苏州地铁盾构隧道结构变形分布式光纤监测技术研究

发布时间：2018-04-14 19:46

本文选题：地铁盾构隧道 + DFOS　；参考：《南京大学》2015年硕士论文

【摘要】：随着城市地铁交通枢纽的建设,我国的盾构隧道工程建设正以前所未有的速度迅猛发展,同时隧道在施工和运营过程中的各种变形引起的安全问题也日益突出,因此探索一种有效的隧道变形监测方法具有重要意义。本文在总结国内外相关成果的基础上,依托苏州地铁运营及开挖后的隧道监测项目,结合课题组在隧道结构变形监测中的研究成果和经验,从盾构隧道变形机理出发,系统的介绍了分布式光纤感测技术(DFOS)及其应用于盾构隧道结构变形监测的可行性;从感测光缆的选型、定点铺设方法的应用、温度补偿方案、监测方案的制定、监测系统的组成和数据的处理分析及隧道结构的评价等方面,对盾构隧道结构变形监测的DFOS技术进行了比较系统的研究,为隧道结构变形监测提供了一种新的有效途径。论文主要内容如下:(1)论述了地铁盾构隧道变形监测的必要性,分析了隧道变形监测技术的现状与不足,介绍了 DFOS技术的优势、发展现状和应用于隧道结构变形监测的可行性。(2)介绍了 FBG、BOTDR、BOTDA、BOFDA等分布式光纤传感技术的感测原理、解调仪的主要技术性能指标和技术优势,对BOFDA和BOTDA两种技术的稳定性和应变测量特性进行了对比研究。(3)结合盾构隧道衬砌结构组成及其变形特点,指出DFOS技术应用于地铁隧道监测的优势,分析了适用于隧道结构监测的感测光缆、FBG传感器、感测光缆固定方式和温度补偿手段。(4)将隧道结构纵向变形及环向收敛作为主要监测内容,设计了 DFOS地铁隧道变形监测方案,并对系统的基本框架、数据处理的基本流程和预警阈值分别进行了阐述。(5)结合苏州地铁运营隧道的结构变形特点,提出了适用于光缆定点铺设方法的夹具类型,设计出可以兼顾隧道两腰、顶底部和环向断面的光纤传感监测方案。监测结果表明:截至2015年5月11日,苏州地铁运营隧道监测段结构纵向存在变形异常,管片接缝最大变形量为1.45mm;道床结构伸缩缝随温度升高逐渐闭合,最大闭合量为0.35mm,远小于其设计预留宽度,验证了 DFOS监测技术应用于运营隧道结构变形监测的可行性。(6)分析了施工期隧道隧道结构变形的原因;根据苏州4号线江兴西路站～流虹西路站光纤监测结果,证明了定点光缆具有空间易定位,定点间应变稳定,监测数据可靠等优点,适合隧道等结构的长距离分布式监测。
[Abstract]:With the construction of urban subway transportation hub, the construction of shield tunnel in our country is developing at an unprecedented speed. Meanwhile, the safety problems caused by all kinds of deformation in the construction and operation of the tunnel are becoming increasingly prominent.Therefore, it is of great significance to explore an effective method for tunnel deformation monitoring.On the basis of summing up the related achievements at home and abroad, based on the tunnel monitoring project of Suzhou Metro operation and excavation, combined with the research results and experience of the research group in the tunnel structure deformation monitoring, this paper starts from the deformation mechanism of shield tunnel.This paper systematically introduces the distributed optical fiber sensing technology (DFOS) and the feasibility of its application in the deformation monitoring of shield tunnel structure, including the selection of sensing optical cable, the application of fixed-point laying method, the temperature compensation scheme, and the formulation of monitoring scheme.In terms of the composition of the monitoring system, the processing and analysis of the data and the evaluation of the tunnel structure, the DFOS technology of the shield tunnel structure deformation monitoring is studied systematically, which provides a new and effective way for the tunnel structure deformation monitoring.The main contents of this paper are as follows: (1) this paper discusses the necessity of deformation monitoring of metro shield tunnel, analyzes the present situation and deficiency of tunnel deformation monitoring technology, and introduces the advantages of DFOS technology.This paper introduces the sensing principle of distributed optical fiber sensing technology, such as FBGG, BOTD, BOTDA, BOFDA and so on, and introduces the main technical performance indexes and technical advantages of the demodulator.In this paper, the stability and strain measurement characteristics of BOFDA and BOTDA are compared. Combined with the structure composition and deformation characteristics of shield tunnel lining, the advantages of DFOS technology in subway tunnel monitoring are pointed out.This paper analyzes the sensing fiber optic cable FBG sensor suitable for tunnel structure monitoring. The fixed mode of sensing optical fiber cable and temperature compensation method. The longitudinal deformation and circumferential convergence of tunnel structure are taken as the main monitoring contents. The DFOS subway tunnel deformation monitoring scheme is designed.And the basic frame of the system, the basic process of data processing and the warning threshold are expounded respectively. Combined with the structural deformation characteristics of Suzhou metro tunnel, the type of fixture suitable for the fixed point laying method of optical fiber cable is put forward.An optical fiber sensor monitoring scheme is designed, which can take account of both sides of tunnel, top and bottom and circumferential section.The monitoring results show that, as of May 11, 2015, the longitudinal deformation of the monitoring section of Suzhou Metro Tunnel is abnormal, the maximum deformation of the segment joint is 1.45 mm, and the expansion joint of the track bed structure is gradually closed with the increase of temperature.The maximum closing value is 0.35mm, which is far less than the designed width. The feasibility of applying DFOS monitoring technology to the deformation monitoring of operational tunnel structure is verified.According to the optical fiber monitoring results of Jiangxing West Road Station ~ Liuhong West Road Station on Suzhou Line 4, it is proved that Fixed-point optical cable has the advantages of easy location in space, stable strain between fixed points and reliable monitoring data, and is suitable for long-distance distributed monitoring of tunnels and other structures.
【学位授予单位】：南京大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U455.43;U231.3

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