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根据京包铁路、包兰铁路路基在1月—6月期间的变形监测和路基土的级配试验,分析了季节冻土区铁路路基的冻胀变形情况及产生原因。分析结果表明,在内蒙古境内的季节冻土区铁路路基冻胀呈现整体性变形特点,但不同里程处的路基冻胀差异较大;在监测区段内,京包线路基最大冻胀率为5.2%,最小冻胀率为2.4%;包兰线路基最大冻胀率为4.2%,最小冻胀率为1.1%;路基的冻胀变形极不规则,严重破坏了路基的整体平顺度。京包线、包兰线路基填土的级配不良是引起路基冻害的首要原因;路基多年的冻害效果累积和基床土质不均导致冻胀变形不均匀发生。
According to the deformation monitoring of Beijing-Baotou Railway and Baotou-Lanzhou railway subgrade during January-June and the grading test of subgrade soil, the frost heave deformation and its causes of railway subgrade in seasonal frozen soil area are analyzed. The analysis results show that the frost heaving of railway embankment in seasonal permafrost region in Inner Mongolia shows the characteristics of overall deformation, but the difference of frost heaving of subgrade at different distance is quite large. The maximum frost heaving rate of Beijing-embankment subgrade in the monitoring section is 5.2 %, The minimum frost heaving rate is 2.4%. The maximum frost heaving rate of BaoLan subgrade is 4.2% and the minimum frost heaving rate is 1.1%. The frost heave deformation of the subgrade is extremely irregular, which seriously damages the overall smoothness of subgrade. The bad grading of filling of Beijing-Baotou line and Baolan-line embankment is the primary reason causing the frost damage of subgrade. The cumulative effect of subgrade freezing damage and uneven soil bed lead to uneven frost heave deformation.