In ice-covered regions, the upward–downward ice-breaking cones are applied widely to reduce the ice load on the vertical jacket offshore platforms. The ice load is affected by the diameter of cone at the water level. In particular, the sea ice can impact on the vertical portion of the platform which is beyond the covered area of the upward–downward cone under the extreme low or high water level. In this study, the discrete element method (DEM) with the bond and failure model is adopted to simulate the breaking process of sea ice acting on conical structure and vertical pile considering the changing of water level. The ice load and ice failure mode simulated with the DEM is compared well with the field data measured in the Bohai Sea. The DEM results indicate that the bending failure of ice cover occurs when it acts on the upward or downward cone. For both of the upward and downward cones, the ice load increases with the increase in the cone diameter at water level, but the ice load on upward cone is larger than that on downward cone. Meanwhile, the breaking length of ice cover on upward cone is smaller than that on the downward cone. The ice load and the breaking length of ice cover are analyzed based on the DEM results and the field observation in the Bohai Sea. When the ice cover impacts on the junction of upward–downward cone, the ice cover can be broken by a local crushing failure, but it has little effect on the maximum of the ice load. The interaction between ice cover and vertical pile is also simulated with DEM under the extreme low or high water levels. The sea ice breaks with crushing failure mode, and the ice load is obviously larger than that of conical structure. The ice loads and failure modes of ice cover are compared when the ice cover impacts on the vertical pile, upward cone, downward cone and their junction portion considering the influence of water level.

在覆冰地区，向上和向下的破冰锥被广泛使用，以减少垂直套管海上平台的冰负荷。冰负荷受水位处圆锥体直径的影响。特别是，在极低的水位或高水位下，海冰可能会影响平台的垂直部分，该部分超出了上下锥体的覆盖区域。在研究中，考虑了水位的变化，采用结合-破坏模型的离散元法（DEM）来模拟海冰作用在圆锥形结构和竖向桩上的破坏过程。用DEM模拟的冰负荷和冰破坏模式与渤海实测数据进行了很好的比较。DEM结果表明，当冰盖作用于向上或向下的圆锥体时会发生弯曲破坏。对于向上和向下的圆锥体，在水位处，冰负荷都随着圆锥体直径的增加而增加，但是向上的圆锥体上的冰负荷大于向下的圆锥体上的冰负荷。同时，向上锥体的冰盖的断裂长度小于向下锥体的冰盖的断裂长度。根据DEM结果和在渤海的实地观测，分析了冰负荷和冰盖破裂长度。当冰盖撞击上下锥体的交汇处时，冰盖可能会因局部破碎失败而破裂，但对最大冰负荷影响不大。在极端低水位或高水位的情况下，也用DEM模拟了冰盖和垂直桩之间的相互作用。海冰以破碎破坏模式破裂，冰负荷明显大于圆锥形结构。