为了解初始损伤对盾构隧道衬砌管片力学特性的影响,基于6组具有初始损伤的盾构隧道衬砌管片进行足尺试验研究.在考虑初始损伤位置以及初始损伤位置处钢筋有效面积减小等因素的情况下,对试件破坏过程、破坏模式、极限承载力、变形规律以及初始裂缝扩展机制进行了研究和分析.试验结果表明:初始损伤的存在对盾构隧道衬砌管片的极限承载能力影响不大,但对其正常使用功能影响很大;初始损伤位置处钢筋有效面积减小不仅影响盾构隧道衬砌管片的正常使用功能,更大大降低了其极限承载能力;增加轴力会削弱初始损伤对盾构隧道衬砌管片的不利影响;初始损伤在加载点比在跨中对盾构隧道衬砌管片更不利;初始裂缝基本沿径向或偏向跨中方向直线扩展.相关研究结果可为建立服役期间盾构隧道衬砌结构健康评估与预知理论、以及进一步开展损伤缺陷盾构隧道数值模拟和极限承载力分析提供借鉴和参考.%The full-scale tests are carried out on 6 groups of shield tunnel lining segment with initial damage so as to learn the influence of initial damage on mechanical properties of shield tunnel lining segment.And then the failure process,failure mode,ultimate bearing capacity,deformation law and propagation mechanism of initial crack of specimens are studied and analyzed considering the influence of the position of initial damage and the decrease of the effective area of steel bars around initial damage.The testing results show that:1)The initial damage has little influence on the ultimate bearing capacity of shield tunnel lining segment;but it has a significant influence on its normal function.2)The decrease of effective area of steel bars around initial damage not only affects the normal function of shield tunnel lining segment but also affects ultimate bearing capacity significantly(reduction).3)The influence of initial damage on shield tunnel lining segment can be reduced by increasing the axial force.4)The influence of initial damage at loading point is more obvious than that at mid-span section.5)The crack propagation path is nearly a line that grows radially or toward to the mid-span section.The related research results can provide reference for establishing the health assessment and predicting theory of the shield tunnel structure during its long-time service,as well as for further conducting the numerical simulation and the ultimate bearing capacity analysis of shield tunnel with damage and defects.
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