ABSTRACT
Contract T3 of Metro C crosses the archaeological area of the historical centre of the city of Rome. In the final part of the contract, the running tunnels, which were excavated using two Earth Pressure Balance (EPB) shields, pass directly under one of the earliest sewage systems of the world, the Cloaca Maxima, functional to the present day. This ancient sewer consists of two arch shaped masonry and conglomerate tunnels, at a relatively close spacing. The monitoring data gathered during the passage of the TBMs underneath the ancient tunnel indicate that the ancient sewers are relatively flexible, substantially conforming to the greenfield displacements.
