Samcot_annual_report

Annual Report 2016

SAMCoT

Uniaxial compressive strength compared to physical

properties of ice cores in one of the ridges measured by

Ervik during N-ICE2015. The left figure shows the ice ridge

cross section: the light blue line is the snow surface, the

dashed blue line is the freeboard, the black lines are the

ice boundaries, the vertical grey line is the ice core posi-

tion and the circles mark the positions of the compressed

samples. The second left figure shows the strength of the

samples versus depth. The middle figure shows the elastic

modulus versus depth. To the right the temperature and

salinity profiles versus depth are plotted.

PhD candidate Evgenii Salganik, under the supervision

of postdoc Aleksey Shestov, spent a period of seven

months (February to August) undertaking research

linked to ice rubble at the UNIS Cold Laboratory.

Increasing levels of transportation and exploration

in the Arctic enhance the significance of ice loads on

coastal and offshore structures. Loads from ice ridges

are often the highest loads. In contrast to level ice,

loads from ice ridges depend on a large number of

parameters that are hard to measure directly in the

field. The thermodynamics of ice ridges governs two key

ICE RUBBLE LABORATORY-SCALE EXPERIMENTS

parameters for ice ridge load value: consolidated layer

thickness and its strength. According to ISO/FDIS/19906

(2010) consolidated layers of ice ridges can be modelled

in a manner similar to that used for level ice with

different levels of ice salinity, crystalline structure and

temperature profiles.

Salganik’s laboratory experiments and models aim to

understand how controlled consolidation parameters (air

and water temperature, initial ice temperature, dopant

fraction and time) could affect the consolidated layer’s

thickness and salinity for laboratory-scale work.

The main goal of this study was to investigate ridge

consolidation processes. Ratios of different thermal

processes (conduction, convection, solidification, salt

expulsion and initial rubble sensible heat at tempera-

ture T_

) are different for different scales. Laboratory

scale is used for basin tests and full-scale is used for

collection and verification of the ice ridge thermal,

mechanical and geometrical parameters.

Experimental setup for 2D and 3D configurations.

Thermistor strings and electrical conductivity, temperature

and depth (CTD) sensors were used to measure the vertical

temperature profile in air, the consolidated layer, rubble,

water, and the water salinity and freezing temperature.

One vertical layer of ice rubble, partly insulated from the

sides and the bottom by acrylic walls, was used as the

2D configuration. A plastic net with a 30x30 cm horizontal

cross-section was filled with ice rubble for the 3D

configuration.

Ice rubble before, during and

after consolidation experiment