Measuring Soil Strain Using Fibre Optic Sensors

  • Susanga CostaEmail author
  • Gayan Kahandawa
  • Jian Chen
  • Jianfeng Xue
Conference paper
Part of the Environmental Science and Engineering book series (ESE)


Monitoring subsurface soil movement is important in many geotechnical engineering applications such as stability of slopes, road embankments and settlement in foundations. Soil displacement measurement is also helpful in understanding the formation of shrinkage cracks. Clay soils undergo shrinkage during drying and experience substantial stresses and strains, which results in shrinkage cracks. This paper presents a novel approach to measure soil strain using Fibre Bragg grating (FBG) sensors. In the experiments described, FBG sensors have been used to investigate the strain development in clay during drying.

FBG sensors are fabricated in the core region of specially fabricated single mode low-loss germanium doped silicate optical fibres. The grating is the laser-inscribed region with a periodically varying refractive index, which reflects a specific light wavelength. Due to the applied strain, ε, there is a change in the wavelength which can be measured and is directly proposal to strain.

Kaolin clay, mixed with water close to the liquid limit, was allowed to dry under room temperature. The specimens were prepared in thin, long linear shrinkage moulds. FBG sensors were placed inside soil at the centre of the specimen. The strain development during drying underwent four phases moving from compression to tension. An oscillating nature of strain was also observed throughout the drying process. Results obtained are useful to develop analytical solutions to describe stress-strain behavior of drying soil.


Clay Drying Fibre optic sensors Strain 


  1. 1.
    Richards BG, Peter P, Emerson WW (1983) The effects of vegetation on the swelling and shrinking of soils in Australia. Geotechnique 33(2):127–139CrossRefGoogle Scholar
  2. 2.
    Costa S, Kodikara J, Thusyanthan NI (2008) Study of desiccation crack evolution using image analysis. In: Toll et al. (eds) Unsaturated soils: advances in geo-engineering. Taylor & Francis Group, LondonGoogle Scholar
  3. 3.
    Shannon B, Kodikara J, Rajeev P (2015) The use of restrained ring test method for soil desiccation studies. Goetechn Test J 38(1):98–112Google Scholar
  4. 4.
    Sanchez M, Atique A, Kim S, Romero E, Zielinski M (2003) Exploring desiccation cracks in soils using a 2D profile laser device. Acta Geotech 8:583–596CrossRefGoogle Scholar
  5. 5.
    Julina M, Thyagaraj T (2018) Quantification of desiccation cracks using X-ray tomography for tracing shrinkage path of compacted expansive soil. Acta Geotech. Scholar
  6. 6.
    Xu DS, Borana L, Yin JH (2014) Measurement of small strain behaviour of a local soil by fiber Bragg grating-based local displacement transducers. Acta Geotech 9:935–943CrossRefGoogle Scholar
  7. 7.
    Hill KO, Meltz G (1997) Fiber Bragg grating technology fundamentals and overview. J Lightwave Technol 15(8):1263–1276CrossRefGoogle Scholar
  8. 8.
    Kersey AD, Davis MA, Patrick HJ, LeBlanc M, Koo KP, Askins CG, Putnam MA, Friebele EJ (1997) Fiber grating sensors. J Lightwave Technol 15(8):1442–1463CrossRefGoogle Scholar
  9. 9.
    Kahandawa G, Epaarachchi J, Wang H, Lau K (2012) Use of FBG sensors for SHM in aerospace structures. Photonic Sensors 2:203–214CrossRefGoogle Scholar
  10. 10.
    Kashyap R (1999) Fibre Bragg gratings. Academic Press Publications, LondonGoogle Scholar
  11. 11.
    Costa S, Kodikara J (2010) Shrinkage development during soil desiccation. In: Buzzi et al. (eds) Unsaturated soils: theoretical and numerical advances in unsaturated soil mechanics. Taylor & Francis Group, LondonGoogle Scholar
  12. 12.
    Kodikara J, Choi X (2006) A simplified analytical model for desiccation cracking of clay layers in laboratory tests. In. Miller et al. (eds) Unsaturated soils 147(2):2558–2567. ASCE Geotechnical Special PublicationGoogle Scholar
  13. 13.
    Costa S, Kodikara J, Barbour SL, Fredlund DG (2018) Theoretical analysis of desiccation crack spacing of a thin, long soil layer. Acta Geotech 13:39–49CrossRefGoogle Scholar

Copyright information

© Springer Nature Singapore Pte Ltd. 2019

Authors and Affiliations

  • Susanga Costa
    • 1
    Email author
  • Gayan Kahandawa
    • 1
  • Jian Chen
    • 2
  • Jianfeng Xue
    • 3
  1. 1.School of Science, Engineering and ITFederation University AustraliaBallaratAustralia
  2. 2.School of EngineeringUniversity of MelbourneMelbourneAustralia
  3. 3.School of Engineering and Information Technology, ADFA CampusUniversity of New South WalesKensingtonAustralia

Personalised recommendations