## 5 Conclusions  
Based on the results of the quantitative coupling model of the seepage field and temperature field, combined with the distribution form of the optical fiber in embankment seepage monitoring, the distribution and interaction of the seepage field and the temperature field in the local area of the cable and its surrounding medium are analyzed. On this basis, considering the engineering practicability, the two-field coupling simplified model is studied and constructed, and the two-field quantitative coupling control differential equation suitable for the optical fiber monitoring of seepage flow inside the embankment is deduced. This lays a theoretical foundation for the monitoring of the seepage flow velocity of the embankment by means of a distributed optical fiber temperature measurement system and supports the monitoring model used in engineering. Considering the coupling effect of the seepage field and temperature field in embankment engineering, based on the two-field coupling simplified model, combined with the DTS temperature measurement system and COMSOL software (with a computational time of less than 30 s), the seepage field inversion of the known temperature field inside the embankment is carried out. Based on the analysis of the experiment, the seepage field of the porous medium is successfully obtained through the inversion of the temperature field of sand or clay inside the sink, and the seepage flow velocity under stable seepage is obtained. At the same time, this paper discusses the accuracy and practicability of the optical fiber permeability measurement and positioning under different working conditions. The accuracy for seepage location detection is 1.3%. The greater the heating power, the better the monitoring effect. However, due to the complexity of the coupling effect of the temperature field and seepage field, this paper only considers the influence of the seepage field on the temperature field and ignores the influence of the temperature field on the seepage field, which is often unfavorable for practical engineering applications. At the same time, how to reasonably lay the optical fiber during application and engineering practice still needs to be studied. Based on the dual-field coupling control equation in this paper, only the stable seepage field inside the porous medium is considered. For practical engineering problems, when seepage failure occurs inside the embankment, the seepage field is often not uniform. Therefore, how to timely and efficiently feedback the seepage inside the embankment and establish the embankment seepage early warning system still needs to be further studied. In future, the field test will be finished. The field test will be based on the fact that there are currently various seepage problems hindering the clarity of the exploration process and principles, and the accurate verification of technology. Therefore, there will be difficulties in finding a suitable field test, including adequate power supply system for outdoor equipment, pre-embedded sensing optical fibers in the structures, and the rapid occurrence of suitable seepage problems. Conceptualization, M.Y. ; methodology, H.L. and M.Y. ; soft-ware, M.Y. ; validation, M.Y. ; formal analysis, M.Y. ; investigation, H.L. ; resources, H.L. and M.Y. ; data curation, H.L. ; writing--original draft preparation, M.Y. and H.L. ; writing--review and editing, M.Y. All authors have read and agreed to the published version of the manuscript. This work was supported by the National Key Research and Development Program of China (Grant No. 2021 YFC3090104),China Postdoctoral Science Foundation (Grant No. 2022M721668), the Science and technology projects managed by the headquarter of State Grid Corporation (5108-202218280A-2-417-XG), the Open fund of National Dam Safety Research Center (Grant No.