Vertical drain consolidation with overlapping smear zones

Vertical drains are used to improve soft soil by providing a horizontal drainage path along which excess pore water pressures caused by a surcharge can dissipate faster than by a vertical drainage path alone. Despite laboratory evidence that, owing to drain installation, permeability decreases gradually towards the drain (Chai & Miura, 1999; Sharma & Xiao, 2000; Hawlader et al., 2002), most analytical models (e.g. Hansbo, 1981; Zhu & Yin, 2004) have included smear effects by incorporating a reduced horizontal permeability that is held constant throughout the smear zone. Assumed radii for a constant-permeability...