Formulation and evaluation of two stress dependent small strain stiffness models

Abstract

Soil stiffness at very small strain range (γ ≤10–5 ) show non-linear relationship with the strainlevel that gives an S-shaped degradation curve. In addition to this, experimental results show that the small strain stiffness and its corresponding small strain level are stress dependent. However, existing small strain stiffness models do not show this stress dependency. In this thesis stress dependency formulations for two selected small strain stiffness models (HS-Small and extended hypoplasticity models) are incorporated. The two updated/proposed models are validated and verified using element tests and boundary value problems. The updated models agree with experimental results at small strain level and improved results for boundary value problems were obtained.