Porto Metro Tunnels, Faria Guimarães and Tunnel J

Nearly 20 years after the first sections of the Porto Metro network were built, the urban transformations it has triggered are clearly visible not just in Porto but also in neighbouring municipalities. Maia has rehabilitated its entire civic centre, Vila Nova de Gaia has structured its main city thoroughfare, Av. da República, and Matosinhos has created a “greenway” along the metro line that weaves through the city fabric. In Porto itself, due to the lack of available space for aboveground lines, the metro was tunneled underground, generating new urban centres at stations that had long been forgotten. Examples include the revival of Campo 24 de Agosto as a public square, the Bolhão station bringing people back to the city centre, and the redesign of space in Av. dos Aliados accompanying its station construction.

This vast “subterranean octopus” was among the greatest challenges for Portuguese civil engineering in the early 21st century, particularly its geotechnical aspect. In a dense urban environment, tunnels were built on multiple fronts within a short timeframe, all the while keeping the city fully operational. Cutting-edge technologies were applied to new tunnelling, while older tunnels, previously used by trains, were reinforced using traditional underground construction methods.

In this edition, Eng. António Topa Gomes, who was responsible for the metro’s construction, and Eng. Jorge Quelhas, currently in charge of its maintenance, share insights on the project’s complexity and the challenges faced in its execution and upkeep.