Seepage Detection Using Passive Temperature Measurements by Fiber Optic DTS

Yaser Ghafoori

Abstract


This article is an extended abstract of the doctoral dissertation “Optimization of early seepage detection in embankments using a distributed temperature system based on fiber optic sensing” [1]. Distributed Temperature Sensors (DTS) measure temperature precisely with high spatial resolution, enabling seepage flow detection through the interpretation of temperature measurement. Active DTS measurement which introduces heat into the soil to monitor its dissipation, has been extensively studied for seepage detection. However, the potential of passive measurement, which measures natural soil temperature, for seepage detection demands further exploration. The doctoral research investigated the capability of passive DTS measurements for seepage detection. The findings show that passive DTS detects very small temperature variations as a result of the seepage flow. Additionally, the results offer valuable insights into the coupled hydro-thermal behavior and the influence of seepage on heat transfer. The thesis classified and compared different techniques for temperature data calibration and interpretation. Furthermore, an interpretation approach based on numerical simulation and a fully dynamic calibration technique were developed.  


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References


Ghafoori Y (2023), Optimization of early seepage detection in embankments using a distributed temperature system based on fiber optic sensing: Ph.D. Thesis. University of Ljubljana.

Ghafoori Y, Maček M, Vidmar A, Říha J, Kryžanowski A (2020). Analysis of seepage in a laboratory scaled model using passive optical fiber distributed temperature sensor. Water, 12, 367. https://doi.org/10.3390/w12020367.

Ghafoori Y, Maček M, Vidmar A, Říha J, Kryžanowski A (2021). Heat transfer by seepage in sand: Influence of saturated hydraulic conductivity and porosity. Acta Hydrotechnica, 34, pp. 61–75. https://doi.org/10.15292/acta.hydro.2021.05.

Ghafoori Y, Maček M, Vidmar A, Říha J, Kryžanowski A (2020). Monitoring of temperature distribution by optical fiber DTS within soil subjected to seepage flow. Second SLOCOLD -MACOLD Symposium on topic Water reservoirs, Skopje, Republic of N. Macedonia, p. 77–84.

Ghafoori Y, Logar J, Říha J, Kryžanowski A (2021). Numerical modeling for identification of seepage by thermal monitoring in the embankment of Brežice HPP. Macedonian Committee on Large Dams (5th Congress on Dams), Struga, Republic of N. Macedonia: MACOLD, p. 99–105.

Ghafoori Y, Vidmar A, Říha J, Kryžanowski A (2020). A review of measurement calibration and interpretation for seepage monitoring by optical fiber distributed temperature sensors. Sensors, 20(19):5696. https://doi.org/10.3390/s20195696.

Ghafoori Y, Vidmar A, Kryžanowski A (2022). A Dynamic Calibration of Optical Fiber DTS Measurements Using PEST and Reference Thermometers. Sensors; 22(10):3890. https://doi.org/10.3390/s22103890.




DOI: https://doi.org/10.31449/inf.v48i2.5750

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