Class A prediction of mechanised tunnelling in Rome

Contract T3 of Line C of Rome underground, currently under construction, crosses the archaeological area of the historical centre, with significant interferences with the existing monumental built environment. A fully instrumented green field control section was established at the beginning of this contract, in representative ground conditions. This paper presents a thorough Class A prediction of the passage of the tunnels through the control section, obtained using a recently developed advanced numerical procedure. The ground was modelled with a non-linear constitutive law, calibrated with all the available data from the geotechnical investigation. The main physical processes occurring around the shield, including cutter-head overcut, shield tapering and tail void grouting were modelled in detail. The numerical results agree qualitatively with the findings from well documented case histories and results from physical models. The installed instrumentation will provide an opportunity to test the ability of the adopted procedure to reproduce quantitatively the measured performance, once the tunnels will cross the control sections and the field data will become available.