This paper demonstrates how to utilize 2D ice pressure data obtained by Akagawa et al. 1999. This data has been obtained through a series of field experiments conducted in the harbor of Notoro Lake near Abashiri-city on Okotuku shoreline with medium scale indentation test system (Nakazawa et al. 1999). We havd presented 2D ice pressure data visualizing the change of ice pressure distributions during the indentation tests in previous papers, such as Sodhi et al. 1998. Utilizing the 2D ice pressure data, a preliminary study on the mechanism of continuos ice pressure generation during ice indentation tests is described in this paper. Analyzing the correlation between the peak ice load ofa continuos ice load time-series record and 2D ice pressure distributions, ice failure modes are discussed to identify what kind of failure will predominantly contribute to a specific peak ice load observed during continuos sheet ice crushing. The 2D ice pressure data supports the concepts of line-like loading (Joensuu and Riska, 1989) and independent failure zones (Takeuehi et al. 1999) previously observed at indentation velocities of 30mm/sec. Furthermore, the 2D ice pressure data suggests that the peak ice load is caused predominantly by the flaking during brittle failure.
It is well known that ice behaves in both ductile and brittle manners. Recent work on these behaviors have been summarized by Sodhi et al., 1998. This paper will combine the work on brittle failure and the independent failure zone concept actively studied by many scientists and engineers to the scale-effect of indentor size on ice pressure. A series of medium scale field indentation tests have been conducted by the authors in Notoro-lake Hokkaido, in order to observe the scale effect on ice pressure for different size ofindentors.