An experimental study on monitoring the phreatic line of an embankment dam based on temperature detection by OFDR.

• Laboratory tests, along with numerical simulations, were conducted to analyze the temperature field distribution inside a dam. • The heat transfer characteristics during seepage in an embankment dam were also investigated. • The distribution of the phreatic line in a dam was determined by the temperature detection curve obtained from OFDR. In this study, temperature detection with distributed fibers was used to obtain data for a laboratory model of seepage heat in an embankment dam, and the temperature was monitored using optical frequency domain reflection (OFDR) technology with high temporal and spatial accuracies. First, the temperature field in the infiltrated region of the dam body during the seepage test showed changes similar to that measured by OFDR temperature-sensing fibers. Then the heat transfer characteristics analysis within the embankment dam during seepage was conducted using numerical simulations of heat-flow coupling. Finally, temperature distribution characteristics during steady-state seepage for different water levels were measured, and the relationship between the temperature curve and the phreatic line was obtained. The results demonstrate that accurate temperature detection by OFDR and its high spatial resolution can reflect the characteristics of the temperature field in the seepage model of an embankment dam. [ABSTRACT FROM AUTHOR]