Three hours are a very long time when pounded with artillery or raked with automatic arms...

You're going to survive three hours of pre-targeted direct or indirect fire?

TIL about Dexpan. Clever idea.

Also, as sibling says, good luck hammer-drilling under fire.

Do you need the hammer-drill if you can coax the OPFOR into firing onto their own fortifications?

Didn't someone make a similar comment about Cheyenne Mountain and SS-18s with 25Mt warheads?

You forgot the 3 hours of complete ceasefire you will require.

How would this work in very thick clay like I have here in Texas? Caliche is the native term.

For those talking about the "3 hours under fire": Dexpan is an expanding cement that cracks concrete over a few hours.

Once placed into a hole or crack, you don't need to hang around to do anything.

The reason for the hammer drill is to make holes in the dragon's teeth to put the Dexpan into. For that, you only a minute per tooth, and it doesn't matter where you put the hole, so you can use the teeth as cover from defensive fire while you drill.

Somehow, this sounds like one of those "use paintballs to blind enemy tanks" things that work out better in theory than practice.

A snazzy demo video for an anti-personnel artillery round: https://www.youtube.com/watch?v=G18Rwoa7c1kt25

The demo starts at :20 or so.