Microtunnelling and direct pipe

1390 – San Zenone al Lambro (Milan – Italy)

Execution of Direct Pipes and construction of a microtunnel in reinforced concrete as part of the works for the Snam Rete Gas pipeline Cervignano-Mortara ND1400 project (56'' DP 75 bar - Lot 1 - Total length of about 33.482 km and related works on the Cervignano - Rognano section.

Snam Rete Gas

Max Streicher S.p.A.

Period of Execution:
September 2017 - August 2018

Works Amount:
€ 10.422.617,00


This challenging project involved the construction of seven Direct Pipes and a microtunnel to cross several waterways such as rivers, streams and canals, as well as an archaeological area.
The extensive use of the Direct Pipe technique for this project was motivated by its particular effectiveness in terms of time and cost optimization, while ensuring high construction standards. The characteristics of the Direct Pipe technique are the possibility to operate with a reduced earth cover at the riverbed, reduced construction site dimensions compared to other excavation technologies, the possibility of directly laying the product pipeline without using r.c. casing pipes and a significant reduction in excavation volumes.
No. 7 Direct Pipes in 56″ diameter for a total of approximately 4.000 m, in fine grounds, with vertical curve of radii R= 1.800 m were executed; the Direct Pipe named “Cavo Borromeo” also has a horizontal curve of Ro= 1.500 m.
The microtunnel crossing the A1 motorway has a very small vertical radius of curve R= 800 m with compared to the diameter of the ND56 pipeline.