Abstract: Large-scale dredging projects of rivers and lakes have made the environmental risk control of sludge dumps a priority in the field of environmental geotechnics, in which the role of the clay isolation layer of the disposal site is crucial. Existing theories on the coupling of compacted clay liner consolidation and contaminant transport have not been able to take into account the effects of soil rheological properties and non-Darcy flow, resulting in significant deviations in contaminant transport predictions. A one-dimensional coupled rheological consolidation and contaminant transport model for compacted clay liners in dredged sludge disposal sites considering threshold hydraulic gradient is developed in this study. The finite difference method was used to numerically solve the established coupled model, and the results were compared with those of the existing consolidation model and the consolidation-contaminant transport coupled model to verify its reliability. Additionally, using the coupled model developed in this study, the effects of the threshold hydraulic gradient and Schiffman rheological parameters (η₀, E₁, and η₁) on the concentration distribution of trichloroethylene (TCE), an organic contaminant, were analyzed. The results show that the breakthrough time of the compacted clay liner predicted by the coupled model considering threshold hydraulic gradient is significantly shorter than that predicted by the coupled model following the classical Darcy's law. When the threshold hydraulic gradient tends to infinity, the transport process of TCE can be simplified to a transport model in a rigid porous media. The rheological parameter η₀ was negatively correlated with the rate of movement of the flow front, with a decrease in η₀ leading to a significant increase in TCE concentration at the bottom of the compacted clay liner. When the rheological parameters E₁ and η₁ are large, the TCE concentration variation curves based on the rheological consolidation model show asymptotic agreement with the linear elasticity model predictions. The coupling model established in this study can provide an important theoretical basis for the optimal design of the seepage control system of dredging sludge disposal site, which has significant engineering application value for groundwater contamination prevention and control.