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SUMMARY:Thermo-mechanical loads of sea ice on structures - Aleksey Marchen
 ko (University Centre in Svalbard (UNIS))
DTSTART:20171106T160000Z
DTEND:20171106T170000Z
UID:TALK94519@talks.cam.ac.uk
CONTACT:INI IT
DESCRIPTION:Thermally induced loads of ice on structures and shorelines oc
 cur due to thermal deformations of confined ice. Thermally induced stresse
 s in the ice follow the temperature changes\, depend on the coefficient of
  thermal expansion of ice and are reduced due to the relaxation. Temperatu
 re changes in sea ice occur due to conductive heat transfer characterized 
 by specific heat capacity and thermal conductivity of ice and due to the a
 dvection of liquid brine depending on sea ice permeability. Coefficient of
  sea ice thermal expansion depends on the amount of liquid brine trapped i
 n closed packets inside the ice. Proportion between the amounts of liquid 
 brines trapped in closed packets and existing in permeable channels depend
 s on the ice temperature and salinity. Relaxation and creep rheology of se
 a ice also depends on the temperature and ice structure.<br><br>Thermo-mec
 hanical model of saline ice taking into account above described properties
  was recently formulated by Marchenko and Lishman (2017). The dependence o
 f the coefficient of thermal expansion of saline ice from the temperature 
 was reconstructed from the laboratory experiments. In the present work the
  model equations are used to estimate and compare the heat fluxes and ther
 mal deformation of sea ice caused by the heat conduction and brine advecti
 on. Further the model is used for numerical simulations of ice loads on th
 e cofferdam of coal quay in Kapp Amsterdam\, Spitsbergen.<br><span><br>Fie
 ld observations and records of the loads from sea ice confined inside the 
 cofferdam were performed since 2013 (Marchenko et al\, 2013\; Wrangborg et
  al\, 2015). Sea ice temperature was measured synchronously with the loads
  over entire ice thickness using thermistor string frozen into the ice. It
  was discovered that sea water brine migrates through the confined ice wit
 h thickness of 2-3 m under the influence of the water overpressure below t
 he ice caused by semidiurnal tide. Horizontal ice loads on the cofferdam w
 alls are also changed according to the semidiurnal cycle. Thermo-mechanica
 l model of saline ice is used in numerical simulations of the observed phe
 nomena by finite element method realized in Comsol Multiphysics software.<
 /span>
LOCATION:Seminar Room 1\, Newton Institute
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