Ground improvement with vertical drains has been an accepted practice for improving soft clay deposits and has been widely used over the 60 years. The time required for the settlement to occur is considerably reduced as the length of the drainage path through soil is reduced. The vertical drains are required to have high permeability and sufficiently high drainage capacity so that pore water escapes in horizontal direction towards the nearest drain. The water then flows freely vertically along the drain to a drainage blanket placed on the soil surface or to a highly permeable layer above or below the clay layer. TechDrains are composite in construction with an inner core wrapped in a non-woven geotextile fiber fabric. The inner core is of polypropylene and the filter fabrics are of polypropylene or polyester.
TechDrain is predictable, in both technical and financial terms. PVD technology has proven itself in hundreds of projects in the last thirty years. Over 1 billion linear meters of similar prefabricated vertical drain have been installed worldwide to date.