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冰川冻土 ›› 2022, Vol. 44 ›› Issue (2): 612-622.doi: 10.7522/j.issn.1000-0240.2022.0063

• 寒区工程与灾害 • 上一篇    

冻融作用下木质素纤维改良黄土力学与热学特性试验研究

董超凡1,2(), 张吾渝1,2(), 张瑞星1,2, 黄雨灵1,2, 高英3   

  1. 1.青海大学 土木工程学院,青海 西宁 810016
    2.青海省建筑节能材料与工程安全重点实验室,青海 西宁 810016
    3.西安交通大学 城市学院,陕西 西安 710018
  • 收稿日期:2022-02-25 修回日期:2022-04-13 出版日期:2022-04-30 发布日期:2022-06-10
  • 通讯作者: 张吾渝 E-mail:dongcf1996@163.com;qdzwy@163.com
  • 作者简介:董超凡,硕士研究生,主要从事环境岩土及地下工程研究. E-mail: dongcf1996@163.com
  • 基金资助:
    国家自然科学基金项目(52168054);青海省科技计划项目(2020-ZJ-738);陕西省科技厅一般项目(2021-JQ-892)

Experimental study of the mechanical and thermal properties of lignin fiber-stabilized loess under freeze-thaw cycles

Chaofan DONG1,2(), Wuyu ZHANG1,2(), Ruixing ZHANG1,2, Yuling HUANG1,2, Ying GAO3   

  1. 1.College of Civil Engineering,Qinghai University,Xining 810016,China
    2.Qinghai Key Laboratory of Building Energy Saving Materials and Engineering Safety,Xining 810016,China
    3.Xi’an Jiaotong University City College,Xi’an 710018,China
  • Received:2022-02-25 Revised:2022-04-13 Online:2022-04-30 Published:2022-06-10
  • Contact: Wuyu ZHANG E-mail:dongcf1996@163.com;qdzwy@163.com

摘要:

冻融循环作用是造成寒区工程病害的主要因素之一。为探究冻融循环对木质素纤维改良黄土力学和热学的影响,通过轻型击实试验、冻融循环试验、不固结不排水三轴剪切试验、热常数分析试验和X射线衍射试验,以木质素纤维掺量、冻融循环次数和围压为变量展开研究。结果表明:随着掺量的增加,改良黄土的最大干密度降低,最优含水率升高;随着冻融循环次数的增加,试样的应力-应变曲线由应变硬化型向应变弱软化型转变;试样的质量损失率、破坏强度、弹性模量、黏聚力、内摩擦角和导热系数均随着冻融循环次数的增加呈下降趋势,在经历第1次冻融循环后衰减率最高,并且总是在掺量为5%时达到最大值;试样的破坏强度和黏聚力在经历6~9次冻融循环后趋于稳定;黄土及掺量为5%的改良黄土在X射线衍射分析中成分相似,未发现新的物质生成,因此,木质素纤维是一种绿色的物理固化材料。该研究成果可为寒区土体加固提供新思路。

关键词: 木质素纤维, 改良黄土, 冻融循环, 力学特性, 导热系数

Abstract:

Freeze-thaw cycle is one of the main factors cause engineering damage in cold regions. In order to investigate the effect of freeze-thaw cycles on the mechanical and thermal properties of lignin fiber stabilized loess, light compaction test, freeze-thaw cycles test, unconsolidated undrained triaxial shear test, thermal constant analysis test and X-ray diffraction test are used in this study. lignin fiber admixture, number of freeze-thaw cycles and envelope pressure are used as variables for this study. The results showed that the maximum dry density of the lignin fiber stabilized loess tend to decrease and the optimum moisture content tend to increase with increased admixture; As the number of freeze-thaw cycles increase, the stress-strain curve of the specimens change from strain-hardening to strain-weak softening. In addition, the rate of mass loss, break strength, modulus of elasticity, cohesion, angle of internal friction and thermal conductivity of the specimens all tended to decrease with the number of freeze-thaw cycles, with the highest decay rate after the first freeze-thaw cycle and always reach a maximum at a admixture level of 5%; the break strength and cohesion of the specimens stabilize after 6~9 freeze-thaw cycles; the loess and the composition of the lignin fiber-stabilized loess with 5% admixture was similar in the X-ray diffraction analysis and no new material was found to be produced; therefore, the lignin fiber is a green physically cure material. The results of this study can provide new ideas and methods for research related to soil stabilization and consolidation in cold regions.

Key words: lignin fiber, stabilized loess, freeze-thaw cycles, mechanical properties, thermal conductivity

中图分类号: 

  • P642.14