PVD Wick Drains
Wick drains, also known as Prefabricated Vertical Drains (PVD) are prefabricated geotextile filter-wrapped plastic strips with drainage channels. The geotextile filter prevents soil particles from entering the channels and clogging the drain. The strips act as vertical drainage paths to take pore water out of soft compressible soil so it consolidates faster.
Each drain is fed down through a hollow steel mandrel mounted on a crane mast, connected at the bottom to an expendable anchor plate. A wick drain leader and stitcher is used to guide the mandrel to design depth at which time the mandrel is removed, leaving the wick drain in place. The wick drain is then cut at the ground surface, a new anchor plate connected to it, and the mandrel is moved to the next location.
A pattern of installed vertical wick drains (with drains generally placed in a square or triangular pattern) provides short drainage paths for pore water, which accelerates the consolidation process and therefore, the construction schedule.
- Drainage acceleration
- Soil stabilisation
- Ground improvement
- Container terminals
- Road and rail embankments