岩土力学 ›› 2022, Vol. 43 ›› Issue (S1): 357-366.doi: 10.16285/j.rsm.2021.0076

• 基础理论与实验研究 • 上一篇    下一篇

压实度与制样含水率对压实黄土微结 构及水力特性的影响

潘振辉1, 2，肖涛1, 2，李萍1, 2   

  1. 1. 西北大学 大陆动力学国家重点实验室，陕西 西安 710069；2. 西北大学 地质学系，陕西 西安 710069
  • 收稿日期:2021-01-15 修回日期:2022-03-10 出版日期:2022-06-30 发布日期:2022-07-14
  • 通讯作者: 肖涛，男，1994年生，博士，主要从事黄土微结构与力学特性方面的研究。E-mail: andyshaw01001@163.com E-mail:193445532@qq.com
  • 作者简介:潘振辉，男，1999年生，博士研究生，主要从事黄土力学与工程方面的研究。
  • 基金资助:
    国家自然科学基金资助项目（No.42007251）；陕西省黄土力学与工程重点实验室开放基金（No.203131900007）；中国博士后基金项目（No.2019M653883XB）。

Influences of compaction degree and molding water content on microstructure and hydraulic characteristics of compacted loess

PAN Zhen-hui1, 2, XIAO Tao1, 2, LI Ping1, 2   

  1. 1. State Key Laboratory of Continental Dynamics, Northwest University, Xi’an, Shaanxi 710069, China; 2. Department of Geology, Northwest University, Xi’an, Shaanxi 710069, China
  • Received:2021-01-15 Revised:2022-03-10 Online:2022-06-30 Published:2022-07-14
  • Supported by:
    This work was supported by the National Natural Science Foundation of China(42007251), the Shaanxi Key Laboratory of Loess Mechanics and Engineering (203131900007) and China Postdoctoral Science Foundation(2019M653883XB).

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摘要： 压实黄土的水力特性受微结构控制，而微结构受制样条件影响。为探究制样条件对压实黄土微结构、饱和渗透系数与土−水特征曲线的影响及机制，对不同制样条件下制备的压实黄土试样开展了压汞试验、变水头渗透试验和土−水特征曲线的测定，获得了它们的孔径分布曲线、饱和渗透系数及其随渗透次数的变化和土−水特征曲线。结果表明：（1）制样含水率通过影响集粒尺寸改变试样中的中孔（2 000 nm < d ≤ 12 000 nm）、小孔（150 nm < d ≤ 2 000 nm）密度，制样含水率越大，中孔密度越小，小孔密度越大；而压实度主要影响集粒的排列进而影响试样中的中孔密度，压实度越大，中孔含量越小。（2）压实度和制样含水率影响着试样的初始饱和渗透系数。压实度较小（85%）时，试样的饱和渗透系数受结构坍塌影响随渗透次数的增大而减小；压实度较大（90%和94%）时，饱和渗透系数则受颗粒流失影响随渗透次数的增大而增大。 （3）压实度与制样含水率影响着水-土特征曲线。制样含水率主要影响试样的进气值和过渡段曲线的斜率，制样含水率越大，进气值越小，过渡段曲线的斜率越小，表明试样的持水性能越好；压实度则主要影响试样的进气值和饱和（质量）含水率，压实度越大，进气值越大，饱和（质量）含水率越小。

关键词: 压实黄土, 压实度, 制样含水率, 孔径分布曲线, 饱和渗透系数, 土?水特征曲线

Abstract: The hydraulic characteristics of compacted loess are controlled by its microstructure, which depends on the sample preparation conditions. This study aims to explore the influence of sample preparation conditions on microstructure, saturated permeability coefficient and soil-water characteristic curve (SWCC) of compacted loess. The mercury intrusion porosimetry (MIP) tests, variable head tests and SWCC tests were carried out on the specimens prepared under different conditions to obtain the pore-size distribution curves, saturated permeability coefficients and their variations with the seepage times, and SWCCs. The results show that: (1) The molding water content affects the density of mesopores (2 000 nm < d ≤ 12 000 nm) and that of micropores (150 nm < d ≤ 2 000 nm) by affecting the sizes of aggregates; the higher the molding water content of the specimen is, the smaller the density of mesopores is, and the larger the density of micropores is. The compaction degree has a significant effect on the density of mesopores by affecting the arrangement of aggregates; the greater the compaction degree is, the tighter the arrangement of aggregates is, and the smaller the mesopores content is. (2) The initial saturated permeability coefficient reduces with the increases of compaction degree and molding water content of compacted loess. When the compaction degree is small (85%), the saturated permeability coefficient of compacted loess decreases with the increase in number of seepage, and it rises with increasing number of seepage when the compaction degree is high (90% and 94%). (3) The molding water content mainly affects air entrance vaule (AEV) and the slope of the transition zone. The greater the molding water content is, the smaller the AEV is, and the slope of the transition zone is. Compaction degree mainly affects AEV and saturated moisture of specimens. The higher the compaction degree is, the higher the AEV is, and the smaller the saturated water content is.

Key words: compacted loess, compaction degree, molding water content, pore-size distribution curve, saturated permeability coefficient, soil-water characteristic curve

中图分类号: TU411
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