院报 ›› 2019, Vol. 36 ›› Issue (4): 145-150.DOI: 10.11988/ckyyb.20180917

• 第28届全国土工测试学术研讨会专栏 • 上一篇    

微观结构对膨胀土土-水特征曲线的影响

齐道坤1,潘燕敏2,张亮1   

  1. 1.国网河南省电力公司 经济技术研究院,郑州 450052;
    2.同济大学 岩土及地下工程教育部重点实验室,上海 200092
  • 收稿日期:2018-08-27 修回日期:2018-10-22 出版日期:2019-04-01 发布日期:2019-04-18
  • 作者简介:齐道坤(1968-),男,河南南阳人,高级工程师,主要从事输电线路工程设计、科研工作。E-mail:qidaokun@126.com
  • 基金资助:
    国网河南电网项目(5217L0160001)

Influence of Microstructure on Soil-Water Characteristic Curve of Undisturbed Expansive Soils

QI Dao-kun1, PAN Yan-min2, ZHANG Liang1   

  1. 1.State Grid Henan Economic Research Institute, Zhengzhou 450052, China;
    2.Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education, Tongji University, Shanghai 200092, China
  • Received:2018-08-27 Revised:2018-10-22 Online:2019-04-01 Published:2019-04-18

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摘要： 为了探究膨胀土吸湿过程土-水特征曲线与微观结构变化的关系,采用渗析法和气相法对南阳原状膨胀土的持水特性进行研究,获得了土样在全吸力(0.01~309 MPa)范围内的土-水特征曲线。利用Van Genuchten模型对试验结果进行拟合;采用扫描电镜试验和压汞试验测定吸湿过程中土样微观结构的变化,从微观的层面对膨胀土土-水特征曲线的趋势进行分析。研究表明:在吸湿过程中,膨胀土的微孔隙和大孔隙体积含量增多,小孔隙体积含量减少;吸湿过程中小孔隙和微孔隙体积含量的动态变化使得膨胀土表现出在土-水特征曲线没有拐点的情况下持续增湿的特性;大孔隙体积含量的变化只影响土-水特征曲线的边界效应段,但是影响较小。

关键词: 膨胀土, 持水特征, 微观结构, 孔隙分布, 吸湿路径, 土-水特征曲线

Abstract: The water retention characteristics of Nanyang undisturbed weak expansive soil were tested using the osmotic technique and the vapor phase technique. The hydrating path of soil-water characteristic curve (SWCC) in the suction ranging from 0.01 to 309 MPa was gained and fitted according to a model proposed by Van Genuchten. Scanning Eelectron Microscope (SEM) and Mercury Intrusion Porosimetry (MIP) tests were conducted to analyse the influence of microstructure modification on SWCC. Results showed that during hydrating process, the volume content of micro-pore and macro-pore increased while that of fine-pore decreased. Changes in micro-pore and fine-pore resulted in the continuous absorption of water by soils with no inflection point on the SWCC. The increase of macro-pore mainly influences the boundary effect segment of SWCC, but such influence is slight.

Key words: expansive soil, water retention characteristics, microstructure, pore size distribution, hydrating path, SWCC

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