Dog is destroying my sod! Help!?

I have a 19 week old std poodle. In the past 3-4 weeks she has started pulling up sheets of sod in my back yard. It becomes a game with her, when I start freaking out she wants to run with a piece then run up and steal another piece from my feet. It's almost as if it's an obsession with her, she has several spots that she seems to alway head to. I've tried a dust thats supposed to deter animals from digging in yards and gardens. It worked for about a day, then she was right back at it. I will not be aggressive (hit) my dog as I believe all dogs derive their energy from us. Any suggestions (or causes) that you can offer to help stop this would be greatly appreciated. I do not have another $3000 to replace the yard again.