不同地下水位变化模式下淤泥质粘土变形特性与微观结构分析  

Analysis of deformation characteristics and microstructure of soft clay under different groundwater table changes

作　　者：黄天荣 卢耀如[2] 王寿生 Huang Tianrong;Lu Yaoru;Wang Shousheng(School of Civil and Traffic Engineering,Shanghai Urban Construction Vocational College,Shanghai 200438,China;Department of Geotechnical Engineering,Tongji University,Shanghai 200093,China;Shanghai Municipal Engineering Design and Research Institute(Group)Co.,Ltd,Shanghai 200092,China)

机构地区：[1]上海城建职业学院土木与交通工程学院,上海200438 [2]同济大学土木工程学院地下建筑与工程系,上海200093 [3]上海市政工程设计研究总院(集团)有限公司,上海200092

出　　处：《工程勘察》2021年第9期1-6,共6页Geotechnical Investigation & Surveying

基　　金：国家自然科学基金项目(41072205);上海市一流专业建设项目(YZ-2019-F-01)。

摘　　要：为揭示地下水位变化对土体变形的影响,本文采用上海第(4)层淤泥质粘土,通过单向压缩试验研究了不同地下水位变化模式下淤泥质粘土的变形特性,并结合电镜扫描与压汞试验进行了微观结构分析。研究结果表明,上海第(4)层淤泥质粘土的变形与地下水位变化密切相关,当地下水位变化引起的荷载小于前期固结应力时以弹性变形为主,大于时以粘塑性为主,等于时则以粘弹塑性为主,同时各级荷载作用下试样孔隙比与加卸荷循环次数满足幂指数函数关系。微观结构分析显示,上海第(4)层淤泥质粘土试验前后均以大孔结构为主,受荷后其高孔隙架空结构逐步向离散型结构演化,颗粒定向分布趋于水平方向。相关结论可为地下水位变化诱发地面沉降的治理与控制提供理论依据与技术指导。In order to reveal the impact of groundwater table change on the soil deformation,deformations of the fourth layer soft clay in Shanghai was studied by uniaxial compression test,and the microstructure evolution was analyzed through scanning electron microscope and mercury injection test in this paper.It was revealed that the deformation characteristics of the soft clay were determined by the groundwater table fluctuation.When the load induced by the change of groundwater level is smaller than the previous consolidation stress,the deformation is mainly elastic;and it is mainly viscoplastic when the load is greater;and it is mainly viscoelastic when the load is equal.The relationship between the internal void ratio and the number of loading cycles fits the power exponent well.The microstructure analysis demonstrates that the main pore of the soft clay is macrospore before and after the test,and the whole structure of the soft clay changes from cohesive structure to dispersive structure.In addition,the directional distribution of particles tends to horizontal.The conclusions could provide theoretical basis and technical support for the treatment and control of land subsidence induced by change of groundwater table.

关 键 词：淤泥质粘土 地下水位变化 变形特性 微观结构 

分 类 号：TU599[建筑科学—建筑技术科学]