Breakthrough

[Schroeder]

Originally Posted by jimbuna

Satellite precision I'm reckoning.

And how do you receive a satellite signal inside a mountain?
GPS doesn't work like that.
(no, I also don't know how they are doing this)

[krashkart]

The GPS data can probably be relayed. That's my guess anyway.

[Oberon]

Did a bit of Googling, here's what I found:

Tunnel surveyors guide them. Tunnels usually begin from both ends and meet in the middle, necessitating considerable mathematical precision. The route of a tunnel of any type, for example sewer or highway, is designed to run from a known point on the map to another known point on the map and at a specific depth. The design route follows specific route engineering principles which can easily be solved mathematically because they are invariably consistent. When you look at a globe, you see latitude lines running around the earth east to west, located so far above or below the equator. [Think of latitude = altitude] Longitude lines run north to south, polar cap to polar cap. Thus, the earth is divided into imaginary mathematical segments for the sake of navigation. The cake is cut again at the federal government level by federal surveyors who set national monuments on a grid pattern. The cake is further sliced at the state level in which state surveyors set state plane coordinate monuments on a grid pattern. GPS in recent years has taken a lot of work, guesswork, and time out of the process. All geometric route designs can be reduced to triangles in solution, whether curving or linear. The basis of this fact lies in trigonometry and plane geometry. Go back to the grid. Imagine that you drive due south for ten miles, then make a hard right turn, at ninety degrees in angle, and drive due west for ten miles. Convention dictates that north and east are positive. So, your new position after leaving 0,0 is -10,-10 (10 south is minus, 10 west is minus). To avoid negative numbers, massive numbers are added to the equation relative to the size of the nation or state, so your new position might actually be N356,023.56, E544,759.47. These numbers have a specific mathematical relationship to any other point on the grid. To save time, you might have driven from 0,0 to -10,-10 along the shortcut, or hypotenuse of the triangle. You drove S45W 14.14 miles. Mathematically, that's the only bearing and distance you could have driven. This process can be reversed through Trig functions to give the latitude and longitude from the known bearing and distance. The instrument you see surveyors working with measures angles and distances with normally considerable accuracy. No matter which way the surveyor turns, he is navigating by mathematically determined position and guiding the mining operation accordingly. Consider that you may have driven from 0,0 to -10,-10 along an arc running from point to point, like a regular road curve. If you trace a path along the hypotenuse then turn 90 degrees to the arc, the position you immediately strike on the arc now has a specific coordinate (north, south) position. The figure described from point 0,0 along the hypotenuse to the 90 degree turn, to the arc and back again is a right triangle. A lot of points like that make an arc obvious; an infinite number of them describe the arc. Calculators and lap tops make mapping and positioning fast and accurate. In the old west, surveyors/engineers on railroad tunnels used log tables, tablets of paper, and fists full of pencils. It took many hours and the only way to check the math was to do it all again. Three times if you got two different answers, more if you're still in doubt.

"Portaling in" is often the terminology for beginning a tunnel. Suppose for simplicity's sake that a flat rock face is ready to be drilled for the first time, and the tunnel is a perfect circle. The surveyor brings in the line (or direction or bearing or azimuth) that the tunnel should proceed on. He has also brought in the correct elevation to the staging area. He can therefore paint a line straight up and down the face of the tunnel, the centerline, and a perpendicular line directly across the circle through the radius point of the circle, determined by the elevation at that specific position (it's all in the blueprints and math). That horizontal line is referred to as the "spring line." From the centerline along the spring line so far, then up so far, will describe a point on the arc. When one has sufficient points, one paints the circle. This is called painting the face and it is done repeatedly for each new drilling cycle. (Drill the holes, pack the dynamite, explode the rock, muck out the rock, drill the holes...) Next, a tunnel drilling machine is maneuvered into position with one drill bit set on a start point, often center-center. The surveyor determines that the drill steel is precisely on line (the rock face might be askew of the desired line of direction) and either dead level or angled according to the prescribed slope. Once the first hole is drilled out, a long wooden loading pole is inserted into the hole with the end protruding. Now all the miners position their multiple drills to follow the alignment of the guide pole and drilling out the circular pattern. The process is repeated until the tunnel is long enough for the dynamite blasts to have minimal effect (usually about 800 feet), whereupon lasers are mounted on either side of the tunnel to constantly point line and grade. All the tunnel faces following the first are straight ahead and on line, or the surveyors adjust as necessary.

