What is the most likely reason for a poured concrete retaining wall with weep holes to be rotating?

A poured concrete retaining wall with weep holes rotating typically indicates an issue with the pressure exerted by the soil behind it. The most plausible reason in this case relates to the absence of gravel behind the wall. Gravel serves several critical functions: it helps to drain water away from the wall, provides support against lateral soil pressure, and reduces hydrostatic pressure build-up that can lead to movement or failure of the wall.

When gravel is omitted, water can accumulate due to poor drainage, leading to increased pressure on the wall from the saturated soil. This pressure can cause the wall to rotate or lean. Therefore, the lack of gravel directly contributes to structural issues by not allowing essential drainage and support, making this the most likely cause of the wall's rotation.