Introduction
ABG Cavidrain is a drainage solution designed to reduce water penetration and relieve hydrostatic pressure in tunnel constructions. It is a cuspated HDPE sheet that forms a void for water to flow freely to an outlet or collector pipe.

Specifications and Applications
Cavidrain is used in tunnel drainage to collect infiltration water from behind tunnel linings and inverts. It can be used as a standalone drainage barrier or as part of a system with geomembranes for waterproofing. The product is available in various depths (3mm to 60mm) and roll widths, with larger prefabricated panels available for customization.

Installation and Benefits
Cavidrain is installed by fixing it to the excavated tunnel face and covering it with shotcrete. It provides a free-draining void and an impermeable barrier to prevent water ingress. The installation is fast and cost-effective, with the profile optimized for maximum bearing area and flow. Benefits include replacing crushed stone in tunnel inverts, high flow capacity, and load capacity equivalent to concrete fill.

Product Variants
The product range includes Cavidrain S3, S6, S10, S20, S40, and S60, each with specific applications for tunnel wall and invert drainage. Cavidrain S3 can be used as a drained liner, allowing sheets to be welded or taped together for an integral waterproof liner.

Contact Information
For specific design and installation guidance, contact ABG Technical Department. ABG Ltd. provides technical data, specifications, and installation instructions upon request.

Disclaimer
All information is supplied in good faith for assessment of ABG products. The suitability of information or material for use is the user's responsibility. ABG reserves the right to update information without notice.