3-D finite element model for destruction process of segment joints of shield tunnel using elastoplastic and damage constitutive methods

Using the elastoplastic and damage constitutive methods for concrete respectively, a 3-D FEM model for segment joints of shield tunnel is established to simulate the process of bending failure under positive and negative loads. By comparing the simulated results with the experimental data, at the initial stage, the deformation curve is almost coincident with the FEM using the elastoplastic and damage constitutive methods, and both of them show a good agreement with the test results. With the increasing load, the results using the damage constitutive method are closer to the experimental values, and it can simulate the dropping process of structural bearing capacity better. Through the convergence analysis of FEM, the rationality of mesh generation is proved, and the grid sizes of similar element models are suggested. Finally, based on the simulated results, some evaluation indices for health assessment of segment joints are proposed.