Generalized analytical solution for 2D plane strain consolidation of unsaturated soil with time-dependent drainage boundaries

This paper discusses the 2D plane strain consolidation problem of unsaturated soil considering the time-dependent drainage boundaries. A set of time-growing exponential functions are firstly used to describe the changes of excess pore-pressures at the drainage boundaries of an unsaturated soil layer. Then, a generalized analytical solution for the 2D plane strain consolidation under these boundaries and constant initial excess pore-pressures is obtained using the finite Fourier transform and Laplace transform methods. Further, the comparisons are presented to verify the accuracy of the proposed solution. It is shown that the proposed solution is more general in the drainage boundary, and in a good agreement with the analytical solution available in the literature and the finite difference solution. Finally, a worked example is presented to investigate the consolidation characteristics under four changing drainage parameters of time-dependent drainage boundaries. The average degrees of consolidation for both air and water phases as well as that for the soil layer are presented and discussed.