Permeability Test of Saturated Clay under Stepwise Loading

Issues in the consolidation deformation of saturated clay have a close relationship with its permeability. In this work, a modified K₀ oedometer was used to conduct a variable water head permeability test. The changing law of the initial water head H₀, effective void ratio, and permeability and effective permeability coefficients were analyzed under various load degrees combined with the concept of efficient void ratio of saturated clay. Our study showed the following results. The initial water head of undisturbed soil could be divided into two stages:rapidly increasing and slowly increasing, the initial water head of disturbed soil was related to the change rate of the total water head. The efficient void ratio of undisturbed soil decreased with an increase in consolidation pressure. The change law of the void ratio of disturbed soil was similar to that of undisturbed soil. In addition, when the soil structure tended to fail, the structural differences tended to be consistent. If the efficient void ratio was large, then the permeability coefficient was also large. The permeability coefficient of clayey soil was related not only to soil structure but also to initial void ratio. Finally, the efficient void ratio and the water head and its change law had a considerable influence on consolidation.