Optical Fiber Strain Measurements and Numerical Modeling of Load Tests on Grouted Anchors
Publication: Journal of Geotechnical and Geoenvironmental Engineering
Volume 145, Issue 12
Abstract
This paper reports on the behavior of a grouted anchor instrumented with a fiber optic strain sensor in the grout body along the entire anchor length. During load tests up to the estimated pull-out capacity, the strain measurements indicate that a delamination occurs in the tendon bond length between the steel tendons and the grout body. The upper delaminated part of the grout body is under compression, whereas the lower bonded part of the grout body is under tension. This delamination gradually progresses as the anchor load increases. Furthermore, a significant part of the load is transferred from the anchor to the soil in the tendon free length. The anchor behavior is further modeled with a one-dimensional finite-element model that includes the steel tendons and the grout body, where an interface damage model is used to account for possible delamination of the interface. The numerical model confirms that the observed compressive and tensile strains in the grout can be related to a delamination of the steel strands in the tendon bond length. The experiment and numerical modeling demonstrate how optical fiber measurements in the grout body can be used, in operational conditions, to assess the anchor behavior, the mobilization of the soil resistance, and the estimation of the remaining anchor capacity.
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Data Availability Statement
The measurement data and model output are available from the corresponding author by request.
References
Barrias, A., J. Casas, and S. Villalba. 2016. “A review of distributed optical fiber sensors for civil engineering applications.” Sensors 16 (5): 748. https://doi.org/10.3390/s1605074810.3390/s16050748.
Boyd, R. W. 2003. Nonlinear optics. San Diego: Academic Press.
Briaud, J.-L., and Y. Lim. 1999. “Tieback walls in sand: Numerical simulation and design implications.” J. Geotech. Geoenviron. Eng. 125 (2): 101–110. https://doi.org/10.1061/(ASCE)1090-0241(1999)125:2(101).
De Borst, R., M. A. Crisfield, J. J. Remmers, and C. V. Verhoosel. 2012. Nonlinear finite element analysis of solids and structures. Hoboken, NJ: Wiley.
Desai, C., A. Muqtadir, and F. Scheele. 1986. “Interaction analysis of anchor-soil systems.” J. Geotech. Eng. 112 (5): 537–553. https://doi.org/10.1061/(ASCE)0733-9410(1986)112:5(537).
Domes, X., and T. Benz. 2015. “Untersuchungen zur Zementfiltration während der Herstellung von Verpressankern in nichtbindigen Böden.” Bautechnik 92 (9): 605–616. https://doi.org/10.1002/bate.201500048.
Fellenius, B. H. 2001. “From strain measurements to load in an instrumented pile.” Geotech. News Mag. 19 (1): 35–38.
Gächter, D., R. Kulmer, and V. Račanský. 2018. “Slope stabilization with multiple anchors monitored by glass fibre technique.” In Proc., 2018 DFI-EFFC Int. Conf. on Deep Foundations and Ground Improvement, 494–503. Hawthorne, NJ: Deep Foundation Institute.
Gioda, G., and S. Sakurai. 1987. “Back analysis procedures for the interpretation of field measurements in geomechanics.” Int. J. Numer. Anal. Methods Geomech. 11 (6): 555–583. https://doi.org/10.1002/nag.1610110604.
Hong, C.-Y., Y.-F. Zhang, G.-W. Li, M.-X. Zhang, and Z.-X. Liu. 2017. “Recent progress of using Brillouin distributed fiber optic sensors for geotechnical health monitoring.” Sens. Actuators A: Phys. 258 (May): 131–145. https://doi.org/10.1016/j.sna.2017.03.017.
Huang, M., Z. Zhou, Y. Huang, and J. Ou. 2013. “A distributed self-sensing FRP anchor rod with built-in optical fiber sensor.” Measurement 46 (4): 1363–1370. https://doi.org/10.1016/j.measurement.2012.12.012.
Huybrechts, N., M. De Vos, O. Tomboy, and J. Maertens. 2008. “Integrated analysis of the load test results & suggestions for a harmonised anchor design and test methodology in Belgium in the Eurocode 7 framework.” In Proc., Int. Symp. on Ground Anchors Limelette Test Field Results, Brussels, Belgium: Scientific and Technical Centre for Building.
Huybrechts, N., M. De Vos, and G. Van Lysebetten. 2016. “Advances and innovations in measurement techniques and quality control tools.” In Proc., ETC 3 Int. Symp. on Design of Piles in Europe. Leuven, Belgium: International Society for Soil Mechanics and Geotechnical Engineering.
Huybrechts, N., G. Van Lysebetten, and M. De Vos. 2017. “Advanced monitoring techniques for a wide range of geotechnical applications.” In Proc., ICSMGE 2017–19th Int. Conf. on Soil Mechanics and Geotechnical Engineering, 2761–2764. Seoul, South Korea: International Society for Soil Mechanics and Geotechnical Engineering.
ISO (International Organization for Standardization). 2018. ENISO22477-5—Geotechnical investigation and testing—Testing of geotechnical structures—Part 5: Testing of anchorages. ENISO22477-5. Geneva: ISO.
Mecsi, J. 1997. “Some practical and theoretical aspects of grouted soil anchors.” In Proc., Int. Conf. on Ground Anchorages and Anchored Structures, 119–130. London: Thomas Telford Publishing.
NBN (Bureau for Standardisation). 2013. NBN EN 1537—Execution of special geotechnical works—Ground anchors. NBN EN 1537. Melbourne, VIC, Australia: NBN.
NBN (Bureau for Standardisation). 2014. NBN EN 1997-1/A1—Eurocode 7: Geotechnical design—Part 1: General rules. NBN EN 1997-1/A1. Melbourne, VIC, Australia: NBN.
Phan, T. S., P. Rossi, and J.-L. Tailhan. 2015. “Numerical modelling of the concrete/rebar bond.” Cem. Concr. Compos. 59 (May): 1–9. https://doi.org/10.1016/j.cemconcomp.2015.02.003.
Spada, A., G. Giambanco, and P. Rizzo. 2011. “Elastoplastic damaging model for adhesive anchor systems. I: Theoretical formulation and numerical implementation.” J. Eng. Mech. 137 (12): 854–861. https://doi.org/10.1061/(ASCE)EM.1943-7889.0000287.
Štefaňák, J., L. Miča, J. Chalmovskỳ, A. Leiter, and P. Tichỳ. 2017. “Full-scale testing of ground anchors in neogene clay.” Procedia Eng. 172 (Jan): 1129–1136. https://doi.org/10.1016/j.proeng.2017.02.170.
Yu, H., and G. Houlsby. 1991. “Finite cavity expansion in dilatant soils: Loading analysis.” Géotechnique 41 (2): 173–183. https://doi.org/10.1680/geot.1991.41.2.173.
Zeni, L., L. Picarelli, B. Avolio, A. Coscetta, R. Papa, G. Zeni, C. Di Maio, R. Vassallo, and A. Minardo. 2015. “Brillouin optical time-domain analysis for geotechnical monitoring.” J. Rock Mech. Geotech. Eng. 7 (4): 458–462. https://doi.org/10.1016/j.jrmge.2015.01.008.
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©2019 American Society of Civil Engineers.
History
Received: Dec 3, 2018
Accepted: Jun 28, 2019
Published online: Sep 18, 2019
Published in print: Dec 1, 2019
Discussion open until: Feb 18, 2020
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