不同细粒含量下高铁路基粗颗粒填料水气迁移特征与冻胀特性

Water-Vapor Migration and Frost Heave Characteristics of Coarse Particle Filler with Different Fine Contents in High Speed Railway Subgrade

采用自行研发的水气迁移试验装置开展单向冻结试验,研究在气态水迁移和水气混合迁移2种水分迁移模式下,不同细粒含量粗颗粒填料的温度场与冻结深度、外界补水量、水分重分布、液态水迁移高度及冻胀变形的变化规律,分析细粒含量对高铁路基粗颗粒填料水气迁移特征及冻胀特性的影响。结果表明:细粒含量和水分迁移模式对粗颗粒填料冻结过程和深度的影响不显著;温度梯度是外界水分向粗颗粒填料试样内部补给的主要内在驱动;增加细粒含量,有利于液态水迁移,一定程度上阻碍气态水迁移;水气混合迁移模式下,细粒含量越高,外界补水量越大,而气态水迁移模式下,细粒含量越高,外界补水量越小;相同水分迁移模式下,细粒含量越高,粗颗粒填料试样冻胀变形越大。

The effects of fine content on water-vapor migration in coarse-grained filler and the frost heave characteristics in high speed railway subgrade were studied experimentally using the self-developed water-vapor migration tracking devices for unidirectional freezing.The changing rules in the temperature field and frozen depth,external water supply,water redistribution,the height of water migration,and the frost heave deformation in coarse-grained filler with different fine contents were researched under two modes of water-vapor migration,which are vapor migration and water-vapor mixing migration.The results indicate that:the effects of fine contents and water migration modes on the freezing processes and frozen depths of coarse-grained filler are not significant.The temperature gradient is the primary internal driving force for the external water to enter the coarse-grained filler specimens.The increase of fine content is beneficial to the liquid water migration,but the vapor migration is restricted to some extent.The higher the fine content is in the water-vapor mixing migration mode,the greater the external water supply is,while the higher the fine content is in the vapor migration mode,the smaller the external water supply is.Under the same water migration mode,the higher the fine content,the greater the frost heave deformation of coarse-grained filler specimens.