Analytical Solutions to the Axisymmetrical Consolidation of Unsaturated Soils

In this study, analytical solutions are presented for the axisymmetrical consolidation of an unsaturated soil stratum on the basis of Fredlund and Hasan's one-dimensional consolidation theory. Two different loading conditions, i.e., instantaneous loading and ramp loading, were considered. The derivation process of the proposed analytical solution is simpler in contrast to the existing analytical solutions and it was verified to be accurate using an analytical solution in the literature. In addition to the analytical solutions under the assumption of free strain, the analytical solutions under the assumption of equal strain were further derived. In the parametric study, the variations in the excess pore-water and pore-air pressures as well as the average degree of consolidation are presented. Graphs are given to show the influence of the different hydraulic conductivity ratios between the air and water phases as well as the construction time (under a ramp loading condition) to the consolidation process. These two factors have significant impact on the consolidation of the air phase but little influence on the consolidation process of the water phase. (C) 2017 American Society of Civil Engineers.