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

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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.