典型天然粗粒盐渍土盐胀微观机制分析  

Research on microstructure of crude coarse grain saline soil under freezing and thawing cycles

作　　者：张莎莎[1] 谢永利[1] 杨晓华[1] 戴志仁[2] 

机构地区：[1]长安大学公路学院,西安710064 [2]同济大学土木工程学院,上海200092

出　　处：《岩土力学》2010年第1期123-127,共5页Rock and Soil Mechanics

基　　金：甘肃省重点交通科技项目(No.GJ2005-02);国家西部交通建设科技项目(No.200331879750)

摘　　要：为研究经多次冻融循环后天然粗粒盐渍土的盐胀特性及盐胀机制,对取自甘肃河西走廊地区嘉安一级公路沿线的某天然料场的粗粒盐渍土进行了室内基本工程性质试验和大尺寸多次冻融循环盐胀模型试验,并对经过多次冻融循环试验以后的天然盐渍土进行水盐迁移及扫描电镜分析。试验结果表明,粗粒盐渍土在降温阶段土体产生盐胀后亦会出现下陷,最终土体溶陷量大于盐胀量,冻融循环次数的增加会使粗粒盐渍土大颗粒骨架塌陷破坏及一维土柱体从上而下表现出热筛效应;多次冻融循环后的水分盐分在粗粒土柱剖面中的迁移呈现出不完全对应的分布关系。In order to research the salt expansion laws and moving patterns of water and solute migration after several freezing and thawing cycles, the crude coarse grain saline soil samples taken from China＇s Gansu province were selected for experiment of freezing and thawing cycles. In addition, the effects of the microstructure of crude saline soil after the testing of freezing and thawing cycles was researched by using SEM. It is shown that salt expansion value of crude coarse grain saline soil is accumulated before the seventh freezing and thawing cycles; but soil body could be dented in the process of cooling; and collapsibility value is accumulated with increasing cycles; and one-dimensional soil column exhibits thermal sieve effect from the top to the lower; the moving patterns of moisture content and different ion content in soil column are different under many freezing-thawing cycles.

关 键 词：道路工程 盐胀 天然盐渍土 冻融循环 扫描电镜 

分 类 号：TU448[建筑科学—岩土工程] U416.1[建筑科学—土工工程]