SNCF – Le Rondeau interchange: the first grabs have unloaded at the DREAL worksite at Le Rondeau, Grenoble

After the DREAL worksite awarded to the consortium made up of Campenon Bernard Center-Est/Soletanche Bachy France/Soletanche Bachy Fondations Spéciales/VINCI Construction Terrassement/Sogea/Eurovia – involving development of the interchange which will expand part of Grenoble's southern bypass, the RN87, from two to three lanes in each direction – another site, located a few meters away, has just been acquired on behalf of SNCF.


SNCF selected the bid from the Campenon Bernard Center Est/Soletanche Bachy/VINCI Construction Terrassements consortium for the construction of two rail bridges to allow the future RN87 road links to pass beneath the railway line.


For the teams, this is a complex site with numerous challenges:

  • A narrow and restricted work area (slopes)
  • Numerous interfaces (technical, scheduling, etc.) with the DREAL worksite and with traffic flowing on the RN87
  • Various special works:
    • 16m diaphragm walls (1000m2) with two complete KS workshops in three shifts over three weekends in March 2022
    • Ground anchors
    • Retaining wall made from adjoining micropiles
    • Grouted raft
  • Civil engineering (prefabricated coated girder deck)
  • Cast-in-situ earthworks (under struts and deck), under water table


Diaphragm wall/ ground anchors/retaining wall/micropiles/ ground raft/ civil engineering/ earthworks

In the middle of the DREAL worksite, an SNCF track (Lyon to Marseille line via Grenoble) crosses the RN87, with the DREAL contract ending on either side of the railway structure.