Abstract: In-situ mechanical testing of Arctic sea ice is of great significance for ensuring the safety of ice navigation and supporting the design of polar ships. During the 15th Chinese National Arctic Research Expedition, systematic in-situ sea ice mechanical tests were carried out in the high-latitude region of the central Arctic Ocean (84°57′N-89°49′N). A total of 63 in-situ borehole strength tests, one full-thickness in-situ cantilever beam flexural strength test, and 43 small-scale three-point bending strength tests were completed. Among them, the borehole strength test and the in-situ cantilever beam test were both conducted by China for the first time in the polar region. Preliminary analysis shows that the borehole strength increases with latitude, rising from 3.9 MPa at 84°57′N to 14.2 MPa at 89°49′N. The flexural strength tests reveal a certain size effect: the full-thickness flexural strength obtained from the cantilever beam test is 226 kPa, while the arithmetic mean of the small-scale three-point bending strength is 384 kPa. This paper provides valuable field data for understanding the mechanical properties of late-summer Arctic sea ice and can support the design of China’s polar engineering equipment and the assessment of navigation safety of ships in ice-covered waters.

Key words: Arctic research expedition, sea ice mechanics, borehole strength, flexural strength

摘要： 北极海冰原位力学测试对保障冰区航行作业安全、支撑极地船舶设计具有重要意义。该文依托中国第15次北冰洋科学考察,在北极中央海域高纬度区域（84°57′N ~ 89°49′N）系统开展了海冰原位力学测试,共完成63组海冰原位扩孔强度测试、1组全冰厚原位悬臂梁弯曲强度测试和43组小尺寸三点弯曲强度测试,其中原位扩孔强度测试与原位悬臂梁弯曲强度测试均为我国首次在极地开展。初步分析表明,扩孔强度随纬度升高而增大,从84°57′N的3.9 MPa增至89°49′N的14.2 MPa。弯曲强度测试则揭示了一定的尺寸效应：全冰厚悬臂梁弯曲强度为226 kPa,而小尺寸三点弯曲强度的算术平均值为384 kPa。该文为认识北极夏末海冰力学特性提供了宝贵现场数据,可为我国极地工程装备的设计与冰区航行安全评估提供支撑。

关键词: 北极科考, 海冰力学, 扩孔强度, 弯曲强度