Moisture flow and equilibria in unsaturated soils for shallow foundations

The performance of engineering structures on shallow foundations in Australia is largely dependent on moisture movement and equilibria in soils which are unsaturated. No suitable theory for the foundation design of these structures exists, and this paper outlines a rational design approach based on considerable experimental evidence. This approach is suggested, not as one that has been tried successfully in many instances and therefore one which can be used without reservation, but rather to convince practical engineers that there is a rational solution to this problem which should lead to adequate design techniques in the near future. Techniques for the measurement of the required soil moisture properties are also mentioned and briefly discussed.