ABSTRACT
Porto Metro has commissioned to Ayesa, the design of the future Rubi Line tunnels. The new line project includes 8 new stations, 4 of which are underground, and approximately 2.6 km of tunnels. These tunnels are double-track railway with an equivalent external diameter of 9 m, and they cover different stretches of the alignment, both in the cities of Porto and Gaia. The tunnels go through different geo and hydrogeological conditions, overburden, topography, and underneath different type of buildings. The foreseen geology is quite complex, including fresh Granite and Schist-Greywacke Complex and their residual soils. Both rocks weathering result in quite deformable and mixed soils, making up a challenging scenario of mixed face conditions. This context has critically conditioned excavations stability, which consequently needed to be fully investigated using advanced 3D modelling. This paper presents how the proposed design solutions tackle the intrinsic challenges of Porto’s complex and heterogeneous geology.
