IMPROVED ACCURACY IN FINITE-ELEMENT ANALYSIS OF BIOTS CONSOLIDATION PROBLEM

Numerical analysis and error estimates of finite element approximation s of Biot's consolidation problem are presented. Initially different o rders of interpolation are employed, leading to lower orders of conver gence for the pore pressure compared to the displacements of the porou s medium. Lower accuracy also occurs in the approximation of the effec tive stress tensor, whether it is calculated directly from the constit utive equation, or through a primal mixed stress formulation. To impro ve the rates of convergence of the pore pressure and effective stresse s, a sequential Galerkin Petrov-Galerkin post-processing technique is proposed.