季冻区高速公路路基冻害调查及试验观测

Investigation on freeway subgrade frost damage in seasonally frozen ground

摘要:

在对吉林省几条高速公路进行的野外冻害调查、现场观测和室内冻胀、水分迁移模拟试验的基础上,依据取得的野外资料和室内试验数据,对季冻区高速公路路基冻害的原因和影响因素进行分析和探讨;对冻害与水分关系、路基冻害水分来源、水分迁移特征以及由于路面底基层二灰土性能恶化失效导致的道路翻浆等问题进行了深入研究.同时利用本项目综合研究的特点,将竖管法毛细水沿高度分布的研究资料与由冻胀试验揭示的各种冻胀率——含水量变化规律有机结合起来进行分析,从而得到了毛细水冻害有效高度,试验结果表明:规范值相对试验值在一些情况下偏低,有的低很多,对路基防冻抗冻设计不利.研究成果对公路路堤最小高度设计和挖方段防冻处理深度设计等防冻措施的采用有实际意义.

Abstract:

According to the filed frost damage investigation,frost heaving test and moisture migration simulation test,this paper describes results from filed and experimental data that investigated the reason and factors affecting freeway subgrade frost damage in seasonally frozen ground region.The results of field observation and the test series are compared to discuss the relationship of frost damage and water content,the origin of water on frost damage,the characteristic of water translocation and the road frost boiling caused by the lime-ash-soil deterioration of the subbase.Furthermore,by virtue of comprehensive study of this project,the distribution data of capillary water along the height by standpipe method are combined with the change law of frost heaving radio and water content,then the effective frost damage height can be obtained.Experimental results show that the values in specification are lower than those in test in some cases,which is unfavorable for the design of the subgrade prevention frostbite and anti-freeze.These results are significant for the design of the least height of road embankment and the depth of prevention frostbite at the site of excavation.