Abstract: An explicit analytical solution of the partial differential equations of consolidation by vertical drains is derived to assess the effects of compressibility and varying hydraulic conductivities of soils in the smear zone on ground consolidation. Equal volumetric strain assumption is adopted. The compressive deformation of soils in the smear zone is considered, together with a linear and a parabolic distribution of the horizontal hydraulic conductivity along the radial direction. Well resistance is also considered, together with an arbitrarily distributed mean stress increasing along the depth of ground. The solution is derived for the consolidation under a linearly time-varied surcharge preloading. The proposed solution is used to analyze the influences of the radius of smear zone, the distribution of horizontal hydraulic conductivity and the coefficient of volumetric compressibility of smeared soils on the global average degree of consolidation. It is found that the rate of ground consolidation is underestimated by the solution derived by applying a uniformly reduced horizontal hydraulic conductivity to the smeared soils. When the radius of smear zone is relatively large, the rate of ground consolidation is overestimated by the solution derived without consideration of the compressive deformation of the smeared soils. These effects should not be overlooked in the analysis of consolidation by vertical drains.

Key words: vertical drain, linear loading with time, smear, well resistance, excess pore water pressure, consolidation degree