Evaluation of the seismic performance of slopes based on a probabilistic approach

Prediction of sliding displacements of slopes induced by earthquakes represents a crucial parameter to evaluate the seismic performance of a slope. In this work a probabilistic approach to evaluate the earthquake-induced slope displacements is presented and, stemming from the Italian strong motion database updated by Gaudio et al. (2019), some results obtained for different sites in the national territory are illustrated. The database includes 954 records of 208 seismic events recorded by 297 stations located throughout the national territory referred to a temporal period ranging from 14/06/1972 to 24/04/2017. Therefore, the updated version of the Italian seismic database includes the seismic records of the recent destructive earthquakes occurred in L’Aquila (2009), Emilia (2012) and the 2016 Central Italy seismic sequence. Using the updated set of acceleration time histories, Gaudio et al. (2019) performed a series of parametric analyses for different values of the yield seismic coefficient ky to evaluate the permanent displacements. To this purpose, they followed the approach proposed by Rampello & Callisto (2008) and Rampello et al. (2010), performing Newmark-type calculations for the simple scheme of rigid block sliding on a horizontal plane (Newmark, 1965). Therefore, for three different subsoil groups and four acceleration levels, updated upper-bound semi-empirical relationships have been obtained, in which the seismic-induced permanent displacement is expressed as a function of the slope resistance through the yield seismic coefficient. The method provides semi-empirical relationships linking the permanent displacements to the yield coefficient and some selected ground motion parameters.