Older tunnel boring machines (moles) had to be guided by lasers and laser targets mounted on the mole fore and aft. Modern moles have automatic guidance systems that are wicked accurate, but basically doing what surveyors have done for countless generations. Greeks and Romans built tunnels.

These are the basics. Tunnels can be very complex. Shafts are another source of challenge.

http://www.answerbag.com/q_view/8061

[Rockstar]

Originally Posted by SteamWake

Well I wouldent expect it to make too much money right now since it is not open yet.

As to why? Its a shortcut under the montains I believe.

I was amazed that in the same article parading the joyous day of joining the two tunnels. There was also mentioned no expectation to recoup their loses and not really sure what the heck it will relieve or promote in the way of commercial traffic. Then throw a party not letting that reality get in the way of the celebration!

It would be like taking a ten million dollar loan, going 5 million over budget in construction of a tunnel from your house to your job or office. With no expectation of recouping your expenditures or that anyone will use it, especially when everyone thinks the existing highway and rail system to their own work areas will do.

The channel tunnel has a purpose and is admitedly quite a monumental feat. This Swiss tunnel on the otherhand seems to be a road to nowhere. Don't understand the fanfare here. As the technical aspects of joining two underground tunnels has been achieved elsewhere already.

[Oberon]

It employed a fair few people during its construction though, so that's a start...but yeah, it's probably not going to pay off, not for a while anyway and now that it's finished, what are the people it employed going to do?
Dig another tunnel I suppose...

[krashkart]

They will probably be digging a few more from what the article pointed out. They have a network of tunnels planned.

[Jimbuna]

Originally Posted by Schroeder

And how do you receive a satellite signal inside a mountain?
GPS doesn't work like that.
(no, I also don't know how they are doing this)

Originally Posted by krashkart

The GPS data can probably be relayed. That's my guess anyway.

Yeah that's what I was thinking, via a wired feed. A bit like a tv ariel.

[Oberon]

Originally Posted by krashkart

They will probably be digging a few more from what the article pointed out. They have a network of tunnels planned.

Good. Keeps people employed. Times like this you need to create public works projects to employ as many people as you can, the trouble is balancing the outgoings with the incomings.

[krashkart]

Originally Posted by Oberon

Good. Keeps people employed. Times like this you need to create public works projects to employ as many people as you can, the trouble is balancing the outgoings with the incomings.

Yeah, that's what always gets me when I think about the infrastructure projects that were talked about over here. We'll have plenty of people employed to rebuild the roadways (and hopefully the bridges, too) but ultimately the overhaul is a stopgap. Where will the influx of employees go when the project is finished? I guess the plan is that the economy will be chugging right along again by that time, and there will be plenty of jobs to go around. I hope that works out.

[Oberon]

Well...and I dare say this is going to get me into trouble through Godwins Law, however, in times like these I do tend to think of the German public works programs which came into being in the early thirties and flourished under the Nazis. I don't know, deficit spending to get out of recession is something that seems rather unpopular amongst the world at the moment, except perhaps in Switzerland, perhaps because it is deficit spending in boom times that have eventually lead into recessions. I'm not so sure, economics is not my strong point, but I do look at Germany in an economic viewpoint from 1933 to 1938 and I see a very strong turnaround (although to be fair, Germany wasn't actually gaining money but losing it through an input/export ratio imbalance), caused perhaps by the military-Keynesianism economic route taken by Schacht, or perhaps it is that coupled with the outlawing of the unions and the gradual erosion of civil liberties. Although, one could definitely argue that the same has happened to a lesser extent in the UK, the unions have nowhere near the power they used to, and CCTV has spread like a weed across every city in the nation. No Gestapo yet though

The channel tunnel has a purpose and is admitedly quite a monumental feat.

