Gil Lorenzo, S, Elshafie, M, Soga, K, Mair, R, Wright, P & Clegg, M 2015, 'Monitoring concrete segmental lining tunnels with fibre-optic and conventional instrumentation', in PM Dight (ed.), FMGM 2015: Proceedings of the Ninth Symposium on Field Measurements in Geomechanics, Australian Centre for Geomechanics, Perth, pp. 373-384, https://doi.org/10.36487/ACG_rep/1508_24_Gil_Lorenzo
(https://papers.acg.uwa.edu.au/p/1508_24_Gil_Lorenzo/)
Abstract: From the early days of tunnelling, developments in lining technology relied on laboratory testing and analyses of field monitoring data. This approach is still commonly implemented by designers to enhance their knowledge on lining performance and to, ultimately, develop, validate and optimise their assumptions, methods and solutions. Novel structural health monitoring techniques such as distributed fibre-optic strain sensing bring an excellent opportunity to capture global behaviour of concrete segmental lining by embedding fibre-optic strain sensors during the segment cast.
Cambridge University, in collaboration with Hochtief (UK) Construction and Crossrail Ltd., has instrumented four rings in the newly constructed Thames tunnel. This has provided a complete set of in situ monitoring data on ring deformations sensed by both conventional and fibre-optic instrumentation. The monitoring regime was purposely designed to capture measurements during the construction process, including tunnelling and cross passage construction. The results will be used in the future to describe the real history of deformations, stresses and forces developed in concrete segmental lining in shallow tunnels excavated in chalk. In this paper, Brillouin Optical Time Domain Reflectometry (BOTDR) and vibrating wire strain gauge (VWSG) strain measurements are compared and discussed to validate the use of the distributed optical fibre sensing technique for concrete segmental linings.