逐级降温工况下道基含盐砾质土盐-冻胀特性  

Salt-frost expansion characteristics of salt gravel soil embankment under progressive cooling conditions

作　　者：韩进宝 王利鑫 张莎莎[2] 余虔 寇璟媛 姚妙娴 王运朋 HAN Jin-bao;WANG Li-xin;ZHANG Sha-sha;YU Qian;KOU Jin-yuan;YAO Miao-xian;WANG Yun-peng(China Airport Planning&Design Institute Co.Ltd.,Beijing 100120,China;School of Highway,Chang'an University,Xi'an 710064,Shaanxi,China)

机构地区：[1]民航机场规划设计研究总院有限公司,北京100120 [2]长安大学公路学院,陕西西安710064

出　　处：《长安大学学报（自然科学版）》2024年第1期36-46,共11页Journal of Chang’an University(Natural Science Edition)

基　　金：民航机场规划设计研究总院有限公司科研项目(mhzyhx-2022-01);陕西省自然科学基础研究计划项目(2019JM-147)。

摘　　要：为探明多因素影响下道基含硫酸盐砾质混合料的盐-冻胀变形特性及特征温度,基于天然级配、剔除大于60 mm粒径颗粒级配及添加5%含量(质量分数)细颗粒级配3种试样,分别开展3种含水率、7种不同含盐量条件下的盐-冻胀试验及冻结温度测定试验,结合PFC3D数值模拟,探究颗粒级配、含水率、含盐量对道基含硫酸盐砾质混合料的盐-冻胀变形规律及冻结温度特性的影响,并揭示其作用机理。研究结果表明:含硫酸盐砾质混合料的冻结温度主要受土体含盐量、含水率所对应的等效硫酸钠质量分数的影响;由于受试验降温方式及试样低含水率、低含盐量的综合影响,试验中未能监测到土试样的过冷温度;道基含硫酸盐砾质混合料的宏观盐胀温度低于冻结温度,添加5%含量细粒土试样的冻结温度略低于其他2种试样,3种试样的冻结温度为-1.58℃~0℃;试验土体的盐-冻胀变形率整体随含盐量、含水率的升高而增大,仅剔除大于60 mm粒径颗粒级配的盐-冻胀变形率与天然级配整体相差不大,而添加5%含量细颗粒使土体的盐-冻胀变形率提高3%~30%,提高程度受土试样含水率和含盐量的影响较大;5%含量细颗粒填充了试样中的大孔隙,减小了孔隙体积,对道基含硫酸砾质混合料的盐-冻胀敏感作用程度显著,道基填筑工程中应严格控制填料中的细粒土含量。In order to explore the salt-frost heaving deformation and characteristic temperature of sulfate containing embankment fill material of gravel mixture under the influence of multiple factors,based on three kinds of samples,namely,natural grading,particle size grading greater than 60 mm,and adding 5%fine particle(mass fraction)grading,salt-frost heaving tests and freezing temperature measurement tests were carried out under three water content and seven different salt content conditions.Combined with PFC3D numerical simulation,the effects of particle size distribution,water content and salt content on salt frost heave deformation and freezing temperature of gravel saline soil foundation were investigated.And the mechanism of action was also revealed.The results show that the freezing temperature of gravel mixture containing sulfate is mainly affected by the equivalent sodium sulfate mass percentage concentration corresponding to the soil salt content and water content.Due to the comprehensive influence of the cooling mode of the test and the low water content and salt content of the sample,the supercooling temperature of the soil sample could not be monitored in the test.The macro salt expansion temperature of the gravel mixture containing sulfate in the road base is lower than the freezing temperature,and the freezing temperature of the sample with 5%fine grained soil content is slightly lower than the other two samples.The freezing temperature range of the three samples is-1.58℃to 0℃.The overall salt-frost heave rate of soil increases with the increase of salt content and water content.The salt-frost heave rate of soil without the gradation of particles larger than 60 mm,which is not much different from that of natural gradation.The addition of 5%fine particles can increase the salt-frost heave rate of soil by 3%to 30%,and the degree of improvement is affected by water content and salt content.The 5%content of fine particles fills the large pores in the sample,reducing the pore volume,and it is significantly

关 键 词：道路工程 道基填料 试验研究 砾质混合料 盐-冻胀量 冻结温度 

分 类 号：U416.165[交通运输工程—道路与铁道工程]