ABSTRACT
The extension of the Yellow Line of the Lisbon Metro between Rato and Santos Stations, to be integrated into the future circular line, included the creation of the 60m deep Estrela Station, a ventilation shaft and two new track tunnels executed with the NATM methodology. The construction solutions foreseen in the design phase, the monitoring and Special Technical Assistance to the construction, the analysis of the instrumentation and the additional measures adopted in the execution of about 1300m of tunnel in Cretaceous calcareous rocks, with a maximum cover of 50m, are addressed. The waterproofing works, the secondary lining execution in the terminus track tunnel which had the unique feature of having a variable section, the excavation of marls and clays from the Caneças Formation and the final stretch of the T34 tunnel partially excavated in tuffs and basalts of the Lisbon’s Volcanic Complex are highlighted.
