Experimental study on self-weight consolidation behavior of hydraulically dredged slurries

The large-strain self-weight consolidation theory is widely used for the design of dredged material disposal sites and the treatment of hydraulically dredged slurries in the disposal sites. The self-weight consolidation behavior of hydraulically dredged slurries in settling column experiments, especially nonlinear compressibility relationship and nonlinear permeability relationship, is still unclear. The self-weight consolidation behavior of hydraulically dredged slurries from Taihu Lake and Baimahu Lake is studied by using a new sedimentation and consolidation experimental method which consists of a settling column, a pore pressure measurement apparatus and a multi-layer vacuum extraction sampling apparatus. It can test the changing rules of the interface height, excess pore pressure, density, effective stress, grain size distribution, compressibility relationship and permeability relationship in self-weight consolidation. The experimental results show that the compressibility relationship is nonlinear. Under low effective stresses, the void ratio changes significantly with a small increase in the effective stress, while under higher values of effective stress, change of void ratio with effective stress is more limited. When values of effective stress are greater than one value, a unique relationship is visible, and when the stresses are below this value, the data points cover a triangular shaped area, so the compressibility is large. The permeability relationship is nonlinear. The compressibility relationship and permeability relationship can be represented by a power function equation.