长江科学院院报 ›› 2015, Vol. 32 ›› Issue (11): 40-44.

• 岩土工程 • 上一篇    下一篇

干湿循环对风化砂改良膨胀土回弹模量影响研究

杨俊1,袁凯1,张国栋1,唐云伟2   

  1. 1.三峡大学 土木与建筑学院,湖北 宜昌443002;
    2.宜昌市交通运输局,湖北 宜昌443002
  • 收稿日期:2015-11-06 修回日期:2015-11-06 出版日期:2015-11-20 发布日期:2015-11-05

Effect of Wetting drying Cycle on Resilient Modulus of Expansive SoilImproved by Weathered Sand

YANG Jun1,YUAN Kai1,ZHANG Guodong1,TANG Yun wei2   

  1. 1.College of Civil Engineering and Architecture, China Three Gorges University, Yichang 443002, China;
    2.Yichang Communications and Transportation Bureau, Yichang 443002, China
  • Received:2015-11-06 Revised:2015-11-06 Online:2015-11-20 Published:2015-11-05

摘要: 以湖北宜昌弱膨胀土为研究对象,通过掺砂改良后的室内回弹模量试验,研究了改良膨胀土的回弹模量与干湿循环次数、风化砂掺量之间的关系。结果表明①在相同的风化砂掺量下,改良膨胀土的回弹模量随着干湿循环次数的增加而逐渐降低,回弹模量的衰减幅度在第1次干湿循环时达到最大,之后逐渐减小,当干湿循环进行至4~5次时,回弹模量基本趋于稳定,回弹模量与干湿循环次数可以用指数函数关系进行拟合,且相关性较好;②在经历相同的干湿循环后,随着风化砂掺量的增加,回弹模量衰减幅度以及土体微裂缝的数量逐渐减小;③通过综合考虑干湿循环次数以及风化砂掺量的耦合影响,建立了干湿循环作用下掺砂改良膨胀土回弹模量的三维非线性预估模型,该预估模型参数较少,形式简单,准确性较高,具有一定的推广价值。

关键词: 膨胀土, 风化砂, 干湿循环, 回弹模量, 预估模型

Abstract: The relationships between resilient modulus of improved expansive soil and wettingdrying cycle and dosage of weathered sand respectively were researched through testing the resilient modulus of expansive soil improved by weathered sand. The weak expansive soil in Yichang was taken as the research object. Results showed that 1) with the same dosage of weathered sand, the expansive soil’s resilient modulus gradually decreased with the increasing number of wettingdrying cycles. The decay rate reached maximum at the first wettingdrying cycle, and then gradually decreased. When the wettingdrying came to the fourth to fifth cycle, the resilient modulus is basically stable. Resilient modulus and wettingdrying cycle can be fitted with exponential function, and the correlation is quite well; 2) after the same wettingdrying cycles, the decay rate of resilient modulus and the amount of soil’s microcracks decreased with the increase of weathered sand dosage; 3) in consideration of the coupling effects of wettingdrying cycles and weathered sand dosage, the threedimensional nonlinear prediction model of weathered sand improved expansive soil’s resilient modulus under wettingdrying cycles was established. The prediction model is of simple form and high accuracy, hence it is worth promotion.

Key words: expansive soil, weathered sand, wettingdrying cycles, resilient modulus, prediction model