Consolidation of unsaturated soil by vertical drain considering smear and well resistance

This paper proposes an approximate analytical solution for equal-strain consolidation of unsaturated soils with vertical drains considering the smear and well resistance effects. According to the modified Fick's and Darcy's laws, the governing equations for the air and water phases are established in the matrix form, and solved using the matrix analysis method. Comparisons with previous analytical solutions and finite difference solution are conducted to assess the correctness of the proposed solution. Upon the successful calibration of the proposed approach, graphical interpretation is presented to elaborate the influence of combined smear and well resistance parameters on the consolidation characteristics. It can be found that the proposed approximate analytical solution is accurate to meet the engineering requirements. Moreover, the smear and well resistance effects decrease the dissipation rate of excess pore-air and pore-water pressures considerably, while the average degree of consolidation at the end of the first consolidation stage does not change much for different combined smear and well resistance parameters.