地下空间与工程学报2024,Vol.26Issue(6) :1867-1876,1912.DOI:10.20174/j.JUSE.2024.06.12

循环荷载作用下原状黄土增湿变形特性研究

Study on the Humidification Deformation Characteristics of Undisturbed Loess under Cyclic Loading

张俊征 王健 郝延周 胡玉平 贺瑞霞
地下空间与工程学报2024,Vol.26Issue(6) :1867-1876,1912.DOI:10.20174/j.JUSE.2024.06.12

循环荷载作用下原状黄土增湿变形特性研究

Study on the Humidification Deformation Characteristics of Undisturbed Loess under Cyclic Loading

张俊征 1王健 1郝延周 2胡玉平 1贺瑞霞2
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作者信息

  • 1. 中化地质河南局集团有限公司,郑州 450003
  • 2. 河南城建学院土木与交通工程学院,河南平顶山 467036
  • 折叠

摘要

为研究增湿过程中原状黄土在循环荷载作用下的变形特性,对天然及不同增湿条件下的原状黄土试样进行动三轴试验.结果表明:不同增湿含水率及不同围压条件下的动应力-动应变关系符合Hardin-Drnevich双曲线模型;动应变随着增湿含水率的逐渐增大而增大,动应力较小时的动应变与增湿含水率曲线呈近似线性,较大时呈上凹型;动应变随振动次数的增大,先线性增大,后趋于平缓;在动应变与振次关系曲线上存在临界振次Ncr,它是动应变与振次关系曲线由线性增大到趋于平缓的界限;原状黄土的累积动应变随增湿含水率的增大而增大;增湿条件下土颗粒间易溶盐被水溶解,土结构破坏是累积动应变增大的主要原因;增湿过程对原状黄土在同一个振动周期内耗散能量的大小影响不大;滞回曲线的形态随增湿含水率和动应力的增大,两顶点间距离被拉长,滞回曲线围成的面积逐渐增大.研究成果对循环荷载作用下原状黄土地基增湿变形控制具有一定的指导意义.

Abstract

A series of dynamic triaxial tests were carried out for the undisturbed loess samples to investigate the deformation characteristics under cyclic loading during the process of humidification.The results indicated that the dynamic stress-strain relationship under different humidification water content and confining pressure conform to the Hardin Drnevich hyperbolic model.The dynamic strain increases with the humidification water content increasing.The curves of dynamic strain and humidification water content are approximately linear when the dynamic stress is small,and the curves are concave when the dynamic stress is large.The dynamic strain increases linearly first and then tend to flatten with the number of vibrations increasing.There is a critical vibration times Ncr on the curve of dynamic strain and vibration times,which is the limit of the curve increasing linearly and tending to be flat.The cumulative dynamic strain of undisturbed loess increases with the humidification water content increasing.The main reason for the cumulative dynamic strain increasing is that the soluble salts between soil particles are dissolved by water,and the loess soil structure is damaged.The process of humidification has little effect on the amount of energy dissipated in the same vibration cycle.With the humidification water content and dynamic stress increasing,the distance between the two vertices of the hysteretic loop is lengthened,and its area is gradually increasing.This study had certain guiding significance for controlling the humidification deformation of undisturbed loess foundation under cyclic loading.

关键词

原状黄土/动应力/动应变/增湿变形/滞回曲线

Key words

undisturbed loess/dynamic stress/dynamic strain/humidification deformation/hysteretic loop

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出版年

2024
地下空间与工程学报
中国岩石力学与工程学会,重庆大学

地下空间与工程学报

CSTPCD北大核心
影响因子:0.886
ISSN:1673-0836
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