高纬度多年冻土区漠北公路路基变形特征分析

Analysis on Deformation Characteristics of the Subgrade of MOBEI Highway in High-latitude Permafrost Regions

通过漠北公路沿线各试验段不同冻土条件和工程措施下各层土体沉降变形状况,分析东北高纬度岛状多年冻土区路基沉降变形主要发生土层部位及其破坏原因。分析结果表明:路基施工完成后早期路基变形较大,主要由工后不均匀沉降变形引起,变形主要由原天然地面下季节活动层的沉降压缩变形等引起,由于运营时间较短,由多年冻土融化引起的沉降变形很小。路基沉降变形主要发生在暖季,在冷季(11月～次年6月)路基基本保持稳定,变形很小。路基整体变形状况与冻土含冰量、冻土地温有一定的关系。高温多年冻土区比低温多年冻土区变形大。

In connection with the settlement and deformation of soil mass at every layer under different frozen soil conditions and engineering measures in the experimental sections along MOBEI Highway, the subgrade in high-latitude patchy permafrost regions in the Northeast is analyzed against the location where settlement and deformation will mainly occur in the soil layers as well as the failure causes. The analysis result shows that the subgrade is deformed to a greater extent in early period after the construction, mainly caused by uneven post- construction settlement and deformation, wherein the deformation is mostly resulted from the subsidence and compression deformation of seasonal active layers under original natural ground surface and that from thawed permafrost is small due to short operating time. The subgrade will be settled and deformed mainly in warm season, while it stays stable with small deformation in cold season （i.e. from November to June of the following year）. The overall deformation has certain relationship with ice content and ground temperature of frozen soil. The deformation in high-temperature permafrost regions is larger than that in low-temperature permafrost regions.