Experimental study on one-dimensional consolidation behavior of soft clay from liquid state to plastic state

Decrease in the water content of soft soil under consolidation will lead to a change from liquid state to plastic state. An experimental study is conducted to investigate the effects of change in the physical state on the compressibility and permeability of soft clay. The saturated and reconstituted clay specimens are prepared with water contents higher than and close to the liquid limit. One-dimensional consolidation tests are carried out under different vertical pressures. Based on the test results, a comparative analysis is conducted on the deformation, dissipation of pore-water pressure, and changes in the coefficient of compressibility and the hydraulic conductivity during the consolidation process. It is shown that in the liquid state, the deformation increases quickly, but the stagnation phenomenon of pore-water pressure dissipation appears clearly. There is an evident change in the relations between the logarithms of the coefficient of compressibility and the hydraulic conductivity and the void ratio when the soil state is transited to the plastic one. It is implied that the effects of the transition of physical state on the changes in the compressibility and permeability parameters should be taken into account in the theoretical analysis of consolidation problems of soft soil.