The construction of tunnels and galleries requires a strong prior investment in both geological and geophysical studies. After the excavation, maintenance and waterproofing a definitive and permanent coating is built to hyde all the above for the remaining life of the installation.
The waterproofing is done with geomembranes, geotextiles and occasionally drainage geocomposite, and thus becomes the highest technical and economic important question about durability and ability to adapt to the movements of internal stabilization-consolidation of the system formed by perforated floor and coating.
So it is very important the correct choice of materials; this is reflected by successive policies of tunnels starting requiring the use of polyolefin geomembranes for waterproofing of tunnels. Geomembrane is the only product assuring extreme durability without changing properties and maintaining deformational parameters very high and stable.