Numerical modelling of the interaction between a deep excavation and an ancient masonry wall

The city of Rome is currently involved in the construction of a new metro line, known as Metro C, which will underpass the historical city centre. This paper focuses on a 30m deep excavation that will be constructed at short distance from the ancient masonry walls of the city, the Mura Aureliane at Porta Asinaria. A numerical investigation is here proposed to analyse the problem along a transversal section using the Finite Element code Plaxis. The Hardening Soil model is employed for the soil strata, while the masonry structure is schematised as an anisotropic elasto-plastic medium, whose properties are derived via homogenisation. The results indicate that the adopted engineering solutions for the supporting structure and the excavation sequence induce relatively small vertical and horizontal displacements in the ground and in the ancient wall, this latter being characterised by an almost rigid-body motion without significant damage induced in its masonry.