A geological model of the buried Tiber River valley beneath the historical centre of Rome

Abstract

The study develops a geological/geotechnical model of the filling of the buried Tiber River valley in the area of Rome. The approach has been multidisciplinary: the fill sediments have been analysed in detail and are given on a cross section based on either the observations of 57 borehole cores and/or the laboratory tests on various types of samples. Information regarding the geology, geomorphology, climate, hydrographic network, urban development and history of the Rome area has been used to interpret this section and to extrapolate the data to the historical centre of Rome in order to formulate the model. The proposed model is a global forecasting rather than a detailed one and can be used as a starting point for projects to be conducted in the Tiber River alluvium or for defining a specific approach to technical problems linked to these projects

Dynamic properties of low velocity alluvial deposits influencing seismically-induced shear strains: the Grottaperfetta valley test-site (Rome, Italy)

“…The change in climatic conditions provoked the glaciers to melt, a fast sea level rise (Bard et al 1996) and the fluvial valleys to be filled by alluvia. The sediments deposited during Holocene within the valleys are generally characterized by a fining-upward succession, with a relatively thin horizon of gravel at the base, grading upward into a thick pack of sand and clay (Bozzano et al 2000). Within this sedimentary body the intercalations of organic material such as carbonized plants and peat horizons are frequent.…”

“…Within this sedimentary body the intercalations of organic material such as carbonized plants and peat horizons are frequent. Therefore, the alluvial deposits are generally characterised as low consistency, saturated, fine-grained soils from normally consolidated to weakly over consolidated in the superficial part and generally characterized by low stiffness parameter values (Bozzano et al 2000).…”

Geometry and seismic characterization of the subsoil below the Amphitheatrum Flavium, Rome

“…From a general point of view, for unconventional and historical structures like the Colosseum, the simplified approach suggested by the NTC08 for soil classification is not adequate and specific studies are needed to build a truly representative model of the subsoil and the buried part of the structure. Bozzano et al [2000], Bozzano et al [2008] and Caserta et al [2012] investigated the different lithotypes constituting the recent sedimentary fill of the Holocene Tiber River Valley under both static and dynamic conditions. Bianchi Fasani et al [2013] reported the typical ranges of shear-wave velocities observed in situ for the pyroclastic units within Rome city.…”

The sundial of Augustus and its survey: unresolved issues and possible solutions

“…Even the most accurate measurement currently possible (given the impossibility of astronomical measurement in an underground environment) would have an accuracy of a few dozen arc seconds. A possible cause of eventual change of the original azimuth of the track is a differential settlement due to the alluvial nature of the ground (Bozzano et al 2000;Camponeschi and Nolasco 1982). Geodynamic movements since antiquity of the sundial's meridian line presumably do not significantly influence the azimuth itself, while an accurate evaluation of geodynamic rotations would require a further study, both for the choice of the correct model and reference De Mets (2013), as well as in function of the specific movements of the Italian peninsula (Devoti et al 2014).…”