Mitigation of tunneling effects via preinstalled barriers: the case of Line C of Rome underground

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. To test the efficiency of pre-installed barriers in reducing tunnelling effects, a line of bored piles was pre-installed in the stretch between Amba Aradam and San Giovanni stations, close to a well instrumented green-field section. This paper presents the monitoring data from both the green-field section and the section where the barrier was installed and compares the observed behaviour with that computed by finite element back-analyses performed using three approaches to simulate tunnel excavation