PSI - Issue 84

Erica Cernuto et al. / Procedia Structural Integrity 84 (2026) 1167–1174

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both factors contribute to the low stability of the slope. Overall, the landslide extends for approximately 1 km along the slope and about 300 m in width, with an average inclination close to 10° and a maximum depth of 80 m. The bridge affected by the landslide consists of three spans (Fig. 1b) and is founded on large-diameter caissons, approximately 6 m in diameter for the abutments and 7 m for the piers, encased in 50 cm of concrete and embedded to depths of about 12 m.

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Fig. 1. (a) Landslide inventory map showing the landslide under study, extracted from IFFI; (b) longitudinal section of the bridge (adapted from Cernuto et al. 2025). 3. Methodological approach The methodological framework adopted in this study combines InSAR satellite monitoring with numerical modelling with the objective of analysing the interaction between the landslide and the bridge. Integrating these two techniques is beneficial, since each provides complementary information that is not accessible when relying on a single method. InSAR offers spatially continuous measurements of surface deformation and its temporal evolution, although LOS data alone do not allow a full reconstruction of the three-dimensional displacement field. Numerical modelling is therefore introduced as a complementary tool, enabling the estimation of the primary movement trajectory on the basis of slope topography and the direction of maximum inclination. While numerical simulations reproduce the kinematics of the landslide in detail, they cannot independently confirm whether the simulated displacements correspond to the actual behaviour of the phenomenon; satellite observations therefore play a crucial role, providing direct evidence of ground motion that can be compared with numerical results.

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Fig. 2. (a) 3D view of the model with the bridge integrated in Plaxis 3D; (b) longitudinal cross-section (adapted from Cernuto et al. 2025).

The numerical model was developed in Plaxis 3D (Brinkgreve et al., 2016) to reproduce slope behaviour and its interaction with the bridge (Fig. 2a). The soil was represented as a homogeneous silty–clayey material, consistent with