In view of the nonlinear rheological characteristics of saturated clayey soil

the secondary consolidation coefficient was assumed as a hyperbolic function of the logarithm of time

and a modified secondary consolidation equation was proposed. Based on this idea

the unified hardening (UH) constitutive model was modified. To verify the effectiveness of the modified UH constitutive model

by taking a kind of reconstituted clayey soil in Henan province as an example

a series of one-dimensional rheological oedometer tests with one-way drainage were carried out. Test results illustrate that there was still some pore water pressure to be dissipated in the soil sample

when the primary consolidation determined by the Cassagrande method was completed. Then

the modified UH constitutive model was applied to simulate the measured data obtained at different loading stages

and results show that the model could fit the data well. Finally

in order to further verify the applicability of the model

some oedometer test results reported in the literature were simulated.