Prof. Lennart Fransson / Luleå Tekniska Universitet, Sweden

A research programme on methods to reinforce ice roads for extreme loads is in progress at the Lulea University. During the winters 1995- 1997 several experiments and full scale tests were carried out in the field and more tests are planned for the winter 1998. The bearing capacity of a homogenous ice sheet can be calculated from ice thickness, strength and the loading geometry. Usually the ice is approximated as a linear elastic thin plate resting on an elastic foundation (Hertz, 1884). When the ice is subjected to concentrated loads such as wheeled trucks this model yields stress levels far above the ultimate strength of ice. An ordinary ice road is therefore severely damaged by cracks induced by the traffic. The maximum load capacity is far above this level and it is somewhat unclear how the load associated with the first radial cracks is coupled with the breakthrough load. Field studies on floating ice beams with fixed ends (Åström & Fransson, 1981; Sodhi, 1995) have shown that the relatively stiff freshwater ice has a capacity to carry load by wedging. The ratio of thickness/length is essential as well as the confinement of the surrounding ice sheet. Further deformation of a cracked ice sheet subjected to vertical loads is likely to be dependent on compression of ice close to the surface and the ability to keep the ice blocks together. For static loads the crack pattern is well known (Panfilov, 1960; Nevel, 1961). Moving loads will however generate a different crack pattern, depending on speed and load level, thus the facilities of the HSVA-ARCTECLAB were used in order to study fracturing and load bearing of the fractured but not submerged floating ice sheet in a controlled environment.

http://www.ce.luth.se/~frans/hsva/

For more information, please contact:
Prof. Lennart Fransson (lennart.fransson@ce.luth.se)