Crossing hydrogeological and ecological sensitive aquifers, water ingress can occur, which can lead to irreversible damage to hydrogeological and ecological systems. In order to avoid this, the rock mass surrounding these hydrogeological sensitive tunnel sections is sealed by injections to reduce the hydraulic permeability, the water inflows and consequently the regional water level drawdowns. In deep tunnels, complete sealing is not possible due to the high water pressures.
Residual water volumes will continue to enter the tunnel. The magnitude...