Waterproofing in Tunnels
Proper waterproofing of tunnels, galleries and shafts is one of the most cost effective ways to enhance safety and function as well as increase useful life of these structures.
Water seeping into the structure endangers block and cast work, especially through freeze/thaw action. Spalling concrete or block, icicles, and effluorescence or stalactites are all evidence of a tunnel with either no waterproofing or an inadequately designed system.
A greater feeling of safety is imparted to the user by optimal use of waterproofing, ventilation, lighting, and emergency stations, which combined offer the greatest degree of comfort and convenience.
Safety is increased because water seeping through the structure and freezing on the road or track surfaces is eliminated. Additionally, spilling of poured concrete or concrete block, due to freeze/thaw action, is avoided, thereby allowing traffic to pass and routine maintenance work to be performed with greater security. This not only allows road and track beds to function as designed, but also permits the proper operation of electrical, lighting, and ventilating systems contained within the structure. The long-term effects of water incursion, such as leaching of lime and minerals from concrete and mortar and the corrosion of reinforced elements are likewise avoided.
Waterproofing tunnels then become a matter of economics. Special maintenance due to untimely deterioration of the structure is virtually eliminated and, more importantly, the structure is able to function as designed over long periods of time.
PVC waterproofing membranes are preferred because of their particularly high resistance to aging and to excellent elongation and tensile characteristics. Application and seaming requirements ensure an installation which is completely secure and leak free.
The most important qualities of PVC tunnel membranes are:
- aging and rot resistance, even under the influence of water containing aggressive elements
- high mechanical strength and load resistance
- sensible and effective installation