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冰川冻土 ›› 2002, Vol. 24 ›› Issue (2): 149-154.doi: 10.7522/j.issn.1000-0240.2002.0025

• 冰冻圈与全球变化 • 上一篇    下一篇

两种不同试验模式下人工冻结土强度与变形的对比分析

马巍, 常小晓   

  1. 中国科学院寒区旱区环境与工程研究所冻土工程国家重点实验室, 甘肃兰州, 730000
  • 收稿日期:2001-07-27 修回日期:2001-10-06 出版日期:2002-04-25 发布日期:2012-04-26
  • 基金资助:
    国家自然科学基金项目(49771024);中国科学院知识创新工程重大项目(KZCX2-306)资助

Comparison of Strength and Deformation of Artificially Frozen Soil in Two Testing Manners

MA Wei, CHANG Xiao-xiao   

  1. State Key Laboratory of Frozen Soil Engineering, CAREERI, CAS, Lanzhou Gansu 730000, China
  • Received:2001-07-27 Revised:2001-10-06 Online:2002-04-25 Published:2012-04-26

摘要: 两种试验模式下的冻土应力-应变曲线均呈双曲线型,但其变形过程明显不同,FC模式 (传统冻土力学试验模式)下的屈服强度明显小于K0DCF模式 (深土冻土力学试验模式)下的.FC模式下,加载应力路径下的破坏变形明显大于K0DCF模式下的,而减载应力路径下的破坏变形小于K0DCF模式下的.在试验围压范围内,两种试验模式下的莫尔包络线均满足莫尔 -库仑准则,且无论是加载还是减载应力状态,K0DCF模式下的剪切强度总是大于FC模式下的,且随着σ的增大,K0DCF模式下加载与减载下剪切强度的差值比FC模式下τ的差值小.通过一定的对应关系可将两种模式下的强度与变形联系起来.

关键词: K0DCF过程, FC过程, 人工冻结土, 屈服强度, 破坏变形

Abstract: With the extensive use of artificial ground freezing technology in construction of mines and deepening of sinking shafts, many engineering accidents occur. A study of frozen soil mechanics in deep alluvium was carried out. The mechanical test method for frozen soil in artificial ground freezing engineering should be first consolidated, then frozen under loading, finally tested (consolidated-frozen-tested or K0DCF manner). It differs from traditional test method of frozen soil mechanics, which is first frozen without load, then consolidated, finally tested (frozen-consolidated-tested or FC manner). Tests show strength of frozen soil changing with test methods. Based on the traditional test method of frozen soil mechanics, a lot of research results have been obtained. In this paper, the difference between traditional test method of frozen soil mechanics and the test method of frozen soil mechanics in deep alluvium is discussed. Again the relation between the K0DCF manner and the FC manner is studied, so that the research results in FC manner can be shifted directly to the K0DCF manner. For providing reliable test basis for studying frozen soil mechanics in deep alluvium and serving to engineering, this paper will probe into differences of strength and deformation between the K0DCF manner and the FC manner through triaxial compressive tests of frozen sandy soil. It is found that the stress-strain curves have the shape of hyperbola for the two testing manners with different deformation process. The yield strength in the FC manner is obviously less than that in the K0DCF manner. In the FC manner, the failure strain is obviously greater than that in the K0DCF manner under loading, and is obviously less than that in the K0DCF manner under unloading. The Mohr’s envelopes all accord with the Mohr-Coulomb’s criterion within the range of confining pressure in tests. Regardless of state of loading or unloading, the shear strength in the K0DCF manner is greater than that in the FC manner and with normal stress, the difference of shear strength between loading and unloading in the K0DCF manner is less than that in the FC manner. Yield strength, failure strain and shear strength in the two testing manners can be joined together through equations (5), (6) and (8).

Key words: consolidated-frozen-tested (K0DCF) manner, frozen-consolidated-tested (FC) manner, artificially frozen soil, yield strength, failure strain

中图分类号: 

  • P642.14