Geotechnical Investigations and Monitoring of the Archaeological Site of Santa Croce in Ravenna (Italy)

The city of Ravenna, in northern Italy, is worldwide famous for the well-preserved late Roman and Byzantine architectures characterized by fabulous mosaics that have earned the UNESCO World Heritage status. The constantly growing attention towards their conservation has promoted research activities that focus on the effect of the considerable cumulated land subsidence on their current conditions. Today, the sum of long-lasting natural and more recent anthropogenic subsidence has brought the level of such ancient archaeological sites and monuments well below the current position of the phreatic water table, still close to the current ground surface of the city centre, as it is the case of the Santa Croce church and its archeologic area. The Church, dating back to the 5th Century AD, is surrounded by ancient Roman floor mosaics, located ~3.2 m from the main street level. In this site, a pumping system must permanently operate to lift to the external sewage network the water collected from the local subsoil by means of a rather old and no longer efficient drainage system. A geotechnical investigation campaign was carried out in 2022, together with the installation of a new piezometric monitoring system, with the aim of investigating the shallow aquifers underneath the monuments. Relevant data interpretation will enable to better understand the current situation and, above all, to devise a proper solution which can combine the long-term conservation of the area with its usability.