I have been for a while also thinking of how to use these nice seal-able steel containers. They were designed to keep the salt and humidity out of the products on ships in the open seas. My thoughts in the past have been along the lines of 4 bolted or welded into a square or rectangle, partly under ground, or not, depending on the soil, connected so as to be able to move from one to the other. Dirt could be piled up on the outside up to the roof to help hold it in place. Maybe other units could be totally hidden for supplies in case of retreat due to being overwhelmed by gangs. If partly under ground I don't know what to do about potential seepage due to all the water. The rectangular configuration would give a protected open area in the middle for entrance and exit. Also, for fighting from - like the old covered wagons -pull them all into a circle. Could have some small well protected windows facing inside so can look out and up at the sky during the pole shift.
Foam padding would provide heat/cold insulation and the ability to hang things after the shaking stops and provide some sound absorption or deadening on the inside. One would need to be careful not to use a product that will continuously out-gas toxic gasses like formaldehyde, etc. I personally don't trust the spray foams I have played with. One could consider prefabricated foam sheets, Some investigation may need to be done to choose this. Should it be open cell, cell tight, firm, or soft? I ran into some ecological (low out-gassing) building products a couple of years back. I just recently looked and was unable to find it now. It might be easier to do an Internet search. I was thinking of using body padding to protect the body as this would move with me in case I am outside when the shaking starts.
Here's another idea which may be even simpler. Take 4 storage units and bolt/weld them together side by side, doors at opposite ends. With a passage way to get from one to the other cut through the walls. Placed on a open rectangular frame work base made of I-beams that sticks out about 10-12 ft on all sides. This I-beam structure would be sitting on the top of the ground with the storage units welded/bolted on top of this. Supports from the edge of this base back to the roof of the nearest storage unit, would make a strong triangle, to support this outer edge. This would be placed in an open area so that if it slid around a lot during the pole shift you wouldn't care. I doubt it would tip over. One would want to keep it away from water, from flooding areas. Having some doors on one end and some on the other end would prevent all the doors from being blocked due to plowing up dirt as it moves during the shift.
Offered by Mike.