I don't see any reason for that, remember that you are bumping not the steel blocks, but relatively soft piles of sand. any bump will immediately join them and if that formation decides to split again it will split in some new place.

in any case this is more sensible than suggesting that aliens sliced continents with big laser.
there is no way that earth could expand with no reason and expecially no reason why such theory would be required, because you will have harder time to explain that expansion mechanism and rewrite half of physic than just accepting some more practical solution.