考虑环间接头力学特性的盾构隧洞纵向分析模型

Longitudinal analysis model of shield tunnel considering mechanical characteristics of ring joints

  • 摘要: 盾构隧洞环间接头具有明显的非线性力学特性,合理模拟其受力变形响应是隧洞纵向变形分析中的难点。针对此问题提出了一种简便实用的环间接头分析模型,采用可传压不传拉的接触面单元模拟环间接触,采用基于埋置梁广义位移法的梁单元模拟螺栓,能够同时考虑环间接头处的非线性接触状态和接头螺栓的轴向刚度和剪切刚度,且适用于各种环间连接螺栓形状(直螺栓、弯螺栓或斜螺栓)。通过算例,将有限元模型与理论解析模型计算结果进行对比,验证了该模型的准确性。将该模型应用于某实际工程中穿越断层破碎带的盾构隧洞的纵向变形分析,结果表明:输水盾构隧洞在均质基岩中状态稳定,在断层破碎带区域衬砌环间缝变形和螺栓应力显著增大,但均在设计控制范围之内。该模型可为工程安全建设及运行提供一定参考。

     

    Abstract: The ring joints of shield tunnels have obvious nonlinear mechanical characteristics, and it is difficult to analyze the longitudinal deformation of tunnels reasonably to simulate the response of the stress and deformation. In order to solve this problem, this paper proposes a simple and practical model for the analysis of joints between rings, that is, the contact surface element that can transmit pressure but not tension is used to simulate the ring-to-ring contact, and the beam element based on the embedded beam generalized displacement method is used to simulate bolts. The nonlinear contact state at the joint between the rings and the axial stiffness and shear stiffness of the joint bolts are considered, and it is suitable for all kinds of bolt shapes between the rings (straight bolts, bent bolts or oblique bolts). A calculation example is used to compare the calculation results of the finite element and the theoretical analysis model to verify the accuracy of the model. The model is applied to the longitudinal deformation analysis of shield tunnels crossing the fault fracture zone in an actual project. The results show that the water conveyance shield tunnel is stable in homogeneous bedrock; and the deformation of the lining ring joints in the fault fracture zone and the bolt stress increase significantly, but are within the design control range. The model can provide a certain reference for engineering safety construction and operation.

     

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