The Development Of Unsaturated Soil Mechanics At Imperial College, London

Abstract

Saturated soil mechanics is a complex subject because of the particulate form of the solid phase of soil, its interaction with the aqueous water phase and also because soil is a product of nature and so has potentially great variability. When the soil dries such that there is also an air phase it becomes unsaturated and its behaviour is far more complex because of the interface between the air and the water and the volumetric response of the air under changing conditions of pressure and temperature. Additionally the pressure in the water phase becomes negative (tensile) and measuring such pressures has until recently been fraught with problems. As many parts of the world are covered by unsaturated soils, understanding their response would significantly enhance engineering design and analysis. This paper describes the research work done at Imperial College over the past decades to advance our understanding of unsaturated soils. The work is considered under four main headings of theoretical formulations, laboratory experimentation, field studies and numerical analysis research.