Abstract:
With the intensification of human engineering activities and natural geological processes, the study of solute transport mechanisms in fractured media has become one of the core topics in the field of environmental geology and geotechnical engineering. As the basic component of the fracture network, the solute transport characteristics of single fracture are of great significance for understanding the solute transport in the fracture network. We summarized the research progress of solute transport in single fracture, focusing on the influence mechanism of fracture geometry (such as roughness, aperture, contact area) and external stress on solute transport. Through numerical simulations and laboratory experiments, the researchers revealed the heterogeneity of solute transport and non-Fickian behavior (such as "early arrival" and "tailing" phenomena). Numerical simulation provides an efficient tool for studying solute transport in fractures under complex geological conditions, while laboratory experiments visually demonstrate the solute transport process in fractures through breakthrough tests and visualization tests. Although significant progress has been made in the existing research, the complexity of fracture geometry, the coupling mechanism of stress-seepage-solute transport, and the quantitative description of non-Fickian transport phenomena still need further research. Future research could combine multi-field coupling mechanism, multi-scale effect and high-precision experimental verification to provide a support for practical problems such as nuclear waste disposal and pollutant migration.