Ricerc@Sapienza

Ground displacements caused by underground excavations in densely urbanised areas often requires the adoption of protective techniques to prevent damage to existing buildings. When the tunnel passes to the side of a potentially affected building, tunnelling-induced settlements can be reduced pre-installing a protective barrier between the tunnel and the building. Usually, this mitigation technique is implemented in practice based on empirical knowledge rather than as a result of a rational design process.

The city of Rome is upgrading its public transportation network with the construction of the 3rd underground railway line. The Line C of Rome underground crosses the historic city centre with significant interferences with existing monuments and buildings of historic value. As a consequence, protective measures are needed to prevent damage to the most sensitive structures.

The paper focuses on the response of framed structures to tunnel excavation in sand. Standard 3D Finite Element analyses, in which the structural elements are explicitly detailed, as well as simplified equivalent beam models were adopted to simulate the influence of the frame and that of the masonry infills. Both approaches well captured the main soil-structure interaction mechanisms. The presence of stiff masonry infills was found to reduce the angular distortions of the frame bays and, as such, to reduce the tunnelling induced damage.