CONSOLIDATION CHARACTERISTICS OF DRAINAGE WELL FOUNDATION IN UNSATURATED SOILS WITH SEMI-PERMEABLE BOUNDARY

Former researches of unsaturated drainage well foundations always treated the foundations with ideal radial boundaries, but did not consider the smearing effect. The construction disturbance can affect the speed of consolidation by decreasing the soil permeability near the inside of a drainage well foundation. In this case, the smearing effect is illustrated with the semi-permeable boundary and is included in a new modeling of drainage well foundation in unsaturated soils. By introducing Bessel functions, analytical solutions with respect to excess pore pressures are achieved in the Laplace domain according to the governing equations. Secondly, by utilizing the Crump's method, the inverse Laplace transform to obtain semi-analytical solutions to excess pore pressures in the time domain is performed. It is shown that the present solutions are in good agreement with the previous solutions in the literature and more reliable. Finally, parametric studies are conducted by the variations of excess pore pressures at different ratios of air-water permeability coefficient and the radius. Results indicate that the semi-permeability coefficients have significant influence on the consolidation, and excess pore pressures dissipate faster with the increase of semi-permeability coefficient.