(1. State Key Laboratory of Frozen Soil Engineering，Cold and Arid Regions Environmental Engineering Research Institute，
Chinese Academy of Sciences，Lanzhou，Gansu 730000，China；2. University of Chinese Academy of Sciences，
Beijing 100049，China)
Abstract：To analyze the stability of Qinghai—Tibet Railway(QTR) which was constructed on the slopes with rich moisture and high temperature in permafrost regions，a test section of traditional slope subgrade in K1139+940 of QTR was seleted to monitor temperature and deformation. A coupled heat-moisture-deformation model was used to simulate the influence of seepage on temperature and deformation of subgrade with the finite element method. The results showed that the temperature difference between the shady and sunny slopes was marked and the annual mean temperature at the depth of 0.5 m in the sunny slope could be over 2.5 ℃ higher than that in the shady slope. At the early operation of QTR，the artificial permafrost table moved downward and the ground temperatures rised under the left shoulder，and opposite under the right shoulder. The temperature difference between the shady and sunny slopes led to the uneven settlements transversely. Seasonal water flow in active layer had more remarkable effects on the temperature and deformation of the sunny slope than those of the shady slope. Moreover，water flow accelerated the warming and subsiding process of subgrade and intensified the asymmetrical distribution of thermal regime and deformation regime in subgrade. The ice-rich layer under the embankment will thaw completely and the maximum lateral deformation difference will be 18cm in 50 years after the constuction. The settlement due to thawing and compression of ice-rich layer and high temperature permafrost will dramatically reduce the stability of the subgrade slope.The effect of seepage on the thermal and deformation regimes should not be neglected for the subgrade slope with rich moisture and high temperature in permafrost regions.
2016, Vol. 35 
