On the basis of traditional model a modified elastoplastic constitutive model for fine sand which can reasonably describing the characteristics of dilantancy and strain softening is proposed. This two-yield surface model reflects the mechanism of shear deformation and mechanism of compressive deformation simultaneously. The traditional dilatancy equation of Cam-clay model is modified and the relativity between phase transformation stress ratio and initial effective pressure is considered. In order to describe the characteristic of strain softening, a strain softening equation using the stress ...
