Research On The DFOS-based Deformation Monitoring Technology For The Subway Construction

Subway transportation is an important symbol of the modern city. In China, the subway construction of the subway is developing rapidly with unprededented speed and scale. In the meanwhile, the safety problem both in construction procedure and operation procedure are increasingly prominent. Based on the previous research of our group, this paper presents the application of DFOS in deformation monitoring during subway construction. Combined with the construction monitoring of Suzhou subway, we study the DFOS-based deformation monitorting technology for the subway construction systematically from following aspects: the method of subway construction and the content of monitoring, the advantages of DFOS, the monitoring plan, and the set-up of monitoring system. The feasibility of application of DFOS in subway construction is further verified. The achievements are listed as follows:1. This paper discusses the monitoring necessity of subway construction from the features of subway construction firstly; then analyses the current situation and shortage of conventional construction deformation monitoring technology; at last the advantages, status and prospects of DFOS is introduced.2. Several kinds of common contruction methods of subway are presented. During these procedures, the subject and content of the monitoring have been clearly figured out.3. The classification of distributed fiber sensing technology and their respective principles and technical parameters are presented. Based on experiments, the advantages and disadvantages of time-domain analysis and frequency domain analysis techniques are compared, from which we can realise that the strain transition section is caused by the properties of coating material, the relationship between sampling and spatial resolution, the test performance of strain analyser.4. According to the characteristics of various kinds of DFOS, the monitoring plan on Shield Tunnelling method, Cover-digging method, Cut and Cover method are demonstrated respectively for their own deformation principles.5. The DFOS deformation monitoring for subway construction system is designed here, including the basic framework and relationship and interact between the subsystems.6. on the basis of above studies, a case study of DFOS technology applied in construction of station of Suzhou subway is presented. Through comparision with convention method, the feasibity of DFOS technique is verified in site. The research demonstrates that there are many method of subway construction, with different monitoring content, while DFOS technology has different characteristics and features. So when the DFOS is applied to the subway construction, on the one hand, the DFOS has huge advantages; on the other hand, the scheme of DFOS can meet the different monitoring requirements. The prospect of DFOS’s application in subway construction monitoring is encouraging.