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Escape tunnels

28K views 54 replies 43 participants last post by  Survivalguy72 
#1 ·
A buddy is thinking of digging an escape tunnel thru his basement foundation and out away from the house(underground). A few questions come up and I figure some folks on here could help out. First, will smashing thru the foundation(small hole about 2ft around) affect the integrity of the foundation? Its a poured foundation, 8ft high walls of concrete in the basement. Second, after excavating the tunnel, should there be some form of support beams installed to assure no cave ins? 4x4's? ANY ideas on this subject would surely be appreciated.
 
#7 ·
I would think that it'd be much easier, and SAFER, after punching the hole in the wall, to just use a back-hoe to dig a ditch the size that you want.
Pour a concrete tunnel, then cover it up. You'd have to pour the tunnel floor, with rebar bending upwards for the sides let the concrete set, then pour the sides, and roof, in the next pour. Don't look to be much of a project.
 
#8 ·
It will be a ton of work, but it's not impossible. I would suggest an in depth search online to see if others have done it. Ultimately, it will compromise the integrity of your foundation, but you may be able to counter that. My guess would be to use floor jacks and braces to support the weight of the house structure above it while cutting out the concrete. Then once you have your hole have a reinforced steel frame measured and welded to tightly fit into place. Mortar around the hole to make a seal again. I'd highly suggest getting a professional opinion before attempting it. Maybe there is one on the boards :)

As for your tunnel the extent of which you reinforce it with is dependant on how much weight will be on it. If you only plan on having it ~6" deep and it's nowhere a car would go past, I think it would be safe to construct out of a 2x4 structure with a 4x4 frame and 3/4" pressure treated plywood. Water is your enemy and you will want to make every effort to seal it up before covering it up with wood. I would suggest building it, then caulking every crack. Then ideally you would use a rubber type spray to coat the tunnel on all sides. At the very least, use several coats of thick primer. Then cover it with a large industrial tarp or better yet, pool liner. When you fill the hole in over the tunnel use pea gravel around the sides. It will help with drainage but would be too heavy to use over the top. I would think that the 4x4 frame should be 48" on center and the 2x4s should be spaced out 6" on center. Dirt is heavy... and you don't want this thing collapsing in on you. Again, consult a professional before doing the project.

If you planned on going any deeper, I would suggest using concrete footers and a reinforced concrete slab over head. Again, moisture is your enemy, and sealing then covering the concrete will make it much safer much longer.

You may be able to get away with less, especially if you are only planning on having a small tunnel, but I'm claustrophobic in small tunnels (could never do the sewer tunnel thing) and would want my tunnels to be at least 48"x48" preferably 48"x72" because I am 5'11". Not having to crouch or crawl away would be nice. But it's not like your going to be using it everyday, so small is ok.

How long are you making the tunnel? how far are you going?. Where, and how are you going to exit the tunnel? All things to consider.
 
#11 ·
People that don't understand the hazards of digging often die from cave in's...people that do still die. I wouldn't try this unless I had a structural engineer give me directions and stamped drawings. That is, unless you don't mind making your house totally worthless and possibly condemned...if you are talking that the society has collapsed already, go ahead and do what you want; but things aren't that bad yet (and it might not happen for a long time).

There is a concrete saw, looks similar to a chain saw...you should hire this done unless you've done it before to make the plunge cut through a concrete wall. You'll also want a trench dug from above from the outside. the trench will need proper shoring while you complete the project. The project will probably involve structural steel in the hole that was cut into the poured wall and culvert matted to it.

The trench will need pea gravel properly compacted for drainage purposes. This is a pretty big project that shouldn't be attempted by a novice without proper engineering (IMHO).
 
#12 ·
Awsome answers. The pre cast concrete tubes would save alot of money. For the sake of OPSEC, I would'nt rent a backhoe for fear of the neighbors. He plans on diggin from the inside out!! Hauling it with 5gal buckets. The tunnel is planned to come out about 80ft away on the downslope of a hill so the "exit point" will be well out of sight. So for all you math heads out there...80ft x 2ft radius is how much dirt to move??
 
#17 ·
exactly what rugster said, and i'll add...

Take it out, a long ways. I don't know your acreage or money pile. That would be huge to pull off. Massive. To do it right and keep it from collapsing you would have to sink a pile into it.

you could look at a local cave system and incorporate that. Hard to find those since agenda 21 in my area at least gobbled that up. =(

a tunnel would be cool. I"m going with the armed to the teeth come and take it approach myself.
 
#18 ·
Just say your putting in a new drainage system etc, Do it the safe way use a backhoe. If you watch movies like the great escape youll see they had many people working and still had collapses to deal with. get some steel pipe and use that as your tunnel, but if its only going to be 2 feet diameter, I would suggest 3 at a minimum, you will need to lay a track and have a cart to move very well.
 
#20 ·
Good Christ. Anybody who thinks it's a good idea to cut an underground hole in their house and dig their way out...with no experience and without consulting an engineer first...deserves what's coming to them. Hopefully they don't have kids depending on them for a place to sleep and food to eat.

"Look Honey...it's the Darwin Award Committee!"
 
#23 ·
Good initative, bad judgement.

Does your friend have any experiance with excavating, concrete work or tunneling?There`s alot more to it than just digging a hole. Its serious work.

Doing this sort of thing without the proper permits or experiance is a good way to get his house condemed.
 
#29 ·
Just for reference sake we recently had a man die by cave in up here. He was working with a company that dug root celleras for the house. he'd been with the company about a year and accidently didn't put up the supports right. Digging anything is alot harder and more dangerous than many people think. It can go really badly really fast.

And I agree with the other posters. If it ever gets found out, you're house can be condemne. Even if it's an amazing A+ job and you dont tell the gov. They'll shut it down. better hope the back door is sealed and well camaflaughed. Don't want people walking in the back door. Plus I really doubt it's easy to sell a house with a hole in the bottom.

Just be careful. It;s a neat idea but might need a bit more thought.
 
#30 ·
First off, I would get some advice from a professional there are way too many things that need to be looked at.

You would need to analyze:

Concrete reinforcement in basement - location, type, spacing, if cutting it is ok.
Soil analysis - will it cave in, will digging damage the foundation (in combination with concrete cutting)
Hydraulic analysis - will water seep in from joints
What materials are going to be used - precast, cast in place
Construction methods - shovels, backhoe, jack and bore
What is the budget - with enough money almost anything can be built
Time/schedule - done tomorrow, next month, next year

These are just a small number of things I would want to look at. I would love to do something like this, and it is possible. I'm an engineer and have thought about it, but it would take a lot of analysis and planning prior to stating. That and I'd need to own a house first and need the money to make it happen.
 
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