The 380kV cable diagonal is one of the city’s most important power lines. The energy transition and the ensuing increase of electro-mobility brings the existing line to its limits. To guarantee Berlin’s energy supply for the future and to consistently implement the energy transition, the cable diagonal is being reinforced. On a seven-kilometre-long section between Rudolf-Wissell Bridge via the transformer station Charlottenburg at Darwinstrasse until transformer station Berlin-Mitte at Bissingzeile, the existing line from the 1970s will be replaced and power capacity significantly increased. While the old cable is buried in the ground, the new line will run in a tunnel.
Tunnel excavation has already reached a length of two kilometres. The tunnelling machine approaches the intermediate shaft at transformer station Charlottenburg and will probably reach it just before or after the Christmas holidays. Drilling is currently done 24/7 before it will take a two week break over Christmas and New Year. Cutting-through to the intermediate shaft will be achieved at the beginning of January. A water filled shaft will be entered and subsequently pumped out to access the cutting wheel from outside for maintenance purposes. Tunnel drilling will then be continued.
Due to the changing geological and hydrological conditions, tunnelling is done by a tunnel drilling machine with fluid-supported shield (hydro shield tunnelling). The cable tunnel runs under densely populated city quarters. In addition to residential and commercial areas, several public buildings, cable lines of public utility companies as well as the parking space “Grosser Tiergarten” and the palace gardens Charlottenburg are located along the route. The planned alignment crosses underneath underground lines U7 and U9, the regional and long-distance train lines between stations Zoologischer Garten and Central Station as well as the train tracks between stations Rudolf-Wissel-Brücke and Schloss Charlottenburg, and is divided in three sections. Moreover, it crosses or runs close to the federal Spree-Oder water way, Spree and Landwehr canals with their numerous bridges and bank stabilisation installations.
Technical key data
Length: ca. 6.7 km
Depth: ca. 20–25 m (tunnel bottom)
Tunnel inner diameter: 3.0 m
Tunnel lining: reinforced concrete tubbings made of 6 stones (parallel and wedge segments)
4 shaft structures (exit shaft Rudolf-Wissel Bridge, intermediate shaft Charlottenburg, intermediate shaft Tiergarten, entry shaft Berlin-Mitte)
Construction company: Implenia Construction GmbH
SSF Ingenieure, in joint venture with ZETCON Ingenieure GmbH and others, signs responsible for construction management and supervision as well as design analysis.
