Vertical Drains [PVD] also known as wick drain are used to accelerate the
consolidation of soft, low permeability soils. Drains are installed in a grid
pattern designed to achieve the optimum time versus cost outcome. The most
common forms of drains are strips which are introduced into the ground using a
PVD have been used for more than half-a-century to promote rapid consolidation of relatively thick deposits of soft fine-grained soils. They are commonly used when an accelerated rate of consolidation of a clay layer is desired, besides they can provide a low-cost, practical and effective means of expediting consolidation settlement.