Consolidation of clay slurry under very low stresses: from novel oedometer apparatus invention to nonlinear consolidation characteristics and finite strain modelling

This study first invents a novel oedometer apparatus for clay slurry, featuring a lightweight acrylic loading cap, a noncontact laser displacement sensor, and a 1:1 dead-weight loading system to improve traditional consolidation devices. The novel apparatus is then used to examine two clays: Hong Kong Marine Deposit and Kaolin clay. The loading with a minimum stress of 0.025 kPa is applied on samples with a maximum initial water content exceeding 9 times the liquid limit. Results demonstrate the “S” shape compression curves influenced by initial water contents, and the power-type relationships between permeability coefficient and void ratio. Empirical equations are obtained to determine the yield stress point based on initial water content and liquid limit. Higher initial water contents increase compression parameters (e.g., recompression index, C r ; compression index, C c ; and creep index, C α ), though C r /C c and C α /C c are almost in the normal range. The C c of Kaolin clay with initial water contents above 3.5 times the liquid limit is significantly relevant to effective stress. Finally, a nonlinear creep model is enhanced and integrated into the finite strain consolidation equations, effectively simulating the oedometer tests and a self-weight consolidation test of clay slurry with nonlinear consolidation characteristics.