Two 11.12m diameter Herrenknecht TBMs are making good progress on the Katzenberg Tunnel, said to be Germany’s longest underground construction project with mechanised tunnelling.
The twin 8,984m long rail tunnels, connected by cross passages at 500m intervals, are being driven by EPB shields through multiple layers of claystone, clay marl, marlstone with embedded limestone and sandstone. T&TI was told such varying conditions demand a high degree of flexibility from the machinery employed.
The contract was awarded in 2003 by Deutsche Bahn AG (German Rail) to the Katzenberg Tunnel Consortium, comprising Ed Züblin AG, Wayss + Freytag AG, Marti AG and Jäger Bau GmbH. Shortly after main contract award, Herrenknecht agreed a contract for the supply of two identical TBMs for the tunnel excavation.
The first TBM, S-264, was launched in May last year and by November, it had driven 776m of tunnel, installing a lining of 388 segmental rings. With the second TBM, S-265, launched in the autumn of 2005, by the second week of January 2006, it had already excavated an impressive 762m of tunnel. T&TI was told that the total progress for S-264 similarly stood at 1,388m, a performance of over 300m per month since November.
The tunnels through the south of the Baden-Württemberg region are being driven to accommodate trains between Karlsruhe to Basel that will travel through southern Germany at speeds of up to 250km/h. One of the key benefits of the tunnel scheme is the noise protection it will afford to residents of nearby towns. The towns are further protected from noise and aggravation during the construction of the tunnels as the 2.6M.m3 of spoil is transported from the tunnels by covered conveyor belts to a quarry near the southern portal, greatly reducing the volume of construction traffic.
