施工期局部破损对成形管片衬砌结构性能的影响

摘要

Due to the unreasonable design and inefficient control of tunnel lining,local damage of segment is likely to occur,affecting the performances of lining structure.With reference to a metro project of damaged segment,the lining structure performances under normal and damaged conditions are compared by using three-dimensional fine finite element model in perspective of internal force,displacement of overall segment and local stress of the damaged segment.The study indicates that the shield damage can lead to segment stiffness weakening,the whole segment is subjected to stress redistribution,but the deformation of the segment before and after damage has no obvious change;segment damage can lead to structural stress changes of minor degree and the main structure materials are still within elastic tension range without the need for replacement of segment,and conventional reinforcement is only required.The research results have important guiding roles in evaluating the performances of damaged segments of shield tunnel.%施工期由于设计不合理、施工控制不当容易导致管片衬砌局部破损,影响成形管片衬砌结构性能.在对施工期管片破损进行致因分析的基础上,以某城市地铁施工期管片破损具体实例为依托,采用构建三维精细化有限元模型的方法,从结构内力、整体位移及破损管片局部应力等方面着手,对正常状态下与破损状态下的管片衬砌结构性能进行对比分析研究,研究提出管片破损导致管片局部刚度弱化,整环管片受力状态发生应力重分布现象,但破损前后管片变形基本无明显变化;管片局部破损导致结构受力出现变化,但其总体量级普遍偏小、结构主体材料仍处于弹性受拉范围内,无须置换管片采取常规加固即可.研究成果对盾构隧道管片破损后的性能评估具有重要指导作用.