盾构隧道管片衬砌的平板壳-弹性铰-地基系统模型

Study on flat shell-elastic hinge-foundation model in shield tunnel

从Reissner-Mindlin板单元入手,研究了盾构隧道管片衬砌结构之间的连接特征及土层与管片衬砌结构的共同作用,提出了盾构隧道管片衬砌结构的平板壳-弹性铰-地基系统模型,在此基础上研制了相应的有限元计算程序。该模型考虑了管片衬砌本身的弯曲、剪切和薄膜作用,考虑了纵向接缝在正负弯矩作用下的转动刚度差异和环向结缝对结构刚度的削弱作用,以及土层与衬砌结构的共同作用。能解决盾构隧道管片衬砌结构的三维受力分析,并能计算出结构的内力和变形,弥补了二维计算模型的某些不足。验证了程序的可靠性,最后给出了工程算例的三维计算分析结果。

Based on the Reissner-Mindlin plate theory, with the study on the deformation character of longitudinal joint and ring joint of shield tunnel, the interaction between the segment lining and soil layers, a flat shell-elastic hinge-foundation model is proposed. Furthermore, the relevant software is developed. The flat shell element is formed by assembly of Reissner-Mindlin plate element which is taken for the bending part and sheafing part, and membrane element, where the bending and membrane effects are uncoupled. The elastic hinge element is employed to simulate the impairment of moment around ring joint and the difference of stiffness around longitudinal joint under positive moment and negative moment. The proposed model demonstrates much advantage in 3D analyzing of shield tunnel, such as inner forces of structure rather than stress. Finally, the presented example shows the validity and effectivity of the model in analyzing of interval shield tunnel, the feasibility of the model and program to other underground structures.