MATHEMATICALLY CONSISTENT FORMULATION OF ELASTOPLASTIC CONSTITUTIVE EQUATIONS. PROCEEDINGS OF THE SIXTH INTERNATIONAL CONFERENCE ON NUMERICAL METHODS IN GEOMECHANICS, 11-15 APRIL 1988, INNSBRUCK, AUSTRIA. VOLUMES 1 - 3

The original subloading surface model proposed by the author (or the bounding surface model with a radial mapping by Dafalias) does not assume a yield surface enclosing a purely elastic domain, and instead it assumes a subloading surface which always passes through a current stress point even in the unloading state. Thus, it describes a continuous stress rate-plastic strain rate relation (smooth elastic-plastic transition) and its loading criterion does not require the judgement whether a current stress lies on a yield surface or not. However, it can not describe an induced anisotropy and a hysteresis effect very well, since the center of similarity of the normal yield or the subloading surfaces is fixed or is not formulated adequately. Recently, the author presented the mathematically exact formulation of the subloading surface model. In this paper, this extended subloading surface model is applied to granular materials, and it is compared with some test data of sand. (TRRL)