Building an underground base

[someone_else]

Let's say that a would-be Evil Overlord wants to build his own secret base undergound.

What would be the best shape? A bunch of road-sized tunnels connected together? A sphere? A dome? A torus/doughnut?
Made of what? Concrete? Steel frame in a hole dug in a very solid rock that stays together on its own?
What would be the best place to dig into and the best depth if it must resist a nuke detonation reasonably close (a few Km or so)?

And the door? Is there something better/faster than NORAD's door?

I read that most nuclear silos were built on springs or something that allowed them to dampen earthshaking after a near nuclear detonation. Is that possible/worthy to be added?

p.s. if this isn't the right section I humbly ask forgiveness.

[Uncluttered]

What's the evil overlords budget?

[Zixinus]

Likely big. Evil overlords and money usually goes together.

Though I wonder whether it would be cheaper to just buy a previously built base (say, built by the military) and renovate/expand that.

[someone_else]

I have no idea of the costs involved, that's why I've postulated an Evil Overlord as buyer.

Add "how much will it cost?" to the above questions.

[Shroom Man 777]

Just build a network of mud tunnels like the Vietnamese, small and crammed and miserable and difficult to detect because satellites won't see giant construction machines if all you use are a hundred Vietnameses with hand-shovels who dig a massive expanse of miserable tiny tunnels through sheer patriotic communist grit. James Bonds and SASs can so easily storm your underground fortress bunkers, or just dump a bunker buster on it. But if your fortress is unseen by satellites, and if it would take days for the spies and special forces to take it, and actually invading it would require them to crawl around hundreds of meters worth of tiny tunnels that only small Vietnamese people can fit in, man. You're invincible! How more Evil Overlordy can you get than a hard core Viet Cong Charlie commie?

I bet your stupid Evil Overlord Lists and dumb TVTRope subversion inversion invaginations don't cover punji pits with bamboo spikes smeared in cow shit and piss, so when the secret agent men step on it their foots get all infecteds and amputateds.

[Solauren]

For an underground base....

your best best would be to either take over one that was built by someone else, and customize it (i.e decommissioned bunkers, missile silos, etc), or find a large natural cave system and reinforce it.

The natural cave system would save you alot of the tunneling and digging (you'd have to do some of that, but not nearly enough). You'd just have to bring in people and some smaller construction machines via moving trucks.

A pre-built base is just that; prebuilt. Unfortunately, unless you acquire it via third parties, the government is going to know you have it.

Pricing is going to vary directly with the size and isolation of the base, just like any other building. Off hand, I'd say take the cost to build a similiar structure above ground, then double the price.

I'd 'budget' a project like this assuming I was building a office twice the projected size of the base (at minimum), and I'd also add on the cost of the required land as if I was in the highest priced area of the nearest major city.

Really, there are a whole lot of variables, but you're probably looking at at least double the price of a similiar above ground structure.

Personally, I think the best place for an Evil Overlord base would be inside a major office building, with lots of other companies also working in it. That makes it harder for the government to storm the building without having to deal with tons of lawsuits and legal nightmares from the other companeis you share the building with.

[Zixinus]

Well, yes, Shroom points out an important point: do you want the bunker to be built in secret or it doesn't matter? Because building in secret is a pain, like because you need to move a good deal of dirt around. Likely, you will have to balance price, secrecy, speed and quality (which can include everything from how protective the thing is, how comfortable it is, how much maintenance it would require, how stable it is, etc). There is also the question of just how deep the base is: something deep underground (or worse, under the ocean) is going to be hell of a lot harder than ground level drilling into the mountainside.

What you first need is a mining engineer. Exact cost would likely vary depending on where you build, what you place in it (what is the base powered powered by? nuclear? geothermal? or "outside" sources like solar or wind or hydro?), how self-sufficient is it (how well can you recycle water? how long do you want supplies to last? how many people and how long should it hold out?) and the site itself. It matters what kind of earth and rock you build, where (do you plan to build in the arctic? the north pole? the south pole? some Amazonian fort? the moon?) and what time. Some rocks will help with stability, others may be prune to crumbling and actually hinder it (you'll have to ask a geologist or even a mining engineer as to which will do which).

