A cantilever retaining wall is one that consists of a uniform thickness wall which is tied to a footing. A cantilever wall usually is asked to hold back a significant amount of earth, so it is a good practice to have these walls engineered. A simple example of a cantilever retaining wall is a typical basement wall of a house.
The width of the footing for a cantilever wall is very important. The footing is designed to resist tipping or sliding forces which the earth exerts upon the wall. Also, the wide area of the footer allows the weight of the earth to actually keep the wall from tipping in some instances.
These walls require significant steel reinforcing in both the footer and the wall structures. The steel also has to extend from within the footer up into the wall so that the two pieces actually become one integral unit. As you can see, this is why these walls need to be designed by structural engineers. If you try to guess yourself at the amount, size and placement of structural steel in this type of wall, you are gambling.
Also, the thickness of both the footer and the wall is extremely critical. Don't be a fool and try to become a weekend engineer. Spend several hundred dollars and get it right the first time!
Counterfort Retaining Walls