Abstract:

A newly developed seepage consolidation odometer is designed to investigate the suction discipline of soft clay under unloading after rebound deformation. Taking saturated soft clay as a study object, the suction characteristics of soft clay with the developed seepage consolidation odometer are analyzed. Test results show that the new odometer apparatus designed and manufactured which improves scalability can collects the water discharged from the soft clay when the consolidation happens; when the unloading ratio is greater than critical unloading ratio, the soft clay specimen rebounds and absorbs water, and its characteristics are related to the preloading duration. The volume change of the clay specimen is equal to the volume of water that enters into the soil when the unloading happens at the end of primary consolidation. When the preloading duration is 24 hours, the soft specimen’s rebound deformation is divided into two stages that include primary rebound and secondary rebound. During the primary rebound stage, volume change of the clay specimen with rebound deformation is equal to the volume of water that enters into the soil; during the secondary rebound stage, the specimen has small deformation but doesn’t absorb water. The ratio of the volume of water absorbed by soil-to-the volume of water drained by consolidation is less then 10% generally.

Key words: unloading, soft clay, consolidation, rebound, test