中文摘要：

作为一项运营期长期监测指标，纵向沉降特别是局部不均匀沉降可有效判明盾构隧道纵向异常，但目前现场普遍使用的人工观测若干等距预设点沉降的传统方法由于缺乏分布性，并不能很好地捕捉到实际盾构隧道中随机出现的纵向不均匀沉降。在先期研究中提出的采用分布式光纤应变传感技术监测结构变形的改进共轭梁法基础上，首允从理论上证明改进共轭梁法对于盾构隧道纵向沉降分布监测的适用性，其次将准分布式光纤光栅应变传感器与静力水准沉降监测系统相结合，提出基于改进共轭梁法的盾构隧道纵向沉降分布监测策略，最后通过纵向盾构隧道缩尺模型试验测试该策略对于模型盾构隧道纵向沉降的监测精度。试验结果表明，该策略监测沉降的最大误差仅为10％。

英文摘要：

As a long-term monitoring index, longitudinal settlement, especially uneven settlement, has been effectively used for the structural safety evaluation of shield tunnels in their operational periods. Due to the lack of distributed characteristic, the widely used traditional monitoring method, which is based on manual observations of settlements at some preset uniformly spaced observation points, may not capture the longitudinal uneven settlements randomly occurred in the practical shield tunnels. Consequently, based on the previous improved conjugate beam method （ICBM） for beam deformation monitoring using distributed fiber optic strain sensing technique, the applicability of ICBM in monitoring the distributed settlements in shield tunnels was theoretically proved. Next, based on the ICBM, a monitoring strategy was proposed to monitor the distributed settlements in shield tunnels by combining the quasi-distributed Fiber Bragg Grating sensors with the hydrostatic level measuring system. Finally, a reduced-scale concrete longitudinal model test was carried out to verify the precision of the proposed strategy for distributed settlement monitoring in shield tunnels. Experimental results show that by using the proposed method, the maximum error in the monitored settlement in the shield tunnel model is only 10%.