When modelling vertical drains in a real boundary value problem the radial flow around a drain needs to be mapped into equivalent plane strain conditions. This can be done by using either permeability, geometry or combined mapping. Whilst the procedure is very simple and straight-forward, the paper suggests that for advanced constitutive models the mapping procedures may need to be done separately for each constitutive model. Three constitutive models are used in the finite element analyses. The S-CLAY1 accounts for initial and plastic strain induced anisotropy and the S-CLAY1S model accounts, additionally, for inter-particle bonding and degradation of bonds. For comparison, the simulations are also performed by the isotropic Modified Cam Clay model.