Then there is the issue of getting the expertese, the workforce, the equipment, the supply, etc. So, really, unless you can give a concrete scenario or at least a location, the question is an open one.

[Sea Skimmer]

Let's say that a would-be Evil Overlord wants to build his own secret base undergound.

What would be the best shape? A bunch of road-sized tunnels connected together? A sphere? A dome? A torus/doughnut?

That depends on if the bunker is constructed by cut and cover or tunneled. Cut and cover you can do anything you want as you are just constructing a building in a hole or on the surface and then burying it, with a tunneled base the only realistic floor plan is going to be a grid of circular tunnels. Tunnel width can be fairly large if you want, Cheyenne Mountain has some really big diameter tunnels, but the larger the tunnel the less shock it can survive. Lining depends on the rock and desired protection, as does bunker depth. The tunnels in Cheyenne Mountain are basically too big, which is one reason why the bunkers protection became obsolete fairly quickly.
http://cache.gawkerassets.com/assets/im ... -NORAD.jpg

You can see here the size of the tunnels, and all the rock bolts holding metal mesh against the walls. This controls spall and ensures that a pretty huge chunk of rock has to break off to crush anything.

Made of what? Concrete? Steel frame in a hole dug in a very solid rock that stays together on its own?

Depends on depth, ground material and desired protection. Cheyenne Mountain has no liner for example, it uses rock bolts.

What would be the best place to dig into and the best depth if it must resist a nuke detonation reasonably close (a few Km or so)?

Depends on how big the nuke is, but the best rock is going to be dry limestone. If you go down over 2,800ft in dry limestone then very little could ever hurt you including direct hits from 50 megaton weapons (other kinds of more common rock would require as much as 8,000ft depth for this(. However the difficulty of providing survivable emergency exits also rises almost exponentially with depth. You also have to worry about the enemy dropping a nuke into the crater of the first one. The US studied missile bases that would tunnel out after attack using tunnel boring machines, but it’s questionable that a TBM crew could survive tunneling through the radioactive crater ejecta.

And the door? Is there something better/faster than NORAD's door?

Not really. The main issue is a blast door needs to be radiation shielding as well as blast protection so it’s just going to have to be huge and concrete filled. You could make it swing faster if you wanted but that’d be really unsafe since it’s a 25 ton swinging weight. A number of steps must be taken to switch over the base from external to internal life support and power, so it’s not certain a faster door would actually let you seal up anymore quickly. A bigger problem is ensuring the door will open again after the attack. You also need blast and surge protectors values on incoming water and air vent lines which is a considerable problem in its own right.

I read that most nuclear silos were built on springs or something that allowed them to dampen earthshaking after a near nuclear detonation. Is that possible/worthy to be added?

Anything that’s going to survive a substantial earth shock has to be on springs; that includes some civilian buildings meant to resist earthquakes. In the case of Cheyenne Mountain the buildings in the tunnels are on springs, and then key equipment within the buildings is on more springs. Nuclear silos being close to the surface work a little differently. The silo isn’t on springs, but the missile within the silo is hanging from the ceiling on chains, the sway of which is controlled by springs.

