Numerical modelling of shaking effects due to strong motions on the tiber alluvial deposits in Rome (Italy)

TL;DR

This study uses detailed 3D geological modeling and numerical simulations to assess how strong seismic motions affect the Tiber river alluvial deposits in Rome, considering both linear and nonlinear soil responses.

Contribution

It introduces a multidisciplinary numerical approach combining 3D geological modeling and site response analysis for historical city deposits.

Findings

Maximum shear strains depend on layer geometry and soil heterogeneity.

Numerical results are compared with soil failure thresholds.

Both 1D and 2D models show different site response behaviors.

Abstract

A multidisciplinary approach is proposed for evaluating the effects of shaking due to strong motions on the Tiber river alluvial deposits in Rome's historical centre. At this aim, a detailed 3D geological model of the Tiber river alluvial deposit has been constructed and a numerical analysis of site response was performed along two geological sections across the historical centre of Rome. The numerical models were performed in both 1D and 2D configurations assuming linear and nonlinear conditions, by applying a three component seismic input. The results show that the maximum shear strains are strongly conditioned by the layer geometries (i.e. 2D or 1D conditions) and by the soil heterogeneity. Moreover, the reliability of the maximum strains obtained by numerical modeling is discussed comparing these values respect to both the volumetric and the degradation dynamic thresholds of the considered soils.