German manufacturer Herrenknecht is at the forefront of large diameter TBM projects in Austria with its machines being used on no less than four projects in the country totalling over 32km of tunnel drives at diameters from 6.8m to 12.98m.
In April this year, an 8.6m diameter machine broke through on the 2.6km long Wientalsammler sewage collector tunnel in Vienna (T&TI, June, p11). The EPB machine was driven through clay and sand by the Porr Tunnelbau and Bilfinger Berger jv. The project even claimed a world record for a large diameter shield operating in closed mode after it clocked up an advance of 36m in one day.
More recently, on 18 August, a 6.8m diameter mixshield machine broke through in Vienna having completed 1.75km of subway tunnel. The TBM was being operated on an extension to the city’s subway system, U2/5, but had already seen extensive service in the city when it had bored the earlier U1/1 line.
T&TI was told by Herrenknecht that in late September a 10.70m diameter single shield machine started drilling for a 10.73km long stretch of the Wienerwald, or Vienna Woods, railway tunnel (T&TI, September 2004, p11). A sister machine is due to be launched on a similar length leg in January next year.
The Porr Tunnelbau / Bilfinger Berger NL Tunnelbau / Bilfinger Berger Bau / Porr Technobau und Umwelt consortium was awarded the US$414.7M contract late in 2004. It will have to drive the tunnels through hilly topography that is expected to consist of flysch and molasses formations.
Finally, a 12.98m diameter single shield TBM is due to start work at the beginning of December on the Tunnelchain Perschling project. This machine will be called upon to build three linked railway tunnels 2.86km, 1.37km and 2.11km long respectively.
Herrenknecht remained confident that involvement on projects such as these would “help mechanised tunnelling to make its breakthrough into the Austrian market”.
