Место издания:Lulea University of Technology Norwegian University of Science and Technology (NTNU), Trondheim
Первая страница:1
Последняя страница:9
Аннотация:Two types of full-scale, in situ tests were conducted in Van Mijen Fiord in March 2013, Barents Sea in May 2013 and Lyb Lake in November 2014. Tests conducted were: (a) cantilever beam tests to determine flexural strength and (b) fixed-end beam tests to determine flexural and compressive strengths. The results of these tests are presented here. Short-term loading of floating ice sheets to failure was investigated. The focus was on flexural strength of the first-year sea ice and fresh water ice. To determine flexural strength cantilever beam tests for a wide range of length-to-thickness ratio L/h were conducted. In fixed-end beam tests two different failure modes have been observed. For ratio L/h>6, initial bending mode of fixed-end beam transform to equilibrium of block structure after propagation of cracks in the center and the roots of a fixed-end beam. The equilibrium of block structure is provided by wedging action as proposed by Sodhi (1998). We present two approaches to explore the transition from the whole beam to block structure: (1) numerical simulation, and (2) full-scale measurements in field tests. For L/h<6 other failure scenario takes place. The cracks break a centre-edge ice block from the beam. This failure type, named punch effect, is a brittle failure in shear. In this case the crushing can be attributed to shear failure envelope in compressive-tensile quadrant (Schulson et al, 1999, 2006). Results of the numerical transition simulation, the stress distributions in vertical, horizontal and diagonal planes of the ice beam are presented for various L/h ratio. Also, the brittle failure mechanism is discussed.