多年冻土路基不均匀变形成因分析

Cause Analysis on Uneven Deformation of Embankment in Permafrost Regions

为了给多年冻土区公路路基病害的防治和冻土路基的设计、施工与养护提供参考,以漠北公路工程为依托,通过理论分析和现场监测对多年冻土区路基不均匀变形状况及成因进行了分析,并得出路基内部不均匀变形随时间的发展规律,探讨了路基不均匀变形的成因。结果表明:多年冻土区高等级宽幅路基横、纵向均存在明显的不均匀沉降变形,变形主要发生在暖季,而在冷季基本保持稳定;在运营初期,路基变形整体上随运营时间的增加呈缓慢增加的趋势,早期路基变形主要为路基下原天然季节活动层压缩变形,且以整体变形为主;随着运营时间的增加,路基工程活动对其下部多年冻土的影响开始逐渐显现,部分路段(尤其是高温多年冻土路段)多年冻土层开始出现不均匀融化,从而导致路基不均匀融化下沉加剧。

To provide a reference for the disease prevention,design,construction and maintenance of permafrost embankment,the uneven deformation status and causes of embankment in permafrost regions were analyzed by theoretical analysis and field monitoring with Mohe to Beijicun Highway as the study object.The uneven deformation law of embankment over time was obtained and the cause of uneven deformation was discussed.The results show that uneven settlement deformations in horizontal and vertical directions for the high-grade wide embankment in permafrost regions are obvious.The deformation occurs mainly in warm season,while it stays stable in cold season.Overall the embankment deformation increases slowly with the increase of operating time in the early operating time. The early deformation mainly presents the compression deformation of original natural season activity layer below the embankment.The main form of embankment deformation is integral deformation.The effect of embankment engineering activity on lower permafrost gradually appears as the operating time increases.Uneven thawing appears especially in the high temperature permafrost region,which causes the aggravation of uneven thawing settlement.