Chris, I think I'd try to put down objects to get in the way of whatever is digging. Annoy them if nothing else and they might go elsewhere. I had a persistent local cat one time that didn't get the hint, so I put down pieces chicken wire laying on top of rocks. They won't normally cross that since it's hard on the feet for them. You might want to try something like that. Of course, if its raccoons, they might try to shift or move the wire, so make it heavy in some way.
