A 400-metre sewer has been installed beneath a railway line and the river Sile in Treviso, Italy, using microtunnelling technology at a depth of 11 metres.
The DN 800 pipeline was constructed for ATS, the local water company, by contractor LF Costruzioni, with ENKI acting as consultant. The scheme forms part of works to support urban infrastructure in the historic city centre.
The project is said to have combined several demanding conditions in a single alignment, including high groundwater levels comparable to those found in Venice, an active railway crossing, and a river crossing beneath the Sile.
A slurry-supported microtunnelling method was used to allow controlled excavation and continuous face support given the groundwater conditions and sensitive surface structures above.
The pipeline was constructed using DN 800 KERA.Drive vitrified clay jacking pipes, supplied by Steinzeug-Keramo, a wienerberger company. The direct-jacked approach removed the need for additional casing pipes.
According to the project team, the pipes were selected for their structural capacity for jacking applications, resistance to corrosion, and water-tightness under external pressure.
The installation was completed without surface disruption to the railway or river, according to the project team, with the pipe system remaining within its performance limits despite the combination of loading conditions.
Lorenzo Vidus Rosin, sales engineer Italy at Steinzeug-Keramo, said: “KERA.Drive is the sustainable solution. Not only from the material perspective, but also from an installation point of view.”
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