北极融冰期海冰内部组构和冲击压缩力学行为研究

Arctic navigation is an important part of Chinese ‘Polar Silk Route’. The physical and mechanical properties of Arctic sea ice during melt season are fundamental scientific issues concerning the design and navigation of polar ships. In view of the fact that the sea ice phase composition changes during melt season and the ice-ship interaction rate is high, it is planned to carry out the observation of internal configuration and the impact compression strength test of Arctic sea ice during melt season. The observation of ice temperature, salinity, density, grain structure and geometric parameters of brine cells and air bubbles of Arctic sea ice are conducted at different locations, and ice cores are extracted to conduct the impact compression strength test. According to the observation data of physical properties, the distribution trend of brine cells and air bubbles inner Arctic sea ice during melt season is investigated, and the quantitative relationship between geometric parameters of brine cells and air bubbles and sea ice temperature, salinity and density is analyzed. According to the mechanical test data, the parameterized equation of the impact compression strength of Arctic sea ice during melt season is formed. Combined analysis of the existing Arctic sea ice uniaxial compression strength data are conducted meanwhile to future reveal the variation mechanism of compression behavior of sea ice. The quantitative relationship between the impact strength and physical properties of sea ice is analyzed, based on which the spatial distribution of Arctic sea ice impact compression strength during melt season is given using the accumulated sea ice physical properties data. These study results of geoscience issues will support the design and operation of polar ships during Arctic navigation in future.

北极航行是中国冰上丝绸之路建设的重要组成部分。北极融冰期海冰物理和力学性质是关乎极地船舶设计和航行的基础科学问题。针对融冰期海冰相成份发生变化和冰-船相互作用速率较高的事实，计划开展北极融冰期海冰内部组构观测和冲击压缩强度测试。在北极不同位置开展融冰期海冰温度、盐度、密度、晶体结构、卤水胞和气泡几何参数观测，采集冰芯开展海冰冲击压缩强度试验。根据物理性质观测数据探究北极融冰期海冰卤水胞和气泡的冰内分布规律，分析其几何参数与海冰温度、盐度和密度的定量关系。根据力学试验数据建立北极融冰期海冰冲击压缩强度的参数化方程，与前期研究的北极海冰单轴压缩强度数据进行联合分析，进一步揭示海冰压缩力学行为的变化机制。分析海冰冲击压缩强度与物理性质之间的定量关系，利用前期积累的海冰物理性质数据给出北极融冰期海冰冲击压缩强度的空间分布。这些地球科学的基础研究成果将为未来北极航行的船舶设计和操纵提供科学支持。

北极海冰快速消融，引起海冰物理和力学性质随之变化。针对北极航行安全保障需要对海冰物理和力学性质的深入了解，对北极海冰内部组构和力学性质开展了现场和实验室试验研究。研究结果认识了当前北极夏季海冰温度、盐度、密度、晶体结构、卤水体积分数和空气体积分数的冰内垂向分布规律，以归一化深度为因子建立了相应的参数化方案，并通过与前人观测结果比较，揭示了北极海冰物理性质的显著变化。自主研发了适用于实验室和现场试验的摆锤式冰冲击试验机、落锤式冰冲击试验机、原位冲击试验机，利用渤海咸水冰成功开展了冰冲击试验测试，探究冲击速度和冲击头形状与冲击荷载的关系，验证了试验设备和测试技术的可行性，为将来在极地开展冰冲击试验积累了可靠经验。开展了南极普里兹湾固定冰压缩强度、弯曲强度和弹性模量的实验室试验，明确了海冰孔隙率与弯曲强度、弹性模量和单轴压缩强度的关系，建立了基于海冰孔隙率的冰层承载力设计方法。开展了北极融冰期海冰物理和力学性质的随机分析，发现了海冰物理和力学性质有良好的空间随机分布特性，并用常用概率密度函数对海冰厚度、密度、弯曲强度和弹性模量等参数的分布进行数学建模。上述研究成果对揭示北极海冰快速变化的物理机制，改进全球气候数值预报模式，保障极地航行和作业安全提供了科学支撑。研究成果在The Cryosphere、Journal of Geophysical Research-Oceans、海洋学报、极地研究等国内外高水平学术期刊和重要学术会议上发表论文15篇，其中SCI检索9篇，EI检索1篇，授权发明专利3项，培养出站博士后1名，硕士研究生4名。