Geotechnical studies for foundation settlement in Holocenic alluvial deposits in the City of Rome (Italy)

This study identifies units characterized by specific geomechanical behaviours within some Holocene alluvial deposits in the City of Rome. In particular, the highly compressible units, which may be responsible for subsidence and settlement phenomena below urban structures, have been identified. Investigations carried out during this study have interpreted nearly 800 stratigraphic sections and physical–mechanical features of the alluvial deposits of the Tiber and those of its right- and left-bank tributaries. The analysis allowed to define, for each investigated deposit, a representative series subdivided into lithotechnical units. When comparing the stratigraphic and geologic features among the series, a remarkable difference in geomechanical behaviour in the deposits from the Tiber's left- and right-bank tributaries and within the river's deposits themselves could be recognized. A yield hazard zoning for urban structures related to recent alluvial deposits has also been defined.