Practical Engineering: Interlocking Block Retaining Walls

A typical new house site in Portland, Ore., where I work, is about 60×60 feet. Within this 60-foot square, the builder has to squeeze the footprint of the house plus find room to maneuver construction equipment. Building would be a whole lot easier if the site were flat, but most of the easy sites were grabbed up years ago. So now we either get into difficult construction, or flatten the site by grading. Grading nice stable slopes that won’t slide or erode takes space, lots of it. A nice comfortable slope for the area immediately surrounding the house is anything no steeper than 5:1 (5 horizontal feet for every 1 foot of rise). Still, this means