What kind of explosive can I use for home excavation?

I'm thinking of building an underground home (hobbit hole if you need a suitable search term), and need at least three feet of dirt above me to also have my dweling legally qualify as a bomb shelter (we'll talk about my rampant paranoia another time ;) ). The only two that I found you can make legally is thermite and tannerite. The problem with thermite though is that, while it burns, it does not explode (at least not that I know of), and the problem with tannerite is that you need to shoot it with a sniper rifle that is going no slower than 2000 fps. As a result I really need to know of any other kind of explosive that I can purchase and/or buy. TNT is out of the question because of a number of obstacles, and where I'm not running a business that requires it, would be completely useless.

Also, just to nip this one in the bud, no I am not some kind of left/right leaning crazy, and no I do not plan to use this for nefarious means. I only plan to use this to make digging through rock easier, and what bit I've got left over, I am either giving away, or storing in the shed away from anything important. As for me having triggered some flags and now being on a US watch list you are talking to the guy whose 9th grade earth science teacher actually okayed a brief amount of research into how to make an atomic bomb as part of a paper that had to be written for class (relax...certain key information on how to do this has been left out for obvious reasons).