The evaluation of the segment internal forces in the construction process of shield tunnel

In this paper, the plane strain elasto-plastic construction FEM is used for analyzing the segment internal forces in the construction process of shield tunnel. In the 2D-FEM, the Goodman joint model is introduced to simulate the special properties of the contact face between ground and structure, the curved beam-joint element is also used to model the segment joint, and a great attention is paid to examine the effects of the gap closing, the grouting pressure distribution and grouting material hardening on the internal forces of structure at the shield tail point. By using variable releasing coefficients which can be obtained from the measured displacements, the different construction sequences of the shield tunneling are simulated continuously. Finally a case study-No.7 line of subway in Osaka is analyzed to evaluate the earth pressure, the axial force and the moment of the lining comparing with the measured ones.