Shear strength of unsaturated soils: experiments, DEM simulations, and micromechanical analysis

Vincent Richefeu (1) , Moulay Saïd El Youssoufi (2) , Farhang Radjai (2)

1 LMGC - Laboratoire de Mécanique et Génie Civil
2 PMMG - Physique et Mécanique des Milieux Granulaires

We investigate shear strength properties of wet granular materials as a function of water content in the pendular state. Sand and glass beads were wetted and tested in a direct shear cell. In parallel, we carried out DEM simulations by using an explicit expression of the capillary force as a function of interparticle distance, water bridge volume and surface tension. Experiments and numerical simulations are in good agreement. We show that the shear strength is mostly controlled by the distribution of liquid bonds. This property results in the saturation of shear strength as a function of water content. We arrive at the same conclusion by analyzing the shear strength from the microstructure and by accounting for grain polydispersity.

Domaines: Science des matériaux [cond-mat.mtrl-sci]

Vincent Richefeu, Moulay Saïd El Youssoufi, Farhang Radjai. Shear strength of unsaturated soils: experiments, DEM simulations, and micromechanical analysis. 2nd International Conference on Mechanics of unsaturated soils, Mar 2007, Weimar, Germany. pp.83-91. ⟨hal-00147621⟩