Physical simulation of glacier motion modes

Abstract

Modes of «dry friction» at glacier-bedrock interface (ice sliding and flow) were simulated under uniform compression with different combinations of mechanical and thermodynamic factors. Effect of ice structure in the intermediate layer was considered in terms of strength of ice adhesion to complex-shaped substrate for typical cases: at frictional contact of ice frozen to the walls of the cylindrical matrix; when ice was pressing-through a confusor (with contraction ratio = 30); extruding the ice in a plastic state through a pipe. For these tests, а collapsible matrix was used. It consists of three sections: the feed cylinder, the convergent channel (confuser) and the forming pipe. Changes of ice during severe plastic deformation were monitored by acoustic emission in the range from 10 Hz to 25 kHz. Relationship between the size of moving structural elements, their natural resonant frequency, density and acoustic capacitance was applied. A theoretical model was verified. Correlation of amplitude-frequency spectra of acoustic emission at the frictional contact with the acoustic spectrum of natural oscillations of the glaciers from distant sources was confirmed. The results can be applied to remote sensing studies of ice movement modes at the glacier bedrock.

Keywords

• acoustic emission
• friction
• glacier
• physical modeling
• rheology of ice