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Abstract In order to study the early stage effects of thermal insulation berm on embankment temperature field of widen embankment，the ground temperature near permafrost table and the change process of permafrost table are analyzed according to observation data of the insulation berm test road along the Qinghai—Tibet highway. A numerical simulation model is established for widen embankment and the early stage effects of insulation berm on permafrost，the thermal stability of permafrost under the shoulder after embankment widening are calculated. Results show that the degradation of permafrost under the berm in sunny slope is accelerated by berm itself，this influence in warm permafrost regions is greater than that in cold permafrost regions and the insulation berm in shady slope has less effect on the thermal stability of permafrost. The pre-melted effect is brought by berm in sunny slope，and the permafrost table under the shoulder does not have significant decrease after embankment widening，which shows as pre-widening effect and it is beneficial to stability of widen embankment. The berm in shady slope has less effect on widen embankment，regardless of whether the insulation berm，the permafrost table change process have less difference after embankment widening.
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Received: 28 November 2012
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2014, Vol. 33 
