Failure mechanism in a highway embankment founded on a sloping tectonised flysch formation

A highway embankment founded on a slope in a tectonised flysch formation of the Apennines chain (Central Italy) has been affected for about 30 years by continuous slow movements that caused some fractures on the road paving thus requiring periodic maintenance works. Due to the relevance of the damaged infrastructure, different investigation and monitoring campaigns have been carried out to collect information about the properties of the involved soils, the groundwater regime and the displacement field. Field monitoring, in particular, revealed that the movements were the result of a failure mechanism affecting both the embankment and the foundation soils. In particular, the observed displacements showed a weather-induced seasonal trend featured by acceleration/deceleration stages during the wet/dry periods. In order to better understand the detected mechanical response, a numerical model accounting for a soil hydrological balance of the interested area has been developed allowing a reliable historical reconstruction of the displacement regime.