Assessing River Embankments Stability to FLoods through Unsaturated Centrifuge Testing In transient Seepage conditions - RES FLUCTIS

River flood is considered one of the most relevant natural hazards in Europe in terms of economic and human life losses and is frequently due to severe damages experienced by retaining water earthworks, under extreme weather events. Moreover, the risk of breach-induced inundations is expected to increase for many river basins in a climate change scenario and a growing land urbanization. In this framework, a reliable assessment of existing river embankment safety conditions, in serviceability and limit states of operation, represents a key aspect to enhance the resilience of these critical infrastructures (CI). A satisfactory solution to this problem cannot disregard the partially saturated state of the earthfill, neither the role of river stage fluctuations on the seepage process within the embankments. Nevertheless, in the current engineering practice, these aspects are frequently neglected, mainly due to the difficulties in estimating the actual suction distribution and shear strength, providing erroneous conclusions on the effective safety margins towards possible slope instability and overall collapses. The proposed research project aims at contributing to a better understanding of the effect of time-dependent hydraulic loadings on the stability of the CI through a series of centrifuge tests. The small-scaled physical model will be characterized by a compacted embankment made of a natural silty sand, representative for a tributary river bank, overlying a homogeneous clay foundation layer. To investigate the hydro-mechanical behaviour and the possible failure mechanisms of the CI induced by transient and stationary hydraulic boundary conditions, pore pressure transducers, displacement sensors and high-resolution cameras will be used to monitor the centrifuge tests comprehensively. The 2-week experimental campaign will include model preparation, execution and dismantling of two tests. The project will provide valuable recommendations to improve standards for the stability assessment of river embankments and support the development of more reliable flood risk reduction strategies.