Torno Internazionale S.p.A.





The design of the sewer along Baku and Galimberti streets in Naples integrates the overall project of modernization and expansion of the railway “Alifana” - “Napoli - Teverola” segment. The construction of the sewer was needed because of the problems which have arisen in the displacement of two sections of sewer insisting along Plebiscito street and “Via dell’abbondanza” of the district Piscinola in Naples. In view of many interferences detected along the whole route and the problems in order of time because of the many movements of underground services, the design choice was oriented towards an application of the technique “mini-tunnel". The highest point above the tunnel passes under the existing buildings with a margin of between 2 and 3 meters. The undergound structures to be executed for the application of the minitunnelling technique consist in n. 5 intermediate thrust-shafts, made with ø 1000 piles, properly coated in reinforced concrete during the excavation stages. The walls will be constrained at various levels, depending of each depth; after the works execution the shafts will serve as manholes for the sewer. From each shaft it will proceed to the implementation of the portion of the sewer to the next shaft, through the installation of a pushed-in r.c. pipe. The lining has an outer diameter variable (2600mm/3000mm), with structural characteristics suitable to the process of embedding in the soil by jacking-machines. The final section is 60m length and falls in the “Secondigliano” prison area. It will be realized, in analogy of the initial upstream, with cut and cover technique, between constrained ø 600 bulkhead piles. Between the bulkhead piles will be built in the rectangular section sewer with circular dome, measuring 250cm x 250cm. Throughout the collector, will be suitably realized a shape for the low flows and the entire section will also be covered in glazed ceramic. In the choice of most suitable technology for the construction of the tunnel to the main collector with a nominal diameter of 220 cm, there was a decisive influence not only on the characteristics of the soil present, but the dense urbanization of the areas to cross. From the analysis of the geological profile has highlighted the presence of exclusively granular soil along the planned route