Underground—EMEA—France—Tunneling
The Tunnel du Chambon: POWER SET Bolts stabilize important
Connection between Grenoble and Briançon
The Tunnel du Chambon in France, which was opened in 1935, is an important connection between Grenoble and Briançon.
The tunnel forms part of the Route Départementale 1091 and is located above Lake Chambon. In the spring of 2015, a landslide
was detected in this area that had caused cracks in the tunnel lining and invert despite its having moved only a few centimeters
per year. On April 10 th 2015, the tunnel had to be closed as a consequence of the damage caused by the rock movements.
As the population of the Haute-Romanche
Valley was completely cut off by this closure,
an emergency route was built on the opposite
lake shore that was opened in November
2015. However, this road is only able to
accommodate approximately 700 vehicles
per day. A long-term solution was urgently
required to prevent further damage to the
region’s economy as a result of the tunnel
closure.
Stabilization of the areas in question was not
economically and technically feasible so that
the decision was made to build a new tunnel
structure that will make a wide-ranging, 500m
long detour around the landslide. The new
bypass tunnel will be excavated from the
28
inside of the existing tunnel and will then open
out into a smaller, existing tunnel. In total,
the Tunnel du Chambon will be lengthened
by 240m, so that it will have a total length of
990m.
To stabilize advancement, DSI France
produced and supplied Type PS 50, 300kN,
4m long POWER SET Self-Drilling Friction
Bolts including 200/200/12 anchor plates.
The patented POWER SET One-Step Bolt
System ensures a safe and easy installation
as well as immediate load-bearing capacity.
Furthermore, the system is characterized by
its high flexibility in regard to changing rock
conditions.
Owner
Conseil départemental de l’Isère,
France
General Contractor
Eiffage S.A., France
Contractor
Groupement TPGEO/DELUERMOZ,
France
DSI Unit
DSI France SAS, France
DSI Scope
Production, supply
DSI Products
Type PS 50, 4m long POWER SET
Self-Drilling Friction Bolts