Study Of Design Methods On Special Subgrade Of Expressway For Permafrost Regions In G214 Highway

G214 has become an important Material supply channels for the yushu country reconstruction after the earthquake which magnitude reach to 7.1stroke.In order to support development of Tibetan areas in Qinghai Province, and guarantee the Astigmatic materials are able to transport into disaster area, our government planning and design the G214 expressway which between the Gonghe to Jiegu. The expressway will pass through the vast permafrost region, and currently there is no construction precedent in permafrost regions of expressway.In order to provide design director for G214 highway in permafrost regions, for one thing, it need to make a survey of e current permafrost distribution by the methods like drilling or geophysical prospecting at the important sections of permafrost;Secondly analysis the reason of diseases in G214 permafrost regions, by summarized disease conditions of G214 highway, through the methods as site investigation and exploration at the key sections; Finally, presented reasonable solution for subgrade design of high-grade highway in G214 permafrost regions, through summarized the principle, application effect, advantages and disadvantages of current treatment measures of special subgrade in permafrost regions, which including fill subgrade, insulation materials, thermal pipe subgrade, replace railway by bridge and so on.According to the research, the ground temperature of permafrost is somewhat warmer and this kind of permafrost belongs to high-temperature of permafrost regions and degradation seriously.The melting permafrost under the subgrade had result in differential settlement of subgrade, which caused the disease of pavement, The research recommended the metal bellows culvert in permafrost regions, which excellent ability of fitting deformation are able to reduce the culvert disease rate. This paper draw up basic principles and control indicators of subgrade design for G214 in permafrost regions, and draw up some treatment design for subgrade in different type permafrost regions, to guiding the design of expressway in G214.