Assessing inertial effects on Rockfall Protection Embankments: field & numerical tests

Reinforced earth embankments (RE-RPEs) represent valuable mitigation measures against rockfalls, particularly effective in case of multiple impacts or extremely high kinetic energies. Their structural response upon impact still presents open questions and unsolved issues. Due to the large costs involved in the experiments, a very limited number of real scale impact tests has been realized so far. By consequence, the dataset to calibrate effective numerical models is limited. To fill this gap, a quasi-static load field test was performed on reduced scale RE-RPE reinforced with geogrids. All the geometrical and mechanical parameters were properly scaled according to the principles of Buckingham Pi - theorem. A geogrid-reinforced RE-RPE was selected. The quasi-static force is applied thanks to a hydraulic jack and the tests are recorded with cameras allowing a photogrammetric reconstruction of the downstream side bank deformations throughout the test. The results of the test were used to validate a finite element model (FEM), specifically developed using the ABAQUS/Explicit code, incorporating reinforced layers (e.g., geogrids and double-twist nets) with realistic wrap-up geometry, compacted soil, and formworks. To assess the capability of the numerical model to reproduce also real scale dynamic test, a back-analysis on real tests performed in the past was performed. Numerical simulations of both static and dynamic tests were then performed to quantify the contribution of the inertia in the resisting mechanisms as a function of the impact kinetic energy