If in doubt, get a bigger bomb. I present the GBU-57.
The stats are ridiculous. 30,000lbs overall. 2.7tons of high explosive. Will penetrate 60m of 5,000psi reinforced concrete, or 40m of rock. And then go 'boom'. Oh, and unlike MOAB which is dropped from a cargo aircraft, this one's designed to fit in a B-2, and it's guided.