大温差环境下新疆伊犁黄土变形特性
Loess Deformation Characteristics Under Temperature Environment with Significant Variation in Ili,Xinjiang
马莉 1叶尔哈力·胡斯曼 1刘学军 2石开欣 1胡扬阳1
作者信息
- 1. 新疆大学建筑工程学院,新疆乌鲁木齐 830017
- 2. 新疆建筑科学研究院(有限责任公司),新疆乌鲁木齐 830054
- 折叠
摘要
为揭示复杂环境下新疆伊犁地区黄土变形特性,在常温和大温差环境中开展加荷、浸水和盐渍等条件下重塑黄土侧限压缩试验,结合体应变结构性参数分析黄土的压缩和湿陷变形规律.研究结果表明:伊犁黄土具有湿陷性大、易溶盐含量高和大温差环境特点,其变形特性与其物质成分、微观结构特征及外界环境因素密切相关.常温下初始含水率6％～17％的重塑黄土孔隙比-压力曲线呈现相似的压缩变形规律,黄土初始含水率越大,压缩变形越大,湿陷性越强,但饱和黄土对水和力的作用敏感性降低;高温干旱条件下伊犁黄土的结构性强,具有深厚湿陷性,强荷载压实黄土有利于消除黄土的湿陷性;土体内水分蒸发减湿导致盐分结晶析出,在一定程度上强化黄土土体骨架结构的稳定性,湿拌法比干拌法更能促进重塑黄土盐分的有效胶结;低温寒冷条件下不同初始含水率的黄土因水分冻结而表现出一定的抗压缩变形能力,但在0～-5℃的低温条件下,黄土内冰水两相转换不稳定,导致黄土的结构性具有一定的波动.
Abstract
To investigate the deformation characteristics of loess under harsh circumstances in the Ili region of Xinjiang,a series of loess confined compression experiments were conducted under loading,immersion,and saline conditions considering significant temperature variation,and structural parameters related to volume strain was adopted to analyze loess deformation and collapsibility.Ili loess has distinguished regional features including strong collapsibility,high content of soluble salt and significant temperature variation,while its deformation characteristics are affected by soil composition,microstructural features,and external environmental factors.At ambient temperature,the porosity-pressure curves of remolded loess with an initial moisture content of 6％～17％display similar compressive patterns.The greater the water content of loess soil,the greater the compression deformation and the collapsibility,but saturated loess decreases its sensibility to water and loading effects.Ili loess forms robust microstructure at high temperature and drought conditions,and heavy loading compaction can eliminate loess collapsibility.The evaporation and dehumidification of water in loess leads to the crystallization of salt,enhancing loess microstructure's stability.Wet mixing process produces more efficient salt cementation in remolded loess compared to dry mixing process.Loess with different initial moisture contents exhibits resistance to compressive loading due to freezing effects below 0℃.The conversion between the ice and water phases in loess at 0～-5℃ is unstable,resulting in certain fluctuations in loess microstructure.
关键词
伊犁黄土/大温差/侧向压缩试验/变形特性/湿陷性/结构性参数Key words
Ili loess/significant temperature variation/confined compression test/compression deformation/collapsibility/structural parameters引用本文复制引用
出版年
2024
NETL
NSTL
万方数据