Abstract: Based on the ground temperature and deformation of the embankment with thawed interlayer at the monitoring sections of P32 and P33 along Qinghai-Tibet railway from 2005 to 2015, artificial permafrost table, maximum seasonal frozen depth, thickness of thawed interlayer and annual process of the ground temperature nearby artificial permafrost table are analyzed. Meantime, annual process of the total settlement of left and right shoulder at P32 and P33 sections, the effect of ground temperature at the left shoulder on deformation at P32 section and the effect of ground temperature difference at the left and right shoulder on its difference of settlement at P33 section are investigated. The results indicate that: at P32 and P33 sections, artificial permafrost table of left shoulder descended annually, maximum seasonal frozen depth remained nearly constant, thickness of the thawed interlayer thickened and the ground temperature nearby artificial permafrost table increased annually; during the monitoring period, the left and right shoulder deformation all performed mainly settlement and its magnitude at P32 section was smaller than at P33 section. Moreover, at P32 section, left shoulder settled during warm season and frost heave occurred slightly during cold season. The occurrence of settlement and frost heave lagged the variation of the ground temperature. The temperature difference can lead to differential settlement under left and right shoulder at the monitoring section of P33, and its value increased annually.

Key words: Qinghai-Tibet railway, permafrost, thawed interlayer, stability of embankment