Soil tests as boundary value problems using hypoplasticity

Constitutive models are mechanical theories which link stresses with the resulting deformation and thus should enable a realistic simulation of material behavior. Constitutive modelling is a core subject in geotechnical engineering, as the quality of every numerical simulation depends on the used model. It is common practice to calibrate and evaluate constitutive models on the basis of standard laboratory tests viewed as so-called element tests. For the calculation of stresses and strains, the soil sample is then assumed to behave homogeneous. Recent experimental studies on sand carried out at the University of Grenoble show that inhomogeneities develop from the very beginning of laboratory tests. Therefore, an element test, which implies homogeneous deformation, is questionable, contrary to the prevalent assumption. The applicant therefore aims to find out how inhomogeneities in the sand sample influence strength and stiffness predictions. For this purpose, laboratory tests will be simulated as so - called boundary value problems using the finite element method with hypoplasticity as constitutive model. The comprehensive simulation-driven analysis in combination with high-quality tomography data from Grenoble will foster the understanding of experiments as well as of constitutive models.