Landslide-Bridge Interaction: A combined approach based on InSAR data and numerical modelling

Landslides that interact with infrastructure, such as bridges, demand a comprehensive analysis to fully understand and address the complexities of this interaction. This study proposes an integrated approach that combines InSAR satellite monitoring with three-dimensional numerical modelling to analyse the effect of a landslide on a bridge. Although the case study is exemplary, the results obtained are of a general nature and applicable to similar contexts. The integration of InSAR and numerical modelling provided complementary and more detailed information compared to the isolated use of each approach. The InSAR analysis offered an overview of surface deformations, allowing for large-scale monitoring of movements, and its limitation in providing complete three-dimensional information was addressed by the numerical modelling, which enabled the decomposition of movements along the main direction of the landslide, precisely identifying the movement trajectory. The results showed predominant movements in the transverse direction, with a less significant vertical component, consistent with the observed kinematics. InSAR data allowed for the comparison of numerical modelling estimates with real observations, enhancing the consistency of the simulations. These data revealed significant movements upstream of the bridge, confirming the critical areas identified by modelling, which compensated for the lack of satellite data downstream, showing intense displacements. The modelling also highlighted significant displacements in the bridge's structural elements, with downstream tilting caused by the horizontal thrust of the landslide. The integrated approach offered a clearer understanding of landslide dynamics and their impact on infrastructure, offering a valuable tool for monitoring and risk management in vulnerable areas.