One of the great things about shipping containers is that they come with two big swing-out doors for easy entry/exit, and loading/unloading. These doors are easily secured and their size is a great boon for customizing and outfitting. Full-bury implies that additional doors or hatches must be constructed on the roof. Any material brought in or out of the container after placement is limited to the size of the hatches and any openings made in the roof must be waterproofed and secured (read locks). There are ways around this that I have thought of, and ways to fit out the container before placement, but none of these are simple or easy. Also, if the container shifts during earth movement there is a chance of any opening becoming blocked or jammed as the box is not rigid but surprisingly flexible. Even in normal use it is possible for the large doors to become jammed if the container is not placed on a flat surface.
Offered by Steve.
My plan is to bury it only 1/3 to 1/2 in the ground and then berm soil up against the sides, with about 3' of cover over top
(possibly with a water proof membrane buried over top). This would greatly reduce possible sidewall pressures and
provide protection against winds and projectiles. I would still do some internal bracing with 6" x 6" wood beams to
strengthen the sidewalls. I would also make sure there is more than one way in or out (I don't want to be stuck in anything
with only one way out that could be blocked), in particular a second access that would be a hatch that could open from the
inside and open inwardly. This emergency hatch should be buried on the roof but with most of the fill on top of it, say 2',
would be pea gravel. You remove the hatch, the small volume of pea gravel falls into the container and you dig out the last
foot of soil. This design is used in commercial under ground shelters and allows you to even dig sideways if there is an
object directly on top. These container suppliers can do just about any modification you want.
Inside, a plywood floor and the whole interior painted white to increase light reflection with a small light source. An air vent and hand pump would be necessary (ala Kearney's Nuclear War Survival book). The one end where the main entrance is would not have soil directly against that end, but a berm that is offset from the entrance. I'm still thinking about this detail but I'm sure I can make it work.
Offered by Kraige.