Deterministic numerical analysis of excess pore water pressure induced by 2012 earthquake in Pieve di Cento (Italy)

Abstract

A large area in the Po River Valley (northern Italy) experienced extensive liquefaction phenomena following the seismic event of 20 May 2012. Several indicators of liquefaction, including ground subsidence, lateral spreading, and the appearance of sand boils, were observed. A significant number of buildings were damaged, displaying signs of tilting or subsidence. A reliable estimate of the excess pore pressure induced by seismic shaking within the soil is crucial for predicting the behavior of the soil on a large scale and, consequently, the effects of the earthquake on the built environment. In this study, deterministic analyses of the excess pore water pressure generated during the 2012 Italian earthquake were conducted at the Pieve di Cento site. The analyses were carried out with varying levels of complexity, ranging from loosely coupled to fully coupled dynamic approaches. The strong agreement in terms of excess pore pressure ratio (r_u) suggests that, if properly calibrated, both loosely and fully coupled models can accurately predict earthquake-induced excess pore water pressure and, consequently, liquefaction-induced damage. Additional insights into the impact of soil-structure interaction on excess pore water pressure buildup were also provided. The results suggest that structural loading alters the effective stress state within the soil, which in turn may significantly influence the excess pore pressure ratio relative to free-field conditions.