Laboratory testing and hydromechanical behaviour of unsaturated soils

Dr Enrique Romero, School of Engineering, Technical University of Catalonia, Barcelona, Spain

The presentation focuses on the hydro-mechanical behavior of unsaturated soils. It is a challenging area of research, from both experimental and theoretical point of view. The role of unsaturated soils is of paramount importance in the design of engineered barriers, in the collapsible and expansive behavior of fills and natural soils, in the driving mechanism of landslides due to infiltration and in the cracking and shrinkage phenomena due to desiccation. The main contents of the presentation were:

1. Laboratory testing of unsaturated soils:
   • Suction, stress and work-conjugate variables
   • Techniques for measuring suction
   • Techniques for suction application
   • Controlled-suction cells
   • Auxiliary techniques
2. Hydro-mechanical behavior of unsaturated soils:
   • Triaxial compression tests interpreted within an elastoplastic framework
   • Aspects of expansive soil behavior. Cyclic tests and double structure
   • Retention curves. Dependence on void ratio
   • Shear strength properties. Effect of water retention hysteresis

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