Study of the factors influencing the thickness of residual thawed interlayers and cooling effect of block-stone embankment

There exists a great amount of residual thawed interlayers along the Qinghai-Tibet Highway (QTH). The unfrozen residual thawed interlayers would result in embankment diseases, such as thaw settlement and wave etc., which exert threat on the highway safety. In this study, based on the drilled information and monitored ground temperature data from Kunlunshan-Wudaoliang section along the QTH, the relationship between the thickness of residual thawed interlayers and mean annual ground temperature and embankment height were analyzed. It is found that the thickness of residual thawed interlayers increases with mean annual ground temperature, and decreases first and then increases with embankment height increasing. Block-stone embankment can help to protect the permafrost beneath it and to decrease the residual thawed interlayers. In order to prove the effect of block-stone embankment, some experiments of block-stone embankment were conducted in Wudaoliang section along the QTH. According to the monitored ground tem