Cut & Cover Tunnels - Waterstops
When concrete structures are submitted to outside water pressures in immersed tunnels, the joints between concrete sections are made watertight with waterstops. For normal purposes our standard rubber waterstop with vulcanised steel strips alongside (type W9U) can be applied.
This waterstop will give water tightness between the concrete and the steel strips. However in practice, caused by shrinkages in the concrete and errors while pouring, in the area around the waterstop the concrete can show fissures, gravel spots and the like. These issues can accommodate water seeping through the concrete. To prevent this leakage, a special type of waterstop is developed, type W9UI an injectable waterstop.