基于微观结构的饱和红黏土孔隙比计算  

The void ratio of saturated red clay calculated from a micro-structure model

作　　者：李涛[1] 刘波[1] 李岩[1] 李鹏[1] 

机构地区：[1]中国矿业大学力学与建筑工程学院,北京100083

出　　处：《中国矿业大学学报》2011年第5期720-725,共6页Journal of China University of Mining & Technology

基　　金：国家自然科学基金项目(50674095);中央高校基本科研业务费专项资金项目(2009QL02);教育部科学技术研究重点项目(109034);教育部新世纪优秀人才支持计划项目(NCET-08-0835);博士学科点新教师类专项科研基金项目(20100023120003)

摘　　要：广州红黏土在地铁建设中极易软化、崩解,对城市地铁工程的安全构成威胁.通过室内物理力学试验、X射线衍射试验、扫描电镜试验,得到了广州饱和红黏土的基本物理性质,以及该类红黏土体的矿物成分、微观结构特点.基于试验结果,提出了一种土体微观模型,分析了微观结构对该类红黏土物理性质的影响,并运用此模型求得了该类饱和红黏土的孔隙比.结果表明:该类红黏土的饱和含水量为62%,自由膨胀率达到40%,黏性矿物所占比率很大,片状和扁平状黏土颗粒相互聚集形成的层状微集聚体是组成红黏土微观结构的主要结构单元体,运用微观结构参数求得的孔隙比为1.62～1.80,与宏观试验结果相一致.The red clay found in Guangzhou easily softens and has caused collapse during subway construction.This threatens urban subway construction and other major engineering projects.Changes in physical properties of this clay caused by moisture changes are the key to the problem.The mineral components of the clay were obtained from X-ray diffraction analysis and the soil micro-structure was determined with a scanning electron microscope.A soil model is proposed to predict the physical mechanics of the red soils in terms of soil micro-structure.At a saturated moisture content of 62% the free swelling of the red soil is 40%,mostly driven by the clay minerals in the soil.Flaky clay particles gather together to form a micro layered aggregate that composes the main structural unit of the micro-structure.The void ratio is about 1.62 to 1.80,based upon the micro-structural parameters.This is identical to the void ratio obtained from macroscopically sized experiments.

关 键 词：饱和红黏土 微观机构 孔隙比 扫描电镜 

分 类 号：TU443[建筑科学—岩土工程]