Case studies of high-sensitivity monitoring of natural and engineered slopes

Werner Lienhart

Graz University of Technology, Graz, Austria

Journal of Rock Mechanics and Geotechnical Engineering (2015), doi: 10.1016/j.jrmge.2015.04.002.

Abstracts: High-sensitivity monitoring solutions are crucial for early warning systems of earth structures. In this paper, we discuss the design and implementation of such systems for natural and engineered slopes using two case studies. At the Gradenbach Observatory, one key element of the monitoring system is a large fiber optic strain rosette embedded in the slope. We demonstrate that the strain rosette can depict landslide deformations much earlier than geodetic sensors like GPS or total stations and is therefore well suitable for an early warning system. In a second application we report the construction of a reinforced earth structure using geogrids. A distributed fiber optic measurement system was installed to measure the current operating grade of the geogrids within the earth structure. About 2 km of Brillouin sensing cables were installed in the project area. It is demonstrated that the developed monitoring system is well suited for assessing the current state of health of reinforced earth structures.

Key words: structural health monitoring; fiber optic sensors; Brillouin optical frequency domain analyzer (BOFDA); SOFO sensors; reinforced earth structures; geogrid; landslides


Artieres O, Beck YL, Khan AA, Fry JJ, Courivaud JR, Guidoux C, Pinettes P. Assessment of dams and dikes behavior with a fibre optic based monitoring solution. In: Garcia RR, Mir MA, Bitrian FH, Dios RL, Caballero MRC editors. Dam maintenance and rehabilitation II, Proceedings of the 2nd International Congress on Dam Maintenance and Rehabilitation. Leiden: CRC Press/ A.A.Balkema, 2010. p. 8.

Bao X, Chen L. Recent progress in distributed fiber optic sensors. Sensors 2012; 12(7): 8601–39.

Brückl E, Brunner FK, Kraus K. Kinematics of a deep-seated landslide derived from photogrammetric, GPS and geophysical data. Engineering Geology 2006; 88(3–4): 149–59.

Brückl E, Brunner FK, Lang E, Mertl S, Müller M, Stary U. The Gradenbach Observatory—monitoring non-stationary deep-seated gravitational creep by geodetic, hydrological, and seismological methods. Landslides 2013; 10(6): 815–29.

Galindez-Jamioy CA, Lopez-Higuera JM. Brillouin distributed fiber sensors: An overview and applications. Journal of Sensors 2012; Article ID 204121, doi:

Gassner G, Wieser A, Brunner FK. GPS software development for monitoring of landslides. In: Proceedings of FIG XXII Congress, Washington, D.C., USA. 2002 (CDROM).

Horiguchi T, Kurashima T, Tateda M. Tensile strain dependence of Brillouin frequency shift in silica optical fibers. IEEE Photonics Technology Letters, 1989; 1(5): 107–8.

Inaudi D. Testing performance and reliability of fiber optic sensing system for long-term monitoring. In: Proceedings of SPIE Volume 5502, Second European Workshop on Optical Fibre Sensors, Santander, Spain. 2004. p. 552-5. doi:10.1117/12.566713.

Iten M. Novel applications of distributed fiber-optic sensing in geotechnical engineering. PhD Thesis. Zürich, Switzerland: ETH Zürich, 2011.

Iten M, Schmid A, Hauswirth D, Puzrin AM. Defining and monitoring of landslide boundaries using fiber optic systems. In: Prediction and Simulation Methods for Geohazard Mitigation: Proceedings of the International Symposium on Prediction and Simulation Methods for Geohazard Mitigation (IS-Kyoto2009), Kyoto, Japan. CRC Press, 2009. p. 451–6.

Krebber K, Lenke P, Liehr S, Nöther N, Wendt M, Wosniok A. Structural health monitoring by distributed fiber optic sensors embedded into technical textiles. In: Proceedings of SPIE, the International Society for Optical Engineering 2012; doi: 10.1117/12.868052.

Liezen Online. Hangrutschung in Schladming. 2011. nachrichten/aktuellesaus-dem-bezirk/item/936-hangrutschung-in-schladming.

Lienhart W. Experimental investigation of the performance of the SOFO measurement system. In: Structural Health Monitoring 2005, Proceedings of the 5th International Workshop on Structural Health Monitoring, Stanford, USA. DEStech Publications, Inc., 2005. p. 1131–8.

Nöther N. Distributed fiber sensors in river embankments: advancing and implementing the Brillouin optical frequency domain analysis. BAM Dissertations, Vol. 64. Berlin: BAM Bundesanstalt für Materialforschung und –prüfung, 2010.

Nöther N, v.d. Mark S. Displacement and settlement monitoring in large geotechnical structures with novel approach to distributed Brillouin sensing. In: Proc. Civil Structural Health Monitoring Workshop (CSHM-4), Berlin, Germany. 2012.

Wöllner J, Woschitz H, Brunner FK. Testing a large fiber optic strain-rosette, embedded in a landslide area. In: Proc. 8th Int. Symp. Field Measurements in GeoMechanics (FMGM-8), Berlin, Germany. 2011.

Woschitz H, Brunner FK. Monitoring a deep-seated mass movement using a large strain rosette. In: Proceedings of the 13th FIG Symposium on Deformation Measurements and Analysis, Lisbon, Portugal. 2008.