If you still don't think it'll work, I get the feeling it's your prejudice or force.

It should work if you make it into frames = 3d prints.

concrete = dried clay after paste.

ocean = bathtub.

 

if that fails, then issue with flattened surface.

uneven. need a material to bind between ground and structure.

but thickness and weight should sustain block from water.

 

when all is done, corners welded can be cut down with a cutting machine following a track.

then, from maybe a pre-installed holding grip. A hollow rectangle metal rod that was embedded into the cement into the walls, can be lefted with a hook. one by one.

Dismantle and use again.