Stardate 20030320.1649

(Captain's log): Paul writes:

I wondered why Saddam's hideout should be anywhere other than deep underneath the Hotel of residence of the foreign press. No utilities and totally safe from bombing.

Please tell me they the US and UK have thought of that and somehow excluded it. I'd love to know how

A building doesn't stop at the surface of the ground. All buildings have to have foundations, and for pretty much any significant structure (say, 3 stories or taller with a steel frame) they're going to have to drive pilings.

When I lived in Boston and worked for a while in a 12-story building in Cambridge (right next to the Alewife parking structure) they decided to build another building, seven floors, on the same site right next to us. So over a period of months I observed the entire process.

And for the first month or so, it was impossible to ignore because there was a piledriver there hammering concrete-encased steel pilings into the ground, hitting every couple of seconds. Even in my office, I could feel the entire building jump a bit every time they hit it. (After a while you learn to ignore it, but it was a relief once they got done.)

In that part of Boston, it's an old river-plain, as well as having been under glaciers for most of the last iceage. The mud and clay goes down a long way. They actually had to drive 150 feet down to find something sufficiently solid to sit on. I might mention that the geology of the Tigris/Euphrates valley is even worse since that entire area has been produced by erosion and sediment deposition by those two great rivers. I suspect that pilings under significant buildings there have to go down a very long way.

For the building next to us, they put down a square grid. There were close clusters of four pilings within a 2 meter square, with clusters spaced about 6 meters apart in both directions under the entire footprint of the building. You have to do that, because if the pilings even settle a couple of inches over the life of the building, it can have disastrous effects, especially if they do so unevenly. If you had X-ray vision, what you'd see is that the entire building is standing on stilts – lots of stilts, closely spaced.

It's not just a matter of the pilings being on something solid at the bottom; the entire volume of soil they run through contribute to supporting the weight of the building. If you go in later and try to mine out a big space down there within the volume that the pilings run through, even if you don't care about having lots of pilings running through that space, you're going to get structural failure in the building topside because the foundation would settle. And if you mine out a space below the bottom of the pilings, you'll be undermining whatever the solid layer was that the pilings ultimately rest on; and the building will still be threatened. It isn't really possible to do that kind of thing without causing at least some shifts in the entire overlying volume of the ground.

The only way such a bunker could be under that hotel would be if it had been built there at the time the hotel was put up, basically being part of the building and sitting on top of the same foundation and same pilings. It'd be sort of like how subterranean parking structures are put under some buildings. In that case, there would be no way to keep it secret, and in that case it (the hotel) would be a legitimate military target.

But if something like that had been done when that hotel was originally built, I think we'd have heard about it by now. That hotel was built before Saddam thought he'd face us in war, and there isn't any other opponent he thought he might face against whom more normal bunkers would not be adequate defense.

Single-story buildings (e.g. schools) don't require foundations like that, and you might plausibly be able to tunnel underneath one and to mine out such a volume. But it's a very tricky problem, especially if the soil is not very solid, which it isn't there.

And if the area you're working in is under the water table, then it's really a bitch. In that case, you're not digging a bunker, you're digging a really strangely-shaped well, and it's going to fill with water unless you are constantly pumping it out. Though there are no foundations to worry about, if you screw up the ground above you could still settle (possibly right on top of your head) and the structure could still be damaged or destroyed.

It should also be pointed out that this kind of tunneling and construction is extremely difficult and requires a lot of extremely specialized equipment, which is only available from a small number of manufacturers in the world. It's also impossible to disguise the fact that this kind of thing is going on. Which is to say, again, that there's no possible way to keep this secret. If they'd been doing this, we'd know it and we'd know where. And if there's a military command bunker underneath a school, then under the Geneva Convention it's a legitimate military target.

Not that Saddam cares, but putting that kind of military structure in or near or under civilian structures is a "war crime", and bombing them is not a war crime. Of course, the political fallout for us would still be a problem if such a thing had been done.

I don't think it probably has been, however. Ignoring any issues of morality, it's just plain tough and expensive. During the years up to 1991, there was no particular reason for Saddam to think he'd need such a thing, and since 1991 I suspect that it wasn't possible for him to buy the equipment he'd need.