Just had an "arena" built. It isn't exactly an arena. It's a 6' wide path with one end a circle for lunging and it extends into a larger oval so I can also ride a straightaway. The excavator (who has done arenas before) stripped off the topsoil down to the clay (about 6") and placed #10 limestone on top. He compacted it with a push machine.
I tried lunging my mare on it today and on the lower end it held. On the top end, it seemed to give on the top and she was slipping. Any ideas on what's happening?