Grenoble to Briançon (D1091) closed

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briantrumpet

briantrumpet

Legendary Member
Location
Devon & Die
I cannot see that the tunnel will ever be reopened - features like this can remain unstable but stable for thousands of years - I doubt they even know the full extent of the potential instability
I wouldn't disagree. Obviously as a trumpeter I'm fully qualified to make such an assessment.
 
Casting my geologist eye on the picture, I can see that there is evidence of a very large historical slumping in the area which would have been checked for stability one would have hoped before the tunnel was bored through. The fresh slip is small in comparison and I think is fairly local looking at the picture, stabilizing the rock in the area will not present too much a problem, if very little water has gotten into any fractures that the the fresh and past slumping has produced. but of cause if the cost of reopening is prohibitive it might well be cheaper to cut a new road through at lake level.
 
Location
Midlands
yup

I can see that there is evidence of a very large historical slumping in the area which would have been checked for stability one would have hoped before the tunnel was bored through.

tunnel was opened around 1935 - so their ability to carry out a little aerial geomorphology might have been a little limited - possibly ditto any drilling programme
 
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briantrumpet

briantrumpet

Legendary Member
Location
Devon & Die
I hadn't realised that stuff moved quite a bit more at the end of July. A nice large photo here:

Chambon-DavidAmitranoISTerre.JPG


http://www.montagnes-magazine.com/a...alls-glissement-montagne-est-nouveau-accelere
 
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briantrumpet

briantrumpet

Legendary Member
Location
Devon & Die
It looks like the work to make a road on the rive gauche of the lake is continuing apace:

La route de secours sera achevée fin octobre

RD%201091-Chambon-route-secours.jpg


"Les travaux d’aménagement de la route de secours en rive gauche avancent à bon rythme, conformément au planning établi. Cet itinéraire bis, solution transitoire dans l'attente d'un rétablissement durable de la RD 1091, sera achevé fin octobre, sauf aléas majeurs. Côté Hautes-Alpes, la plateforme est aménagée sur 4 km (sur les 5,3 km à réaliser) avant mise en œuvre de la couche de roulement. L’éperon rocheux, qui fait l’objet de tirs de mine réguliers et qui constitue la principale difficulté de l’opération, sera franchi en toute fin de chantier. La mise en place le long de l’itinéraire de protections contre les chutes de blocs, est quant à elle réalisée à 80%. Cette route de secours est aménagée pour permettre le trafic local et fera l’objet de mesures particulières pour les périodes d’affluence touristique. Un autre itinéraire d’accès aux Hautes Alpes sera par ailleurs conseillé."

That all basically says that this alternative minor road will be finished by the end of October, with anti-rockfall defences in place. No doubt it'll be a great relief to the locals, apart from anyone else.

https://www.isere.fr/actualite?itemid=467
 
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briantrumpet

briantrumpet

Legendary Member
Location
Devon & Die
Impressed. Very.
This is one of the bits about the French I love. It's evident in their mad balcony roads, and bridges like the one at Millau. It's almost like the art of the sculptor, looking at the shapes that nature has given them to work with, and seeing the shapes of roads beneath the surface. And then making it happen.

I have a suspicion the if this were in Britain, there would have been a few years of feasibility reports, engineering surveys, budget enquiries, and H&S studies before starting. The French start digging, as see if it falls down.
 
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