Ok, I have a russian tortoise, and he will NOT stop clawing at the walls of his enclosure. I have a sulcata that I've had for 10 years that digs a lot, but he doesn't claw at the walls.
The russian just goes into a corner, and claws, literally, for 10-12 hours a day. When I feed him, he eats, and when I take him outside or whatever, he moves around and basks in the sun, but in his enclosure indoors, it's the same thing from morning til night.
Thump. Thump. Thump. Thump. It's like chinese water torture listening to this all day (I work from home and have an office downstairs)
His enclosure is pretty big, it's an opaque white plastic container, with the normal substrate (shredded newspaper, sometimes grass or repti-sand) He's got a water bowl which he'll occasionally bathe (and go to the bathroom) in. he's got a hidey box on one end, away from his heat lamp, and a food bowl near the middle.
I've heard that clear plastic or glass walls can stress a tortoise, because they see through, and think they can get to what they can see, and will attempt to claw through, but his enclosure is not see-through.