Abstract: The smooth fracture seepage flow of rock can be described by the cubic law, but the permeability of fracture in vesicular rock differs due to vesicles on two sides of the fracture surface. In this research, four kinds of vesicular basalt samples with significant differences in vesicle distribution were selected from the volcanic area of Haikou to conduct single fracture permeability test based on the vesicle characteristic parameters. Furthermore, the permeability law of vesicular fracture was obtained by transforming the test results using the influence factor (λ) of fracture surface structure. Finally, the mechanism of vesicular structure affecting fracture permeability was expounded through numerical analysis verifying the rationality of laboratory test result. The results demonstrat that vesicular structure has a significant impact on the seepage of fracture. When the Reynolds number is low (Re<200), vesicular structure boosts the seepage flow of fracture; when the Reynolds number is high (Re>200), vesicular structure hinders the seepage flow of fracture. The influence factor λ is negatively related to the Reynolds number (Re) within a certain range.

Key words: smooth fracture of rock, vesicular structure, permeability test, numerical simulation, seepage flow of fracture