Waterproofing materials in the construction of the protection and leakage after maintenance is also a difficult problem, after any part of the penetrability of the damage.
防水卷材在施工后的保护和漏水后的维修亦是难题，任何部位的贯穿性破损。
2
Grouting technology is used in subsea and river-crossing tunnels for various purposes such as waterproofing, pre-reinforcement and corrosion protection.