3. Behavior models

3.1 General

The complexity of unsaturated soil behavior and, in particular, the difficulty of providing an integrated account of the mechanism of irreversible volume reduction during rewetting under constant stress (collapse), has long delayed the development of behavioral models. This is a reminder of the importance of ensuring a good match between the complexity of the model chosen and the problem to be solved, in order to avoid, where possible, having to use highly complex models for relatively simple problems. In the case of unsaturated soils, we will see the value of elastic models, not necessarily linear, for monotonic loading situations, such as the construction of a dam or an embankment in compacted soil.

Theoretically, assuming isotropic behavior, three...