GEOMETRICALLY NONLINEAR FULLY COUPLED MODEL FOR THE CONSOLIDATION OF SOFT PARTIALLY SATURATED SOILS

H. A. DI RADO; P.A. BENEYTO; J.L. MROGINSKI; J.E. MANZOLILLO

Buenos Aires

Conferencia; 15th Pan-American Conference on Soil Mechanics and Geotechnical Engineering, XV PCSMGE 2015; 2015

Argentinian Geotechnical Engineering Society (SAIG)

The main scope of this paper is to present a fully coupled numerical model for isothermal soil consolidation analysis based on a combination of different stress states. Being originally a non symmetric problem, it may be straightforward reduced to a symmetric one, and general guidelines for the conditions in which this reduction may be carried out, are addressed. Non linear saturation-suction and permeability-suction functions were regarded. The model was delivered considering geometric non linear effects using an updated lagrangian description with a co-rotated Kirchhoff stress tensor. This description also leads to a non-symmetric stiffness matrix. An alternative, using a symmetric constitutive matrix is addressed and some of its main mathematical and numerical characteristics are highlighted. The whole equation system was solved using an open finite element code developed by the authors. In order to validate the model, various examples, for which previous solutions are known, were solved. The use of either a strongly non linear and no symmetric formulation or a simple symmetric formulation with accurate prediction in deformation and pore-pressures is extremely dependent on the soil characteristic curves and on the shear efforts level, as well. Numerical examples show the predictive capability of this geometrically non linear fully coupled model for the consolidation of soft partially saturated soils