GhostWithTheMost
Previously HoboSquirrell
Do you realize how much work it would be to dig over 860 cubic feet of dirt and rock by hand (12x12x6)? Underground shelters are a fine idea, but they're generally just bermed, not totally buried. Since you're doing this without help of motorized equipment, I'll assume you don't anyone to find out about it. Depending on where you're digging, this undertaking could take many months of work hours. You should seriously consider getting help with the digging. Also if you want to not risk death while putting in supports, you'll want to take the top of the hill off and fill it back in when you've finished the main structure and piping. I would also recommend reading the Fifty Dollar and Up Underground House Book by Mike Oehler. Be safe, and good luck!
You're making this sound A LOT more technical than Im actually planning, think simplified Hobbit House Im gonna add the supports as I get back into the hill, so It should be ok. I am Completely ok with Hours of manual labor. But thank you for the Ideas