Role of the facing on the behaviour of soil-nailed slopes under surcharge loading

Soil nailing is an economic and efficient method to reinforce soils, involving the insertion of threaded bars into natural unstable slope for increasing the overall stability or into cut slopes during the top-down process of excavation. The retained soil, the resisting reinforcements and the external facing are the main components of a soil-nailed structure. Their composite interactions determine the performance of soil-nail construction in terms of deformations and stability. Even if the international codes deal about the possibility of use rigid or flexible external facing, the role of facing stiffness is not sufficiently studied and evaluated. To this aim, some tests with various facing types, differing in stiffness and continuity, were carried out so far in 1g small scale physical model. The experimental results show the importance of both flexional and axial stiffness of facing in controlling the deformation of the wall during excavation and the maximum surcharge applicable at the rear of wall