Author(s): Shuang Yu; Xiaodong Chen; Anliang Wang; Qinglin Duan; Shunying Ji
Linked Author(s):
Keywords: Sea ice; Melting season; Compressive strength; Columnar and granular ice; Loading directions; Porosity
Abstract: To investigate the anisotropy of compressive strength in Arctic summer sea ice, ice core samples were collected at six sites along the cruise track during China’s 15th Arctic Ocean Scientific Expedition in 2025. The samples were transported to a low-temperature structural laboratory under continuous cold-chain conditions, where uniaxial compression tests were conducted with loading applied in both the horizontal direction (parallel to the ice growth column) and the vertical direction (perpendicular to the ice growth column). By preserving the original spatial orientation of the samples, compressive strength profiles with depth were obtained for different sampling sites. All tests were performed at -5 ℃ with a loading rate of 0.02 mm/s, and all samples exhibited ductile failure. Salinity and density were measured concurrently during the experiments. The results indicate that compressive strength in both loading directions increases with ice depth. Due to summer melting, near-surface sea ice is characterized by high porosity, and failure is primarily controlled by pores and pre-existing defects; consequently, no significant difference in compressive strength was observed between the two loading directions. In contrast, deeper sea ice remains partially unmelted and preserves an intact columnar crystal structure, leading to pronounced compressive strength anisotropy. where the vertical compressive strength is approximately two to three times that in the horizontal direction. Notably, two sampling sites are identified as multi-year granular ice, which displays mechanical isotropy owing to its randomly distributed granular crystals. In contrast, the four first-year ice sites possess dominant columnar structures, resulting in prominent compressive strength anisotropy.
Year: 2026