Dynamic characterization of fine-grained soils in Central Italy by laboratory testing

• Published in: Bulletin of earthquake engineering Vol. 18; no. 12; pp. 5503 - 5531
• Main Authors: Ciancimino, Andrea, Lanzo, Giuseppe, Alleanza, Giorgio Andrea, Amoroso, Sara, Bardotti, Roberto, Biondi, Giovanni, Cascone, Ernesto, Castelli, Francesco, Di Giulio, Anita, d’Onofrio, Anna, Foti, Sebastiano, Lentini, Valentina, Madiai, Claudia, Vessia, Giovanna
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01-09-2020; Springer Nature B.V
• Subjects: Civil Engineering; Confining; Damping; Damping ratio; Dynamic loads; Earth and Environmental Science; Earth Sciences; Earthquake damage; Earthquakes; Environmental Engineering/Biotechnology; Fine-grained soils; Frameworks; Geological hazards; Geophysics/Geodesy; Geotechnical Engineering & Applied Earth Sciences; Ground motion; Hydrogeology; Investigations; Laboratories; Laboratory tests; Mathematical models; Municipalities; Outliers (statistics); Plasticity; Plasticity index; Prediction models; S waves; S.I. : Seismic Microzonation of Central Italy; Sample disturbance; Seismic activity; Seismic hazard; Seismic velocities; Shear tests; Shear wave velocities; Simple shear tests; Soil; Soil dynamics; Soil investigations; Soil testing; Soils; Strain; Structural Geology; Tests; Wave velocity; Italy; Laboratory tests; Soil dynamics; Shear wave velocity; Shear modulus and damping ratio; Small-strain material damping
• ISSN: 1570-761X; 1573-1456
• DOI: 10.1007/s10518-019-00611-6

The investigation of soil response to dynamic loads is necessary to predict site-specific seismic hazard. This paper presents the results of cyclic and dynamic laboratory tests carried out after the 2016–2017 Central Italy Earthquake sequence, within the framework of the seismic microzonation studies of the most damaged municipalities in the area. The database consists of 79 samples investigated by means of dynamic resonant column tests, cyclic torsional shear tests or cyclic direct simple shear tests. Results are firstly analysed in terms of field and laboratory values of small-strain shear wave velocity, highlighting the influence of the sample disturbance and of the mean effective consolidation pressure. The cyclic threshold shear strains as a function of plasticity index are then compared with findings from the published literature and the outliers are analysed. Subsequently, the dynamic soil behaviour is investigated with reference to the small-strain damping ratio. Differences between results from different tests are analysed in the light of the loading frequencies. Finally, the database is used to develop a predictive model for soil nonlinear curves according to plasticity index, mean effective confining stress, and loading frequency. The model represents a useful tool to predict the nonlinear stress–strain behaviour of Central Italy soils, necessary to perform site-specific ground response analyses.