Liquefaction potential assessment of volcaniclastic soils in foundation of a rockfill dam in Southern Italy

The foundation soils of a rockfill dam in Southern Italy are made of volcaniclastic materials. These are challenging soils to characterize, especially regarding their liquefaction potential, as they have distinctive features (lightness, high porosity, crushability as well as the angular and rough surfaces) in comparison with hard-grained sands. Several methods of increasing complexity have been used to determine the liquefaction potential of these soils, spanning from conventional simplified procedures to dynamic nonlinear effective stress analyses which rely on advanced laboratory tests and appropriate constitutive models to estimate the excess pore water pressures. Limitations of the standard procedures applied to volcaniclastic materials and advantages of advanced testing to capture the cyclic soil response and to calibrate pore-pressure generation models are presented and discussed.