大象传媒

The Gotthard Base Tunnel below the Swiss Alps will be the longest, deepest tunnel in the world. It will allow passenger trains and shuttles carrying lorries to cross the Alps, reducing energy use, pollution and congestion on the roads above. The tunnel is being built in phases and electronic systems are used to ensure the sections meet up to within 25cm. The engineers explain how they have developed a way to use the rubble from the excavations to produce high quality concrete to line the tunnel walls.