Anne Barker

Laboratory experiments of ice scour processes: buoyant ice model

Abstract A laboratory program was carried out to measure the loads and seabed response due to a buoyant ice block scouring sand and gravel representative of the Grand Banks seabed, offshore of eastern Newfoundland, Canada. The results complement previous experimental work carried out at the Canadian Hydraulics Centre (CHC), which used a rigidly affixed ice block to scour sediment material [Cold Reg. Sci. Technol. 35 (3)(2002a) 195]. The present study used the same sediment to create a model seabed; however, in this test series, the model was towed along an ice tank, free to move throughout the water column. Six tests were carried out. Freshwater ice, built up into a large block with an overall dimension of 0.76×0.76×0.71 m, was used to scour the seabed at depths up to 0.2 m. The scouring loads, displacement, angular movements and resulting trenches were measured. This paper provides a description of the test arrangement and the experimental results.

Numerical Simulation of Ice Interaction with a Wide Cylindrical Pier

A depth-averaged, hybrid Lagrangian-Eulerian model for ice interaction is described, and used to evaluate ice loads on a 10m-wide, cylindrical pier. Additionally, results previously calculated using a discrete element model, and those from analytical formulas commonly used to estimate ice forces, were compared with the full-scale data. The comparisons are conducted in order to verify the results of these different types of approaches for calculating ice loads. There was good agreement between field observations from similar structures and the hybrid models calculated values. The results obtained using the discrete element model also compared favourably to full-scale data. In contrast, forces estimated from analytical formulas were much higher than those from the field measurements.

SEASONAL STRATEGIES FOR EVACUATION FROM OFFSHORE STRUCTURES IN THE BEAUFORT SEA

This paper discusses the results from an integrated research project, carried out over many years, which examined a variety of evacuation strategies for offshore structures in the Beaufort Sea. The objective of the project was to address the safety of offshore personnel working in Canada’s Arctic environment, by examining the issues surrounding emergency evacuation from an offshore structure under the diverse range of conditions in the Beaufort Sea. This was accomplished through: the development of decision flow-charts for the establishment of on-ice evacuation shelters and their associated costs and logistics; field measurements of personnel movement rates across different ice morphologies; an investigation into ice rubble stability and roughness and its influence on evacuation systems; an examination of ice management options when ice rubble is present around an offshore structure; and the presentation of generic means of evacuation and their adequacy for four “seasons” of evacuation: open water, moving pack ice, quasi-stable rubble and stable rubble/landfast ice. The project results provide 1) information related to the viability of systems for a range of realistic ice conditions, especially those involving ice rubble, 2) provide input into the development of the evacuation and rescue options and strategies for Beaufort Sea structures and 3) be used by Operators and Regulators to examine the feasibility of proposed evacuation systems for the Beaufort Sea.