Analysis of the stability of a rock cavern: The fontanelle cemetery

Abstract

The paper reports the study conducted to evaluate the stability condition of one the most suggestive rock cavity located in the city of Naples (Italy), the Fontanelle (little fountains) Cemetery. It is a chamber and pillar cavity, with a rectangular and elongated plan, consisting of three naves. The cavern was excavated in the Neapolitan Yellow Tuff, a soft rocks widespread used as construction material in the city and its origin goes back to the 16th century while its expansion to the 17th century, when the city was quickly battered by popular uprising, famines, earthquakes, eruptions of the Vesuvius and epidemics. The cavity was addresses to different uses; destined to become an ossuary in the 18th century, progressively turned into a Christian worship place, suffering many events during 400 years of life, until it finds, in the modern age, its stability as a place of worship. The paper reports the numerical analyses by means of a 3D finite difference code, carried out to evaluate the stability condition of the cavity and the hill on which was excavated, taking into account the various stages of life. The results obtained show that there are some stability problem for the roof of the cavity; further investigations on the shape of the pillars, partially hidden by the fill, and on the mechanical properties of the tuff are needed for a more satisfactory evaluation.