A road over swamp?

   / A road over swamp? #1  

yaouk

Bronze Member
Joined
Dec 18, 2001
Messages
52
Location
Yaouk, Snowy Mountains, Australia
Tractor
Dong Feng 254 (25 hp)
Repairing a dirt road is one thing, building a road over swamp is another.
I have about a 70 metre stretch of swampy ground that I needed to get vehicles across. It was covered in tussock grass. The mud is very, very deep; I actually don't know how deep but I know its over two metres! The New South Wales Lands Department would not allow any sort of digging or pipes or culverts because the wetland is protected under some UN agreement. I also was not crazy about digging the place up. I researched the benefits of geotextiles and geogrids but the ground was just too soft. So my only option was to utilise a flotation system much like a pontoon. If you can build a pontoon to drive cars over water, surely you could build a platform over mud. Trouble was the corrosive nature of that mud would decompose timber and even steel quite fast. Moreover, building a 70 metre road would take a lot of timber and steel!
Solution: I managed to get about 600 old car tyres, laid them flat on the ground (no digging) and bolted 'em together to form a kind of permanant form work. From overhead it looked like a column of "000000". You'd be surprised how eager tyre dealers are to get rid of these things. Moreover, tyres are extremely tough, environmentally stable, and they should last about 100 years in that mud. A row of about six or seven tyres makes about a width of 3.6m. A good width for such a long stretch. Then I got 100 tonnes of crushed concrete (25mm). This stuff has jagged edges and so locks in together quite well. And its small enough to give a smooth ride. Each tyre had to be packed tightly by hand, and that was mighty tough. The tyres act like formwork holding the aggregate together; end result is the whole shootin' match 'floats' on the surface. As a vehicle rolls over it, the natural tendency of mud is to splay out to the sides. The aggregate aslo tries to do this but the amazing strength of the tyres holds everything in place. What really surprised me is how well the thing works! (or maybe that it worked at all!) There are some holes underneath that twist tyres up and they break loose but I just rip those up and fill in with more aggregate. The Lands department were happy with this system because the hydraulics of the wetland system were not disturbed and because water can easily flow up and over and even through the aggregate. The vegetation is starting to return to the construction site after a few months and it does not look as ugly as it used to.
Surely this system is not for evryone but I was happy to utilise so much recycled (and clean) material to make my crossing. My estimates set the load rating at about 5 tonnes max. It could take more but it would cause damage.
Its always satisfying to do something bizarre, that works!
Merry Xmas
 
   / A road over swamp? #2  
Yaouk,

Must have pictures!! Please!!

So the Enviromental people didn't have any problems with the use of the tires, that is interesting.

Sounds like a really creative and great solution to your problem.

Terry
 
   / A road over swamp? #3  
I'm impressed. That's a very ingenious way to solve a nasty problem!

Good job!
Henry

P.S. Picture's would be appreciated!
 
   / A road over swamp? #5  
Hey George !

Sounds like a great project.

Welcome to TBN from a fellow Aussie Member !

There are very few of us here so it is great to see another one of us elite Aussies !

These yanks think they know things..... Well !!!!!!! /w3tcompact/icons/tongue.gif

Only kidding guys - We luv yous all !!!!

Cheers

<font color=blue>Neil from OZ.</font color=blue> /w3tcompact/icons/smile.gif
 
   / A road over swamp? #6  
Yaouk,

Interesting solution to a difficult problem. I can only imagine how much work it took to bolt all those tires together, not to mention hand packing all of that stone. I would guess it took more than a day or two./w3tcompact/icons/smile.gif

I am not sure I understand what keeps the stone from being pushed through the center of the tires? It would seem that with 2 meters of mud under tires, the stone would just work its way deeper into the mud each time it was driven over.

I also think it is great to find a way to reuse materials that would end up in a landfill. Sure hope you will let us know how thing hold up to time.

