Constitutive Equations of Soils

Abstract

The history of plasticity has begun with the study on deformation behavior of soils by Coulomb (1773) when he has proposed the yield condition of soils by applying the friction law of himself. Thereafter, the soil plasticity has been deprived the leading part by the metal plasticity. One of the reasons would be caused by the fact that soils exhibit various complex plastic deformation behavior, e.g., the pressure-dependence, the plastic compressibility, the dependence of the third invariant of deviatoric stress, the softening and the rotational hardening. Explicit constitutive equations of soils will be described in this chapter, based on the elastoplastic constitutive equations in Chapters 6-8.