Round earth-sheltered structure?

Anyone know of / have ideas for an earth sheltered circular (or hexagonal, octagonal, etc) structure? It seems that structurally this could introduce additional challenges compared to structures based on rectangles and might require some adaptations of the design (e.g. roof beams). Any thoughts?

I do not think so, to be honest with you, but I could see where a person might get that idea.

I have never lived in a round house, nor have any experience with natural building, but as a railroader I spent years working inside a "roundhouse" which is where they worked on locomotives. It was round because of how the turntable out front could send locomotives into twenty different bays.

I no longer work inside that round type of building, but I remember thinking of the structural details while doing so, that it was pretty simple and ingenious how they made it all work. In fact, I have always kind of thought that natural building in the round, like a WOFATI would actually be easier because of the inherient strength that comes from arches.

One thing I often do too, is look back to how people did things years ago. This could be a farm implement, a means of farming, or in this case, building a building. But my thoughts have always been, "if they could do it that way 100-200 years ago, that is definitely something I can do DIY in 2019." So to that end, I think of the original Fort Knox located here in Maine. That fort was built in the 1850's, and it is almost 100% comprised of brick and granite masonry in arches and vaults. That fort shows pictures on how it was being constructed, and so it has always given me hope, that if they could do so in 1850, surely it is something we could do in 2019 on a smaller scale with what we have.

This is not a very good picture of what I am describing of Fort Knox-Maine, but it does show how they were able to vault masonry so that it held cannons on the Fort's Roof above, and earth-sheltered the fort from bombardment.