Insights into the Hydromechanical Behavior of a River Embankment through Physical and Numerical Modeling

In the framework of a climate change scenario and growing land urbanization, a reliable assessment of river embankment safety conditions represents a key aspect to enhance the resilience of these critical infrastructures and support the development of design guidelines and flood risk reduction strategies. This paper aims at contributing to a deeper understanding of the effect of hydraulic loadings on the hydromechanical behavior of unsaturated river embankments through physical and numerical modeling. To fulfill this scope, two centrifuge tests were conducted on a small-scale physical model, representative for the tributary bank systems of the main river in Italy, the Po River. The model embankment featured a trapezoidal-shaped cross section and was made of a compacted silty sand mixture, overlying a homogeneous clayey silt foundation layer. A comprehensive laboratory investigation was carried out to estimate the geotechnical properties of both materials and the main outcomes are herein presented. To monitor the model response to the imposed hydraulic boundary conditions, the middle section of the embankment was extensively instrumented with miniaturized tensiometers, pore pressure transducers, and displacement sensors. Subsequently, a coupled flow-deformation finite-element (FE) model was set up to replicate the two centrifuge tests. Once validated, the numerical model was adopted to study the performance of an embankment under realistic flood scenarios as its hydraulic characteristics varied. The development of this numerical model made it possible to create a predictive tool for the assessment of the hydromechanical behavior of existing river embankments.