Port of Brisbane, Queensland
Vertical Drains are used to accelerate the consolidation of soft, low permeability soils. Drains are installed in a grid pattern designed to achieve the optimum time v. cost outcome. The most common forms of drain are strip or “Wick” drains and are introduced into the ground using a mandrel containing the drain material being installed into the soil. The mandrel is pushed to the design depth, where it releases the drain and is withdrawn leaving the drain in place. Menard Bachy has developed the use of small diameter circular plastic tube drains, which are more efficient than the flat “Wick” drains. These circular drains have particular application in the Vacuum Consolidation process.
Menard Bachy has developed its own range of purpose made drain installation equipment to cope with a variety of ground conditions and which can be fitted to standard hydraulic excavators.
Ground inclusions of columns of sand or other granular materials are also used to create, generally, larger diameter and shallower vertical drains.
Often, surcharge in the form of a temporary embankment is used in conjunction with vertical drainage to enhance its effectiveness and to target the achievement of total primary consolidation and limit long term secondary consolidation.
Vertical Drains are an integral part of the Vacuum Consolidation method.
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