CUED Publications database

The monitoring of an existing cast iron tunnel with distributed fibre optic sensing (DFOS)

Gue, CY and Wilcock, M and Alhaddad, MM and Elshafie, MZEB and Soga, K and Mair, RJ (2015) The monitoring of an existing cast iron tunnel with distributed fibre optic sensing (DFOS). Journal of Civil Structural Health Monitoring, 5. pp. 573-586. ISSN 2190-5452

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Abstract

© 2015, The Author(s). Instrumentation is vital to tunnelling projects for validation of design assumptions, monitoring of trigger levels during construction and also serving as a feedback loop to understand the deformation mechanisms of the particular problem which could be used to improve future designs. It can also be used for long term monitoring of the tunnel for maintenance purposes. Distributed fibre optic sensing (DFOS) systems based on brillouin optical time domain reflectometry are able to provide continuous and distributed strain measurements to be taken along the entire length of, for example, an existing cast iron tunnel where the fibre optic cable length is fully attached. This enables engineers to understand the stresses and strains that develop within the lining caused by external influences; which in this case, the construction of a new tunnel directly underneath it, rather than relying on discrete point measurements of displacement from conventional methods of monitoring. Nonetheless, proper installation of DFOS is of paramount importance to obtain high quality data. This paper aims to provide some practical guidance on the planning and installation of DFOS and presents a brief case study on the monitoring of London’s Royal Mail tunnel during the construction of the large Crossrail platform tunnel, located directly below it at Liverpool Street Station. It demonstrates the potential benefits of using such systems in complex tunnelling scenarios.

Item Type: Article
Subjects: UNSPECIFIED
Divisions: Div D > Construction Engineering
Div D > Geotechnical and Environmental
Depositing User: Cron Job
Date Deposited: 17 Jul 2017 19:05
Last Modified: 21 Nov 2017 03:08
DOI: