Water Ingress in Corrugated Tunnel Sealed

The University of Leicester enlisted the services of a U.K.-based specialty repair contractor to evaluate and rectify a steel corrugated tunnel/pipe approximately 1.8 meters in diameter.

The tunnel was exhibiting signs of persistent and significant water intrusion due to damage caused by corrosion, which led to the formation of cracks and perforations at the base of the duct.

The contractor devised and implemented a solution that could be applied from the confined interior space of the tunnel. The aim was to extend the lifespan of the structure by an estimated 25 years.

Given the substantial degree of water ingress from the elevated water table, a solution was needed that would not only stop the current water flow but also provide a robust barrier against future water infiltration and leakage.

The contractor identified a proven hydrophobic, hydro-active polyurethane water stop foam resin as the most suitable solution to tackle the fractures showing severe pressing water conditions.

Sealboss 1510 Water Stop Foam, NSF certified and activated by the 15x Accelerator, was the selected chemical grout to mitigate the severe and pressing water conditions.

The advantage of using this specific waterproofing injection grout in sealing the corrugated tunnel stems from its ability to seal not only wide, gushing water leaks but also the smallest of pores and capillaries in building elements that might otherwise allow water to seep to the surface.

The low viscosity of SealBoss 1510 chemical foam grout, coupled with the specially formulated SealBoss 15X Accelerator – which can be mixed at ratios ranging from 2% to over 20% by volume with the resin – enables a range of reaction profiles. These range from slow absorption into the concrete building components, sealing all capillaries and pores, to rapid water stop high-foamer expansion for sealing larger gaps and voids.

Carefully regulated addition of the accelerator allows for controlled expansion from nearly no expansion to forty times expansion. Due to its controlled expansion, the resin will either cure to form a tough semi-flexible seal or a compression seal gasket when expanding at pressure.

Following the injection as per specification, the corrugated tunnel repair now provides a watertight seal to the concrete, effectively preventing further deterioration of the building components due to water infiltration and seasonal frost.

Products used for Tunnel Water Stop and Leak Sealing Injection