The missile launch control bunker meanwhile is basically a concrete pipe about 30-40ft underground with a metal building hanging from chains inside of it.
http://img169.imageshack.us/img169/460/ ... lityde.jpg

Shallow facilities like this can survive into the range of 1,000psi-1,500psi under optimal design conditions (US missile facilities are at the lower end of this range and originally designed for only 300psi), bunkers built on the surface can survive up to about 250psi (really excessive mounding over with earth might raise that but it’d get insane quick). These values wont let you survive a direct hit like a 3,000ft deep bunker would, but they do force a high yield nuke to land within less then a kilometer. More importantly they make entry and exits easy, you can have plenty of space, you can even have aircraft (I’d suggest quick escape is absurdly better then riding out nuclear attack, use surviving bunkers AFTER the attack to survive the fallout) ready to roll of out of hardened shelters. Deep bunkers can work well as military command centers, but they pretty much assume its OKAY that escape may be impossible. All that matters is ensuring a coordinated nuclear counter attack is launched. This is why facilities like Cheyenne Mountain are rare. Even if money is no issue, dozens of smaller bunkers simply make more sense for 99% of tasks.

[Shroom Man 777]

Also, Skim, aren't those hardened bunkers very much not secret because Soviet/American/whatever spies and spy satellites basically see them doing the construction process, and all the men and material needed and the building time basically makes them very visible, not to mention the earthworks needed for that kind of stuff makes them easy to spot in spysats? Aren't quite a few of those HUEG bunkers used as missile sponges, where they are built precisely so that the Soviets/bad guys will target missiles at them and waste their warheads on missile sponges instead of hitting other more valuable targets? Say, like, build HUEG BUNKER A not because you want to hide in it, because it WILL be destroyed by ICBMs, but because it WILL be destroyed by ICBMs and the enemy will waste his ICBMs in nuking the HUEG BUNKER A instead of nuking SAC BOMBER BASE B or some shits? And the enemy can't afford to NOT nuke HUEG BUNKER A because of the possibility that the facility might actually be useful! Man, doublethinking!

So this means that a HUEG BUNKER secret fortress is not actually so secret and is actually a very visible target for the enemy?

[Sea Skimmer]

Also, Skim, aren't those hardened bunkers very much not secret because Soviet/American/whatever spies and spy satellites basically see them doing the construction process, and all the men and material needed and the building time basically makes them very visible, not to mention the earthworks needed for that kind of stuff makes them easy to spot in spysats?

Yeah most large bunkers are going to be spotted in the construction phase. However if you built your bunker inside an existing building it’d be very feasible to conceal its presence given enough money. Basically take a two story deep basement built with a reinforced foundation (bunkers are damn heavy, having soil able to support them is a serious issue), fill the upper basement floor with concrete as protection and put the bunker on the lower floor. You can move in materials by small tunnels running to other buildings, so the construction truck traffic is dispersed. Also this removes the need for excavation and thus disposal of large amounts of earth. Saddam had a bunker like this in downtown Baghdad but the Swiss guy who helped them build it then went and gave the plans and location to the US government. The thing still survived every conventional weapon we had in 2003.

The problem with urban bunkers, aside from urban centers being nuclear targets, is rubble. If the bunker is under a building then a nuke or conventional attack can bring the building down on top of it. That means air vents and escape routes are easily blocked and need a lot more physical protection then a bunker buried under a treeless mound of earth. But this really depends on local geography; a park across the street from a government building for example could provide some nice low profile manholes for emergency use.

Aren't quite a few of those HUEG bunkers used as missile sponges, where they are built precisely so that the Soviets/bad guys will target missiles at them and waste their warheads on missile sponges instead of hitting other more valuable targets?

Cheyenne Mountain certainly wasn’t built as a missile sponge, and I am very skeptical any other large bunker was deliberately built as a decoy. The only exception might be the UK continuity of government facility at Corsham Quarry. However that is only semi deliberate construction, as the underground quarry had already been extensively built up as an underground aircraft factory in WW2. It also had really bad protection in the first place. Quarrys and mines can provide ready made underground space, the problem is the floor plan of the tunnels tends to suck and the roof wont be supported in an optimal manner for military purposes.

