I didn't speak about the weight of the raised structure (foundations, ground, structure, ...). [#-o]

As for soil volume and depth, you probably want to consult an arborist / read up on different root systems, shallow and deep. But yes, gut feeling says depth, volume and weight should not be major obstacles for a raised atrium. Whether Miker777 likes the solution from an aesthetic point of view is, of course, a different matter. Just trying to be a pain-in-the-rear besserwisser. ok