盾构管片接头破坏的弹塑性–损伤三维有限元模型研究

分别采用弹塑性本构和弹塑性损伤本构,建立盾构管片接头三维有限元模型,模拟正负弯矩下接头压弯破坏全过程。与实验对比后表明:初始加减阶段采用弹塑性本构和损伤本构得到的结构变形曲线基本重合,且与试验值吻合较好;荷载进一步加大后,采用损伤本构进行分析,其结果更接近试验值,且可更好地模拟结构承载力下降过程。通过有限元网格的收敛性分析,证明网格划分的合理性并给出此类有限元模型网格大小的建议值。最后根据数值模拟结果给出管片接头健康评价指标。

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.