Direct Pipe

Direct Pipe® is an evolution of traditional microtunnelling and TOC, which until today could be applied on ducts with a diameter from a maximum of 56"to a minimum of 36".

For pipes with smaller diameters, the aforementioned system could not be applied, therefore, a new method called Mini Direct Pipe® was created, which can be used on diameters of 28" – 26" – 24", which is especially useful for the installation of pipes up to 1,500 m long.

The particularities of the Direct Pipe® are:

  • • the exclusion of the entry of personnel into the pipeline, eliminating the risk of work in closed and confined spaces (Italian Presidential Decree no. 177/2011), while ensuring the continuous monitoring, remotely, of all the elements for guidance and advancement;
  • • the construction of a more compact componentry with reduced dimensions, due to a lower stress of the elements at play;
  • • the use of jet pumps, which guarantee excellent efficiency but with smaller dimensions than centrifugal pumps and can be installed inside pipes up to DN 600 (24").

The Mini Direct Pipe® method therefore allows the burial by thrust of a continuous pre-assembled pipeline, in consecutive steps, above ground and pre-inspected, operating from a single station point.

In a single solution, an excavation of limited dimensions (starting point) is carried out and the pipeline is installed, with the advantage of having a higher speed and consequently a significant cost-effectiveness in the final burial.

From the launch area, the ground is excavated through a milling head equipped with optical guidance and joints useful for possible trajectory corrections. The excavated soil is removed thanks to the hydraulic circuit that is installed along the pipeline to be launched and ends in the separation system installed above ground.

The continuous pipe (and/or column trolls) is pushed into the borehole at the same time as the excavation, thanks to the action of the pipe thruster, i.e. a jaw pusher unit engages the pipe on the external surface and, moving forward, pushes the pipe inside the borehole. The maximum travel of the pipe thruster is 5 metres and the maximum thrust power is 500 tonnes.

At the geological level, the use of Mini Direct Pipe® technology is possible in any type of soil: from fine soils, to rocks, to heterogeneous and water-permeable soils. The uphill and downhill tracks, as well as the curved sections, are precisely managed by the guidance systems with gyroscope, calibrated with total station and optical prisms, thus reaching accuracy per centimetre.

In addition, another potential that this technology has is the possibility of being applied also in environmental areas conditioned by a strong prevalence.
We used this technology for the first time in 2023, in the construction of two crossings that are part of the construction of the Snam Rete Gas "Recanati Porto San Elpidio" pipeline..

In this case, the first crossing under the "Ete Morto" canal near Recanati was the pilot project for the launch of Mini Direct Pipe® technology in Italy with DN26 piping.

The second project was carried out in the Civitanova Marche area, for the crossing of the "Chienti" River.