Which type of cracking may indicate foundation movement at the subgrade?

Alligator cracking is characterized by a series of interconnected cracks resembling the skin of an alligator. This type of cracking typically occurs in flexible pavements, particularly when there's a structural failure beneath the surface layer. When a foundation or subgrade experiences movement due to various factors such as moisture variations, soil settlement, or poor compaction, stresses can accumulate in the pavement surface, leading to alligator cracking.

The underlying mechanism involves the loss of support from the subgrade, which may cause repeated loading and stress concentrations in the pavement. As a result, the surface begins to fail, manifesting in this specific cracking pattern. The presence of alligator cracking signals potential instability below the surface, often prompting further investigation into the condition and movement of the foundation.