Compressive Ice Failure during Indentation with Temporally and Spatially Non-uniform Interface Conditions

在北极和亚北极海洋的船舶、结构和海底基础设施设计中，与冰山和多年冰脊等大规模冰特征的潜在相互作用所造成的危险是一个主要考虑因素。在这种冰-结构相互作用期间，结构方面，例如结构几何形状和界面条件的表面性质，通常保持不变。然而，由于随机的局部断裂过程和冰接触几何形状的持续演变，显著的空间和时间变化将导致冰荷载。对于冰川冰，砾石或其他沉积物可能在崩解之前被截留在冰川的表层中，或者颗粒可能在与海床的接地或冲刷相互作用期间嵌入冰龙骨中。如果这种“装甲冰”与结构物相互作用，非均匀分布的固体颗粒（例如砾石）可能被截留在冰和结构物之间的界面中或附近。这被称为粒子增强冰结构界面（PAISI）条件。在目前的工程实践中，PAISI条件目前被排除在外，因为：（a）该区域的现场观察表明，这种颗粒存在的可能性足够低，可以在设计中忽略这种情况（这将分析限制在没有颗粒的“纯冰”）;或（B）对于可能适用PAISI条件的相互作用，部件（例如海底电缆或管道）应挖沟或埋在海床下，以避免接触。在后一种方法中，假设冰和结构之间的任何接触都会导致失效，这就不需要对PAISI相互作用进行详细分析。假设所有结构在这种影响下都会失效是过于保守的，需要重新考虑这些假设，以便对新的防冰设计方法进行更明智的、基于科学的评估。在PAISI条件方面存在着重大的知识差距。拟议的研究将解决这些差距，以提高对PAISI条件对传递到结构的冰压力的影响的理解，并支持为这些条件开发新的冰荷载模型。这反过来又将支持创新的新冰保护战略/结构的发展。这些成果的应用涵盖许多领域，包括：海底数据和电力传输、航运、邮轮旅游、渔业、近海和采矿，以及北方社区的政府主权和基础设施。这项工作的好处包括减少冰荷载估计的不确定性，通过新的创新和科学决策提高设计的安全性和经济性。培养一个多元化、包容性的世界级HQP团队是该研究计划的重要组成部分。

In the design of ships, structures and subsea infrastructure for arctic and sub-arctic oceans, hazards posed by potential interactions with large-scale ice features such as icebergs and multiyear (MY) ice ridges are a dominant consideration. During such ice-structure interactions, structural aspects, such as structural geometry and surface properties of the interface conditions, generally remain constant. However, significant spatial and temporal variations will result in ice loads due to random local fracture processes and the continual evolution of the ice contact geometry. For glacial ice, gravel or other sediments may become entrapped in the surface layer of the glacier prior to calving or particles may become embedded in ice keels during grounding or scouring interactions with the seabed. If such “armored ice” interacts with a structure, non-uniformly distributed solid particles (e.g. gravel) could become entrapped in or near the interface between the ice and structure. This is called a particle-augmented ice-structure interface (PAISI) condition. In current engineering practice, PAISI conditions are currently excluded since either: (a) field observations for the region indicate the likelihood of such particles being present are sufficiently low to neglect this scenario in design (which limits the analysis to “pure ice” without particles); or (b) for interactions where PAISI conditions may apply, the components (e.g. subsea cables or pipes) are trenched or buried below the seabed to avoid contact. In the latter approach, it is assumed that any contact between the ice and structure results in failure, which eliminates the need for detailed analysis of PAISI interactions. It is overly conservative to assume all structures fail during such impacts and reconsideration of these assumptions are needed to allow for a more informed, science-based assessment of new design approaches for ice protection. Major knowledge gaps exist in relation to PAISI conditions. The proposed research will address these gaps to improve understanding of the effects of PAISI conditions on ice pressures transmitted to structures and support the development of new ice load models for such conditions. This in turn will support the development of innovative new ice protection strategies/structures. Applications for these results span many sectors, including: submarine data and power transmission, shipping, cruise tourism, fishing, offshore, and mining, as well as government sovereignty and infrastructure for northern communities. Benefits of this work include reducing uncertainty in ice load estimation, leading to increase safety and economy of designs through new innovations and science-based decision making. The training of a diverse, inclusive team of world class HQP is an essential part of this research program.