The paper concerns special ground improvement works to allow the execution of two vertical elevators inside a cliff on which rest a city of high historical and architectural value. The soils to be excavated and subjected to ground improvement are constituted by an alternation of pyroclastic soils and tuffs of different consistency and cementation degrees. The ground improvement has been carried out by some series of guided jet-grouted columns performed in order to preconfigure a connection room with an access tunnel. The effectiveness and continuity of the treatment was verified by direct control tests and geophysical surveys. In order to limit the environmental and work impacts on the historical city center, the excavation of the vertical shafts have been performed by a special raise boring machine. A sophisticated monitoring system allowed to verify the effects of vibrations on the historical and artistic buildings during both the ground improvement and the shaft excavation phases.
Subjects: Ground improvement, jet-grouting, historical center, raise boring machine
Author: Massimo Grisolia, Ignazio P. Marzano, Giuseppe Iorio, P.E., Giuseppe Panetta, P.E., Ferruccio Cribari and Giuseppe Trovato
Publisher: DFI, EFFC