Project Rosny-sous-Bois, France

Grand Paris Express - La Dhuys station

new station on expansion of line 11

Realizing a whole metro station in the middle of the city requires some technical and logistical skills...

Technical specifications

Diaphragm wall for the covered trench

  • 23 panels
  • 155 linear meter
  • 12 to 17 m deep
  • thickness 0.6 m and 1 m


The circular well is also realized using the diaphragm wall technique.

A three steps jobsite

Heavy deep foundations work in the middle of the city do need some organization. We therefore worked in three phases on this project:

The first job was to realize an entry well for a tunnel boring machine, that will be digging the expansion of line 11 towards Montreuil, Carnot and Gainsbourg stations.

Second part is the covered trench of the metro station, that passes under the main street.

Third and last, we will be realizing the last section of the covered trench, which is actually located under the road diversion that has been placed on the surface for the time of the first two phases.

La Dhuys station

Because of the large infrastructure works needed for the construction of the circular entry shaft, the terrain had to be cleared off of its buildings. The Société du Grand Paris and the city of Roisny-sous-Bois are now looking at different urban projects to give a new life to this parcel of land once the works will be done.

The La Dhuys station will have two entries of equal importance, made of kiosks. The subway platforms will be placed 25 m under the street level. 


The "Grand Paris Express" project

With the Grand Paris Express project, the French capital will receive a second metro network aimed at serving its suburbs. 
The scope of the work is impressive: four whole new lines, extensions of two existing lines, seven new technical centres and no less than 68 new stations, this ambitious project will double the size of the current Paris subway (from 220 km to 445 km), which serves principally the 20 districts located inside the Paris ring road (périphérique). 

The new lines of the Grand Paris Express will be connected to the existing transport network. Essentially underground, the new metro will cross the municipalities of the greater Paris metropolis to connect them among themselves and with the capital. This will make it easier to get from one part of the Île-de-France to another without going through Paris, but also to reach more quickly the heart of the capital from its suburbs.

The Grand Paris Express will serve the major business areas (airports, business centres, research and university centres) and other suburbs that are currently difficult to access. It will bring everyone closer to their workplace and make daily journeys faster and more pleasant. Finally, it represents a new alternative to the car, thereby reducing pollution, traffic jams and helping to create a metropolis that is more respectful of the environment.

It is the largest urban project in Europe nowadays.

Project details

Project name

Grand Paris Express - La Dhuys station


Railways, Tunnels


Diaphragm wall

Contract type



Rosny-sous-Bois, France



Building Period

2017 - 2018



Total value

€ 5 million

While working on the circular well

Bentonite installation

First part of the covered trench

Worksite in the city

Excavation of a panel of the diaphragm wall

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