Although the use of spray ice as a construction material in the Arctic has gained wide acceptance, little quantitative information has been published on the time dependent deformations experienced by spray ice structures due to internal and externally-applied loads. This paper describes a finite element analysis of the time dependent, viscoelastic (creep) behavior of Amoco's MARS spray ice island. Two dimensional, plane strain elements were utilized to model the island. Emphasis was on the deformation of the structure due to its self-weight and the weight of the drilling rig, as well as from lateral displacements occurring in the surrounding ice sheet. The analysis was limited to secondary (steady state) creep behavior. Required values for all physical parameters were obtained from actual island measurements, including those from in situ pressuremeter tests carried out at the island.

The analytical results were compared to actual island performance characteristics, measured during its operating life over the winter and spring of 1985-86. The results show reasonably good agreement between modeled behavior and actual island performance. Observed discrepancies are discussed in the paper.

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