GNGTS 2023 - Atti del 41° Convegno Nazionale

Session 3.2 ___ GNGTS 2023 Liquefaction assessment of gravelly soils using geophysical surveys: the case study of Sulmona (Italy) N. Salvatore 1,2 , A. Pizzi 1 , K.M. Rollins 3 , A. Pagliaroli 1,4 , S. Amoroso 1,5 1 Università degli Studi “G. d’Annunzio” Chieti-Pescara, Pescara, Italy 2 Università degli Studi di Catania, Catania, Italy 3 Brigham Young University, Provo, Utah 4 Consiglio Nazionale Ricerche, Istituto di Geologia Ambientale e Geoingegneria, Rome, Italy 5 Istituto Nazionale di Geofisica e Vulcanologia, L’Aquila, Italy Introduction The occurrence of liquefaction, intended as the reduction of stiffness and shear strength in loose water-saturated cohesionless soils associated with major earthquakes, is well documented all over the world both for sandy and gravelly soils (e.g., Rollins et al. 2021). Despite of this, geologists, and engineers, who try to develop effective techniques to predict the susceptibility of soils to this phenomenon, focused their attention mostly on sandy soils, e.g., Idriss & Boulanger (2008), Boulanger & Idriss (2014). A relationship between susceptibility to liquefaction and grain size was firstly proposed by Tsuchida & Hayashi (1971), plotting the grain-size distribution of soils at Japanese liquefaction sites, and tracing the grain-size boundaries of the most liquefiable and potentially liquefiable soils. These grain-size boundaries are still widely used and are included in national building codes (e.g., Italy, NTC, 2018). However, these liquefaction susceptibility boundaries do not include gravelly soils that have been observed to liquefy in well documented cases, analyzed by Rollins et al. (2021) and reported in Fig. 1a.