What it is
This techniques involves the installation of artificial drainage paths or vertical drains into soft compressible soils. The prefabricated vertical drain (PVD) used by Cofra are specially designed to work effectively under high settlements (i.e. under buckled or kinked conditions).
How it works
Highly permeable soils like sand can adjust rapidly to loads and the corresponding compression / reduction in voids due to the ability to easily drain the excess porewater. Low permeable soils like clay and peat do not have this ability and show a delayed compression with the dissipation of the excess pore water. This process of dissipation of excess pore pressures, also known as consolidation, can take up to years depending on the thickness of the deposit. Vertical drains or also known as wick drains are used to shorten the dissipation path of the excess pore water and to accelerate the consolidation process to a few months or even weeks when the PVD is placed at close center to center distances.