长江科学院院报 ›› 2016, Vol. 33 ›› Issue (9): 72-77.DOI: 10.11988/ckyyb.20150992

• 岩土工程 • 上一篇    下一篇

蒙脱土失水缩裂过程的边界摩擦与温度效应

杜文凤a,b,王菁莪b,刘清秉b,项 伟a,b,黄 伟a
  

  1. 中国地质大学(武汉)a.工程学院;b.教育部长江三峡库区地质灾害研究中心, 武汉 430074
  • 出版日期:2016-09-25 发布日期:2016-09-22
  • 通讯作者: 王菁莪(1985-),男,湖北大冶人,助理研究员,主要从事岩土体的工程性质与地质灾害方面的研究,(电话)15927663040(电子信箱)wangjinge@cug.edu.cn。
  • 作者简介:杜文凤(1991-),女,山东枣庄人,硕士研究生,主要从事岩土工程性质方面的研究,(电话)15927663040(电子信箱)duwf10@lzu.edu.cn。
  • 基金资助:
    国家自然科学基金项目(41572286);中国博士后科学基金项目(2014M552117)

Effects of Boundary Friction and Temperature on the Process
of Shrinkingand Cracking of Pure Montmorillonite During Pore Water Evaporation

DU Wen-feng1,2,WANG Jing-e2,LIU Qing-bing2,XIANG Wei1,2,HUANG Wei1
  

  1. 1.Faculty of Engineering,China University of Geosciences,Wuhan 430074,China;2.Research Center on Geo-hazard
    in Three Gorges Reservoir Area of Ministry of Education,China University of Geosciences,Wuhan 430074,China
  • Published:2016-09-25 Online:2016-09-22

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摘要： 膨胀土失水收缩产生裂隙的现象是造成其工程性质恶化的主要原因之一。现有研究成果揭示了膨胀土在失水过程中吸力增大与分布不均是造成收缩与开裂的主要原因。然而,已有关于膨胀土缩裂的试验研究很少考虑到土样边界条件对缩裂过程的影响。采用纯蒙脱土作为试验材料,设置玻璃与凡士林2种土样边界摩擦条件,测试了不同温度条件下,边界摩擦效应对土样缩裂过程与结果的影响;对产生裂隙的形态与数量进行定量化对比分析,提出了黏性土失水收缩产生裂隙的概念模型。试验结果表明:土样从饱和开始逐渐失水的过程中,低摩擦力的凡士林接触面土样开始出现裂隙的时间较晚,开裂时的临界含水量显著低于玻璃底面土样;在20,30,40 ℃环境温度条件下,凡士林接触面土样比玻璃接触面土样的最终裂隙量分别减少了70.3%,79.6%,77.6%;而在相同的边界摩擦条件下,温度越高则土样失水的速度越快,产生裂隙的数量也相对较高。

关键词: 蒙脱土, 收缩, 裂隙, 边界摩擦效应, 温度效应

Abstract: The shrinking and cracking of expansive soil during pore water evaporation is one of the main causes which greatly deteriorate its engineering properties. Latest research indicates that the increase of suction and inhomogeneous distribution mainly lead to the shrinking and cracking of expansive soil. However, few experiments about the expansive soil shrinking consider the effect of boundary condition on the shrinking process. In this research, pure montmorillonite is taken as test material，and its shrinking process in the presence of glass and vaseline friction boundaries are tested at different temperatures. The computer image processing technique is employed to quantify the geometric structure and morphologic characteristics of cracks. A conceptual model of shrinking and cracking of clay is established. Test results indicate that during the process of saturation dehydration, cracks of specimens with vaseline surface occur late and the critical water content of cracking is obviously lower than that of glasssurface specimens. At temperatures of 20℃, 30℃ and 40℃, the final amount of cracks of vaseline surface specimen is smaller than that of glass surface specimen by 70.3%, 79.6% and 77.6%, respectively. Additionally, in the presence of the same boundary friction, the pore water evaporation accelerates and the final amount of cracks increases with the increasing of temperature.

Key words: montmorillonite, shrinkage, crack, boundary friction effect, temperature effeect

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