EK462
Retaining walls backfilled with cohesionless soils (sand and gravel) tend to rotate slightly around the base. Behind such a wall, a wedge of soil tends to shear along inclined plane. […]
EK308
If the retaining wall moves toward the soil, a passive soil pressure develops.
EK307
Under soil pressure, the retaining wall may deflect or move a small amount from the earth, and active soil pressure develops.
EK306
If the retaining wall is assumed absolutely rigid, a case of earth pressure at rest develops.