Design of an underground railway station beneath a historic building in Rome and class A predictions of the induced effects

The railway station Flaminio, currently located at street level, will be relocated underground to connect the railway with the existing line A metro station. This paper describes the technical and technological solutions adopted in the design to minimize tunnelling-induced effects on the surface and, in particular, on an old masonry building, whose foundations are very close to the roof of the new three-tunnel station. To reduce the risks, pre-confinement works and soil improvements were designed; furthermore, a very stiff pre-support system consisting of 36 horizontal steel pipes filled with concrete, located just above the tunnels and installed using a special Micro Tunnel Boring Machine, was devised. The paper also presents the numerical models developed both in 2D and 3D to study the soil-structure interaction and the class A predictions in terms of expected settlements and potential damages induced.