Controllable deformation by plastic strain control for geomaterials

This paper theoretically presents the effective measure of plastic strain control, which has an advantage to describe the strain softening behavior unconditionally. An elasto-plastic constitutive model for geomaterials is formulated on the plastic strain rate space. The proposed model has an additional plastic deviatoric strain hardening parameter as the extended form of the modified Cam clay model. The description of strain softening succeed by the approximate plastic strain-control and the softening mode is diversified with the magnitude of applied plastic strain. The stabilization of mechanical unstable behavior can be shown and the new interpretation of stability problem is discussed.