Impending sinkhole in Carlsbad, NM

This article from New Mexico In Depth has an image/graphic that gives you a better idea of the sinkhole’s potential size.

I suppose you could go in with bolts and metal and drill into the rock to add in supports.

That would still be a monumental undertaking.


Because dirt will compact,leaving voids, and wash away.

What is the cost of re-routing the roads?

There are various options for shoring up sinkholes; we’ve dealt with the issue a few times at the plant I work at. In one situation, they backfilled with a foamed concrete (which will actually float if underfilled with groundwater). Another situation, they stacked blobs of… something, dunno if plasticky or concrete, which provide support to what’s atop the roof of the cavity. For the latter, the volume needing filled was too big for the concrete foam.

Average cost of concrete $90/cubic yard.

700’ x 300’ x 50’; more or less, we don’t know the inner height and doubtful it is a convenient rectangular space, just for rough estimate purposes = 390,000 cubic yards.

Cost of concrete alone: $35.1 million.

Plus the entire operation, man hours, machinery, boring holes to get it in there, making sure the whole thing doesn’t collapse while they’re working on it, etc.

Still, prolly a lot cheaper than the damages, cleanup and rebuild will cost.

When the forces of nature are doing something that big, sometimes the best thing to do is get out of the way.

I was hoping I could see the cheerleaders, what with all those football fields…

You willing to bet a few dozen to a few hundred lives that it will remain stable while they dig a huge ramp down into it and drive tens of thousands of trucks into it to fill it up?

I would imagine that it would be filled with riprap or gabions prior to laying down an artificial barrier, subsoil and finish grade. Dirt has to be compacted, rocks don’t.

Maybe we could get that impending landslide to slide right into it?

That doesn’t sound right. $90 for a cubic yard? Sure if you’re a domestic user, but buying in such bulk should drive the cost way down.

You’re not going to use mixer trucks. Standard ones only carry 8 cubic yards so you’d have huge queues of trucks. Better to have portable mixing plants on site and pipe it in directly. Wikipedia shows one which can do 550 cubic yards per hour. You’re still going to have long queues of trucks, but as they’ll be carrying dry materials, they can carry much more in a single load and you have a water source nearby. Just one at full capacity will take ~700 hours - about a month working 24/7 - to fill the hole so if you can feed four then you’ll be done in a week. The hardest bit is likely creating a tunnel big enough for people to enter to ensure the concrete spreads properly. Make sure they have inflatable rafts so they don’t sink in the concrete and breathing apparatus and lighting and <contd p.97>. Okay, it’s not quite that simple :slight_smile: and the devil is always in the details but it’s a start.

Great match of publication and topic!

It’s not my bet to make and I have no idea why you’d try and personalize this.

A bit of an overreaction there. Nothing personal and it wasn’t an attack.

Just an observation that this isn’t all that easy and the whole dirt vs. concrete thing is a red herring if you* can’t actually get in there long enough and safe enough to do it.

*obviously not ‘you’ on a personal level.

Okay; thanks. I don’t know how I might have gotten the impression that you were somehow implying that I was someone who would gamble “a few dozen to a few hundred lives” on what might be a dubious project.

Well according to the article I linked in the OP, that’s what they are talking about doing:

Well, if they determine that it is safe enough to do, then obviously that’s a better choice then waiting for it to collapse and take out the highway, all the nearby stuff and a lot of people in the process.

I agree in principle, but I started to have serious doubts about whether or not it’s even possible once I saw the map in blondebear’s link. I’m actually starting to think maybe

is the best policy here, but I know that sometimes humans have a hard time doing that.