Watter Wittke - Prof. Dr.-lng. W. Wittke, Beratende lngenieure fiir Grundbau und Felsbau GnibH (WBI), Aachen, Germany

Within the city of Stuttgart (Germany) a number of railway and highway tunnels have been constructed in horizontal layered rnudstones, limestones and lime-sandstones of the Lower Jurassic (Black JurassiclLias a). One example is the dsterfeld tunnel at the eastern highway ring in Stuttgart-Vaihingen, which ~~ndercrosseress idential buildings and a railway line with low overburden. The stability of the construction stages and small deformations have been achieved, by an advancing vault excavation with a curved temporary invert supported by shotcrete. For the same reasons the round lengths were kept short and an advancing pipe umbrella was installed in the area of the railway crossing where the overburden amounted to only 5-6 m. As part of the design three-dimensional finite element stability analyses have been carried out. The results of these analyses were a valuable tool for the design and corrlpared well with the results of monitoring.