考虑细颗粒含量的季冻区公路路基水分迁移特性  

Water migration characteristics of highway subgrade in seasonal frozen areas considering fine particle content

作　　者：刘红平 李昊 魏进[3] 卞海丁 LIU Hong-ping;LI Hao;WEI Jin;BIAN Hai-ding(Engineering Design and Research Academy,Chang’an University,Xi’an 710064,Shaanxi,China;Chongqing Communications Constructiong(Group)Co.Ltd,Chongqing 401120,China;School of Highway,Chang’an University,Xi’an 710064,Shaanxi,China)

机构地区：[1]长安大学工程设计研究院,陕西西安710064 [2]重庆交通建设(集团)有限责任公司,重庆401120 [3]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4期27-37,共11页Journal of Chang’an University(Natural Science Edition)

基　　金：中央高校基本科研业务费专项资金项目(310821173701);陕西省交通运输厅科技项目(22-24K)。

摘　　要：季冻区公路冻胀翻浆现象严重,冻胀翻浆等病害主要由路基土中水分迁移造成。为探明季冻区路基土中水分迁移特性与细颗粒含量(质量分数,下文同)的关系,以西藏贡觉—芒康公路改扩建工程为依托,设计非冻结路基土和冻结路基土的水分迁移试验,研究细颗粒含量对毛细水上升高度、温度梯度及入流通量等特性的影响规律,建立迁移势与细颗粒含量的修正模型。研究结果表明:控制初始含水率与干密度不变,随着细颗粒含量的增加,毛细水上升高度和入流通量均呈线性增加,温度梯度呈曲线增加;随着细颗粒含量的减小,冻土体的总入流量随时间的变化曲线由拱形变化为轻微S形,入流通量随时间的变化曲线由递降变化为峰值形;考虑基质势对入流通量的影响,建立季冻区路基土体水分迁移势与细颗粒含量的修正模型,发现迁移势随着细颗粒含量的增加先变大后减小,与不考虑基质势的迁移势模型相比,迁移势修正模型计算值偏小,峰值点也偏小,结果相对安全;细颗粒含量小于22%的路堤填筑高度应不小于1.5 m。The phenomenon of frost heaving and frost boiling on highways in seasonal frozen areas is severe,and diseases such as frost heaving and frost boiling are mainly caused by the migration of water in the subgrade soil.In order to explore the relationship between water migration characteristics and fine particle content(mass fractions,the same below)in subgrade soil in seasonal frozen areas,based on the reconstruction and expansion project of the Gongjue to Mangkang Highway in Xizang,water migration tests for non-frozen and frozen subgrade soil were designed,the influence of fine particle content on the characteristics of capillary water rise height,temperature gradient,and inflow flux were studied,and a modified model for migration potential and fine particle content was established.The results show that when keeping initial water content and dry density constant,with the increase of fine particle content,the capillary water rise height and inflow flux both increase linearly,and the temperature gradient increases in a curve.As fine particle content decreases,the total inflow of frozen soil changes from an arch shape to a slight S-shape with time,and the inflow flux changes from a decreasing shape to a peak shape with time.Considering the influence of matrix potential on inflow flux,a modified model for water migration potential and fine particle content of subgrade soil in seasonally frozen areas is established.It is found that the migration potential first increases and then decreases with the increase of fine particle content.Comparing with the migration potential model without considering matrix potential,the calculated values and peak point of the migration potential modified model are smaller,resulting in relatively safe.The minimum filling height of embankments with a fine particle content of less than 22%should be controlled above 1.5m.2tabs,16figs,27refs.

关 键 词：道路工程 路基土 室内试验 水分迁移特性 细颗粒含量 迁移势 

分 类 号：U416.1[交通运输工程—道路与铁道工程]