Axisymmetric Consolidation of Unsaturated Soils with Vertical Drain with Radial and Vertical Drainage

In this paper, an analytical solution is presented to study the axisymmetric consolidation of a vertical drain inserted in a finite unsaturated soil layer. In the derivation, the decoupling process is employed to convert the governing equations of excess pore-air and pore-water pressures into essentially the same homogeneous partial differential equations (PDEs). Later, the solution with time is obtained by employing the separation variable method. Additionally, validation exercise is conducted by degenerating current solutions into that for the consolidation of vertical drains in saturated soils. Finally, the changing regularity of excess pore-air pressure, excess pore-water pressure and normalized settlement is studied against the ratios of air-water permeability, the ratios of radial-vertical permeability and depth. It is concluded that the solution presented in this paper is reliable and the research method has a reference to more complicated consolidation problems.