Trimming mesh and solid problems

Hey there!

Okay, I’m creating some 3D printed puzzles of terrains, so I just obtained a very accurate mesh with the actual shape of the terrain, and then I had extruded the pieces as solids, hoping to trim them with the mesh and obtain the solid with the shape of the terrain, but when I apply the command, apparently nothing happens.

Can you give any idea of how to do it?

(I share the file though Drive: