New Mainz Tunnel Mainz
Well situated in the loose rock
The tunnel construction in the inner-city area of Mainz took place in connection with the expansion of Mainz - Mannheim railway section. A number of conditions had to be observed: Firstly, the surrounding rock was very loose. Infillings of gravel, sand and silt, stemming from the various construction activities since the time of the Roman settlement, reach down to 11.4 metres below the modern ground surface. Secondly, numerous endangered buildings are located above the tunnel with minimal coverage. And thirdly, the distance to the old Mainz tunnel is only a few metres.
Low-deformation tunnelling was thus essential. For this purpose, the tunnel cross-section was divided into segments (two side wall drifts, flattened dome, and core/floor) and the cavity was opened towards the front piece by piece. In addition, KREBS+KIEFER expected shallow depths and possibly quick bottom terminations. In addition to reinforced shotcrete, tunnel support arches, rock bolts, pre-seizing elements in addition to anticipatory injection pipe screens and working face anchors were implemented as securing devices.
- Design planning
- Structural Engineering