Application of variable moduli models to soil behavior

Abstract A mathematical material model is described in which the basic constitutive law is an isotropic relation between the increments of stress and strain. No unique stress-strain relation, per se . exists. Neither is there an explicit yield condition. The bulk and shear moduli, however, are functions of the stress and or strain invariants. The behavior of two simple models of this type is examined for the two generally available soil tests, i.e. uniaxial strain and triaxial compression. In each case qualitative agreement with the behavior of real soils is obtained. For one model, unloading and reloading is also considered. The latter model is also compared with a simple elastic-plastic model. Many similarities between the two become apparent, but so do significant differences, e.g. the direction of the “plastic” strain increment.