本文通过对多年冻上区冻上特性、冻上现象及其危害性的阐述.以青藏线部分地段选线实例为依据，重点说明线路通过多年冻上不良地质地段时，地质选线的重要性

The paper expounds the characteristics of frozen soil，the phenomenon of frozen soil and its harmfulness in the multi-year tundra. Based on the practical examples of route selection in partial section of the Qing-Zang railway line，the importance of geologic route selection arc explained emphatically during the railway line passing through the harmful geologic section in the mulit-year tundra of Qing-Zang railway line.