On April 10, 2015, the Chambon tunnel was closed by local authorities following a threat of collapse.
A landslide on the section overlooking the large Chambon tunnel is calling into question the safe use of the RD1091 and its tunnel.
The road linking the departments of Isère and Hautes Alpes, France, is therefore cut off.
The tunnel was built in 1935 in parallel with the construction of the Chambon dam.
The civil engineering work to restore the link has been entrusted to Eiffage Infrastructures (Lyon and Royans Travaux branches).
The work will involve digging the new tunnel and building engineering structures, including the Lavoir bridge.
New Chambon Tunnel digging video: https://www.youtube.com/watch?v=xkwJ7wZFu9Q
Alpes Tétiers SN worked on the structures, making the formwork for the fire tanks, the Lavoir bridge and the tunnel’s downstream entrance.
On December 16, 2017, the RD1091 reopened, providing the long-awaited Isère / Hautes Alpes link at the start of the winter season.
We would like to thank the teams at Eiffage Infrastructures for their trust and congratulate them on a job well done.
Video Opening of the Grand Tunnel du Chambon: https://www.youtube.com/watch?v=YT-IfuJaLls