岩土力学 ›› 2019, Vol. 40 ›› Issue (4): 1351-1357.doi: 10.16285/j.rsm.2017.2473

• 基础理论与实验研究 • 上一篇    下一篇

非饱和压实黄土结构特性试验研究

王娟娟,郝延周,王铁行   

  1. 西安建筑科技大学 土木工程学院,陕西 西安 710055
  • 收稿日期:2017-12-12 出版日期:2019-04-11 发布日期:2019-04-25
  • 通讯作者: 郝延周,男,1982年生,博士,讲师,主要从事黄土强度与结构特性方面的研究工作。E-mail: 30010508@hncj.edu.cn E-mail:juanjuan0022@163.com
  • 作者简介:王娟娟,女,1980年生,博士,高级工程师,主要从事黄土地区工程地质、环境地质方面的教学与科研工作。
  • 基金资助:
    陕西省教育厅专项科研项目(No. 16JK1448)。

Experimental study of structural characteristics of unsaturated compacted loess

WANG Juan-juan, HAO Yan-zhou, WANG Tie-hang   

  1. College of Civil Engineering, Xi’an University of Architecture and Technology, Xi’an, Shaanxi 710055, China
  • Received:2017-12-12 Online:2019-04-11 Published:2019-04-25
  • Supported by:
    This work was supported by Special Scientific Project of Shaanxi Education Department (16JK1448).

摘要: 对增(减)湿到相同含水率及相同干密度的不同结构性非饱和压实黄土进行土-水特征曲线试验和三轴剪切试验,研究制样含水率引起的结构变化对非饱和压实黄土基质吸力、应力-应变特征及结构性参数的影响。研究结果表明:制样含水率引起的结构性对非饱和压实黄土的土-水特征曲线有明显的影响,小于塑限时基质吸力随制样含水率的增大而增大,最优制样含水率时非饱和压实黄土具有均匀小孔隙的团粒凝聚结构使其吸力相对最大;应力-应变曲线在最优结构状态时位于坐标最上端,小于最优制样含水率时的结构弱化程度相对较低,其应力-应变曲线逐渐下移,大于最优制样含水率时土样的结构弱化程度较高,其应力-应变曲线位于最下端;定义的结构性参数m?r能够合理反映压实黄土的结构性,弥补了压实土工程中用最优含水率和最大干密度指标无法反映土结构性影响的不足;屈服结构性参数m?r0能够合理反映出不同制样含水率压实黄土的结构弱化程度,结构弱化程度还反映在三轴剪切破坏强度上。

关键词: 压实黄土, 制样含水率, 结构性, 基质吸力, 应力-应变曲线, 结构性参数

Abstract: A series of soil water characteristic curve tests and triaxial shear tests were carried out on different structural unsaturated compacted loess samples after increasing or decreasing moisture to the same water content and dry density. The influence of different structures caused by the change of molding water content on matric suction and stress-strain characteristics as well as the structural parameter was investigated for the unsaturated compacted loess. The results indicate that the structure caused by the molding water content has a obvious effect on the soil water characteristic curve of unsaturated compacted loess. The matric suction increases with the increase of the molding water content when it is less than plastic limit. The compacted loess, which has the agglomerate structure with uniform pore size, results in relatively maximum suction at its best water content. The stress-strain curve of sample with optimum structure state is at the top of the coordinate. The degree of structural weakening is relative lighter when the water conent is less than the optimum molding water content, resulting in the stress-strain curve moves downward gradually. On contrarily, when the water conent is higher than the optimum molding water content, the degree of structural weakening is relative higher, which makes the stress-strain curve at the bottom. The proposed parameter m?r can reasonably reflect the structure of compacted loess, which overcomes the deficiency that the optimum moisture content and maximum dry density indexes cannot reflect the influence of soil structure in compacted soil engineering. The yield structural parameter m?r0 can reasonably reflect the degree of structural weakening of compacted loess with different molding water contents, and the degree of structural weakening is also reflected in the triaxial shear failure strength.

Key words: compacted loess, molding water content, structure, matric suction, stress-strain curve, structural parameter

中图分类号: 

  • TU 443
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