Critical speed phenomenon for floating ice sheets

• Main Author: Whitten, John Joseph
• Format: Thesis
• Language: English
• Published: Memorial University of Newfoundland 1987
• Subjects: Ice Sheet
• Online Access: https://research.library.mun.ca/7991/; https://research.library.mun.ca/7991/1/Whitten_JohnJoseph.pdf; https://research.library.mun.ca/7991/3/Whitten_JohnJoseph.pdf

In Canada’s Northern Regions floating ice sheets are often used as roads for vehicular traffic, including large trucks, and as runways for aircraft. Operators have found that a critical speed exists for movement over these roads and runways. Movement over the ice sheet at this critical speed causes large amplitude waves to be generated in the sheet near the load. Thus, it is very important that operators avoid this speed. -- Experimental work has been done on this phenomenon, and researchers have developed theoretical means to determine this critical speed. Until quite recently (mid 1980s), there had been no measurements of predictions of the wave patterns generated in ice sheets, and the limited predictions were conflicting. -- In this thesis, an experimental approach was taken to determine the wave patterns generated in a floating ice sheet by a moving load. Several different moving loads were used, and the ice was modelled in various ways: EG/AD/S model ice, styrofoam sheeting, and polyethylene sheeting. Theoretical predictions of the patterns were also produced. The generated patterns agreed with the predictions. -- It was also determined that the deflection depression caused by the load at speeds less that the critical changed shape with speed. The tests also indicated that the critical speed is much more than a function of sheet characteristics than load characteristics.