Subterranean Rammed Earth

I was musing about an alternative to tires/PSP as structural elements for underground housing.  Would reinforced rammed earth (externally insulated on earth bermed walls, 5% cement) be feasible as a load bearing surface for an underground building?

Thoughts?

also, first post, long time reader

Cheers,

I was thinking this as well. I feel the problem would be the lateral strength of a rammed earth wall. Being that there is not as solid of cohesion as a stone or concrete wall.

It may work with proper reinforcing. Though when i read the underground house book it seemed he was using rammed earth he just left the forms in place. I believe he would put up some boards add plastic the ram the earth behind it.

I think the universal answer "it depends" applies.  How thick?  How tall?  How much load?  Tapering bottom?

And maybe, "How much cement was added to the rammed earth?"

Kathleen