The world's largest machines
How are tunnels constructed through the highest mountains of the Alps, under the English Channel, and under large cities? How do the longest train and highway tunnels in the world come into being with the help of tunnel boring machines? How are these 200 meter long and about 4,000 tons heavy machines controlled? And above all: How precisely do they have to be guided through the tunnel in order to reach their goal? That's what students find out in our tunnel boring machine experiment.
Tunnel boring machines are technologically very sophisticated. In major projects like the Gotthard Base Tunnel or the planned Brenner Base Tunnel, several counter-rotating tunnel boring machines advance from opposite sides of the mountain. But how can the two boring teams working deep down in the mountain manage to meet up precisely in the middle? This is where a geodetic guidance system comes into play to assure that only minimal deviations are allowed in the way to the place where the two tunnels connect. The precision now being achieved is amazing: for the 57 kilometer long Gotthard Base Tunnel the horizontal and vertical deviation at the meeting point was only one centimeter.