Adaptive finite element analysis of multi-phase problems in geotechnics

Adaptive FE solution strategies for coupled two-phase and three-phase problems involving porous soils with the pore space filled with water and/or (compressed) air are presented. The errors are estimated by applying the well-known Zienkiewicz-Zhu error estimator to each phase. The mesh is improved by mesh regeneration from scratch employing the advancing front method. Two different adaptive strategies, based on the error estimation either of incremental or total quantities, are pursued. The developed adaptive strategies are applied to the numerical simulation of a laboratory test and a full-scale in situ test, considering the flow of compressed air in an elastic deformable soil skeleton.