Coral sand, as a kind of filling material, is widely used in the construction of artificial reefs or roadbeds in coastal areas. With the widespread use of the artificial grounding freezing method in the coastal area and the seepage environment faced, it will exert a significant impact on the macroscopic properties and micro-structure of coral sand. To study the macroscopic and microscopic properties of coral sand subjected to freeze-thaw with and without seepage, the one-dimensional soil column freezing test, scanning electron microscope, direct shear test, and particle sieve test were carried out. The test results showed that there was obvious water migration in the coral sand during the freezing process, and the increase of water content in the frozen zone was large in the absence of seepage, while the difference of water content in the frozen zone, phase-transition zone and unfrozen zone of coral sand was not significant under seepage effect. The scouring effect of seepage resulted in increased friction on the surface of sand particles, and the small particles produced by freeze-thaw damage of large particles increased inter-particle shading, resulting in greater shear strength of coral sands with seepage than without seepage. Regardless of the effect of seepage, all zones of the coral sand increased in the range of particle size from 0.5 mm to 0.25 mm and decreased in the range of particle size from 0.2 mm to 0.1 mm. Freezing increased the number of small pores within the coral sand. This study provides a reference basis for understanding the macro and micro mechanical properties of artificially frozen coral sand under seepage.

来源平台：CONSTRUCTION AND BUILDING MATERIALS