MarkV
 
   / A road over swamp?
  • Thread Starter
#7  
Thanks all for your kind words.
MarkV is quite right. It is a very labour intensive system and it took a very long time to complete. But sometimes you have no other choice (especially when you have no life) :(
On some spots the aggregate does get pushed down, but then I go over and fill in with more. It does not take much fill before enough is in to provide a solid surface. The mud is not like water; it does have some consistency.
As the tyres are bolted together, they act as one peice of material, like a raft on the surface, and as you would expect spreading the weight over a larger surface means it is much harder to make it sink. Under vertical pressure the aggregate tries to splay out to the side, so the circumference of the tyre takes this load. Why it does not go straight down is, I think, just a matter of sharing the downward load laterally onto the circumference of the tyre as well as vertically onto the surface of the mud.
By the way, I used the loader on my little 25hp Tractor to loader aggregate onto the back of my truck and then backed it out to the worksite and shovelled the stuff in.

Here are two piccies that were taken when the crossing was half way across. They were taken in late winter so all the grass is brown and bowed over from the weight of the snow. I live in one of the few places that get snow in Australia. The distance shot gives a a perspecitve of size with one bank in the foreground and the rising ground in the distance is the other bank. You can just make out where I cut the grass; thats where the crossing eventually went.
Remember the crossing itself is only half way across in this shot. Don't be fooled by that big rock, its all muddy out there.
The close up shot shows some filled and some empty tyres. It aslo shows that the water table can rise when its wet. That water can diffuse through or run over the top.
Mud is starting to be trapped in between the aggregate now and water cannot filter throguh as easy as before. I don't mind too much because, hopefully, it might promote some vegetation growth which would take up some water and provide extra consistency for the structure. (well thats what I hope)
Whats funny is that the local rock wallabies and wombats have got clued in on the crossing as a way of keeping their paws dry to cross the swamp. Sometimes driving across at night is a slow process as you drive at a snails pace behind a fat wombat, wobbling his/her way across. They won't jump off into the mud anymore. At first it was cute, now I am starting suffer wombat rage!
 

Attachments

  • 33-92439-crossing.jpg
    33-92439-crossing.jpg
    52.6 KB · Views: 2,705
   / A road over swamp? #8  
yaouk,

That's quite a project. I, too, have a muddy swale that cuts across the entire width of my property. I have to cross it to get to the other half of my property. It is not nearly as large an area as yours.

It is is true that vegetation will help support the weight of the tractor--sort of like a strong layer of surface tension. Howver, left unchecked, my vegetation in the area is 10' high phragmites (reeds) and 6' high cattails in the wetter areas. My theory is that keeping them cut will help dry the area a little from evaporation. The problem is I keep burying my tractor when I break through the vegetation surface as I am trying to mow. Then, as in your pictures, I dont have much nearby to attach a winch to, even if I had a winch, which I dont.

I am considering trying to drain the area, or buying very wide tires for my tractor, or building a few floating roads with beams and planks. The problem with the floating road approach is that I will still want to try to mow the vegetation because it grows so tall it blocks my entire view of my property. So, while I wallow around in indecision, my tractor ends up wallowing around in the mud.
 
   / A road over swamp? #9  
I had to build a road through a wet area. My road is only 90 meters long, but I was able to use fill and culvert pipes. I don't understand why they wouldn't let you use culvert pipes?? Most wet areas like that do not have a great deal of volumetric water flow, otherwise it would be a river... Anyway, you have definitley solved the problem for such severe road building constraints. Great job!

Joe
 
   / A road over swamp? #10  
I resurrected this old post...in hopes that someone has seen an idea for similar solution for a road over a swamp.

I have a large swampy area that divides my property. I sure would like to have a light-duty (8000# max) road crossing about 100 yards of this lowland. I've read about corduroy logging roads from time gone by....and giving it some thought. (I've got lots of pine timber and sandy fill to use.)

Suggestions? Other posts you've seen? Thanks!
 
 
Top