冻融条件下路基温度场和湿度场分布式感知试验  

Laboratory Study on Temperature Field and Moisture Field Distributed Sensing of Subgrade in Freezing and Thawing

作　　者：凌建明[1] 张玉[1] 钱劲松[1] 吴振吉 郑纯宇[3] LING Jianming;ZHANG Yu;QIAN Jinsong;WU Zhenji;ZHENG Chunyu(Key Laboratory of Road and Traffic Engineering of the Ministry of Education,Tongji University,Shanghai 201804,China;Southwest Design and Research Institute Co.,Ltd.,CACC,Chengdu 610000,China;Jilin Provincial Transport Scientific Research Institute,Changchun 130012,China)

机构地区：[1]同济大学道路与交通工程教育部重点实验室,上海201804 [2]民航机场建设集团西南设计研究院有限公司,四川成都610000 [3]吉林省交通科学研究所,吉林长春130012

出　　处：《同济大学学报（自然科学版）》2024年第4期582-591,共10页Journal of Tongji University:Natural Science

基　　金：国家重点研发计划(2018YFB1600200);吉林省交通运输科技项目(2018-1-6)。

摘　　要：搭建土体冻融多物理场感知室内试验装置,布设传统点式传感器和分布式光纤,对土体冻融过程中路基温度场、湿度场和变形情况开展试验监测,探究单端冻结、双端融化条件下土体温度场和湿度场的分布式感知特征,验证主动加热分布式光纤技术的监测效果。试验结果表明,-15℃单端冻结条件下,土体冻结过程按降温速率分为快速冷却、逐步降温、稳定平衡三阶段,冻结锋面逐渐下移,最大冻深约占土柱高度的35%。孔隙水受冻胀迁移力影响向冻结锋面移动,引起冻融前后土体湿度场重分布,并导致土体冻胀变形,变形量为土体最大冻深的7.8%~10.9%。分布式光纤可准确得到冻融过程中土体温度场、湿度场变化特征,识别土体内冻结区域范围,温度、湿度监测拟合优度R2分别达0.98和0.94。In this paper,a laboratory test device for multi-physical field sensing during soil freezing and thawing was established.Traditional point sensors and distributed optical fibers were used in the test to monitor the temperature field,moisture field,and deformation of the subgrade during freezing and thawing process.Distributed sensing characteristics of the temperature and moisture fields of the soil under single-ended freezing and double-ended thawing condition were investigated,and the monitoring performance of the active heating distributed optical fiber technology was verified.The results show that,under the condition of−15℃singleended freezing,the soil freezing process is divided into three stages according to the cooling rate,i.e.,the rapid cooling stage,the gradual cooling stage,and the stable equilibrium stage.The freezing front gradually moves down during freezing,and the maximum freezing depth is about 35%of the height of soil column.The pore water is affected by the frost heave migration force to the freezing front and causes the redistribution of soil moisture field before and after freezing and thawing,thus causes frost heave deformation of the soil,which accounts for 7.8%to 10.9%of the maximum freezing depth of soil column.The distributed optical fiber can accurately obtain the characteristics of the soil temperature and moisture fields during the freezing and thawing process,and identify the range of the freezing area in the soil.The goodness of fit R2 of temperature and moisture monitoring reaches 0.98 and 0.94,respectively.

关 键 词：路基工程 温度场 湿度场 分布式感知 季冻区路基 主动加热光纤 

分 类 号：U416.16[交通运输工程—道路与铁道工程]