Cavidrain Liner

Cavidrain® Liner is a combined drainage and waterproofing liner that is welded to form an integral waterproof system. The sheets are easily fixed to the smoothed excavated walls with a sealed fixing detail and the system is finished with shotcrete.

Cavidrain® Liner has been specifically designed to be highly flexible to accommodate the contours of excavated tunnel walls.


  • New tunnel construction
  • Repair of existing tunnels
  • Highway tunnels
  • Railway tunnels
  • NATM constructed tunnels
  • Drill and blast tunnels
  • Metro underground stations
  • Cable tunnels
  • TBM tunnels


  • Simplified tunnel lining system
  • Materials & labour cost reduction
  • Reduced installation requirements
  • Improved drainage capacity
  • Minimised damage caused by mineral calcification

Traditional methods of groundwater exclusion are difficult to install with any degree of reliability in modern tunnel constructions. Cavidrain® Liner provides a drainage layer that collects infiltration water from the excavated tunnel face, while also acting as the waterproofing function.

In typical installations, Cavidrain® Liner is fixed to the smoothed, excavated face of the tunnel with rondels and covered with shotcrete. Shotcrete can be sprayed directly to Cavidrain® Liner to create the surface finish, offering 20% less rebound loss than a smooth PVC liner.

Cavidrain® Liner being LLDPE is highly flexible and acts to minimise the build-up of hydrostatic pressure, thus protecting and enhancing the integrity of the tunnel.

Typical Client Profile

  • Tunnel Engineers
  • Tunnel Contractors
  • Railway Engineers
  • Consulting Engineers
  • Utility Service Providers
  • Waterproofing Contractors

Additional information

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