Abstract: This paper presents a model developed for one-dimensional consolidation of unsaturated soil. This model uses the piece-linear finite difference approach and considers soil nonlinearity and large strain problems. Fortran programming package is used to implement the computation of the model. This model is verified by analytical solutions and experimental results. The numerical solution of this model agrees with the existing solutions in the case of instantaneous loading. In process of loading, the approximation of consolidation settlement obtained by this model is in good agreement with the test results. Then this model is implemented for a large strain consolidation. The case study compares the settlement occurred at the instantaneous deforming stage and the subsequent consolidation stage. The case study also investigates the effect of the pore air permeability to the hydraulic conductivity ratio on soil layer settlement, saturation degree, and consolidation degree of different strain. It also analyzes the difference of pore water (air) pressures and soil layer settlement on large and small deformation consolidation theory of unsaturated soil.

Key words: unsaturated soil, nonlinear, large strain, one-dimensional consolidation, settlement