Large bunkers do have a missile sponge effect, but it’s the combination of heavy bunkers and ABM that would be the real killer. Now you don’t know if shooting 12 missiles at one bunker is even going to work at all, even if the enemy only has 50 ABM missiles and you have 200 attacking missiles. So you better shoot at least 51 missiles at that bunker… now we have some real attrition. Course ABM got banned, but that was after the first wave of large bunkers like Raven Rock and Cheyenne Mountain where built in the 1950s and 60s.

Anything much newer then like the reported Russian megabunker at Yamantau may well just be deep enough to survive any feasible bombardment. Mines in South Africa go as deep as 12,000 feet, nothing is stopping someone from placing a nuclear powered command center that deep if they wanted though 8,000ft seems to be a more realistic max depth for what would ever be required. This chart shows some estimated burial depths for withstanding a 100 megaton ground burst. The top depth value is the best case scenario, the lower depth is the certain protection depth at which point a 800 megaton bomb is estimated to be required for a kill. This assumes a moderately hard tunnel liner. Concepts exist for superhardened ICBM silos that can survive within the edge of a nuclear crater at the surface, no absurd depth needed, but its unlikely human personal could ever survive inside those silos while they rode out of the blast.

Most bunkers are just built near the surface, because aside from being cheaper it’s just astoundingly easier to operate and maintain such facilities as useful space. It means you can have features like the ability to drive trucks of supplies and kidnapped hero’s girlfriends right into the facility. Also you have the realistic chance of someone digging you out of all entryways are collapsed, a serious threat from a modern conventional weapon attack.

Say, like, build HUEG BUNKER A not because you want to hide in it, because it WILL be destroyed by ICBMs, but because it WILL be destroyed by ICBMs and the enemy will waste his ICBMs in nuking the HUEG BUNKER A instead of nuking SAC BOMBER BASE B or some shits? And the enemy can't afford to NOT nuke HUEG BUNKER A because of the possibility that the facility might actually be useful! Man, doublethinking!

If the bunkers didn’t cost so much that’d make sense. In reality missile sponge is more of a tacked on role, a reason not to get rid of facilities which are effectively obsolete as anti nuclear protective structures. Missile sponge capability couldn’t even matter until after the SALT treaty capped the expansion of nuclear arsenals in 1969.

Concrete and tunneling aren’t that expensive really, making bunkers to merely shelter equipment against conventional weapons pretty cheap options. But when you want people to live in a bunker and ride out a nuclear attack you need some very lavish fittings, the blast doors alone for a bunker can be a quarter to a half of the entire cost of the place, and this makes decoys fairly illogical. The enemy after all has a very long time to figure out if the bunker serves a useful purpose or not.

So this means that a HUEG BUNKER secret fortress is not actually so secret and is actually a very visible target for the enemy?

If it was going to go into the tens of thousands of square feet then you aren’t keeping it secret, especially not today when so many additional civilian reconnaissance satellites are operating. However you can hope to prevent the enemy from knowing what the hell the bunker is being used for, particularly if you have a budget to order extraneous equipment and build decoy support structures on the surface (air vents ect…). That’s a time when once more, numerous smaller bunkers start to make a lot of sense. So in bunker spam North Korea and evil overlord is going to do better hiding then if he tried to build in some peace loving craphole that never had a duck and cover drill in its entire history.

[Shroom Man 777]

I still say we outsource this to the Viet Cong.

[someone_else]

I bet your stupid Evil Overlord Lists and dumb TVTRope subversion inversion invaginations

The best base is no discernible base at all. But this isn't what I was asking for.
You raise a good point on satellites spying stuff and detecting the equipment with ease. I'll address it in the answer to Zixinus below.

your best best would be to either take over one that was built by someone else, and customize it (i.e decommissioned bunkers, missile silos, etc), or find a large natural cave system and reinforce it.

