Numerical simulation of non-linear phenomena in geotechnical engineering

Geotechnical problems are often characterized by the non-linear behavior of soils and rock which are strongly linked to the inherent properties of the porous structure of the material as well as the presence and possible flow of any surrounding fluids. Dynamic problems involving such soil-fluid interaction can be treated numerically using a finite element formulation based on the theory of poro-elasto-plasticity.

However, due to the complex nature of the governing differential equations, commercial finite element codes often rely on a simplified formulation, which neglects the inertia of the fluid. In this thesis, a finite element code has been developed, which incorporates the full equation set. The code is used to evaluate the difference between the full and simplified formulations for the simulation of the dynamic tensile resistance of a suction bucket.

Further, the thesis deals with the development and implementation of constitutive models for use in the finite element method with particular focus on rock materials where the empirical Hoek-Brown material model is commonly used. In particular, the thesis deals with numerical implementations that is capable of simulating crucial aspects of the strength characteristics observed in rock materials such as strength softening and limited tensile strength.