/diy/ - Do It Yourself

I have an idea of how to do it.

You build something above ground first, a solid cube-like structure, then you dig a big hole and place it into it and bury around the structure except the top.

Of course, such a thing would be incredibly heavy and hard to move and might be better to construct while inside of the hole, but it would work.

And here is a hastily made animation of what I mean.