Analysis of climate change impacts on the shrinkage-swelling phenomenon of clayey soils to adapt infrastructures

Cerema, Institut Carnot Clim’adapt, Agence de Blois, France

^* Corresponding author: lamine.ighil-ameur@cerema.fr

Abstract

As a tendency in France, the well-known shrinkage-swelling phenomenon of clayey soils intensifies naturally and durably under climate change effects after the severe droughts happened post 2015. More than 10.4 million houses are highly exposed to this phenomenon and the new national zoning shows that high or medium exposure now concerns 48% of the metropolitan soils. Roads are also severely impacted by the shrinkage-swelling phenomenon through damage characterized most often by longitudinal cracks close to the edges and very significant deformations that can be a danger for the safety of users. The aim of this research is first to understand how the natural unsaturated clay soils shrink and swell under numerous drying-wetting cycles using several devices at the laboratory scale. The second approach consist of several in situ experimentations of different techniques to reduce the shrinkage-swelling impact on unsaturated clay soils. The first results show that at the laboratory scale, the unsaturated clay soils can be significantly affected after some drying-wetting cycles. In the other hand, in situ monitoring results show that some techniques allow clay soils to save their hydromechanical properties at a hydric equilibrium state which can reduce settlement deformations. The main goal of these research works is to better understand how the shrinkage-swelling phenomenon of clayey soils evolves under climate change in order to develop the new solutions allowing the adaptation of the infrastructures.