In Stuttgart, the Rosenstein-Tunnel is currently under construction in combination with the third Leuze-Tunnel, which is also under work. This will improve the traffic conditions in the highly populated city areas, located north of downtown Stuttgart. The owner, the City of Stuttgart, had to face challenging conditions when setting up the project. This includes the impact of urban environment at both tunnel portals and within the open cut sections. Intensive actions were required concerning cable and pipe routing and various traffic phases with local detours, which have to manage the traffic and to enable the construction works at the same time. The ground conditions with the presence of mineral water have a major impact on the tunnel construction works. As the project is partly located in an area, in which dewatering of groundwater is not allowed, restrictions of the tunneling sequence and the provision of injections became necessary.
1 Introduction to the Project
Stuttgart, as the capitol of the south German federal state of Baden-Württemberg, has an important meaning for economy and politics and has become one of the most prospering zones in southern Germany. The improvement of the traffic infrastructures for the major federal roads as well as for the German railway is the dominating actual topic in Stuttgart and this will continue at least for the next 5 years.
At the south bank of the river Neckar in the district of Bad Cannstatt, the junction of the two federal main roads B 10 and B 14 shall be released by a new third tunnel near the thermal bath Leuze.
Following the river downstream, the B 10 circumnavigates the Wilhelma zoo by a road "knee". This edge will be shortened by the new Rosenstein-Tunnel with a length of totally 1.3 km, from which approx. 750 m are realized by underground excavation of two separate tunnel tubes, which are connected by four cross-cuts. Additionally, in the center of the tunnel length there is a section with an extended cross-section for emergency stops, which is a major safety issue of the tunnel. Figure 1 displays the general project layout for the Rosenstein-Tunnel.
The major urban challenges in this project area can be introduced such as follows: