Large-strain consolidation theory is widely used for the management of dredged disposal sites. The theory is universally accepted to deal with this problem, though the determination of the material properties is not yet standardised. Decisions made on this level can lead to the prediction of a totally different consolidation history. This paper describes the results of a prediction exercise, performed using a batch of sediment from the river Schelde (Antwerpen, Belgium). Numerical modellers were given the data of four calibration experiments and were then asked to predict another experiment. Settling column experiments (0·2–0·6 m in height) with density and pore pressure measurements provided the basis for the calibration data. The prediction demonstrated the significance of the soil compressibility at low effective stresses, when time-dependent behaviour is observed.

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Summary. Sediment layers deposited under water undergo a deformation that for low soil concentrations can be described by a scalar nonlinear hyperbolic conservation law. The associated flux function is non-convex and compound shock waves arise, which are shocks followed or preceded by a rarefaction with the shock speed equal to the wave speed at the point of attachment. The paper describes an experimental study of compound shock waves in sediment beds and the numerical modelling of the sedimentation process using an experimentally obtained flux function for kaolinite soil. The work also fits in a broader investigation of the transition parameter between the physical processes of soil sedimentation and consolidation, as the data obtained allows identification of this parameter.