Field Experiments on the Friction Coefficient of Sea Ice on Sea Ice

The friction of sea ice on sea ice is important for a number of processes in which ice is interacting with ice or offshore and coastal structures. Friction experiments with sea ice on sea ice were performed in the Adventfjord at Spitsbergen in March and April of 2011. The tests included study of the dependence of the kinetic friction coefficient on normal pressure (4 - 45 kPa), sliding velocities (6 - 43 mm/s), the presence of sea water at the sliding interface, and ice block orientation during the sliding. In addition, several tests were performed to study the effect of repeated sliding over the same track on the kinetic friction coefficient and the effect of the stationary contact time (the hold time was 5 s, 20 s and 80 s) on the static friction coefficient. The kinetic friction coefficient decreased with increasing sliding velocity and did not change with a change in the normal load. Stick-slip was observed in all experiments with a sliding velocity less than 10 mm/s. The presence of sea water at the interface decreased the kinetic friction coefficient at a low sliding velocity (similar to 10 mm/s) and had no effect at a high sliding velocity (similar to 40 mm/s). Repeated sliding on the same track smoothed the surface and decreased the kinetic friction coefficient significantly. The orientation of the blocks during the sliding had no effect on the friction coefficient. The obtained data are compared with existing friction models.