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冰川冻土 ›› 2016, Vol. 38 ›› Issue (4): 1028-1035.doi: 10.7522/j.issn.1000-0240.2016.0119

• 特殊土的力学特性与工程问题 • 上一篇    下一篇

干湿循环作用下红黏土收缩特征研究

朱建群1, 龚琰2, 胡大为3, 李雄威1, 施维成1   

  1. 1. 常州工学院 土木建筑工程学院, 江苏 常州 213032;
    2. 常州市建筑科学研究院股份有限公司, 江苏 常州 213001;
    3. 湖南科技大学 土木工程学院, 湖南 湘潭 411201
  • 收稿日期:2016-01-25 修回日期:2016-07-25 出版日期:2016-08-25 发布日期:2016-09-19
  • 作者简介:朱建群(1975-),女,江西上饶人,教授,2007年在中国科学院武汉岩土力学研究所获博士学位,现从事特殊土土力学研究与岩土工程教学.E-mail:zhu-jq@163.com
  • 基金资助:
    国家自然科学基金项目(41302226);江苏省自然科学基金项目(BK20131141);常州工学院校级科研项目(YN1501);岩土工程稳定控制与健康监测湖南省重点实验室开放基金项目(E21620)资助

Research on shrinkage characteristics of red clay with drying and wetting cycles

ZHU Jianqun1, GONG Yan2, HU Dawei3, LI Xiongwei1, SHI Weicheng1   

  1. 1. Department of Civil and Architecture Engineering, Changzhou Institute of Technology, Changzhou 213032, Jiangsu, China;
    2. Changzhou Architectural Research Institute Co. Ltd, Changzhou 213001, Jiangsu, China;
    3. School of Civil Engineering, Hunan University of Science and Techology, Xiangtan 411201, Hunan, China
  • Received:2016-01-25 Revised:2016-07-25 Online:2016-08-25 Published:2016-09-19

摘要: 以贵州某高速公路沿线红黏土为研究对象,开展了干湿循环作用后红黏土的收缩特性试验研究,探讨了干湿循环次数和初始含水率对红黏土收缩性状的影响.试验结果表明:同一循环次数内,各试样的环向收缩率在6~8 h时达到稳定,而轴向线缩率则需更长的稳定时间;随着初始含水率增加,各试样的初始轴向线缩率减小,而初始环向收缩率增加;28%含水率试样具有相近的最终轴向变形和环向变形量,而34%含水率的试样环向变形量高于轴向变形量;初始含水率变化不大,但体缩率的变化率却明显不同,说明干湿循环过程使得土体内部结构变得不稳定,但颗粒间相互作用的本质未发生明显变化;干湿循环作用对重塑红黏土最优含水率位置的基本无影响,这说明其未能改变黏土集聚体内对结合水的最大吸附能力.通过压汞试验得到了不同干湿循环作用后试样的孔隙分布情况,随着干湿循环次数的增加小孔径尺寸和分布密度改变较小,而大孔径尺寸减小,分布密度也在减小.干湿循环作用对聚集体内孔径的影响大于对微聚体内孔隙影响,与所测得的宏观收缩规律相吻合.

关键词: 红黏土, 干湿循环, 收缩曲线, 收缩变形, 含水率

Abstract: Shrinkage of red clay with the drying and wetting cycles has profound effects on its engineering properties. It is important for red clay to analyze the effects of numbers of drying and wetting cycles and initial water content. In this paper, laboratory tests were performed on compacted specimens of red clay, which came from a position near a highway constructed in Guizhou. It was found that within a drying and wetting the hoop shrinkage rate would be stable after 6-8 h, and the axial shrinkage rate had a longer time than the hoop shrinkage. The axial linear shrinkage rates of samples with the increase of initial water content during initial test were decreasing, and the hoop shrinkage rates of sample were increasing. The final axial shrinkage and final hoop shrinkage of sample with initial water content of 28% was similar, but the final hoop shrinkage of sample with 34% was higher than the finial axial shrinkage. Although the initial moisture contents had changed a little, the change of the volume shrinkage ratio was significant. It was showed that the effect of drying and wetting cycles on the aggregate of red clay was clear and important. The optimum water content location of the reshaping red clay was independent of the drying and wetting effects. Then, the drying and wetting effects failed to change the maximum adsorption of clay aggregate to absorbed water. It is shown from specimens of the pore size distribution curves acquired by the mercury intrusion pores method that the cycle time has different effect on pores with different diameter. The diameter and distribution density of small pores lied in intra-aggregate had little change, but that of larger pores lied in inter-aggregate was decreasing with the drying-wetting cycles. The micropore structure is corresponding to the shrinkage characteristics of specimens with drying-wetting cycles.

Key words: red clay, drying and wetting cycles, shrinkage curve, contraction deformation, moisture content

中图分类号: 

  • TU443