Abstract: In order to solve the problems of single factor and shortterm prediction in the existing calculation methods of shield tunnel settlement, a simplified calculation method of tunnel settlement under the combined action of consolidation and rheology of soft soil is proposed, which is verified by a practical engineering case. Firstly, the consolidationrheological coupling model is established based on the Merchant rheological model and TerzaghiRendulic theory of twodimensional consolidation. The longterm settlement of shield tunnel is divided into two parts by the model, i.e. the main consolidation settlement caused by excess pore water pressure dissipation and the secondary consolidation settlement caused by soil rheology. And then, the longterm settlement analytical formula of the tunnel is solved by considering the influences of surface load, soil characteristics, structure selfweight and train load. Lastly, three typical sections of the new shield tunnel are selected to predict the longterm settlement of the tunnel, and the dissipation time of excess pore water pressure, settlement rate and final settlement are compared and analyzed. The results show that: (1) In the initial stage of operation, the dissipation speed of the excess pore water pressure of the soil around the tunnel is faster, especially in the first 2 years. With the passage of time, the dissipation speed of each section tends to be stable gradually. (2) The longterm settlement of the shield tunnel is related to the character of the underlying soil; the greater the thickness, the worse the character of the underlying soil layer, and the larger the settlement. The final settlement prediction values of sections 1, 2 and 3 are 146.8 mm, 97.6 mm and 46.1 mm, respectively.

Key words: deep soft ground, excess pore water pressure, consolidationrheological coupling model, shield tunnel, longterm settlement