Deutsche Bahn is having a new track section between Wuerzburg and Frankfurt constructed. This section is mean to replace the existing passage through the Schwarzkopf Tunnel. BAUER Spezialtiefbau GmbH from Schrobenhausen in Bavaria, Germany, will carry out the specialist foundation work in a joint venture with Alfred Kunz Untertagebau, Baresel GmbH, Schaelerbau Berlin und der Leonhard Weiss GmbH & Co. KG.
There are two main reasons for the “Schwarzkopf Tunnel Bypass” project. One is that the Schwarzkopf Tunnel, which was built in 1856, no longer meets modern rail requirements; passenger trains – including ICE high-speed trains – must slow down to 70 km/h when traveling through the tunnel. Another is that freight trains require a second locomotive to handle the steep grade from Aschaffenburg to Heigenbrücken.
The contractor for the new section of track is Deutsche Bahn, with its construction subsidiary DB ProjektBau GmbH. It will take four new tunnels to reduce the grade. The 2,600 meter long Falken Tunnel will replace the Schwarzkopf Tunnel, and the three other tunnels will be cut through the terrain to make the grade flatter in the future.
The work done by Bauer Spezialtiefbau on the approximately 43 million Euro contract will include the portions of tunnel construction that will be done in several sections with open-cut rather than mining technology, with a total length of 2,800 meters. This is the case for most of the tunnel sections in the flatter terrain. The excavation pits for these sections will be stabilized by piled walls and retaining walls. In addition, pile foundations with a total length of 50,000 meters will be constructed for the embankments of the new track section using the CFA (continuous flight auger) method. As well as this, soil nailing, reinforcements and anchorages will be installed along 550 meters of the existing track. In order to prepare for the mining tunnel work, portal excavations were dug and shotcrete walls with heights of up to 30 meters were built for the ten tunnel portals included in the project. This work was done by Bauer Spezialtiefbau together with SPESA Spezialbau and Sanierung GmbH, another company of the BAUER Group.
The piles, whose diameters range from 900 to 1,500 millimeters, will be deployed in hard diorite, gneiss, and Bundsandstein (coloured sandstone). They extend to a depth of 25 meters, where they are integrated into the bedrock for lengths of up to five meters. Currently, two BG 40, two BG 28 and one BG 20, three anchor drilling rigs, and a number of nail drilling rigs and shotcrete units are being used. The new track section will be built between fall 2013 and the end of 2017. The major work by Bauer will be completed by fall 2015.