Based on the local supervising data of air temperature decreasing period of Beiluhe testing segment of the Qinghai-Tibet Railway during the past two years

and through analyzing the ground temperature rule of the vent-pipe embankment

cast-detritus protecting slope embankment and heat preservation material embankment testing segments

and calculating the accumulating temperature of the above segments; the results show that the three engineering measures have some effects on protecting the permafrost roadbed. In some way

it can be used for reference in constructing the Qinghai-Tibet Railway in permafrost regions.