Author(s): Aleksey Marchenko; Peter Chistyakov; David Cole; Evgeny Karulin; Marina Karulina; Vladimir Markov; Nataly Marchenko; Alexander Sakharov; Andrey Sliusarenko; Devinder Sodhi
Linked Author(s):
Keywords: Sea Ice; Ice Mechanics and Properties
Abstract: To further our understanding of the in-situ fracture and failure of first-year sea ice we have conducted experiments since 2013 on land-fast ice in the Van-Mijen Fjord in Spitsbergen. The experiments employed the fixed-ends beam geometry introduced by Sodhi (1998) to investigate the wedging action during the vertical loading of floating ice sheets. The test results were also utilized for the calculation of flexural and compressive strength. The beams were loaded at their center in either the vertical or horizontal direction. External measurements included applied force and load point displacement. For the experiments conducted in 2021, acoustic emissions sensors were frozen to the ice surface in the tension and compression zones, and internal stress sensors were frozen into the compression zones at the center and at 2 m from the center. The beam length was 7.8 m, the beam width was 0.8 m, and the ice sheet thickness was 0.9 m. It was observed that beams with a length/thickness ratio of ³ 5 failed by the formation of cracks in the center of the beam and near the beam roots at the first stage of the loading, and by compression at the later stage. The cracks did not propagate through the compression zones. We discovered that the applied force reached maxima during 40 s, and the internally monitored ice pressure reached maxima 70-80 s later. Maximal acoustic emission occurred in the compression zones together with maximal ice pressure. Physical effects influencing the time lag are discussed in the paper.
Year: 2022