Variable rate CPTU in liquefaction-prone silty sand deposits of the Emilia-Romagna region (Italy).

This paper presents the results of a set of piezocone tests (CPTU) recently carried out in the silty sand-sandy silt deposits forming the subsoil of Mirabello village (Emilia-Romagna, Northern Italy), where an earthquake sequence took place in May 2012, triggering extensive liquefaction-induced ground effects. Attention is focused on the analysis of a number of piezocone tests performed at different, non-standard penetration rates, ranging from 10 to 130 mm/s. The idea is to investigate the rate effects on penetrometer measurements in these intermediate soils, taking into account that in such sediments partial drainage conditions are very likely to occur during cone penetration at standard penetration rates and that such effect should be taken in careful consideration in order to properly interpret field data for geotechnical characterization. Results from piezocone tests, including a number of pore pressure dissipation measurements, are analyzed according to well-established procedures as well as advanced methods recent-ly proposed in the literature.