### id262791609 difference between gravity wells and cantilever wells > Your first inclination might be to extend the footing on the outside of the wall to extend the lever arm like an outrigger on a crane. However, it’s actually more beneficial for the footing to extend inward into the retained soil. That’s because the earth behind the wall sits atop the footing, which acts as a lever to keep the wall upright against lateral forces. Retaining walls that rely only on their own weight and the weight of the soil above them to remain stable are called gravity walls (for obvious reasons), and the ones that use a footing like this are called cantilever walls. - [View Highlight](https://read.readwise.io/read/01fqy7777bzgftdt45jyxspmrf) - [[Why Retaining Walls Collapse by Grady Hillhouse#id262791609 difference between gravity wells and cantilever wells|View in Vault]]