Hamster burrows in the wild can be a few metres deep. Males are often a bit more lazy, but female hamsters have potential pups to think of, so have an instinctive urge to dig deep tunnels. If she can't get past an obstacle with her paws, she will try her teeth and even try to lick at it to "soften" it, but plastic is not like plants and cannot be bitten or licked through (unless you are a gerbil). I'm not sure what the solution is. Other girl hamster custodians might have solutions for digging and biting.