Measurement of shotcrete lining deformation during tunnel and shaft excavation

Tunnel lining integrity monitoring during the construction the Semmering Base Tunnel

  • Shotcrete sensor integration
  • Strain measurement in tunnel lining
  • Shape sensing and deformation
  • Comparison with conventional geodetic instruments (fiber Bragg gratings, vibrating wire (VWS), and total station measurements).

Read the Case Study - PDF

Technical Paper – Christoph M. Monsberger · Werner Lienhart
Distributed fiber optic shape sensing along shotcrete tunnel linings: Methodology, field applications, and monitoring results. Journal of Civil Structural Health Monitoring
External link

Video of tunnel excavation and sensor installation (automatic English subtitles available)

Monitoring Singapore’s used water underground infrastructure

Monitoring of the structural integrity of the Deep Tunnel Sewerage System (DTSS)

  • Network of more than 100 km of fiber-optic sensors embedded in the tunnel walls, monitoring the tunnel’s structural health
  • Cable installation design provides 3D information
  • Continuous distributed strain and temperature measurements provided in real time for several decades
More details - PDF Link to project
Longsgraben Landfill site

Geotechnical ground movement and structural deformation monitoring (landfill site)

Detecting ground movement and structural deformation with fiber optic sensing

  • Ground movement, creep and long term erosion monitored continuously over 5 years in an earth retaining structure
  • Strain detected and cause identified during construction
  • Detection of risks during construction
  • Fiber optic and geodetic measurements compared

Read the Case Study - PDF

Technical paper: Lienhart W, Buchmayer F, Klug F and Monsberger CM Distributed fibre-optic sensing applications at the Semmering Base Tunnel, Austria. Proceedings of the Institution of Civil Engineers – Smart Infrastructure and Construction External link

Photo © ÖBB/Ebner


Static Pile Loading Tests

Continuous strain measurements for pile evaluation

  • Large bored pile equipped with fiber-optic strain sensing cables
  • Direct concrete embedding provides continuous mechanical strain transfer

Kindler, A., and Nycz, K., “Static Pile Loadings Using Fiber Optics High Spatial
Resolution Strain Measurements”, DFI SuperPile 2017 – Piling Design and Construction
Conference, San Diego 2017

Link to project

Rail condition monitoring

Strain measurements to prevent derailing and rail breakage

  • Rail deformation monitoring at heavy load and large temperature cycles
  • Fiber-optic sensing cables directly applied to the rail

Lienhart, W., et al. ‚Condition monitoring of railway tracks and vehicles using fibre optic sensing techniques.‘ International Conference on Smart Infrastructure and Construction, Cambridge, 2016

Link to project

Offshore Pile Monitoring

Static load tests on steel pile foundations

  • Metal tape fiber-optic sensing cable design welded to the inside of the steel pile
  • Subsequent strain measurements along a 90 m pile, up to 50 MN load
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Railway embankment monitoring

Settlement measurements in geotechnical unstable region

  • Fiber-optic strain and temperature sensing cables soil-embedded during restoration of embankment
  • Recurring measurements over 3 years

Großwig, S. “Application of distributed Brillouin optical fiber sensor systems in geo-technical monitoring”, 6th Asia Pacific Optical Sensors Conference, Shanghai, 10.-14.10.2016

Link to project

Static Pile Loading Tests

Referenced pile foundation evaluation

  • Direct concrete embedding of fiber-optic strain sensing cables
  • Distributed strain measurements referenced to classic discrete extensiometers

Nöther, N. Krcmar, M.: “Industry challenges on resolution, linearity and optical budget of high-accuracy distributed Brillouin sensing”, International Conference on Smart Infrastructure and Construction, Cambridge, 2016

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Borehole strain and temperature monitoring

Measurements of strain occurrence in fiber-optic downhole cable

  • Fiber-optic sensing cable for temperature measurements embedded between surrounding rock and borehole casing
  • Measurements referenced to Raman DTS temperature data

„Nöther, N. et al., “Application of distributed optical fiber sensors to borehole temperature and strain monitoring”, Proceedings of SENSOR+TEST Conferences 2011, Nürnberg, 2011

Link to project