Impact Load by an Ice Floe against a Structure

我们进行了中等规模的实验有关的影响施加的浮冰对结构使用自由落体浮冰在各种条件下。冲击载荷随冰温的降低而线性增加，冰温对冲击载荷的影响大于对压缩强度的影响。在本研究的试验条件下，冰温对冲击载荷的影响比动能更大。当冰引起脆性破坏/分裂，并且碎片在与结构物撞击后自由移动时（特别是当浮冰与结构物相比较大时），与没有破坏的情况相比，撞击载荷或冲量较小，并且无论动能或动量的水平如何都变成恒定值。我们还做了关于木材和钢材沿着海冰的实验，考虑了与海啸有关的碎片，如木材，集装箱和船只。对于没有脆性破坏的木材和钢材，其冲击载荷一般比海冰大一个数量级。我们还开发了一种数值方法，使用离散元模拟的影响和破坏的结构，我们得到了一个实用的工具，估计海冰的冲击载荷。

We performed medium-scale experiments regarding the impact applied by ice floes against a structure using free-falling ice floes under various conditions. The impact load increased linearly with decreasing ice temperature ; accordingly, it was presumed that the effect of ice temperature on the impact load was larger than that on compressive strength. The impact load was also more strongly influenced by ice temperature than by kinetic energy under the test conditions of this study. When ice causeed brittle failure/splitting, and fragments moved freely after impact with a structure (especially when the ice floe is large compared to the structure), the impact load or the impulse was small compared to cases without failure, and became a constant value regardless of the level of the kinetic energy or the momentum. We also made experiments regarding timbers and steels along with sea ice, considering tsunami-related debris such as timber, containers and vessels. In case of the timbers and the steels without brittle failure, their impact loads were generally one order of magnitude larger than those of sea ice. We also developed a numerical method using DEM to simulate the impact on a structure and its failure, and we obtained a practical tool for estimating an impact load of sea ice.