Investigations on the stability conditions of a tuff cavity: the Cimitero delle Fontanelle in Naples

The paper is dedicated to one the most suggestive cavity located in the city of Naples (Italy), the Cimitero delle Fontanelle (Little Fountains Cemetery). The quarry, excavated in Neapolitan Yellow Tuff (NYT), is a typical chamber and pillar cavity; during 400 years of life, the site experienced a series of events until finding, in the modern age, its current destination as a worship place for the population. The paper summarizes the experimental and numerical studies conducted in the recent years to evaluate the stability condition of the cavity. A joint interpretation of traditional in situ investigations and geophysical tests (ERT, GPR, HVSR, MASW and near-surface Seismic Refraction Survey) allowed for defining an accurate geotechnical soil model. The evaluation of the static stability condition of the rock cavity was investigated considering simplified approaches, compared with 2D and 3D numerical models using the finite difference analysis. The results of the numerical analysis were expressed in terms of plastic zones, pillar load and acceleration time histories due to real earthquake event.