- Response of river embankments subjected to transient seepage conditions and assessment of their vulnerability. The research activity on this topic was developed upon completion of the INFRASAFE research project funded within the POR-FESR- – Asse 1 “Ricerca e Innovazione” of the Emilia-Romagna Region, which implemented, among many other things, an advanced monitoring system to investigate the associated collapse risk connected to a river embankment section along the Secchia river, near Cavezzo (Mo). The experimental data collected in the time period between 2017-2019 were used to investigate the soil-water dynamics inside the aforementioned river embankment under transient seepage conditions. The hydraulic and retention parameters of the numerical model were calibrated by means of inverse analysis and using the available extensive database. Limits and potentialities of this calibration technique were explored with reference to the chosen section.
- Soil-water retention behavior as obtained by various laboratory techniques. Filter paper, psychrometer, high-capacity suction probe and pressure plate were used on a fill material belonging to a full-scale, highly instrumented embankment (BIONICS project, “BIOlogical and eNgineering Impacts of Climate change on Slopes”). For the investigation of the mechanical behaviour under unsaturated conditions of the same soil, a series of constant water content triaxial tests were carried out in a double cell triaxial equipment on samples compacted at different water contents and on samples subjected prior to wetting and drying cycles. The aforementioned tests were conducted in the geotechnical laboratory of the School of Engineering and Computing Science of Durham University (UK).
- Analysis of the risk connected to backward erosion piping phenomena, which turn out to be one of the most threatening collapse mechanisms for Po River embankments. Two river embankment sections along the Po river, close to Guarda Ferrarese (FE) and Mazzorno Sinistro (RO), affected by many episodes of sand boil reactivations during flood events, were selected as representative case studies. A detailed stratigraphic soil profile as well as a careful geotechnical characterization of the riverbank sediments, were carried out on the basis of laboratory and in-situ tests. The installation of a piezometric monitoring system in both sections provides continuous experimental data for the subsequent numerical modelling. This study, developed in the context of a research project promoted by Aipo (Po river basin Authority), aims to elaborate numerical models of the investigated sections reproducing accurately the piping phenomena by means of an in-depth calibration through in situ experimental data. The elaborated model will be used for predictive analyses and implemented in early warning systems at the service of local management authorities.
- Influence of the transpiration contribution by long-stem plants on soil suction distribution and its consequences on the stability assessment of earthen slopes. This topic was addressed during the research period conducted in the Priority Research Centre for Geotechnical Science and Engineering of the University of Newcastle (Australia). The research activity included the design and set up of a laboratory scale experiment in which the influence of a young long-stem plant on the suction distribution in soil was investigated for different applied boundary conditions. The experimental data collected from the large-scale experiment were used to reproduce the different experimental phases and to calibrate the root water uptake (RWU) spatial distribution of the chosen plant. Once defined the RWU distribution, a quantification of the impact of the plant transpiration on slope stability as a function of root dimensions and plant spacing could be carried out.
- Soil profiling in fine-grained deposits characterized by a relevant post-depositional history (microstructured horizons by cementation and aging) using laboratory and in-situ tests. The chosen cases study are the alluvial deposits underneath the Two Towers of Bologna and in proximity of Ferrara city, both characterized by an alternation of pedogenized and not-pedogenized horizons forming packed succession of paleosols. This study has been carried out with the collaboration of the Department of Geological Science of the University of Bologna and Modena.
-The complex soil-structure interaction between historic foundations and the soil deposit underneath, is investigated by means of laboratory and in situ tests. This research topic has been carried out with reference to the case studies of the Two Towers in Bologna (Asinelli and Garisenda), of the Osservanza religious complex in Bologna and of the Santa Croce Church in Ravenna (H2020 SHELTER project). The collected data allowed the numerical modelling of each case study taking into consideration multiple aspects governing the past and actual behavior of the architectural heritage under analysis, as construction phases and technologies in use, construction materials, inclinations records over time, in-situ boundary conditions (groundwater conditions, subsidence effects..), depositional and post depositional history of the soil units etc. A continuous monitoring system, designed ad hoc, has been implemented in each of these sites in order to acquire new insight on the in-situ conditions and on the “state of health” of the investigated monuments.
