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The leakage of earth rock dams exhibits characteristics of space-time randomness, concealment, and significant destructiveness. Prompt detection and identification of dam leakage are critical to ensuring the structural safety of these constructions. The distributed optical fiber temperature measurement method, which is based on optical frequency domain reflection (OFDR) technology, possesses attributes such as high spatial resolution, minimal temperature error, short response time, and real-time monitoring. As a result, it is an ideal technique for experimental research on leakage monitoring of earth rock dams. In this study, a model test was conducted on a clay core rockfill dam to investigate the feasibility of utilizing distributed optical fiber for identifying dam leakage. The variation pattern of partial distributed optical fiber temperature measurements in the dam body under the leakage state was compared and analyzed using the gradient method and the thermal pulse method. Furthermore, the heat flow coupled numerical simulation method was employed to verify and expand the findings of the indoor tests. The results of this study indicate that the OFDR distributed optical fiber leakage monitoring method using the thermal pulse approach can entirely reflect the temperature changes that occur during leakage, thereby providing strong reliability and exhibiting considerable potential for leakage location. The study offers valuable insights and a reference for the practical use of distributed optical fiber to monitor earth rock dam leakage. • Investigating core rockfill dam leakage monitoring using OFDR distributed optical fiber sensing technology. • Combining gradient and thermal pulse methods to analyze temperature field changes in dam seepage state. • The application of temperature tracer method in leakage monitoring was analyzed. [ABSTRACT FROM AUTHOR]

This paper expounds on the process of deformation and seepage field change of single coarse fracture under normal stress and puts forward a numerical simulation framework based on fluid-structure coupling method to reasonably link contact deformation of fracture surface with seepage field change. The geometric model of a three-dimensional rough single fracture surface with controllable JRC is established based on the random surface generation method. The numerical test model of radiation flow of single fracture in rough rock is constructed, which is consistent with the laboratory test. Through carrying out numerical simulation tests of different JRC and normal stress conditions, this paper discusses the phenomenon and intrinsic nature of the influence of JRC on fracture seepage characteristics. The increase in eddy current intensity and eddy current area ratio is the inherent characteristics of the seepage field characteristics after JRC increases. With the rise of energy loss, the macroscopic seepage flow decreases. In addition, with the advantage of the fluid-structure interaction method, the fracture deformation characteristics under different normal stresses are reflected by the ratio of the contact area. The correlation among fracture surface deformation, velocity vector, and seepage pressure are analyzed. Finally, the cubic polynomial correlation between gap width ratio and contact area ratio is established and verified. It is of positive significance to quantify the influence of coarse single fracture contact ratio on deformation-seepage coupling characteristics under normal stress. • A numerical simulation method for coupled stress and seepage experiments of a rough single fracture was established. • The influence of roughness on the seepage characteristics of 3D fractures was discussed. • The fluid-structure coupling characteristics of single fracture under normal stress were analyzed. • The relationship between the gap width ratio b max / b h and the contact ratio r vc is proposed. [ABSTRACT FROM AUTHOR]

• 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]