Adaptive computation of localization phenomena in geotechnical applications

摘要

The numerical treatment of unsaturated soil plays a dominant role in geotechnical engineering, as for instance in the investigation of deformation and localization behaviour of the subsurface. Proceeding from the second law of thermodynamics, unsaturated soil is described within the well-founded framework of the Theory of Porous Media (TPM), by a porous, materially incompressible, elasto-plastic or elasto-viscoplastic solid skeleton (soil), a viscous, materially incompressible pore-liquid (water) and a viscous, materially compressible pore-gas (air). Based on quasi-static considerations, numerical computations are based on weak formulations of the momentum balance of the overall triphasic medium together with the mass balance equations of the pore-fluids. The resulting system of strongly coupled differential-algebraic equations can be solved by use of the finite element tool PANDAS. Finally, the formulation is applied to various initial-boundary-value problems, as e. g. the simulation of the fluid-flow situation or the slope failure of embankments.