基于塑性损伤模型的管片接头阶段分析

基于上海地铁13号线管片接头足尺加载实验,结合ABAQUS中混凝土塑性损伤模型和混凝土结构设计规范,对混凝土CDP模型的参数进行标定,并建立盾构管片接头塑性损伤三维有限元模型,研究管片接头在弯矩和轴力共同作用下的损伤破坏的全过程,对破坏过程中四个阶段的弯矩、裂缝张开量、挠度和损伤之间的关系进行详细分析。结果表明:塑性损伤模型计算得到的挠度-荷载曲线和试验曲线吻合较好,管片接头经历全截面受压阶段、小变形阶段、大变形阶段和接头接触挤压破坏阶段。以裂缝张开量为基础,结合管片接头挠度、弯矩和拉伸损伤带的损伤平均值,提出盾构管片接头损伤破坏的健康评价指标。

Stage analysis of segment joint based on the damage-plastic model

Based on segment joint full-scale loading test of line 13 in Shanghai, the parameters of CDP model were calibrated and a 3-D damage-plastic FEM model for segment joint of shield tunneling was established combining the damage-plastic model for concrete in ABAQUS and the code for design of concrete structures. Under the interaction of moment and axial force, the whole damage and fracture process of concrete was studied. What''s more, the relationship among moment, splaying amount, deflection and damage during four stages of the whole damage process was described in detail. The results show that the deflection-load curve is closely consistent with that of the test, and the segment joint of shield tunneling goes through four stages, which are global section compressed stage, small deformation stage, large deformation stage and joint contact-extrusion failure stage. Finally, based on the splaying amount, combining the deflection, moment, and the average value of tensile damage strip, the health evaluation index about the damage and failure of the segment joint was proposed.