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为进一步研究高寒冻土区路基变形破坏演化过程,以漠北公路K6+200断面处的高温高含冰量冻土区路基和K8+200断面处的低温高含冰量冻土区路基为研究对象,在路基不同部位和路基下不同深度处土体埋设温度传感器和变形传感器,研究了高纬度、高寒冻土区不同冻土条件下路基实测温度和变形演化过程及其特征。研究结果表明:在高温高含冰量冻土区,在公路建成2年后,路基下出现了明显的融化盘偏移现象,新建宽幅路基呈现出明显的横向不均匀变形特性,路基下形成了2个融化盘,其中一个明显向路基坡脚处偏移,左坡脚和路中冻土上限明显下降了3~4m,路基下原天然地表处沉降达4~9cm,而路肩处冻土上限基本保持稳定;在低温高含冰量冻土区,在保证一定路基高度的条件下,除了建成初期路基土体存在一定的变形(工后沉陷)外,由路基下多年冻土不均匀融化导致的变形很小,因此,在低温冻土区公路路基稳定性相对较好。可见,研究结论进一步阐释了高温冻土区路基、路面变形严重的成因,为高纬度、高寒冻土区路面结构抗融沉破坏设计和病害防治提供了参考,揭示了高温多年冻土区路基纵裂、沉陷等不均匀变形破坏的特征和成因,相比高温多年冻土区,在保证一定路基高度下低温多年冻土区路基具有相对良好的稳定性,这一结论对于高纬度、高寒冻土区不同冻土条件下冻土路基的设计及病害防治具有重要意义。
In order to further study the deformation and failure process of embankment in the alpine frozen region, taking the subgrade at high temperature and ice-rich permafrost zone at K6 + 200 section of Mubei Highway and the subgrade at low temperature and ice-rich permafrost zone at K8 + 200 section as research objects, Temperature and deformation sensors embedded in soil at different depths and under different subgrade sections, the measured temperature and deformation evolution process and its characteristics under different frozen soil conditions in high latitudes and permafrost regions were studied. The results show that in the high temperature and ice-rich permafrost region, two years after the completion of the highway, obvious melting disk migration appears under the roadbed. The newly built wide roadbed shows obvious lateral non-uniform deformation characteristics and the subgrade forms 2 A melting disc, one of the obvious shift to the foot of the roadbed slope, left foot and the frozen soil in the road significantly reduced the upper limit of 3 ~ 4m, the subsidence of natural subsidence up to 4 ~ 9cm, and the upper limit of permafrost at the shoulder In the low temperature and ice-rich permafrost region, under the condition of certain subgrade height, the deformation caused by the non-uniform melting of subgrade permafrost except for the initial deformation of subgrade soil (post-construction subsidence) Therefore, the stability of highway subgrade in permafrost zone is relatively good. It can be seen that the conclusion of the study further explains the causes of serious deformation of roadbed and pavement in permafrost regions and provides reference for the anti-melting and destructive design of pavement structures and disease prevention and control in high latitudes and permafrost regions. Compared with the high temperature permafrost region, the subgrade at low temperature and high temperature in a certain subgrade level has a relatively good stability. This conclusion is valid for high latitude and permafrost The design and disease prevention and control of frozen soil embankment under different frozen soil conditions are of great significance.