i'm going with lucky guess. not only that, but these phrases are often taken however someone wants to. i've seen people take the same verse from the bible, and make it mean to opposite things. and if you look at it, it makes sense both ways.
i will say though that you seem to be taking two verses and misconstruing there meaning. while i will agree it is possible that is what they mean, it would seem more likely that the more obvious meanings is actually the meanings. for example, the verse “Do not the Unbelievers see that the heavens and the earth were joined together (as one unit of creation), before we clove them asunder?" would seem as if the most obvious way of taking this is that they seperated heaven from earth, like it says? it doesn't say anything about expansion, merely a splitting of the two. the other verse “We have built the heaven with might, and We are expanding it." seems to obviously saying that they basically made heaven through battle, and through battle are taking more, which still has nothing to do with expansion.
I'm not saying they couldn't be taken that way, it just seems like a stretch, from theists trying to justify their beliefs for which there is no justification. it's been said before, but i'll say it here anyway. you are supposed to take facts, and come to a conclusion. not take a conclusion, and look for facts to back it up.