Modelling prefabricated vertical drain improved ground in plane strain analysis

Abstract

The methods for modelling the effect of a prefabricated vertical drain (PVD) in plane strain finite-element analysis have been reviewed. The methods are classified into four groups of using: (1) solid element; (2) macro-element; (3) one-dimensional (1D) drainage element; and (4) equivalent vertical hydraulic conductivity (kve) to model the effect of the PVD, respectively. With the kve method, a PVD improved subsoil can be analysed the same as for an unimproved one. For all the methods, the average degree of consolidation in a plane strain analysis is matched with that under an axisymmetric condition by modifying the hydraulic conductivity of subsoil, and/or the spacing or the discharge capacity of plane strain drains. Finally, the effectiveness of the kve method has been demonstrated by modelling a large-scale model test of PVD consolidation. The numerical results indicate that the kve method performs as well as that of explicitly modelling the PVD consolidation under axisymmetric condition.