基于原位监测的装配式地铁车站结构拱顶接头力学性能分析

Mechanical Property Analysis of Top Arch Joint for Prefabricated Underground Metro Station Structure Based on In-suit Monitoring

为研究对装配式结构承载起到关键作用的拱顶接头力学性能,基于长春地铁装配式车站长期原位监控量测,对承受弯矩较大的拱顶接头进行整个施工期的力学行为分析,讨论拱顶接头应力、相对变形量以及相对转角随施工进程的变化趋势,分析拱顶接头在不同施工阶段的性能表现,并与数值计算结果进行比较。研究表明:1)顶部构件落拱拼装成环刚开始,结构有一段时间的自适应期,接头应力和变形较大;2)覆土回填以及水位恢复之后,接头所受轴力增大,应力和变形减小,对接头承载起到正向作用;3)接头应力整体变化幅度不大,施工期间双榫接头的2个榫头依靠彼此的咬合作用承担外力,并表现出一拉一压2种不同的性质,施工结束之后最终都稳定在压应力状态;4)拱顶接头整体变形较小,安全余量较大。

Top arch joints are critical in the bearing capacity of prefabricated structures. The mechanical properties of the top arch joint are investigated by analyzing the mechanical behavior of top arch joints with large bending moments during the construction period based on long-term in-situ monitoring data in the Changchun metro prefabricated station. Variation trends of joint stress, relative deformation, and relative rotation angle varying with the construction progress of the top arch are discussed. Finally, the performance of top arch joints in different construction stages is analyzed and compared with numerical calculation results. The results show the following.(1) At the beginning of the top components′ assembly into a ring, the structure has a self-adaptive period and the joint stress and deformation are large.(2) After soil backfilling and water-level recovery, the joint′s axial force increases, and the joint′s stress and deformation decrease, positively affecting the joint′s bearing capacity.(3) The joint stress′s overall variation range is small. The two tenons of double-tenon joints rely on each other′s occlusal action to bear the external force and reflect the different properties(one pulling and one pressing) during the construction. After completing all construction stages, the doubletenon joints stabilize in a compressive stress state.(4) The top arch joint′s overall deformation is small and the safety margin is rich. The research results have practical guiding significance for prefabricated metro stations′ joint and structure design.