Bosphorus TBM en route
28 August 2013A 13.6m Mixshield from Herrenknect was completed early last month in Schwanau and is now on its way to the Bosporus jobsite in Turkey, Herrenknect announced recently.
The route of the project runs around 100m below sea level at its deepest point. The interior diameter of the tunnel will be 12m so that two lanes in each direction can be accommodated. They will extend one above the other on two levels. 3.34km of the tunnel with a total length of 5.4km are being created by a Herrenknecht TBM that will begin its underground mission from a launch shaft on the Asian side.
"The project is certainly one of the most challenging tunnelling operations currently being addressed in the world." said Georg Schleer, project manager, Herrenknecht.
Extensive geological and hydrogeological preliminary investigations showed that the tunnel builders must reckon with water pressures of up to 12 bar. Schleer added: "The machine's engineering presented us with a real challenge. Even if the pressure is extremely high up front at the tunnel face, the client must be able to change the cutting tools quickly and safely if necessary."
