Mechanically coupled distributed dynamic strain measurement for track systems and earthworks
Mechanically coupled distributed dynamic strain measurement for track systems and earthworks
Distributed optical fibre sensors are one of the few sensing technologies that could be embedded into our infrastructure to provide quantitative and mechanistic measurements of the condition of the infrastructure at network scales. This study considers the analysis of a sensing fibre deployed along 50 m of rail with a 7.5 m section buried beneath the line of the rail in the trackbed. The fibre was interrogated using a Distributed Acoustic Sensing (DAS) system based on Phase Optical Time Domain Reflectometry (ϕ-OTDR). This technique offers a short gauge length and high sample rate suited for measurement of moving loads. Data were captured as the site was trafficked by passing trains. Complementary simulation and measurements (using accelerometers and pressure sensors) were used to aid and improve the interpretation of the signal from the sensing fibre. In general, the measured signal agreed with the simulation indicating that the buried fibre provides a means of measuring horizontal strain in the ground under moving loads. Results from the different measurement systems led to a consistent interpretation of site behaviour, particularly where local variation of stiffness and load distribution were detectable at the same locations along the track. These analyses support the idea that DOFS have the potential for providing quantitative and high-resolution, and hence, high-utility sensing by interrogating an optical fibre embedded in infrastructure.
Fibre Optic Sensors, Railway Track, Strain Measurement
Milne, David
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Powrie, William
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Watson, Geoff
a7b86a0a-9a2c-44d2-99ed-a6c02b2a356d
Masoudi, Ali
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Brambilla, Gilberto
815d9712-62c7-47d1-8860-9451a363a6c8
Harkness, John
026f02e8-41d9-403f-83be-0d880058ecf1
Lee, Benjamin Robert
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Le Pen, Louis
4a38e256-d113-4bba-b0d4-32d41995928a
12 June 2025
Milne, David
6b321a45-c19a-4243-b562-517a69e5affc
Powrie, William
600c3f02-00f8-4486-ae4b-b4fc8ec77c3c
Watson, Geoff
a7b86a0a-9a2c-44d2-99ed-a6c02b2a356d
Masoudi, Ali
8073fb9b-2e6c-46c9-89cf-cb8670d76dc0
Brambilla, Gilberto
815d9712-62c7-47d1-8860-9451a363a6c8
Harkness, John
026f02e8-41d9-403f-83be-0d880058ecf1
Lee, Benjamin Robert
791c9c18-0abb-493a-8837-22d558d51b10
Le Pen, Louis
4a38e256-d113-4bba-b0d4-32d41995928a
Milne, David, Powrie, William, Watson, Geoff, Masoudi, Ali, Brambilla, Gilberto, Harkness, John, Lee, Benjamin Robert and Le Pen, Louis
(2025)
Mechanically coupled distributed dynamic strain measurement for track systems and earthworks.
Transportation Geotechnics, 53, [101605].
(doi:10.1016/j.trgeo.2025.101605).
Abstract
Distributed optical fibre sensors are one of the few sensing technologies that could be embedded into our infrastructure to provide quantitative and mechanistic measurements of the condition of the infrastructure at network scales. This study considers the analysis of a sensing fibre deployed along 50 m of rail with a 7.5 m section buried beneath the line of the rail in the trackbed. The fibre was interrogated using a Distributed Acoustic Sensing (DAS) system based on Phase Optical Time Domain Reflectometry (ϕ-OTDR). This technique offers a short gauge length and high sample rate suited for measurement of moving loads. Data were captured as the site was trafficked by passing trains. Complementary simulation and measurements (using accelerometers and pressure sensors) were used to aid and improve the interpretation of the signal from the sensing fibre. In general, the measured signal agreed with the simulation indicating that the buried fibre provides a means of measuring horizontal strain in the ground under moving loads. Results from the different measurement systems led to a consistent interpretation of site behaviour, particularly where local variation of stiffness and load distribution were detectable at the same locations along the track. These analyses support the idea that DOFS have the potential for providing quantitative and high-resolution, and hence, high-utility sensing by interrogating an optical fibre embedded in infrastructure.
Text
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More information
Accepted/In Press date: 6 June 2025
e-pub ahead of print date: 8 June 2025
Published date: 12 June 2025
Keywords:
Fibre Optic Sensors, Railway Track, Strain Measurement
Identifiers
Local EPrints ID: 503123
URI: http://eprints.soton.ac.uk/id/eprint/503123
ISSN: 2214-3912
PURE UUID: 3051b794-fe05-4788-8c4a-630e95944a7d
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Date deposited: 22 Jul 2025 16:33
Last modified: 22 Aug 2025 02:21
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Author:
Ali Masoudi
Author:
Gilberto Brambilla
Author:
Benjamin Robert Lee
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