Numerical Simulation of Local Flow-Field Characteristics in the Sand–Gravel Transition Zone under Localized Leakage

DOI: https://doi.org/10.62517/jes.202602316

Author(s)

Jiahui Liang1,2, Chen Peng3, Meng Yang1,2,*, Yu Jia1,2, Lei Tang1,2, Pinzhi Luan1,2

Affiliation(s)

1Materials & Structural Engineering Department, Nanjing Hydraulic Research Institute, Nanjing, Jiangsu, China 2The National Key Laboratory of Water Disaster Prevention, Nanjing, Jiangsu, China 3Dayu College, Hohai University, Nanjing, Jiangsu, China *Corresponding Author

Abstract

Local leakage in asphalt concrete core walls is usually highly concealed, and its influence on the downstream transition materials is difficult to characterize directly. To reveal the flow-field response of the sand–gravel transition zone under localized leakage in the core wall, a three-dimensional equivalent seepage model of the downstream sand–gravel transition zone was established. The local velocity field, pressure field, velocity head, and velocity distributions along two virtual survey lines were analyzed under concentrated leakage conditions. The results show that a localized leakage inlet can generate a flow field with clear spatial directivity in the downstream sand–gravel transition zone. The high-velocity region is concentrated near the leakage inlet and spreads along the dominant seepage direction, while the pressure decreases continuously along the seepage path. Along the elevation direction, the high-velocity zone occurs near the elevation range affected by the leakage inlet, with the velocity decreasing gradually toward lower elevations. Along the dam-axis direction, the velocity distribution exhibits higher values in the central region and lower values on both sides, and the peak position corresponds well to the projection of the leakage inlet. These findings indicate that the leakage-driven flow field in the sand–gravel transition zone exhibits identifiable spatial response characteristics, which can provide a basis for understanding local seepage mechanisms and arranging subsequent monitoring sections.

Keywords

Asphalt Concrete Core Wall; Sand–Gravel Transition Zone; Localized Leakage; Local Seepage Field; Virtual Survey Line; Spatial Response

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