Tunnel Waterproofing Solutions

Challenges underground

Tunnel waterproofing is demanding and challenging. Damage from hydrostatic pressure, corrosive chemicals carried by groundwater, and extreme temperature fluctuations can compromise a tunnel’s structural integrity. Just as critically, many tunnels are routed under sensitive locations where any failure can lead to not just substantial repair expenses, but disruption of essential activities that the tunnel’s meant to route around. And even then, repairing failed tunnel waterproofing may not even be possible without removing tons of overburden—creating even greater disruption and further driving up repair costs.

Raising the bar with dependable, high-performance products

From deep tunnels bored through solid rock to cut-and-cover in friable soil, CETCO combines extensive field expertise in planning and implementing tunnel structure projects with a broad range of specifically-designed, high-performance products. We provide single-source, beginning-to-end tunnel waterproofing support that you can depend on for performance—and peace-of-mind.

Combined with our comprehensive approach and backed by a best-in-class quality assurance program no other manufacturer can match, CETCO’s complete and integrated tunnel waterproofing line ensures your tunnels stay dry for decades of service.

Anatomy of world-class tunnel waterproofing

Proven in the most extreme conditions, CETCO’s reliable tunnel waterproofing technologies prevent water penetration to the tunnel interior. Critical elements for successful and long-lasting tunnel waterproofing include:

• Smoothing Shotcrete - Applied to the bored rock surface, this provides a suitable substrate to attach the waterproofing membrane.
• Anchoring System - Safely secures the tunnel lining’s rebar cage without any penetration through the waterproofing membrane.
• Waterproofing Membrane - Affixed to the shotcrete substrate using induction welding plates, this prevents water from reaching the underlying tunnel structure.
• Induction Welding Plates - Secured to the tunnel wall, these attach the geotextile drainage to the shotcrete substrate, also functioning as an induction welding attachment point for the waterproofing membrane.
• CETCO Induction Welding - Our patented magnetic welding process that features:
  • Superior attachment - No penetration of the waterproofing membrane.
  • Speedy installation - Attachments are made on the membrane’s exterior, instead of working behind already-deployed panels and manually welding to a PVC disc.
  • Safer working environment - Induction welding reduces risk of fire, explosions, and toxic fumes.
• Water Barriers - Hot air welding of the waterproofing membrane creates a barrier ring that further controls water intrusion.
• Geotextile Drainage - Positioned over the smoothing shotcrete and held in place with induction welding plates, this helps direct water flow away from the tunnel waterproofing structure.
• Tunnel Grouting System – Easy to install, this forms a thick, low-permeable layer that fills voids and seals small concrete cracks.
• Active Waterstops - Continuous in all cold pour joints, the hydrophilic strip expands in contact with water to form a positive seal and stop water ingress.
• Drain Tile & Gravel - Installed at the base of a tunnel to remove excess groundwater.

High-performance features

Because in some installations they must perform flawlessly for up to a century, CETCO’s durable tunnel waterproofing products stand up to cuts, punctures, and fire, providing unmatched longevity through industry-leading features that ensure decades of dependability:

• Micro-organism and chemical resistance - CETCO T-SERIES—as well as our other composite membranes—protect against high levels of salts, fuels, organic solvents, and other contaminants that can damage tunnel structures.
• Excellent hydrostatic resistance - Our membranes have been tested to resist up to 100 m (231 feet) of hydrostatic head pressure—exceeding the ASTM D5385 maximum resistance pressure requirement.
• Non-reinforced and reinforced options - Available with both non-reinforced and reinforced layers, CETCO waterproofing barriers resist puncture, elongation, and tearing.
• Flexible and reliable welding - Our specially formulated PVC thermoplastic features heavier density material for superior welding.
• Passive and active options - Even slight damage to the water barrier during installation can cause major problems later—but not for CETCO’s premier waterproofing membranes. With their tough, high-performance PVC layer and the self-sealing properties of an active polymer layer, they significantly reduce risk resulting from apparently minor damage.
• Root resistance for shallow tunnels - For cut and cover tunnels that are closer to the surface—where roots can grow in and damage the water barrier—our durable PVC tunnel membranes protect against root growth damage.
• Fire and heat resistance -Fire retardant, CETCO water barriers are self-extinguishing, preventing the spread of flames when most other membranes burn and fall apart, protecting against potentially devastating loss due to spark, flame, and heat incidents.
• Construction durability - Tough and reliable CETCO waterproofing membranes stand up to numerous types of damage—everything from extreme temperature fluctuations to UV rays.

CETCO - Pioneer and leader in waterproofing, with over 60 years of proven experience

CETCO is the leader and pioneer in cutting-edge waterproofing membranes and solutions. Around the globe for the last half-century, our innovative teams of clay mineralogists, chemists, and polymer scientists transform ordinary minerals into extraordinary technology to solve day-to-day problems worldwide.