Theory and experiments indicate that ice–bed separation during glacier slip over 2-D hard beds causes basal shear stress to reach a maximum at a particular slip velocity and decrease at higher velocities. We use the sliding theory of Lliboutry (1968) to explore how friction between debris particles in sliding ice and a rock bed affects this relationship between shear stress and slip velocity. Particle–bed contact forces and associated debris friction increase with increasing slip velocity, owing to increased rates of ice convergence with up-glacier facing surfaces. However, debris friction on diminished areas of the bed counteracts this effect as cavities grow. Thus, friction from debris alone increases only slightly with slip velocity, and for sediment particles larger than ~60 mm in diameter, debris friction peaks and decreases with increasing slip velocity. The effect on the sliding relationship is to steepen its rising limb and shift its shear stress peak to a slightly higher velocity. These results, which exclude the effect of debris friction on cavity size and debris concentrations above ~15%, indicate that the effect of debris in ice is to increase basal shear stress but not significantly change the form of the sliding relationship.

中文翻译：

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冰川滑动过程中的碎屑床摩擦与冰床分离

理论和实验表明，在二维硬床上冰川滑移过程中，冰床分离会导致基础剪应力在特定的滑移速度下达到最大值，并在更高的速度下减小。我们使用 Lliboutry (1968) 的滑动理论来探索滑动冰中碎屑颗粒与岩床之间的摩擦如何影响剪切应力和滑动速度之间的这种关系。由于冰与面向冰川的表面的收敛速度增加，颗粒床接触力和相关的碎片摩擦力随着滑动速度的增加而增加。然而，随着空腔的增长，床体缩小区域上的碎屑摩擦抵消了这种影响。因此，仅来自碎屑的摩擦力仅随滑移速度略微增加，对于直径大于约 60 毫米的沉积物颗粒，碎屑摩擦随着滑动速度的增加而达到峰值和减小。对滑动关系的影响是使其上升的肢体变陡并将其剪切应力峰值转移到稍高的速度。这些结果排除了碎片摩擦对空腔大小和碎片浓度高于~15%的影响，表明冰中碎片的作用是增加基础剪切应力，但不会显着改变滑动关系的形式。