Geotechnical Aspects in the Assessment of Stability Conditions of the Volumni Hypogeum in Perugia

Volumni Hypogeum is part of the Palazzone Etruscan necropolis, an archaeological site dated back to Hellenistic period (V sec B.C.). The Hypogeum is a large underground cavity excavated in a partially saturated alluvial soil deposit located in the outskirts of Perugia city. Stability conditions and safety requirements of the vault and the lateral walls are analysed based on the available field results. The physical properties of the material in which the Hypogeum was excavated, such as, natural water content, soil suction, relative humidity of the rooms, temperature, as well as the groundwater conditions undoubtedly influence the state of conservation of the site itself. The variations of these properties may significantly affect the mechanical behaviour of the soil-materials and, in turn, the stability conditions of the ceiling/walls. Moreover, the site is daily exposed to road/rail traffic-induced vibrations. If also considering seismic actions, this site is extremely vulnerable. A multi-scale approach methodology has been recently undertaken aiming at the preservation and protection of the soil/monument system. The present study focuses on a very recent investigation of the microstructural features of the in situ materials. Preliminary numerical analyses of the cave have been performed in order to investigate on the stability conditions.