Russian tunnel

[blue streak 1]

Tunnel completed that has a diameter of 31+ feet.  Wonder what oversized traffic they expect ?  Some one who know geography point us to where this is ?

 

http://www.railwaygazette.com/news/infrastructure/single-view/view/second-mansky-tunnel-bore-opens.html

 

 

[billio]

Somewhere along a 500(?)-mile stretch of railroad in southern Siberia. Perhaps it connects to the Trans-Siberian at the western end of the segment. No, it's not for high speed rail; there aren't any cities worthy of the name along the line, and the line meanders through mountainous territory. Why the high clearance over the rails? Some guesses: container traffic, oil rigging and industrial gear, military equipment. As to where along the line the tunnel lies is anyone's guess.

[MidlandMike]

They used a 31' dia. boring machine, maybe this does not include a liner.  The bottom of the bore had drainage and ballast, and the top had cat wire.  The remaining clearance would be less generous.

[BaltACD]

In having to build track, construct drainage  and hang catenary - 31 feet gets used up real quick.  From the picture with the article, there doesn't appear to be much room above, what appears to be some form of hopper, to the catenary.

[Overmod]

blue streak 1

Tunnel completed that has a diameter of 31+ feet.  Wonder what oversized traffic they expect?

That's not the size of the tunnel, it's the size of the head on the TBM.  You can expect the tunnel itself to be smaller by the amount of the shell and lining.  Compare the size of the TBM that was to have been used for boring the ARC tunnels, which were only expected to pass commuter rail equipment...

[tomikawaTT]

Not in Russia, and not bored by TBM, but the five tunnels on the U.S.Government Railway (Boulder City to what is now Hoover Dam) were bored to clear segments of 56 foot diameter penstock pipes.  They are now called the Tunnel Trail, and they are HUGE!

A tunnel bored by TBM will lose 2X the thickness of the liner segments in diameter as the liner is put in place.  The head diameter might measure 31 feet, but that comes down to about 27 feet before adding the first lump of ballast.

Chuck

[CSSHEGEWISCH]

Technical question:  Is a tunnel-boring machine a modern variation of tunnel shields used in the boring of the original St. Clair Tunnel between Port Huron and Sarnia?

[tomikawaTT]

Shields, as used by sandhogs in digging the tunnels around Manhattan, are fixed wall-like structures with doors through which drilling and excavation take place.  Once there's clearance for another ring of lining (usually segmented cast iron) the shield is jacked forward and the lining is placed and grouted.  The shield is only a few feet thick.

A present-day TBM has a rotating cutter head (think oil well drill head on steroids) which cuts, shaves and mucks out automatically (nobody in front or inside, please) while applying constant pressure to the face.  The rest of the machine includes a waste material removal conveyor and semiautomatic mechanisms to place lining segments.  The whole thing is as long as a football field.

If you Google Yucca Mountain images, you'll find photos of the cutter head holing through and the entire machine in the open.  Quite an impressive piece of equipment.

Chuck