Geotechnical Yield Criteria and Constitutive Relations in Strain Space

Based on Ilyushin's postulate, this paper deals with the necessity and features of researching the geotechnical elasto-plastic theory in strain space. In the paper, we established the relations between stress in variants and elastic strain invariants, brought about the transformation from the stress yield surfaces into the strain yield surfaces, derived and discussed the strain expressions from 12 yield criteria expressed by stress. By normality rule, we also derived 12 constitutive relations for ideal plastic materials associated with the above expressions. The results presented here can be applied to practice and are helpful to the study of the plastic theory in strain space.