How did the two tunnels that made the channel tunnel meet?

LOL!!!! You know, 10,000 years from now, scientists and archaeologists will be baffled at this feat. AND the conspiracy theorists will shout from the mountain tops that the tunnel was built by ancient aliens. Mankind could never be that clever.

Dont you mean that in 10,000 yrs the tunnel would be gone from continental drift?

Originally posted by andy1033
Could the lasers penetrate the rocks, and meet under the sea? Is that what your saying they did?

I was a Rodman on a survey crew for about 7 years;

You start at a known point, and you set and shoot what is known as a traverse point. its usually just a nail in the ground that you use to make your calculations. Bores dig a little, then they set more traverse points on the recently dug sections, and shoot the laser BACK OUT OF THE HOLE, to other known points like foundation landmarks or even property corners in most normal non chunnel cases. They work out the angles through trigonometry, and sometimes even a compass. then they keep building along the planned route as long as all the numbers are exactly what they should be, if not, they will move the bore closer to the path it needs to take. they check and re check the route to make sure that it is EXACTLY where they want it to be by shooting lasers to a Guy holding a prism mirror (very fancy mirror) on a pole of known fixed height who checks each of the traverse points, and there are guys on the other side doing the exact same thing until it is complete.

it is the exact same way they made the cotenetial railraod in the united states even though its above ground

[edit on 6-1-2010 by drsmooth23]

Originally posted by smoov

The satellites send signals to the GPS unit and time how long it takes the signal to get back.

There is no signal sent back, as the gps you are holding is only a receiver. This receiver calculates its position by receiving timing data from several satelites and then extrapolates its position from that timing data. The positioning accuracy has improved due to the US military removing error data that once only gave accuracy to about 150 metres (about 500 feet).

[edit on 5-1-2010 by smoov]

Is there a reason that you reworded my post?

MessOnTheFED!

Originally posted by dereks
I doubt that GPS's were used inside tunnels to ensure that they were aligned....

There is no way that survey grade GPS will work iin a tunnel. Not at all. No GPS used on this project. MAybe to set their control points above ground but not underground.

MessOnTheFED!

reply to post by drsmooth23


You know what you are talking about.

reply to post by MessOnTheFED!


Sorry, meant to just reply to your post.
Nothing more.

reply to post by smoov


its all good friend

2

Originally posted by Now_Then
Man you are so dumb! - The only way on Earth light will travel through rock (and for your information most of the channel tunnel was prob not bored through rock

) is for that very laser to BURN through it...

Originally posted by Now_Then
Laser seeing through rocks? Did you go to school at any point?

So you're telling me that radio waves can't penetrate walls?

GPS does not work through rock.

I know how they got the tunnels to meet as i worked on a TBM on the Superconducting Super Collider tunneling project in Texas.
www.damninteresting.com...
en.wikipedia.org...
en.wikipedia.org...

The channel tunnel would have been easy compared to boring a 54.1 mi circle tunnel.
www.slac.stanford.edu...

We used a laser to back shoot to laser reflectors behind us.
and each of these reflectors was set by back shooting to the reflector behind it.

reply to post by ANNED


LOL thats deffinately a gross misuse of the .

I bet that was an awesome job.

MessOnTheFED!

reply to post by tracey ace


The idea started nlong before that...as far back as 1802!

en.wikipedia.org...

Construction on both sides began in 1973 but the Brits stopped in 1975 which the stopped the French on thier side. Constructions began again in 1988 and tunneling machines as long as two football fields bored thru the chalky earth. You can watch some of the machines in action here:

blogs.howstuffworks.com...

Also keep in mind that there are 3 tunnels and that we have been digging tunnels using math for a long time from mines to oil wells...in fact oil technology helped with the Chunnel project. Geologist determined the best place to dig and engineers (Loads of them) made the calculations