| Frost heaving is main problem of roadbeds of railways and roads in the frozen soil areas all the time, and it is the most important technical indexes which reflect the properties of roadbed. Especialy in the last few years, with trains speed raising, the study of frost roadbed under train loads is very important to prevent frost heaving and make sure trains operate safely. At present, the study of frost heaving of roadbed under dynamic load is hardly reported, so it is necessary to make effort to do the study. The frost heaving study of Bao-Lan railway in the paper bases on in-door experiment.First, the thesis represents conventional geotechnical test of Bao-Lan railway, and introduces natural water content, liquid and plastic limit, particle analysis, salt content and freezing temperature. Analysising the datas of water migration and frost heaving amount of fine grained soil under different water contents different cold junction temperature,different static load and dynamic load, we can draw a conclusion:First, with soil sample freezing, the water of the soil migrates once again under soil moisture tension and the water is migrating from the warm end to cold end. Second, the amount of water migration under dymanic load is more than static load, so the frost heaving under dynamic load is huger. Third, freezing rate which is controlled by cold end temperature increases with decreasing of the cold end temperature, and is hardly related to water content and load. Finally, frost heaving amount monotonically increases with water content or cold end temperature decreases, frost heaving amount is inhibited significantly by load. Although amount of frost heaving is huger under dynamic load than under static load, the frequence of dynamic load is hardly related to frost heaving.The thesis calculates frost heaving amount of experimental model by solftware ansys, the calculated results are in agreement with experiment in certain degree. The method is be helpful to forecast frost heave.
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