Oooh, what an interesting thread. Ergo: delurk mode. Yes.
John, there are two main thoughts that your post inspires me, I believe.
The first is: when writing genre fiction, well, it's probably pretty darn important to know your genre. To read the masters, or at least to know about their work. Not just to avoid your current misadventure: I think it's Charlie Stross who observed that science fiction is a pretty tightly knit world, with writers constantly building onto each other's ideas. I don't have to tell you what a Dyson sphere or a generation ship are, because the concepts have already been developed by others; now we can use them with no string attached, and concentrate on the higher purpose of storytelling. And maybe build our own new ideas on top of theirs, for others still to reuse later on. Till then: let's keep reading.
The second is: what defines a writer is a unique voice, not necessarily a unique universe. From your brief overview of your novel, you've managed to convey to me something painted in very different colors from the works of Banks. So surface details match; my point is, maybe it doesn't matter. IMB's Culture universe is a canvas onto which he draws intricate plots with complex political and moral conundrums. You're going to use an outwardly similar canvas for entirely different stories, your stories. And that's fine. Especially in the genre of sci-fi, which, as said, reuses concepts a lot.
For sure, your work will get compared to that of Banks. Big deal, it's a flattering comparison! Maybe it's like negative reviews: it's bound to happen, so try not to let it get to you, and keep writing.
From there, the next stop is pretty obvious, I think. Get those Culture novels and devour them. I daresay you'll enjoy them; Banks is a brilliant writer with a vivid voice and a knack at constructing complex morally ambiguous situations. While there, I believe, you'll discover that your work and his are not so similar after all; only you can write your own stories, and if Banks were try, he'd fail big time.