I'd like to ask if a natural cave system is a safe place for a structure that must resist nukes (or bombings for that matter).
I know that most rocks that have caves in them are not particularly strong, and a nearby explosion may heavily damage the cave (dropping BIG rocks on my equipment) or outright collapse it.
Am I right or not? Althoough Sea Skimmer talks about dry limestone as the best material, and that's a rock were natural caves aren't so uncommon.

do you want the bunker to be built in secret or it doesn't matter? Because building in secret is a pain, like because you need to move a good deal of dirt around.

I hope hiding in plain sight is easier than hiding in the shadows.
I was thinking about piggybacking another Big Engineering project, like dams, mountain-tunnelling, building a cyclotron, a mine and so on to have a good reason to move so much earth and have so heavy equipment, then using them to build the base nearby.
The Big Engineering project will be funded by the Evil Overlord's pockets and/or made by his engineering/mining companies and that will probably rise the cost of the secret base to sheer ludicrousness, but the structure used as a cover may be able to pay for itself (dams, mines, mountain tunnels) or receive funds from the government (cyclotrons and similar research stuff).
Will that make a secret underground base remotely feasible (albeit at a very high costs) or not?

A particualrly evil (although maybe extremely stupid) idea. What about building an underground base in the water basin of a dam? That will keep earth-moving to a minimum since it is close to surface, but then will add the water on top. Assuming the base is made to hold the additional weight (if it is at all possible), will that body of water protect from a nuke to any significant degree? Or will it just make a "depth charge" effect where the overpressure wave in the liquid comes to bite my underground ass?

Personally, I think the best place for an Evil Overlord base would be inside a major office building, with lots of other companies also working in it. That makes it harder for the government to storm the building without having to deal with tons of lawsuits and legal nightmares from the other companeis you share the building with.

while the "meat shield" idea isn't wrong, I think any kind of base is a bad idea since it can be stormed anyway. It's not like they will care of lawsuits if they want to stop a Doomsday Device or something along the same line. The best way is to scatter the organization and keep in touch with Blackberries or computers using Tor or some other anonimity-oriented data transmission protocol. Which is more or less what serious terrorists do today.
But is soo gritty and unglamorous.

Two posts

Thank you. A lot. Some thoughts about them below.

However the difficulty of providing survivable emergency exits also rises almost exponentially with depth.

No problem, I've got NUCLEAR DRILLS!!!! BWAHAHAHAHA!!!!
Yeah. It's ludicrous, but extremely fun.

but it’s questionable that a TBM crew could survive tunneling through the radioactive crater ejecta.

Well, they can tunnel orizzontally for some kms before rising to the surface. Although that may require a lot of time.

The main issue is a blast door needs to be radiation shielding as well as blast protection so it’s just going to have to be huge and concrete filled.

I was thinking, radiations go straight, so if you make a door in one ned of a L-shaped tunnel, radiation will only irradiate some empty corridor.
Although this doesn't help in dampening the blast, so the weight saved is debatable.

A number of steps must be taken to switch over the base from external to internal life support and power, so it’s not certain a faster door would actually let you seal up anymore quickly.

I admit my ignorance on this . Can you explain a little more? What steps and how long?
That's for a large base like NORAD or even smaller bunkers have to?

The missile launch control bunker meanwhile is basically a concrete pipe about 30-40ft underground with a metal building hanging from chains inside of it.

They used chains since it was cheaper than using springs for a so small bunker or was there another good reason I don't see?

Also you have the realistic chance of someone digging you out of all entryways are collapsed, a serious threat from a modern conventional weapon attack.

Are bunkerized and redundant escape tunnels of multiple km lenght going in any direction possible (albeit maybe a little expensive)?

This chart shows some estimated burial depths for withstanding a 100 megaton ground burst.

"this chart"? What chart?

[The Grim Squeaker]

Buy an old abandoned Nuclear silo in the us, and patch it up. There are a lot of them, some isolated, some not, and some even come with their own underground railway lines. Cheap, cost effective, and awesome (it's tons of space for pennies! Under tons of reinforced concrete ).
Power would be best served by a mix of geothermal [best] and hydro [better] or solar [bad] or wind [worst - least reliable] power - it's not THAT expensive, and works better as a back up than a gasoline generator.

