The builder just sent me a photo of the extra depth he had to go to in order to hold up the driveway on this sloping block. I can't believe the size of the hole needed for the foundations, or the exta concrete he will have to pour to fill it.
It extends 2-3 times bigger than what you can see in the photo. The photo is the west-east portion of the retaining wall. There's also a north-south portion that runs to the house.
I gotta say - if I were planning to dig a hole this big - I wish it were for a nice big wine cellar or bomb shelter rather than just holding up my driveway.
On the other hand - who wants a sloping driveway that risks collapsing the retaining wall in on the house.