水热力作用下铁路基床翻浆冒泥力学特征试验研究  

Mechanical characteristics of mud pumping in railway subgrade under hydrothermal action

作　　者：常文正 王天亮[2,3] 王林 CHANG Wen-zheng;WANG Tian-liang;WANG Lin(Hebei Key Laboratory of Traffic Safety and Control,Shijiazhuang Tiedao University,Shijiazhuang,Hebei 050043,China;State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures,Shijiazhuang Tiedao University,Shijiazhuang,Hebei 050043,China;Key Laboratory of Roads and Railway Engineering Safety Control,Ministry of Education,Shijiazhuang Tiedao University,Shijiazhuang,Hebei 050043,China)

机构地区：[1]石家庄铁道大学河北省交通安全与控制重点实验室,河北石家庄050043 [2]石家庄铁道大学省部共建交通工程结构力学行为与系统安全国家重点实验室,河北石家庄050043 [3]石家庄铁道大学道路与铁道工程安全保障省部共建教育部重点实验室,河北石家庄050043

出　　处：《岩土力学》2024年第11期3304-3314,共11页Rock and Soil Mechanics

基　　金：国家自然科学基金面上项目(No.52378453,No.51978426);石家庄铁道大学2024研究生创新资助项目(No.YC202435)。

摘　　要：考虑基床水位线高度与冻融循环的影响,开展有砟轨道基床翻浆冒泥试验,分析动荷载作用下有砟轨道基床翻浆冒泥过程中水与细粒土迁移和泥浆形成特征。研究结果表明:在常温加载初期,水分自下而上发生迁移,随着动荷载的持续施加,基床填土内部孔隙水压力逐渐消散,孔隙水压力梯度减小,各层土体含水率趋于稳定;水位线位于基床中部时,基床上部土体处于非饱和状态,体积含水率较小,仅为26%左右,未能发生细颗粒迁移,基床表层有效应力远大于0,未形成泥浆造成翻冒;水位线位于基床顶部时,颗粒迁移较为明显,且基床表层有效应力在荷载的作用下迅速减小到0以下,并发生翻浆冒泥现象;冻结加载相较于单向冻结,冻结锋面下降速率慢,水分迁移量更大;融化加载条件下,基床上部土体先于下部土体融化形成冻土夹层,由于冻土夹层阻隔,上部土体含水率较大,在荷载作用下基床表层有效应力迅速发展到负值,更易形成泥浆导致翻浆冒泥。Considering the impact of the subgrade water level and freeze-thaw cycles,experiments were conducted on ballast track subgrade mud pumping.The study analyzed the migration of water and fine particles,as well as the characteristics of mud formation during the mud pumping process of the ballast track subgrade under cyclic loading.The research findings indicate that,during the initial loading stage at ambient temperature,moisture migrates upwards from the bottom.As dynamic loading is continuously applied,the internal pore water pressure in the subgrade soil gradually dissipates,resulting in a decrease in the pore water pressure gradient and a stabilization of the moisture content in each soil layer.When the water level is positioned in the middle of the subgrade,the upper soil is in an unsaturated state with a relatively low volumetric water content of approximately 26%.Fine particle migration does not occur,and the effective stress at the subgrade surface is much greater than zero,thus preventing mud pumping.When the water level is at the top of the subgrade,particle migration is more pronounced.The effective stress at the subgrade surface rapidly decreases to below 0 under the action of the load,resulting in mud pumping phenomena.Compared to unidirectional freezing,freeze-thaw loading results in a slower descent rate of the freezing front and a greater amount of moisture migration.Under thawing conditions,the upper soil layer of the subgrade melts before the lower soil layer,forming a frozen soil interlayer.Due to the isolation effect of the frozen soil interlayer,the upper soil layer retains a higher moisture content.Under the action of the load,the effective stress at the subgrade surface rapidly develops into negative values,making it more susceptible to mud pumping.

关 键 词：水热力耦合 翻浆冒泥 水土迁移 泥浆形成 

分 类 号：TU473[建筑科学—结构工程]