二次受力情况下深埋盾构隧道力学特性研究

Study on Mechanical Characteristics of Deep-buries Shield Tunnel under Secondary Stress

为探究二次受力情况下深埋盾构隧道衬砌结构的力学特性及破坏模式,结合深圳前海—南山深埋排水隧道工程开展了足尺试验研究。介绍了试验加载和测试方案,并对试验现象和数据进行了分析,得出了结构在二次受力情况下的受力特征。试验结果表明:试验结构的破坏链为259.75°纵缝内弧面、191.25°纵缝外弧面、348.75°纵缝外弧面混凝土相继压碎,最后90°管片主筋屈服,形成4个塑性铰后丧失承载能力。二次加载后,结构在加载至侧压力系数1.07时变形开始有所恢复;加载至侧压力系数1.18时,仍有56%的残余变形无法恢复。

In order to explore the mechanical characteristics and failure modes of the deep buried shield tunnel lining structure under secondary stress,a full-scale experimental study was carried out in combination with the Qianhai-Nanshan deep buried drainage tunnel project in Shenzhen.The test loading and test scheme are introduced,and the test phenomena and data are analyzed,and the stress characteristics of the structure under secondary stress are obtained.Test results show that structure is under the following process:the concrete at longitudinal joints concrete at crushed successively at 348.75°,191.25°and 259.75°.Finally,the main reinforcement of the segment at 90°finally yielded,forming four plastic hinges and losing the bearing capacity.After the second loading,the deformation of the structure began to recover when the lateral pressure coefficient was 1.07;When the lateral pressure coefficient is 1.18,56%of the residual deformation can not be recovered.