Hydraulic tunnels can be subject to severe service conditions, such as high hydrostatic heads and water velocity that may cause severe deterioration of the concrete. The resultant cracking and spalling will allow seepage of water through the structure that can undermine its stability. In addition, the increased roughness of the surface will reduce the water flow.
Carpi waterproofing geomembrane systems are used in new construction and in rehabilitation, and applied to all types of free-flow and pressure tunnels, to surge shafts and expansion chambers. In rehabilitation, the geomembrane is left exposed with water velocities of several meters/second. In new construction, the geomembrane can be left exposed or be embedded between the excavation line and the inner layer of concrete.
The benefits are:
provide watertightness even for cracked structures, protect the tunnel structure from further deterioration
if exposed, increase the water flow, reduce the formation of vegetation and algae
minimise future maintenance
In waste water tunnels the Carpi lining systems are very effective in avoiding pollution of the surrounding soil and ground water.