The works consist of excavation and reinforcement of 1.670 tunnel meters. Two one-track subway tunnels will be excavated, after few hundred meters each tube will be widened for a junction and in the remaining part of the course four tubes will be excavated until finalization. The two tubes will be connected through one crosscut which will be 10 m long. The whole project will be excavated using the New Austrian Tunneling Method. Due to the preexisting geological conditions the use of explosives is not necessary and the whole project will be excavated using tunnel excavators.
The cross section of the tubes in their regular parts will be 43,4 m2, in the crosscut 53 m2 and in the widening areas 126,3 m2. The distance between the tubes will be 4 – 10 m, the overburden 4,5 – 22 m.
The relocation of subway line U12 is part of the mega project „Stuttgart 21“, which consists of construction of new tunnels and railway lines. Stuttgart´s main station will be relocated underground, the long-distance transport system in Stuttgart and it´s outer areas will be adjusted. "Stuttgart 21" is part of a wider system "TEN-T" (Trans-European Transport Networks) aiming on improvements to European transport system. This particular project is "TEN No 17" and will connect Paris with Bratislava.
The special challenges to Adval´s experts will be the narrow conditions on site in the city center and the noise and emission restrictions by the authorities. All processes between involved companies have to be discussed and adjusted with a great precision, in time and reliably as every inefficiencies would produce high costs and time delays. Our personnel has to cope with this narrow location, housings and surrounding facilities and with very low overburden in some areas. Among other challenges the two tubes will cross below one existing city rail tunnel with up keeping traffic in it.
