Answer:
You will never stop a rabbit from digging any more than you can stop a cat from meowing... it is what they do.
This said, some bunnies do dig more and some rabbits hardly ever dig. Often it is the girls who are most keen on digging.
You can try to channel the digging into something more productive, or less destructive, giving a bunny a big box filled with newspaper and hay can work by getting them to dig somewhere they are not doing damage.