基于盾构扩建地铁车站结构的Y型装配式节点抗震性能分析

Seismic Performance Analysis of Y-Shaped Assembled Joints Based on Shield Expansion Subway Station Structure

【目的】为了提高盾构扩挖地铁车站结构的力学性能,提出了一种可用于连接装配式盾构管片和现浇车站主体结构的Y型装配式节点。【方法】采用ABAQUS有限元数值软件,建立了Y型装配式节点的三维非连续弹塑性损伤模型,对节点在拟静力作用下的破坏机理、滞回特性、刚度退化特性等进行了研究。【结果】结果表明:①节点破坏主要原因为接触位置管片底部混凝土被压碎破坏,管片与墙柱接触位置的中上部出现塑性流动现象;②节点滞回曲线呈现非对称性,滞回环呈现较为明显的捏拢效应;③节点骨架曲线呈反S形,且呈现明显的非对称特性。【结论】研究揭示了Y型装配式节点的抗震特性,可为今后类似节点的设计及施工提供有益的借鉴和参考。

[Purposes]In order to improve the mechanical performance of the subway station built by enlarging the shield tunnels,the study proposes a Y-shaped prefabricated joint that can be used to connect the prefabricated shield segments and the main structure of the cast-in-place station.[Methods]This paper establishes a three-dimensional discontinuous elastic-plastic model of the Y-shaped prefabricated joint by ABAQUS.The failure mechanism,load displacement hysteresis characteristics,and degradation characteristics of concrete´s stiffness were studied.[Findings]The results indicate that:①the main factor of the joint failure is the crushing of the concrete at the bottom of the segment at the contact position.Plastic flow phenomenon occurs in the upper middle part of the contact position between the segment and the wall column;②the hysteresis curve of the node exhibits asymmetry,and the hysteresis loop exhibits a significant pinching effect;③the skeleton curve of the joint shows an inverse S-shape,and the curve exhibits obvious asymmetric characteristics.[Conclusions]This study reveals the seismic characteristics of the Y-shaped prefabricated joints and can provide useful reference and guidance for the design and construction of the similar joints in the future.