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冰川冻土 ›› 1985, Vol. 7 ›› Issue (1): 41-49.

• 研究论文 • 上一篇    下一篇

天山乌鲁木齐河源1号冰川表面应变率的初步研究

韩建康, 陈晓梅, 孙作哲   

  1. 中国科学院兰州冰川冻土研究所
  • 收稿日期:1984-10-11 出版日期:1986-02-25 发布日期:2012-04-26

Preliminary Study on Strain-Rate on Surface of Glacier No.1 at the Headwater of Urumqi River, Tianshan

Han Jiankang, Chen Xiaomei, Sun Zuozhe   

  1. Lanzhou Institute of Glaciology and Geocryology, Academia Sinica
  • Received:1984-10-11 Online:1986-02-25 Published:2012-04-26

摘要: 冰川运动研究中,在注意运动速度时空分布特点的同时,人们更注意研究冰川的应变率分布状况。因为它可以从根本上揭示冰体流动速度的变化特点,表明速度的变化梯度,以及速度变化的动力学原因,而且能把流动速度的分布与冰川表面形态、槽谷形状等影响因素有机地联系起来。同时,通过对应变率的分析,还可以发现它与冰川物质平衡等的关系。对乌鲁木齐河源1号冰川表面应变率的研究,就是在上述思想指导下开展的。

Abstract: Based on theory of plasticity, the authors have analyzed Glacier No.1 for its strain-rate distribution on the surface and the relation of crevasse pattern to strain-rate distribution. Following conclusions have been reached1) The distribution of strain-rate on glacier surface is under the direct control of ice mass conditions, such as ice thickness and slope of the surface, as well as the shape of channel and the pattern of ice movement (extending flow or compressing flow). Crevasses, the reaction of ice to strain-rates, are remarkable signs. The areal strain-rates on the surface represent variation in strain-rate gradient in a relative wider range.2) The marginal shear strain-rates play a prominent role on the profile where longitudinal strain-rates are smaller. This explains why crevasses develop more strongly near the margin area of a glacier.3) Generally speaking, crevasses form when the greatest principal extending strain-rate exceeds 0.01 a-1 on Glacier No.l. It was found smaller than 0.03 a-1 on Blue Glacier in U. S. A..4) The distribution of strain-rate on glacier surface is a result of integration of many factors. Thus, it is unreasonable to divide glacier surface into extending strain-rate region and compressing strain-rate region by snow-line only.5) The shape of the channel above all its curvature, has great effect on the distribution of strain-rate. Usually, where there is greater curvature in the channel, higher compressing strain-rates occur on the concave side, while OH the convex side, higher extending strain-rutes form. This is commonly rtue for all valley glaciers.