Traditional methods of groundwater exclusion are difficult to install with any degree of reliability in modern tunnel construction. Cavidrain geocomposite drainage provides a drainage layer to collect infiltration water from behind tunnel linings. Cavidrain may be used alone or form part of a system incorporating geomembranes for waterproofing.
In typical installations the Cavidrain is fixed to the excavated face of the tunnel and covered with shotcrete which adheres to the back of the Cavidrain sheet.
When used in invert drainage the high strength core is specifically designed to withstand the compressive loads arising from placing wet concrete and once poured the concrete fills the back of the dimples making the ultimate load capacity that of the concrete