预埋承插式接头错缝拼装盾构隧道受力性能及管片开裂原因分析  

Analysis of Mechanical Performance and Causes of Segment Cracking in Shield Tunnel with Pre-embedded Socket Joint Staggered Assembly

作　　者：瞿欣阳 邵华 QU Xinyang;SHAO Hua(Track Works Branch of Shanghai Metro Maintenance Support Co.,Ltd.,200233,Shanghai,China)

机构地区：[1]上海地铁维护保障有限公司工务分公司,上海200233

出　　处：《城市轨道交通研究》2024年第S01期73-78,共6页Urban Mass Transit

基　　金：上海申通地铁集团有限公司科研项目(JS-KY22R005-3);上海市科技创新行动计划技术标准项目(22DZ2206200)。

摘　　要：[目的]以上海轨道交通某区段新型隧道顶部管片开裂为背景,分析预埋承插式接头错缝拼装隧道在外荷载作用下变形特点及管片开裂原因,并提出此类隧道的运维侧重点。[方法]根据盾构推进时间、保护区历年变化及隧道收敛变形数据,分析了隧道管片开裂原因。并且发现顶部有无拼接缝的隧道环,在变形程度及裂缝产生方面存在差异。通过与相同环境下单圆通缝隧道收敛变形数据进行对比,得出了新型隧道与单圆通缝隧道受力性能的异同及相对刚度。[结果及结论]此次管片开裂是由侧方拔桩施工导致水平方向土压力变小以及正上方填土使得竖直方向土压力增大两者叠加产生的。顶部为整块管片的隧道环相较顶部为拼接缝的收敛变形更小,但容易开裂,运维时宜重点关注顶部为整块管片隧道环的收敛变形数据。新型隧道横断面刚度约为单圆通缝隧道的2.5倍,峰值处的荷载会传递到邻近的隧道环共同承担,使得隧道收敛变形较为平缓,隧道在外荷载消除后变形恢复能力更强。因这种裂缝而产生的渗漏水病害及通路很难通过隧道回缩愈合。[Objective]In the context of segment cracking in a new tunnel section of Shanghai Rail Transit,the deformation characteristics and causes of segment cracking in shield tunnels assembled with embedded socket joints misalignment under external loads.Additionally,maintenance for such tunnels is proposed.[Method]Through analysis of shield tunneling advancement time,changes in protection zone over the years,and tunnel convergence deformation data,the causes of segment cracking are examined.Differences in deformation and crack generation among the segments with or without joint staggered assembly at the top are observed.By comparing convergence deformation data with single-ring segment tunnels in the same environment,similarities and differences in mechanical performance of the new tunnel and the single-ring segment tunnels,as well as their relative stiffness,are determined.[Result&Conclusion]The segment cracking observed is attributed to reduce horizontal soil pressure caused by side pile extraction construction,combined with increased vertical soil pressure from overlying backfill.Tunnel rings composed of single-piece segments exhibit smaller convergence deformations compared to those with jointed top segments,but they are more prone to cracking.Therefore,maintenance efforts should focus on monitoring convergence deformation data for tunnel rings composed of single-piece segments.The stiffness of the new tunnel is approximately 2.5 times that of single-ring segment tunnels,allowing peak loads to be shared among adjacent tunnel rings,resulting in smoother convergence deformation and enhanced post-load recovery capability.However,cracks formed due to this phenomenon may lead to water leakage issues,and it is challenging to heal them naturally through tunnel shrinkage.

关 键 词：上海轨道交通 盾构隧道 错缝拼装 预埋承插式接头管片 收敛变形 

分 类 号：U457[建筑科学—桥梁与隧道工程]