The primary goal has been to clarify the rheological observations in such porous media with a new conceptual approach. The proposed unified theoretical framework, which relies on the concept of effective stress, was implemented into an engineer-accessible finite element software. The built-in hydro-mechanical coupling is a noticeable advance that readily improves the verification processes in civil engineering, in relationship with the present and future environment.
As the interactions between water, gas and solid phases are comprehended, the study contributes to sustainability-oriented design of structures by accounting for future or extreme climatic scenarios. It also generates outcomes in risk assessment and durable mitigation. The model was applied to the case studies of a practical earth dam and an instrumented landslide.