Tunnels in soft ground for German high speed railway line Cologne-Frankfurt

The new line Cologne-Frankfurt is the centerpiece of the German and the future European highspeed traffic network and links important national and international long-distance lines ( Figure 1 ). With a planned maximum speed of 300 km/h and seven stops time for travelling will be reduced significantly. At the 184 km long new line a total of 18 bridges (total length = 6 km) and 30 tunnels (total length = 47 km) will be constructed. This report is about two particular tunnel projects (Wandersmann-Tunnel and Schulwald-Tunnel) which are being excavated under difficult rock and groundwater conditions. Due to several extraordinary geotechnical conditions such as underpassing a highway with a cover of about 15-20 m in NATM and driving through a landslide area by means of a large diameter shield machine, the drivings are accompanied by an intensive geotechnical monitoring programme.