ABSTRACT
Measuring 4.4 km, the Uetliberg Tunnel is the longest of the four tunnels which will make up the Zurich western bypass. A variety of driving techniques are being employed on the Uetliberg Tunnel, the most interesting of which is the use of the tunnel boring machine with the tunnel bore extender (TBE), with its undercutting technique and a boring diameter of 14.40 m, which will be in action from spring 2003.
