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Trenchless pipe laying

Special applications


Trenchless pipe laying

With the growth of urbanization, demography and the scarcity of drinking water, project managers have to preserve our natural resources by ensuring that water is transported under impeccable outstanding sanitary conditions and with respect of the imposed environmental criteria. Trenchless pipe laying is a modern technique that addresses these concerns.

Saint-­Gobain PAM’s ductile iron, thanks to its exceptional qualities, its anchored joints and its coatings, passed all the tests. It is ideal for trenchless pipe laying using techniques such as micro tunneling or pipe bursting. Laying by micro tunneling, pipe bursting or pulling through a casing are alternative techniques to the traditional method of laying in trenches. These solutions are ideal for locations where conventional methods of implementation would be difficult, if not impossible!

There are numerous examples:

  • passing through dense urban areas,
  • crossing rivers,
  • crossing canals,
  • passing through factories,
  • crossing railway lines,
  • crossing roads,
  • crossing unstable terrain, etc.

Trenchless pipe laying techniques keep the social costs of a project to a minimum. When pipes are being laid, the nuisance caused to citizens (slowing down of road and pedestrian traffic, diversion of traffic, noise and disturbance of local commercial activity, etc.) has to be limited as much as possible.


The curved trajectory of micro tunneling makes it possible to pass a pipe under obstacles starting from ground level. This technique involves three distinct steps:

  1. The creation of a pilot hole using a drilling machine guided from the exterior
  2. Boring of the pilot hole
  3. Pipe assembly and pulling of the string of anchored pipes from the downstream well toward the upstream, using the drilling machine.
trenchless pipelaying
Frist step of the drilling, assisted by a drilling unit and bentonite
exit of the earthworks
Second step of the drilling: exit of the earthworks


Laying by pipe bursting

Pipe bursting is used to replace one damaged pipeline with another of the same diameter or, often, a slightly larger diameter. The old pipeline can be burst in-situ or removed piece by piece and broken up as it is pushed out of the tunnel. This replacement procedure can only be used for straight sections. An initial diagnosis is required, with a video inspection of the pipeline to be replaced, to ensure that there are no obstacles to impair its extraction or destruction.

pipe bursting
Pipe bursting

Pulling through a casing

Pipe laying through a casing consists of introducing a pipeline intended to transport a fluid (drinking water, waste water, rain water, dry networks, etc.) into a circular sleeve that already exists or is installed specifically for this application. Ductile iron pipelines are perfectly suited for this application since the anchored joints can withstand significant pulling forces while retaining the flexibility offered by elastomer gaskets. This laying method is suitable for specific rehabilitation techniques, for laying new networks that cross a natural obstacle, and for trenchless work.

pipelaying in casings
Pipelaying through casings


The coatings in the DIREXIONAL range are made of extruded polyethylene, reinforced polyurethane or cement mortar and fully address the requirements of trenchless technology. They completely protect the pipes from any impact that might occur during pulling and also improve the way they slide through the ground.

Saint-Gobain PAM Forage Dirigé
Pipeline Direxional - Microtunelling under the Loire

Calculation tools for trenchless pipe laying

Saint-Gobain PAM provides the prime contractors or study two calculation tools to improve the organization on construction sites.

More than 90,000 linear meters of PAM pipes have been laid to date using micro tunneling. The equivalent of 2 Channel tunnels!


Saint-Gobain PAM microtunelling
Pipeline Direxional - Microtunelling under the Loire
Saint-Gobain PAM microtunelling
Pipeline Direxional - Microtunelling under the Loire
Direxional - Saint-Gobain PAM microtunelling
Pipeline Direxional - Microtunelling in Uckange


PAM DIREXIONAL - La pose sans tranchée
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Logo de la gamme Direxional

See also

Ductile iron pipes DN 60 to 1000 can be laid without a trench using either techniques: new pipe laying by horizontal directional drilling (HDD), or trenchless replacement of existing pipes.