兰新铁路路基冻结过程中水分迁移及冻胀规律试验研究  

Experimental Study on Water Migration and Frost Heaving Rules during the Freezing Process of Subgrade in Lanzhou-Xinjiang Railway

作　　者：夏琼[1] 窦顺 赵成江 

机构地区：[1]兰州交通大学土木工程学院,甘肃兰州730070 [2]中铁西北科学研究院有限公司,甘肃兰州730000

出　　处：《中国铁道科学》2012年第5期1-7,共7页China Railway Science

基　　金：铁道部科技研究开发计划项目(2008G014)

摘　　要：通过室内冻胀试验,研究兰新铁路路基冻结过程中水分迁移和冻胀规律。结果表明:冻结后,封闭系统下试样上部含水率增大,且随初始含水率增大而增大,压实度对其影响较小,而下部含水率减小,中部含水率基本不变;开放系统下试样上部和下部的含水率均增加较多,且随压实度的增大而减小,中部含水率增加最少,但随压实度的减小和初始含水率的增大而增大。封闭系统下,试样的冻胀率随初始含水率的增加和压实度的减小明显增加,开放系统下各试样均会发生特强冻胀。兰新铁路路基基本处于封闭系统,其起始冻胀含水率在塑限附近,冻结过程中约有6.3～53.6mm的冻胀量,且极易发生严重的春季融沉病害。单纯采用增大路基压实度的方法不能有效整治路基冻融病害,而采用疏干排水孔群放软式透水管方法,可有效地隔断水分迁移的通道,并使融化水排出路基本体外,能有效整治路基冻融病害。兰新铁路K411+326里程路基采用该措施后,路基的平均最大冻胀量从38mm降至仅有2mm左右。The rules for water migration and frost heaving during the freezing process of subgrade in Lanzhou-Xinjinag Railway were studied with indoor frost heaving tests. Results show that, after freezing in closed system, water content in the upper of sample increases, which increases with initial water content and is little affected by compaction degree. Whereas, water content in the bottom of sample decreases and water content in the middle of sample almost remains unchanged. In open system, after freezing the water content in the upper and the bottom of sample increases more and decreases with the increase of compaction degree. The water content in the middle of sample increases the least and increases with the decrease of compaction degree and the increase of initial water content. In closed system, the frozen-heave factor of sample increases obviously with the increase of initial water content and the decrease of compaction degree. In open system, all samples have experienced extra-heavy frost heaving. Lanzhou-Xinjiang Railway subgrade is generally in closed system, and its initial frost heaving water content approximately equals to plastic limit. There are about 6.3~53.6 mm frost heaving amount during the freezing process of subgrade, which is liable to arise severe thaw settlement disease in spring. The freeze thawing disease of subgrade can not be treated effectively by increasing the compaction degree of subgrade alone. With the method of soft penetrated pipes in drain holes, the water migration passageways can be effectively separated and the thaw water can be drained out of subgrade body, so the freeze thawing disease of subgrade can be treated effectively. At K411+326 section of Lanzhou-Xinjiang Railway subgrade, after this treatment measure being taken, the average maximum frost heaving value is reduced from 38 mm to only 2 mm.

关 键 词：路基 冻土 水分迁移 冻胀率 

分 类 号：U213.14[交通运输工程—道路与铁道工程]