The Experimental Study Of Frost Heave In Subgrade Of High-speed Railway In Cold Regions

The frost heave problems have been discovered in subgrade of high-speed railway in winter in north of China. The frost heave of soil ocurred in high-speed railway that the uneven deformation have been emerged, thus the normally and safety operation of high-speed railway was seriously affected.The high-speed railway in cold regions as the background of this paper, combining the geology and weather characteristics of the line, the main reasons that the frost heave occurred in subgrade was analyzed and the frost heave ratio was introduced as the main index to evaluate the frost heave.In this paper, the study objects were the different components of the subgrade (subgrade filler, bedrock and surface graded gravel), and determined that the main frost heave amount emerged in graded gravel in surface layer of subgrade. The construction technology that remediation the deformation of subgrade was investigated and the frost heave and stability of graded gravel after grouting.In this paper, the frost heave of anti-frost filler was investigated, and the frost heave of filler meet the requirement; the water absorption, frost heave of bedrocks was studied, and analysis the influence of strength of bedrocks in freezing-thaw cycles; the main factors that affect the frost heave of graded gravel in surface layer was studied and discovered the frost heave in different moisture content, fine content and porosity.The graded gravel was improved by grouting in laboratory test, and the permeability, frost heave and the stability in freezing-thaw cycles and dry-wet cycles of graded gravel were investigate after grouting. Based on laboratory test, the process of grouting improvement was studied by model test, and the grout ability of slurry, the feasibility of grouting and process of grouting was determined, and provide a reference for field trail of grouting.