[Shroom Man 777]

Uh, no. You need to be in a geothermically active place to use geothermal energy, you need a body of water for hydro, solar panels outside for solar, and windmills for wind. Whereas you can take a fossil fuel generator, horde up on fuels, and run it inside of your underground lair irregardless of seismic activity, or if your local waterfall's run dry, or if the day is cloudy or whatever. Or you can use an RTG. Sorry, DAETH.

Graph me, Shep.

[LadyTevar]

There's thousands of abandoned mines throughout the world that could be purchased cheaply, many of which have miles of underground tunnels. Some Appalachian towns have massive mines tunneling beneath them, a ready-made screen from satellites. The town would also supply a ready work force.

[Sky Captain]

Yeah, forgotten abandoned mine might be the best bet if you want to keep it secret. Most mines already have many km of tunnels. Also those tunnels provide a convinient place to dump dirt if you decide to modify the existing layout of mine so no suspicous traffic of heavy trucks carrying dirt out of abandoned mine. Or you could simply establish a mining company as cover, buy and reopen an old mine and start mining ore there while also building your base. After all it's not uncommon to have old mines reopened when better extraction technology comes or price of the metals go up making it profitable to mine lower ore concentrations.

[Uncluttered]

The reason I brought up budget, is if you are willing to give up the nuclear bunker, or want to be a hip urban evil overlord, you can use an abandoned pump station.

I've spelunked a few recently while working on a project.
Some of these are HUGE and they go 10 or more floors deep. Inside are:
Giant pumps
control rooms
massive open topped concrete bays.
elevators
conveyors for grit.
Generator rooms
Boiler rooms
Brackets for mounting a pneumatic tube system.
Radio room
Bunk rooms (these were manned 24x7 before automation)
kitchens
small cafeteria
Some have high fences around the top shack.
Some shacks are surrounded by marshland.
Each station has a wet side, and a dry side. The sides can be crossed with a watertight ship hatch, but many designs force the workers to go up and down through the first floor on the surface.
Some shacks were made to look like brick houses, and are blended into neighborhoods.
One station had a stone house near a shopping mall. By knocking down an underground wall, you might be able enter the mall basement garage.

There are often side tunnels to sewer, subway, and even nearby basements of buildings. One even had a 10 foot wide tunnel that went out into the ocean. From there it was distributed miles out into the ocean.
The pumps are often too big, or too obsolete to move, so they are usually left there when the utility abandons it.
I'm sure an evil overlord can find a good use for them.
Many of these are connected to the newer pump stations, but the entrances are welded or bricked up.

Here is the best part.
To find some of these places, I had to look into the utilities paper archives. Many of the surface buildings have been removed, and the only thing left at the address is a welded shut brick shack on the corner of a soccer field or playground.

Instead of building a huge base. Co-opt one of these. To hide it, simply destroy the paper blueprints.

The sad part is. No single location has everything an evil overlord could desire.
The one with the ocean entrance would be great for mini subs, but the building on top was conspicuous.
The one near the mall had potential for evil vehicle parking, but the bunk room was gone.

For a few million dollars worth of labor, I think these are a better purchase than an old bunker.

[madd0ct0r]

Uncluttered may have it for a Minor Evil genius's budget

But for real over the topness, why not use the Nuclear Mole itself as a base?

Beef up the size and power output and you should be able to move a little faster then the estimated 100m/day, especially if you aren't concerned about leaving a nice tunnel behind you.

Replenishment of different elements should be possible - just extract them from the gasses given off by the molten rock.

[Sea Skimmer]

A pump house would be pretty cool if you could forego nuclear protection, but it also seems like its just begging for the hero to find a way to flood the place. That new Japanese mega storm drain system would make an exceptionally awesome secret base complex if it was somehow forgotten.