Tunnel lining production
Around 48,000 tunnel lining segments are being made for the two tunnel tubes in an on-site factory. That amounts to 16 tubing rings a day.
A ring is 2 metres wide and consists of 6 tubbing segments and a keystone segment, which is about half the size. The rings are screwed together and encircled by a seal. The tunnel becomes 2 metres longer every time a tubing ring is put in place.
The tubing segments are made on site. In the on-site factory there are a number of casting moulds or formwork systems.
The reinforcing steel is placed in them first,
and they are then filled with concrete.
The concrete hardens in a few hours.
The finished tubing segment is then removed from the formwork and transported to the storage yard.
Depending on requirements, up to around 1000 complete rings are kept in stock. That corresponds to about 7000 individual tubing segments.