What is a wick drain?

The wick drain, also known as a prefabricated vertical drain (PVD), is a relatively simple device which is used to provide drainage paths for water fluid in the soil or between rocks. Wick drains are installed using specialized equipment called a stitcher.

What is the purpose of wick drains?

Wick drains, also known as Prefabricated Vertical Drains (PVD) are prefabricated geotextile filter-wrapped plastic strips with molded channels. These act as drainage paths to take pore water out of soft compressible soil so it consolidates faster, often from decades to months.

What is an earthquake drain?

Earthquake drains are prefabricated vertical drains made of a perforated pipe wrapped with a geotextile filter fabric. These drains have a high flow capacity that helps water dissipate, reducing build-up of excess pore pressure in soils below the water table.

How do earthquake drains work?

Earthquake drains are installed by vibrating the insertion mandrel during penetration and removal. Typically, the insertion mandrel consists of a heavy-gauge steel pipe with three equally spaced fins to transfer vibrations to the adjacent soil.

What are wick drains and what do they do?

Wick drains serve as atmospheric vents or drainage paths for relief of excess pore water pressure generated by the surcharge loading. With wick drains the consolidation time period can be reduced to a matter of months.

Why are wick drains used in soft soil?

Wick drains, also called Prefabricated Vertical Drains, are installed in soft soils in order to accelerate consolidation of the soil by providing additional drainage paths for pore water to escape. Other names and variations of this technique are: deep drains, sand drains, sand wicks, band drains, pre-fabricated band-shaped drains.

How are prefabricated wick drains used for primary settlement?

These prefabricated wick drains are used to shorten pore water travel distance, reducing the preloading time. The intent is to accelerate primary settlement. Pore water will flow laterally to the nearest drain, as opposed to vertical flow to an underlying or overlying drainage layer.

Why does it take so long for wick drains to consolidate?

Deep deposits of soft cohesive soil can take a long time to consolidate even when pre-loaded. The low permeability of these soils and the long drainage path lengths produce slow rates of consolidation. The time for consolidation to occur is a function of the square of the length of the drainage path.