Even after all its restructuring , grants, cash injections, ongoing subsidies, and writing off of massive debts do you think the channel tunnel will ever turn a real overall profit?

This Swiss tunnel on the otherhand seems to be a road to nowhere.

So is the channel tunnel, after all it only goes under the sea and there are alternate routes for passengers and freight so what was the point?

There was also mentioned no expectation to recoup their loses and not really sure what the heck it will relieve or promote in the way of commercial traffic.

The relief and promotion is dependant on the follow up projects...rather like those projects that followed the channel tunnel.

[frau kaleun]

Originally Posted by SteamWake

I'm always amazed at how they can dig two tunnels thousands of feet from opposite directions and end up joining right were they are supposed to.

Not so long ago they couldent even accomplish this task with roads.

http://en.wikipedia.org/wiki/Twenty_Mile_Bend,_Florida

The ancient Greeks managed it on Samos in the 6th century BCE.

http://en.wikipedia.org/wiki/Eupalinian_aqueduct

[Skybird]

Relaying a signal to use satellites for navigation under a mountain makes no sense, since that way you only get the position of the relay you have set up, not the position of the main interest that it is linked to.

GPS also does not help you to determine your level precisely (="altitude").

They most likely have used extremely precise theodolites, or technical clones of these: instrumentations that developed the principle further for greater precision, but base on theodolites' basics. That is what I also take from the article Oberon has linked, as far as I understood it.

The woprk took ten years, but it was planned over decades. Also, they have had a referendum in Switzerland, where the people got asked whether to build it or not. A vast majority of the Swiss voted "Yes" back then.

There are plans and visions in Switzerland to tunnel even more traffic in the country, not only under mountains, but in flat areas as well - to get the traffic density disappearing from the surface. In parts of Swittzerland and Austria, truck traffic is a big problem, along the major axis of transit traffic from Northern to Southern Europe.

Hope the Swiss never find a Balrogh.

Relaying a signal to use satellites for navigation under a mountain makes no sense, since that way you only get the position of the relay you have set up, not the position of the main interest that it is linked to.

Errrrrr.....taking the fix from the known point is what works.
Since the relay is known the target becomes established.
So it makes perfect sense.

GPS also does not help you to determine your level precisely (="altitude").

I always wondered what datums were for.
So your GPS establishes your position and you get your level from an established benchmark and then use that info for your final target.

They most likely have used extremely precise theodolites, or technical clones of these:

Modern theodolites with built in sat recievers and computers where you no longer have to have a visible target to establish its location.....what will they ever think of in the last century

There are plans and visions in Switzerland to tunnel even more traffic in the country, not only under mountains, but in flat areas as well - to get the traffic density disappearing from the surface.

That has more to do with the local climate and alleviating the problems which snow causes on major routes

[Skybird]

It seems I assumed right, this is an engineer's diploma work at the university of applied science in Mainz, on the construction of the 57 km basic tunnel, and was done with support by one of the main companies running the navigation part of the work. Unfortunately, it is all in German, (except the preface, which is English and German).

http://apps.geoinform.fh-mainz.de/ab...marbeitNST.pdf

The engineer authoring this work mentions gyroscopes and gyrotheodolites as the main source of precision, since the length of the tunnel was such that classical theodolites alone could not acchieve the needed precision.

Other sources also mention laser scanners, and something that is called "Glasfaserdehnungungsmessung", that would be "glass-fibre-elongation measuring".

Satellite-assisted navigation does not get mentioned anywhere. At least not on the first 5 pages of results I had from Google.