Abstract: Soft clay that deposits offshore has poor engineering properties, strong thixotropic and rheological property. Under the fluctuation of the water level, significant settlement deformation and rebound deflection might occur. Unsaturated Shanghai soft clay from the water fluctuation zone was used to conduct experiments for its deformation characteristics. The cyclic watering and draining conditions in the conventional oedometers were manually created in order to simulate the impact of the water level fluctuations as well as the cyclic numbers on the deformation properties of unsaturated soft soils. Results of these tests can be used in the interpretation of the unsaturated soft soil properties impacted by the groundwater level fluctuation induced by the cyclic extraction and recharge of groundwater.

Key words: Unsaturated Soft Soils, Groundwater Fluctuations, Consolidation Tests, Deformation Response