Geotechnical monitoring in tunnel construction

Tunnel integrity measurements and landfill construction at Semmering Base Tunnel

  • Shotcrete sensor integration
  • Sensor installation fixed to geosynthetics
  • Load optimization of trucks

Lienhart, W., et al. „Reinforced Earth Structures at Semmering Base
Tunnel–Construction and Monitoring using Fiber Optic Strain Measurements.“ 10th
International Conference on Geosynthetics (10ICG). 2014.

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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

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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

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Offshore Pile Monitoring

Static load tests on steel pile foundations

  • Metal tape fiber-optic senisng 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, W. “Application of distributed Brillouin optical fiber sensor systems in geo-technical monitoring”, 6th Asia Pacific Optical Sensors Conference, Shanghai, 10.-14.10.2016

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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

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