Construction in different parts of the world really interests me a lot..
I've never seen this type of construction before. Here in Canada, and most of the USA, you would pour concrete in the basement, and most times at the end, when the house is pretty much built! Mind you the concrete that will be used will not be the same stuff as you buy at the store in bags and mix with water. They have higher density/pressure concrete that's infused with fibers (think of it like fiber glass concrete!) which will make it super strong and resist cracks.
The only thing I can think of that comes close to this kind of construction is cottage construction. Many cottages are build on the "canadian shield" which is basically rock. The only way to break this "earth" is with explosives! In this case, cottages don't have basements, but are rather build on piers. But even the base floor is from wood, and not concrete due to weather (-30 to -40 degrees C is common in the winter .. with concrete you'd freeze! Wood is an "ok" thermal break for sub floor)
In any case, keep up with the pictures .. very interesting.