海冰与直立结构相互作用的破坏模式研究

Study on failure modes of interaction between sea ice and vertical structures

海冰在结构前的破坏模式以及产生的冰载荷与结构尺度和海冰厚度密切相关。采用海冰离散元方法(DEM)模拟平整冰与直立结构相互作用过程中的海冰破坏模式及整体冰载荷。该离散元方法的计算参数通过与Norströmsgrund灯塔的现场实测数据对比进行了可靠性验证。在此基础上,对不同宽厚比(结构宽度与海冰厚度的比值)工况下平整冰与直立结构作用过程中的海冰破坏模式和整体冰压力进行了离散元分析。模拟结果表明:当宽厚比<10时,海冰破坏模式主要为挤压破坏;当10≤宽厚比<30时,海冰混合破坏发生;当宽厚比≥30时,海冰屈曲破坏发生。从海冰断裂长度与平均冰压力两个方面进一步说明了海冰破坏模式的转变过程。最后,构建了直立结构极值冰压力计算公式。研究成果可为寒区直立结构的整体设计提供参考。

The failure mode of sea ice in front of the structure and the resulting ice load are closely related to the structure scale and ice thickness.The discrete element method(DEM)was adopted to simulate the failure modes of ice and ice forces during the interaction between flat ice and vertical structures.The computational parameters in DEM were verified with the field measured data on Norströmsgrund lighthouse.Based on this study,the failure modes of sea ice and the global ice pressure during the interaction between flat ice and vertical structure under different width-thickness ratios were analyzed by DEM.The simulated results show that when the width-thickness ratio is less than 10,sea ice crushing failure occurs;when the width-thickness ratio is more than 10 and less than 30,sea ice mixed failure occurs;when the width-thickness ratio is more than 30,sea ice buckling failure occurs.The sea ice fracture length and average ice pressure further illustrate the transition process of sea ice failure mode.Finally,a novel approach to calculate extreme ice pressure for vertical structures is proposed in this paper.This study can provide reference for the global design of vertical structures in cold regions.