Characteristics and Hazards of Permafrost along the Xinjiang-Tibetan Highway, Xinjiang

Permafrost is widespread developed on alpine mounds, central plateau valleys and lake basins along the Xinjiang-Tibetan Highway in Xinjiang due to high altitude, cold and arid climate and deeply loose Quaternary deposits. Permafrost distributes continuously between K306+000～K310+000 and K515+000～K705+000 with the length of 191.6Km. Most of permafrost belongs to low ice content type with characteristics of weak frozen bulge and thawing settlement, only few segments belong to rich ice content type with characteristics of medium frozen bulge and thawing settlement. The roadbed and surface are threatened by permafrost such as salivary ices, thaw settlement, frost swelling, aqueous slurry, thaw slumping, gelifluction and desertification. With highway reconstruction and hazards mitigation, the water and heat balance of former permafrost will be destroyed by highway engineering activities, degradation and hazards of permafrost become worse in near future. The designing principle of permafrost protection is put forward based on characteristics of regional permafrost,countermeasures such as avoiding permafrost, elevating roadbed height, paving thermal insulation pavement, improving drainage system, optimizing earth field and monitoring permafrost variation are put foreword to reduce destabilization and destruction by engineering works.