复合材料叠合衬砌加固管片接头抗负弯矩试验研究

Experimental study on flexural behavior of segment joints strengthened with high strength fibre and mortar-filled steel tubes composite lining under negative moment

复合材料叠合衬砌是加强各种隧道的一种新型结构形式。这种结构具有强度高、操作轻便、施工效率高、构件所占空间小等优点,特别适合于城市地铁隧道修复时复杂的施工条件。通过复合材料叠合衬砌加固管片接头抗负弯矩试验,对加固前后管片接头的荷载-挠度曲线、荷载-接缝张角、荷载-转角刚度曲线等进行了对比分析,研究了复合构件加固接头的破坏形态。结果表明,加固管片接头在挠度10mm时负弯矩承载力较未加固提高221%,负弯矩极限承载弯矩较未加固提高101%,加固管片接头平均转角刚度较未加固接头提高约4.3倍,复合材料叠合衬砌有效提高了管片接头在负弯矩区的抗弯承载能力和接头转角刚度,可作为隧道管片加固的一种新方法。

In strengthening a tunnel structure,the mortar-filled fibre tube composite lining( FMTCL) is a new structure with the advantages of high strength,convenient operation,efficient installation,small occupied space,and especially suitable for reinforcing the structure of urban subway. In the current study,a series of experiments were conducted on standard / reinforced segment joints to investigate the flexural behaviors of segment joints strengthened with FMTCL under negative moment. The load-deflection curves of the standard and reinforced opening segment joints were then obtained.The load-angle and load-stiffness curves and the failure patterns of the standard and reinforced segment joints were furthermore analyzed. It shows that the negative flexural bearing capacity of segment joint reinforced with FMTCL,corresponding to the mid-span deflection of 10 mm,is 221% higher than that of unreinforced segment joint. The ultimate bearing capacity of reinforced segment joint is 101% larger than that of unreinforced segment joint. The average rotation stiffness of reinforced segment joints increases about 4. 3 times than the unreinforced one. Therefore,FMTCL may efficiently enhance the flexural bearing capacity and rotation stiffness of segment joints in the negative moment area;FMTCL is a new technique in reinforcing the structure of shield tunnel in the future.