ABSTRACT
The project of the Campalto tunnel is characterized by the crossing of Gobbi street ensuring the opening to vehicular traffic during the work. The tunnel is located in the Venetian lagoon, within inconsistent soil with the presence of a significant hydraulic surcharge. To ensure the minimization of subsidence allowing the presence of traffic the highly innovative solution of the ‘Pipe Arch’ has been used consisting in a double arch of concrete micropiles reinforced with fiberglass and sub-horizontal metal insertions passing through the whole rock mass, from side to side. To protect the excavations and the near existing buildings plastic diaphragms in bifluid jet grouting ϕ800 mm and jet grouted ϕ1500mm columns made by trifluid jet-grouting intervention were realized to counteract the thrust from the water. The article will highlight how the jet grouting treatments, calibrated through instrumented test fields, and the Pipe Arch technique have allowed the success of the work.
