Saturated clays rebound when a part of confining pressure is removed. Strength of soils in over-consolidated state is smaller than that before the removal of a consolidation pressure. In practice,rebound of soil is likely to take place when a soil sample is left for long time after sampling or when a part of surface loading is removed in a pre-loading work.
　The present paper reports the rebound of saturated clays observed in consolidation tests. Amount of rebound is investigated statistically for 390 specimens of a lluvial clays in Japan. In addition to the investigation in conventional consolidation tests,the behaviour of unloaded saturated clays in long term consolidation tests is observed. Effect of remoulding on rebound characteristics is also studied.
　As the result of investigation it is found that, when a soil sample is allowed to rebound completely under no confining pressure, an unconfined compression strength is reduced to about 50% of insitu strength. Considering the rebound characteristics of soils, remarks on soil tests and sampling techniques are given.