  In this general report, experimental systems and procedures of investigating
the hydro-mechanical behaviour of unsaturated soils are presented. The water
retention properties of unsaturated soils are commented and linked to various
physical parameters and properties of the soils. Techniques of controlling
suction are described together with their adaptation in various laboratory
testing devices. Some typical features of the mechanical behaviour of
unsaturated soils are presented within an elasto-plastic framework. An attempt
to describe the numerous and significant recent advances in the investigation
of the behaviour of unsaturated soils, including the contributions to this
Conference, is proposed.
