低液限粉土填料掺盐抑制冻胀效果研究  

Study on Controlling Frost Heave by Mixing Salt with Low Liquid Limit Silt Fillers

作　　者：沈宇鹏[1,2] 汤天笑 刘建坤[1] 田亚护[1,2] 蔡小培[1,2] SHEN Yupeng;TANG Tianxiao;LIU Jiankun;TIAN Yahu;CAI Xiaopei(School of Civil Engineering,Beijing Jiaotong University,Beijing 100044,China;Beijing Engineering and Technology Research Center of Rail Transit Line Safety and Disaster Prevention,Beijing Jiaotong University,Beijing 100044,China)

机构地区：[1]北京交通大学土木建筑工程学院,北京100044 [2]北京交通大学北京市轨道交通线路安全与防灾工程技术研究中心,北京100044

出　　处：《铁道学报》2018年第7期93-99,共7页Journal of the China Railway Society

基　　金：国家自然科学基金项目(41731281;41772330;51578053);神朔科技开发项目([2015]10号)

摘　　要：采用室内单轴冻结试验,对比封闭条件下神朔重载铁路低液限粉土填料掺盐前后水分迁移和冻胀特性,并分析不同类型盐分、含盐量下抑制土体冻胀效果。结果表明:(1)低液限粉土的起始冻结温度随含盐量的增加而降低;掺入NaCl后起始冻结温度明显降低,有效抑制了土体的水分冻结;Na2SO4也能降低起始冻结温度,但效果不如NaCl。(2)随着盐含量增加,土体水分迁移量减少;加入NaCl后,冻结深度减小,冻结锋面含水率降低;加入Na2SO4后冻结深度无明显改变。(3)掺盐可有效抑制土体冻胀,且冻胀量随含盐量的增加而减小,NaCl抑制土体冻胀效果强于Na2SO4。建议该地区优先掺入NaCl来抑制路基冻胀,且掺入量控制在1.5%~2%之间。In this paper,the indoor uniaxial freezing test was used to compare the moisture migration and frost heave characteristics of the low liquid limit silt fillers of Shenmu-Shuozhou heavy-haul railway before and after salt mixing in closed condition.Simultaneously,the effects of different types of salt and salinity on soil frost heave suppression were analyzed.The results show as follows：（1）The initial freezing point of the low-liquidlimited silt decreases with the increase of salt content.After the incorporation of sodium chloride,the initial freezing temperature obviously decreases,resulting in effective inhibition of the freezing of the soil.The sodium sulfate can also reduce the initial freezing point,but the effect is not as good as sodium chloride.（2）With the increase of salt content,the amount of water migration in soil decreases.After the addition of sodium chloride,the freezing depth and the frozen water content decrease.The freezing depth after addition of sodium sulfate does not change significantly.（3）Salt can effectively inhibit soil frost heave.The frost heave amount decreases with the increase of salt content.The inhibition effect of sodium chloride on soil frost heave is stronger than that of sodium sulfate.It is suggested that sodium chloride should be preferentially incorporated to inhibit the frost heave of the roadbed,and the incorporation amount should be controlled between 1.5% and 2%.

关 键 词：低液限粉土 冻胀 水分迁移 起始冻结温度 含盐量 

分 类 号：U213.15[交通运输工程—道路与铁道工程]