Dynamic TPM models for mass transport in elastoplastic soils

In this thesis failures in geomechanical constructions as pit foundations and excavations are simulated from an academic point of view. Using the Theory of Porous Media (TPM) as a homogenization approach to the heterogeneous nature of soils in which solid and liquid components are inseparably mixed, different mechanic and numeric aspects of the underlying mechanical theories are discussed. Since most soils have an elastoplastic material behavior, the incorporation of two different yield criteria, Drucker-Prager and Ehlers-7-parameter, into the TPM and their influence on the final outcome are examined. Further on, the TPM offers the possibility to simulate a mass exchange between different components which is used to model the detachment of soil particles from the main soil body and their subsequent movement within the liquid inside the boundary value problem (bvp). To cope with initial loads and the resulting oscillating mechanical responses, the dynamic facets of the TPM were considered requiring an intensive study of the applied material time integration schemes such as the stiffly accurate, explicit, singly, diagonally implicit Runge-Kutta (saESDIRK) method. The numerical treatment of these problems is executed with the classical Finite Element Method (FEM) and one focus of this thesis is the reduction of computational costs by the use of well-chosen equational setups and adaptive time integration methods. Several numerical calculations are performed to examine the different aspects of this geomechanical problem, among others the elastoplastic material behavior as well as the mass exchange, and their mutual interference.