Analysis Of Stability Of Embankment Upon The Slope In The Extreme Instability Permafrost Area At Anduo Section Of Qinghai-Tibet Railway

Qinghai-Tibet railway advances across 550 km in permafrost area. Since embankment construction on permafrost would substantially change the heat and mass transfer balance between the ground surface and the external environment, sequentially the whole temperature field, permafrost table and the thickness of the active layer would also be changed, at the same time, non-homogeneous deformation would occurred on the different parts of the embankment. It is very important to run safely for the embankment upon slope which was constructed in high extremely temperature permafrost area and in the complex geological conditions sector.This paper is based on the field monitoring data on the Anduo Embankment, through researching the characters of ground temperature, permafrost table, horizontal displacement and analyzing different deformation of the embankment. Meanwhile, physical mechanics parameters were deduced by field and indoors test which evaluate the stability of the slope. Though applying FEM software, the stability coefficient and latent slide plane of slope embankment are simulated. Different methods indicate that stability coefficient reaches minimum on Jan. to Feb. and becomes maximum on Oct. Comparing diverse situations, it is obvious that the stability coefficient of slope embankment is maximal at the same season when geotextile is added and there is no crack. Then the climate gradually warming is considered, temperature field of ground and artificial upper limit of permafrost embankment are simulated using FEM software in 50 years. According to the upper limit, the character of deformation of embankment in 50 years also is simulated. In a word, the embankment upon the slope is safe and emergency capacity by analyzing its stability under the condition of normal run.