Image analysis for determination of triaxial test parameters

The thesis introduces a 3D image-based system for measuring deformations in soil samples during triaxial tests, and a direct optimization method for determining parameters for soil constitutive models. The study begins with finite element analysis to assess the effects of imperfect boundary conditions on traditional measurement methods, proposing a 'point-cloud' approach for the 3D-PIV system. Validation tests using PVC dummy samples and nine soil triaxial tests demonstrate the system’s effectiveness. The thesis also presents a direct optimization method, facilitated by a purpose-built algorithm, for parameter determination in the Hardening Soil and Hardening Soil with small-strain Stiffness models.