Memory of Stress History in Single and Two Surface Plasticity for Granular Soils

ABSTRACT Recent studies have identified limitations in Manzari and Dafalias' 1997 and 2004 sand plasticity models, particularly regarding one‐way unloading/reloading and ratcheting loading modes. These models are widely accepted as bounding surface models in the geotechnical engineering community; thus, concerns have arisen about a fundamental lack of memory for stress history in the mathematical theory of bounding surface plasticity. This work challenges the notion that memory loss is intrinsic to bounding surface plasticity, arguing instead that it results from specific constitutive choices within Manzari/Dafalias models. The study critically examines differences among the Armstrong/Frederick single‐surface kinematic hardening plasticity, Krieg's two‐surface plasticity, and Dafalias‐Popov two (bounding) surface plasticity. It demonstrates that, although the Manzari/Dafalias models incorporate concepts from all three plasticity theories, their core mathematical structure remains a non‐linear modification of the single‐surface kinematic hardening framework, limiting the models' ability to simulate cyclic hardening. Finally, this study proposes a clear classification of SANISAND models to foster a better understanding of their capabilities and limitations.