Just an idle thought of mine: Wouldn’t it be easier and more effective to build a fortress out of shipping containers? It’s not like you can’t find thousands of them almost everywhere. And if you put them one on top of another you’d get a wall 19 feet high and 8.5 feet wide. It’d also be crazy heavy and you could fill it with dirt or whatever to make it heavier.
That’s a good idea.
Hey you stole my plan! ;-)
It’ll take a lot of fuel, which will be too hard to obtain during the ZA.