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Discussion Starter · #1 ·
After trawling through the archives for tunnel building ideas, I decided to follow in the best tradition of MLS members and put in something to get archaeologists scratching their heads in the year 2350.

This was originally going to be a cutting but the longer I thought about it a tunnel seemed more fun. Photo below shows first digs Nov last year when a cutting was flavour of the month.



I finally started the build last weekend. First up marking out size for concrete pour, all up 1.6m long on centreline, grade of 0.5% and a slight curve to boot. /DesktopModules/NTForums/themes/mls/emoticons/whistling.gif" border=0>



Bent up some 3/8” reo for the first concrete pour - 3 U shapes and 2 bars for each of the bottom and sides. I planned for 300mm clear height and width through the tunnel.









And in goes the concrete for the base. I left the conduit in place for something to attach the track to and put a slope either side of the roadbed to help with drainage.





That lot dried for a week while I made the centre former. I scored some plywood off the neighbour who had picked up half a dozen sheets from a mattress company that was chucking them out.

Getting the curve right was a bit tricky. In the end I screwed 6 spacers to the inside wall that was already cut to length and height then attached the outside wall at one end only. I held the assembly in place on the base and shoved the outside wall till it looked right, then with my third hand quickly screwed it to one of the spacers. Took a couple of goes to get right…

Bit hard to see the curve in the photo but it fitted pretty well. Eventually.





A couple of side forms were added where the dirt was too far away to be useful holding the concrete.





I poured the sides this morning just after the above photo was taken and finished as it started raining. 2 hours later this was the view from our dining room.



The tunnel is under the blue tarp. I guess winter’s here.

Can’t wait to see how it turned out.

Cheers
Neil
 

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Quite the construction project! :) That snow is looking pretty good compared the high 90's we had today and for the next few days. /DesktopModules/NTForums/themes/mls/emoticons/sad.gif

-Brian
 

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Posted By wigginsn on 06/07/2008 2:14 AM

After trawling through the archives for tunnel building ideas, I decided to follow in the best tradition of MLS members and put in something to get archaeologists scratching their heads in the year 2350.

I finally started the build last weekend. First up marking out size for concrete pour, all up 1.6m long on centreline, grade of 0.5% and a slight curve to boot.

<

And in goes the concrete for the base. I left the conduit in place for something to attach the track to and put a slope either side of the roadbed to help with drainage.

That lot dried for a week while I made the centre former. I scored some plywood off the neighbour who had picked up half a dozen sheets from a mattress company that was chucking them out. Getting the curve right was a bit tricky. In the end I screwed 6 spacers to the inside wall that was already cut to length and height then attached the outside wall at one end only. I held the assembly in place on the base and shoved the outside wall till it looked right, then with my third hand quickly screwed it to one of the spacers. Took a couple of goes to get right… Bit hard to see the curve in the photo but it fitted pretty well. Eventually.
  Can’t wait to see how it turned out. Cheers Neil


Wow. This project almost looks like it could be the real thing !   I am impressed with the way you went about it.  
 

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Looks like something an archaeologist would describe as a "cult site" and write a scholary paper about the worship at the site :D
 

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Discussion Starter · #7 ·
Worship indeed! Perhaps I should scratch some weird markings into the walls to add to their confusion. /DesktopModules/NTForums/themes/mls/emoticons/tongue.gif

I pulled the center out yesterday but the photos are at home, will post a couple tonight.

Spent some time yesterday looking at how concrete cures below freezing, you know just for curiosity. Looks like it doesn't do very well at all which kinda matches the crumbly look I seem to have got. /DesktopModules/NTForums/themes/mls/emoticons/sad.gif

Cheers
Neil
 

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Discussion Starter · #9 ·
Hmmm, that’s not a bad idea. Wonder what the air miles on one of those would be?

This is what it looks like after the forms are out. You can see where I packed the concrete in a bit too hard and the former straightened up a bit. The narrowest part is 27 cm - that’s a bit more than 10.5” so still heaps of room.





I’m going to let this lot set up for a week or so then pop on the lid.

Cheers
Neil
 

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Neil, looking grand! Well done! Thanks for the pics and details. Will you need to put a tunnel access on top, or is it short enough that you can reach any potential derailment?
 

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Discussion Starter · #11 ·
Jim,

Well spotted. No access planned from above - mainly because there will be 2 - 3' of dirt and rocks on top. The length is just a bit too long for easy reach, a touch over 5'.

I'm thinking (hoping) that say 2' from each end would be arm reach and add a bit for the equipment that falls off so I should be ok. /DesktopModules/NTForums/themes/mls/emoticons/ermm.gif I plan to line the inside walls with foam to help ease any damage if I end up having to prod stuff towards one end to get it out.
 

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Hey I did the same thing only different.

I built mine with a form like yours only I made a form to form the top and sides and I did it on a work bench out side.

The bottom was poured in place.

Mine was the infamous 480 LB tunnel.

My other two tunnels were made using Cinderblock and handi board the stuff you use for sub flooring in bathrooms.

Then I poured the top.
 

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Discussion Starter · #13 ·
Heh heh, I wondered if you would see the similarities.

Blocks are a great idea and I though about it but I didn't have any lying around. This lot has only cost me the steel at this stage.

I'm scoping out using some spare concrete roof tiles for the lid - with a small amount of concrete and steel of course. /DesktopModules/NTForums/themes/mls/emoticons/tongue.gif Thats where the 300mm width I mentioned earlier came from so they fit nicely in the gap.
 

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Discussion Starter · #14 ·
Well, the lid went on last Saturday.



I glued some foam rubber to the walls first to stop any serious scraping if when we get a derailment in the tunnel, screwed some track down, then checked clearances

.







I used some old concrete roof tiles to cover in the tunnel.  I trimmed them up after this photo with a masonry cutting disc to make them fit together a bit better.  The blue tarp is stuffed in the tunnel to hold the foam against the walls while the glue took hold.





A bit more steel…  Yeah, overkill I know but I was  havin’ waaay too much fun by then..  :D







Then the final pour.  I just used dirt on the sides as formers and wedged in a couple of bits of ply at the ends to keep things roughly in shape.





And  this is the end result.







Portals are next.   At the moment I like the idea of having the tunnel entrances hewn straight from rock so I need to do some thinking around putting that together. 



Hope you’ve enjoyed..



Cheers

Neil
 

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Copy Cat:D:D:D:D I used Re bar in my tops too/DesktopModules/NTForums/themes/mls/emoticons/shocked.gif It was a good idea.
 

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Discussion Starter · #16 ·
Thought I'd throw in a quick update with the finished portals.

Eastern portal:





And the other end..





Cheers
Neil
 
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