Evaluation of constitutive models in soil mechanics

There exist a large variety of models that have been proposed in recent years to characterize the stress-strain and failure behavior of soils. All these models have certain inherent advantages and limitations which depend to a large degree on their particular applications. No one mathematical model can completely describe the complex behavior of real soils under all conditions. Each soil model is aimed at a certain class of phenomena, captures their essential features, and disregards what is considered to be minor importance in that class of applications. Thus, a constitutive model meets its limits of applicability where a disregarded influence becomes important. This is why Hooke’s law has been used so successfully in soil mechanics to describe the general behavior of soil media under short-term working load conditions, while the Mohr-Coulomb’s law of perfect plasticity providing good predictions of soil behavior near ultimate strength conditions, because plastic flow at this ultimate load level attains a dominating influence, whereas elastic behavior becomes of relatively minor importance.