摘要
针对西宁地区湿陷性黄土,通过侧限压缩试验,分析埋藏深度和增湿含水率对黄土在增湿条件下湿陷变形和压缩变形变化规律,并结合电镜扫描对不同增湿含水率黄土试样的微观结构进行定性定量分析,宏微观结合分析黄土试样微观结构与湿陷变形之间的相互关系。结果表明:(1)随着含水率的增大,同一压力下的增湿湿陷变形量和压缩量逐渐变小,且当含水率增加到一定程度时,土体被挤密、强度提高,压缩性减弱、湿陷性减弱或无湿陷性;(2)由于黄土应力历史影响其结构性和湿陷性,随着埋藏深度和含水量增加,5m的黄土较于3m的黄土所表现出的增湿湿陷变形量和压缩变形量相对较小;(3)浸水前后随着含水率的增加,孔隙的排列方式逐渐趋于稳定,颗粒分布逐渐集中且团粒化程度变高、孔隙面积比例逐渐减小、孔隙形态逐渐变得狭长与浸水前后黄土宏观增湿变形表现一致。
This paper aims to examine the collapsible loess in Xining area.The burial depth and humidifying water content are analyzed with the confined compression tests for the change regularity in the collapsible deformation and compressive deformation of loess under humidifying conditions.Qualitative analysis is carried out on the microstructure of different humidification loess samples by means of scanning electron microscopy.Macro-microscopic analysis is further carried out for the relationship between the microstructure of the loess sample and the collapse deformation.The results show the follows.(1)With the increase of water content,the amount of collapse deformation and compression under the same pressure gradually become smaller.The soil will be compressed,the strength will be increased,the compressibility will be weakened,and the collapsibility will be weakened or there will be no collapsibility when the water content increases to a certain extent.(2)Due to the influence of loess stress history on its structure and collapsibility,with the increase of burial depth and water content,the 5m loess exhibits less humidification and deformation and compressive deformation than the 3 m loess.(3)With the increase of water content before and after immersion,the arrangement of pores tends to be stable,the particle distribution is gradually concentrated.The degree of agglomeration becomes higher,the proportion of pore area gradually decreases,the pore morphology gradually becomes narrow and the macroscopic humidifying deformation of loess before and after water immersion consistent performance.
作者
高英
马艳霞
张吾渝
郭佳庆
GAO Ying;MA Yanxia;ZHANG Wuyu;GUO Jiaqing(Qinghai University,Xining 810016)
出处
《工程地质学报》
CSCD
北大核心
2019年第4期803-810,共8页
Journal of Engineering Geology
基金
青海省科学技术厅计划项目(2017-ZJ-792)
国家自然科学基金(51768060)
青海省科技厅应用基础研究计划(2018-ZJ-749)
青海省科技厅科技基础平台(2018-ZJ-T01)资助~~
关键词
湿陷性黄土
增湿变形
压缩变形
微观结构
Collapsible loess
Humidification deformation
Compression deformation
Microstructure
