ABSTRACT
Appropriate constitutive models of soils are the key to a successful prediction of the behaviour of geotechnical structures. A large number of models based on various constitutive theories have been proposed in the last three decades. All of them assume a-priori, a mathematical framework of the model and the material parameters corresponding to the assumed framework have to be identified from physical material tests. Many material parameters in complex constitutive theories have no physical meaning, are difficult to determine and have to be identified by trial and error from numerical simulations.
