盾构隧道管片及纵向接头力学性能数值模拟研究

管片接头作为盾构隧道衬砌结构的薄弱部位,其力学行为直接反映隧道结构整体受力性能。考虑到接头由相邻管片连接而成,本文首先选用非线性有限元法对单个管片的静力响应开展研究,并与文献试验结果对比以验证数值模型。借此模型分析了混凝土剪胀角、拉压损伤行为等对管片结构力学行为影响。在此基础上,依托文献中管片纵向接头静载试验,详细地考虑了接头构造及接头处的相互作用,建立相应模型模拟试验加载过程,同时将数值分析结果与实测试验结果的破坏模式对比分析。基于提出的有限元模型,进一步研究了管片纵向接头力学特性随各关键因素变化规律,包括接头外侧间隙、螺栓倾斜角度及伸入管片长度、接缝两侧密封垫弹性模量和厚度,以及螺帽与手孔混凝土间初始接触状态。获得不同工况下接头挠度、接缝变形及接头转角等变化规律。

Numerical Investigation on the Mechanical Behaviour of Shield Tunnel Segment and Their Longitudinal Joint

The mechanical performance of shielded tunnel lining is directly influenced by the segmental joints, which is a weak link in the lining system. In this study, the numerical investigations to study the structural response of one single segment were firstly conducted using nonlinear Finite Element(FE) methods. The established numerical model was calibrated by comparing the results obtained from experiments in the literature and the FE analyses. Then, the verified FE model was utilized to investigate the effect of several factors such as concrete dilation , tensile and compressive damage behaviour. By considering detailed configuration and interaction of joints, a FE model was proposed to investigate longitudinal joint behaviour according to an experimental test in the literature. Based on the numerical model presented above, parametric studies were further carried out to illustrate the effects of various structural properties on the behaviour of the segmental longitudinal joints, including the outer gap of joint, the inclined angle and extended segmental length of bolt, the elastic modulus and thickness of rubber gasket, the initial contact status between bolt nut and hand hole concrete. Some useful findings were obtained from the parametric studies.