Sediment stacking pattern effect on sand liquefaction inferred from full-scale experiments in the Emilia alluvial plain (Italy)

The geometry and the depositional configuration of sand bodies affected by the 2012 Emilia earthquakes (Bondeno site, northern Italy) were reconstructed and the role of the sediment stacking pattern was tested using data from full-scale blast experiments. The research integrates remote sensing and surface geological mapping, subsurface investigations including stratigraphic coring and cone penetration tests, grain-size and petrography of sands, geotechnical and geophysical monitoring. Data are compared with the Mirabello blast test site, also in the epicentral area. The results highlight the preeminent role of sediment heterogeneity and their mechanical and compositional properties in modulating liquefaction in alluvial settings. The lateral confinement of the buried sandy bodies, their thickness, and the occurrence of a thick non-liquefiable crust influence the dissipation of the excess pore water pressure, as indicated by the blast monitoring, and therefore the duration of liquefaction phenomena, according to the local stratigraphic architecture.