Surfaces to melt on surface

I’m trying to make a sidewalk with height 20cm. I want to project all the surfaces above to the blue surface below that I created from the curves in the left. I tried tutorials that I see on internet and nothing worked the way I want it. What I’m searching is for a grasshopper that will melt the surfaces on the blue surface keeping their geometry but follow the terrain of the blue surface.

problem.3dm (690.0 KB)