The BeiHei Black Highway Island Permafrost Degradation Effect On Subgrad Stability Research

With global warming, permafrost degeneration. Frozen soil on highway project affects the stability of engineering disease research has become a hot and difficult, and people pay more attention to. In Heilongjiang province of China the small northern Xingan mountain area, part of the low-lying Valley swamp and river valley terrace shady areas, there are a large number of island permafrost distribution. The North black expressway research sections K161+420Island permafrost is belong to the ancient glacial depositional remnants, the moisture content in peat layer:this layer with high formation temperature, fast heating, the thermal characteristics of strong interference sensitivity. The permafrost melts, soil mechanical parameters change greatly, is extremely easy to thaw, thawing and strong thaw collapse of geological disasters, to this area highway construction has brought great difficulties.This paper relies on the" melting permafrost and landslide section of highway roadbed widening project technology on the stability of subject study", K161+420section in permafrost degradation trend as well as the permafrost degradation on subgrade stability influence. First research on North black expressway along the natural geographical conditions and the permafrost area distribution characteristics, research leading to the permafrost degradation factor. According to the survey and drilling results, draw out the North black expressway K161+420section geological profile, visually presented the study section of soil layer distribution. Then through the indoor test of soil, the soil physical parameters and permafrost to melt the soil mechanical parameters. Based on the test data, calculate the permafrost degraded gradually until all the melting process of frozen soil, phase transition, from soil compression properties change and soil elastic modulus change two calculation method, calculation of permafrost degradation leads to Subgrade deformation. As the permafrost area highway engineering design, construction, maintenance work provides a theoretical basis.