

Also consider that you have to add in some safety margin just for shits and giggles plus to compensate for the materials aging over time.
I spent quite a lot of time in Iraq and saw some of the buried shelters that were only underground partway, and they were all buckling under the pressure. Not saying that you CAN’T bury a shipping container as an underground SHTF bunker if you do your homework and spend a lot of extra money and effort supporting it but you CAN’T just bury one in the ground at any appreciable depth without some supporting engineering and there are other considerations above even that.
Just for reference, a cubic yard of dirt weighs somewhere between a ton and 2700 pounds or so.
I bet you were thinking that I was about to give you plans about how you should dig a hole for a cheap underground bunker with a door to be used for a simple SHTF/TEOTWAWKI survival bunker. What I’m here to tell you is that if you listen to pretty much all of the crap advice on the web, that you’ll be wrong again. They’re called Intermodal Freight Containers because they can be moved on trains, boats, helicopters, whatever. They were not to be buried or cut into, and certainly weren’t designed to be used as underground bunkers.
Once you do that, you start changing their effectiveness.