Analysis Of Roadbed Deformation In Typical Permafrost Sectors Of Qinghai-Tibet Railway

In this paper the author analyzed the monitor data of roadbed deformation and ground temperature of Qinghai-Tibet railway and concluded that the deformation of permafrost roadbed is made up of frost-heaving and the deformation of thawing-collapse of soil of seasonal thawing layer and compression deformation of frozen soil with relative higher temperature under the frost-thawing interface. Thawing and freezing process of roadbed in permafrost region and its results under the effects of different environmental temperature and permafrost temperature are the mechanics and controlling factors of the roadbed deformation. And author classified roadbed construction in permafrost region of Qinghai-Tibet railway into three types which are roadbed constructions with low environmental atmospheric temperature and ground temperature, high environmental atmospheric temperature and low ground temperature, and high environmental atmospheric temperature and ground temperature. Analysis of deformation monitor data and computer simulation show that the deformation of the roadbed at present is stable and safe and the development trend of it can guarantee the safety of the railway in the following decades. But in the sectors of simple fill roadbed and low-height roadbed the reduction of fill temperature and lifting of permafrost table are limited because of the limitation of such roadbed structure. Therefore additional measures such as thermal rod roadbed structure should be used in such sectors in order to lift permafrost table, reduce ground soil temperature and guarantee the stability of roadbed construction in permafrost region.