Weather induced post failure kinematics of a highway embankment founded on a marly sandstone slope.

A highway embankment founded on a sloping tectonised marly-sandstone flysch formation located in the Apennines chain (Italy) has been affected for about 30 years by continuous slow movements. Given the strategic importance of the involved infrastructure, different investigation and monitoring campaigns have been carried out to get information about the properties of the involved soils and collect data about the displacements and piezometric regime. Field monitoring, in particular, reveals that the observed displacements result from a failure mechanism involving both the embankment and the foundation soils. However, significant gaps in monitoring jeopardize the possibility to assess the long-term trends in the displacements and piezometric regime and the significance of weather forcing in regulating the phenomena. To address such research questions, a procedure, easily transferable in different contexts, is proposed and applied to the test case: a simple hydrological proxy indeed permits evaluating the rate of movement featured by weatherinduced seasonal variability. Such a mechanical response has been confirmed by the results of a simplified numerical model aimed at finding out the main features of the observed kinematics accounting for a hydrological balance of the involved area.