The experimental evidence shows that the residual earth pressures produced by the compaction of sand behind a rigid retaining wall are significantly higher than would be expected from the self-weight of the soil alone. However, only very small movement (4mm) of the test wall away from the soil were sufficient to reduce the earth pressures to the active condition for a fill height equivalent to 3.4 metres. A study of the passive case showed that a peak lateral thrust occured on a metre high test wall after a movement of about 25 mm of the wall into the soil