Installation Stress in Prefabricated Vertical Drains

Prefabricated vertical drains (PVDs) normally consist of a core and a filter (sleeve) made with polymeric materials. Modern installation rigs are capable of installing them at considerable speed in soft soil deposits. This note reports the tension developed in a PVD filter sleeve during the installation process, which was monitored with strain gauges. A tension of about 1,000 N was measured near the shoe shortly after the commencement of mandrel withdrawal. The need to watch the stresses in PVD in relation to the material properties of the components is highlighted.