Distributed Fiber Optics Strain Measurements For Monitoring Geotechnical Structures

Kenichi Soga, Hisham Mohamad, Peter J. Bennett

University of Cambridge, Cambridge, CB2 1PZ, U.K

ABSTRACT

Recent advances in strain measurement using optical fibers provide new opportunities for monitoring the performance of geotechnical structures during and after construction. Brillouin optical time-domain reflectometry (BOTDR) is an innovative technique that allows measurement of full strain profiles using standard optical fibers. In this paper, two case studies illustrating the application of the distributed optical fiber strain sensors are presented. One is monitoring of an old masonry tunnel when a new tunnel was constructed nearby and the other is monitoring the behavior of secant piled walls for basement construction. Both sites are located in London. The advantages and limitations of this new sensor technology for monitoring geotechnical structures are discussed.

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