It sounds like you want to ask a question that is fairly open-ended. We discourage that because we want to stay closer to a site full of "problems with direct solutions ranked from most to least useful" and farther from a site full of "conversations where a group of people discuss and guess and speculate about something but there's no clear solution."
We do accept questions about engineering history and to me that potentially includes historical designs and proposals. It's just so much harder to find a concrete problem to solve if the project was just an idea that was never actually constructed, built, attempted, etc. In this case, the idea being closely associated with some radical socio-political movement also introduces some risk of attracting off-topic discussion and argument.
It would be within reason to ask a question that focuses on a specific technological challenge that a project like Alantropa would have faced, and to mention Alantropa as part of the background of the question. But the focus on technology and/or design has to be there and the challenge has to be somehow comparable in scale to actual projects.
I can illustrate "comparable in scale to actual projects" for you by analogy:
So from how you describe your question, I agree with Glen; it would probably be closed as too broad. The scale is too far beyond what's realistic. Even if you limited yourself to asking and the proposed dam across the Strait of Gibraltar, rather than the entirety of Alantropa, we'd be talking about a dam an order of magnitude larger (guesstimate-by-volume) than the largest dams ever constructed, on a site that seems very unlike any existing dam site, so that might still be too broad (or borderline; I am no dam engineer).