FLOATING SEA ICE ROAD STRENGTH FROM BOREHOLE JACK DATA: NORTHSTAR 2000

摘要

The sea ice roads (70°29′ N, 147°42′ W) were constructed from the sea ice sheet and free flooding techniques where 50mm layers of seawater were applied and allowed to freeze. The Borehole Jack was inserted into a 150mm diameter borehole in the floating thickened ice. Pressure and displacement data were collected with a data logger at 10 Hz. Strength profiles were measured from January to May 2000. The temperature profile of the ice was recorded from thermistor strings and the ice salinity profile determined from retrieved cores. The recorded data were processed to determine the ice strength. The method is amenable to mainly automatic processing rather than relying heavily on the maximum pressure and is discussed and compared with previously used techniques. The average strength over the depth of the ice sheet was approximately twice the 7.6MPa specified strength and varied only slightly between January and May 2000. The ice did not show any significant reduction of strength up to May 01. A linear relationship between strength and root brine volume was found correlating with other data on uniaxial ice strength.