The first fully mechanized shield machine drills through Munich
In the years 1966 and 1967, the North-South-Line (Line 6) of the Munich underground railway was built in a joint venture under the technical leadership of Wayss & Freytag. This double-track line runs from Odeonsplatz under Ludwigstraße past the university and then under Siegestor and Leopoldstraße to Giselastraße. The line consists of two tunnel tubes each 1,860 m long and three stations (Rheinberger Straße, Universität, Giselastraße).
For the first time in underground railway construction, a fully-mechanized tunnelling machine (TBM), designed by Wayss & Freytag, was used. The outer diameter of the TBM was 6.72 m and its length was 5.37 m. The TBM was controlled by 24 thrust cylinders. The lining of the tunnel tubes consisted of rings with four concrete segments each, whereby key stones were not used, and an inner in-situ concrete lining. A layer of Torkret-cement mortar 2 cm thick served as the adhesive base.
The maximum rate of performance during the tunnel drive was 20 m/day. Despite difficult ground conditions and relatively low surface cover, the ground settlement remained below 20 mm in the road areas and less than 15 mm under adjacent buildings, so that no damage to buildings or roads occurred.