Cavidrain Invert

Cavidrain Invert geocomposite for tunnel invert drainage

Cavidrain® Invert has been optimised for high in-plane flow to mitigate problems caused by mineral calcification.

Cavidrain Invert

Cavidrain® Invert provides a pre-formed drainage layer into which the concrete floor slab can be easily cast. Cavidrain® Invert replaces the crushed stone and pipes traditionally used to collect and transport away infiltration water.


  • New tunnel construction
  • NATM constructed tunnels
  • Cut & Cover tunnels
  • Drill and blast tunnels
  • TBM tunnels
  • Metro underground stations
  • Cable tunnels
  • Highway tunnels
  • Railway tunnels


  • Simplified invert drainage system
  • Reduced excavation requirements
  • Significantly reduced project time scales
  • Materials & labour cost reduction
  • Reduced installation requirements compared to traditional invert drainage methods
  • Improved drainage capacity
  • Minimised damage caused by mineral calcification
  • Designed in bespoke panels to suit tunnel dimensions

ABG Cavidrain Invert geocomposite tunnel drainage

Once installed the load capacity of Cavidrain® Invert is equivalent to the strength of the concrete used.

Traditional tunnel invert constructions favour the extensive use of crushed stone together with a longitudinal collection pipe. There is a significant cost in time and money associated with excavating the trench, crushing and grading the stone before installation. Large quantities of stone are also required to meet drainage requirements.

Cavidrain® Invert provides a pre-formed drainage layer into which the concrete floor slab may be cast and replaces both the invert trench and pipe to collect water from the tunnel invert. Cavidrain® Invert has an in-plane water flow capacity far in excess of crushed stone. Installation is fast and cost effective as excavation and material movement is significantly reduced. The Cavidrain®  Invert profile is optimised for maximum bearing area and has been designed to withstand the compressive loads arising from the placement of wet concrete. Once the concrete has cured, the ultimate load capacity of Cavidrain® Invert is that of the concrete infill.

Cavidrain® invert has been used successfully throughout the world in a number of major tunnel projects.

Tunnel construction using ABG Cavidrain Invert drainage geocomposite
ABG Cavidrain Invert geocomposite tunnel drainage

Typical Client Profile:

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


Tunnel Invert Drainage, Sydney Metro, Australia

Tunnel Invert Drainage, Brisbane Australia

Tunnel Invert Drainage, Brynglas Tunnel, M4 Motorway, UK

Tunnel Invert Drainage, Black Hills Tunnels, Hong Kong

Structural Basement Drainage, Dounreay Nuclear Decommissioning, UK

Tunnel Invert Drainage, Graz, Austria

Related Products

The following similar products provide solutions for drainage and may be relevant:

ABG Cavidrain Invert - a drainage geocomposite used in a tunnel construction
Close-up showing the invert drainage

Associated System Products

Within a tunnel construction, our technical team are at hand to discuss you unique requirements. The following products may be used in conjunction with Cavidrain:  

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