Double hardening soil model for soil behavior. Formulation, implementation and application

Abstract

The aim of this thesis is the application and validation of a Double Hardening Soil Model(DHSM). In this model, two hardening mechanism are comprised named volumetric hardening from a unified Critical state model for Clays and sands (CASM) by Yu (1998) and shear hardening from Hardening soil model (HSM). The basic equations and corresponding parameters are discussed. Some improvements and modifications of DHSM are introduced and the constitutive model is implemented in to Plaxis finite element code. In addition, a serial of tests on low plasticity clay performed by Gens (1982) have been carried out. Among them, drained tests including different consolidation rate and isotropic-anisotropic condition on the low plasticity clay are identified and applied by DHSM program. Variety of complex geomaterial behaviors are examined and studied based on both laboratory and numerical simulation results. Through the results, the model corresponds well with the drained test through real parameters especially during overconsolidated condition. The strain rate can be significantly decreased during hardening process which is more closed to the real behavior. Meanwhile, the enhanced model E-DHSM proved to be powerful in the “dry side” state which agrees well with the deviatoric stress . Finally, considering various consolidation condition, the framework of DHSM agrees well in a wide range of soil tests and geomaterial behavior. It proved to be powerful for implementation and application in soil behavior.