Study On Design And Construction Technology Of Red Clay Subgrade In Southern China

Red clay distributed mainly in the south China, such as Guangxi, Guizhou, Yunnan, Guangdong and Hunan provinces, the total exposed area of more than 20 million square kilometers. Red clay is a special kind of filling material in raod,and with high moisture content, high liquid limit, high plasticity, high void ratio, and other special Engineering Properties, and compaction difficult in Construction of Subgrade. Coupled with more rain in the south, red clay subgrade strength and stability of long-term decline in wetting and drying cycles and repeated traffic loaded,and subgrade produce a variety of diseases. Currently ,the use of red clay embankment construction technology is still not perfect, and in the follow-up among highway construction, there will be a lot of red clay road technical aspects. Therefore, the use of red clay subgrade, how compaction and construction,are both will require further study. It will provide a basis for the design and construction for future highway construction area of red clay ,but may also can improve project quality, reduce project cost and reduce the ecological environment destruction. Therefore, with great economic and social benefits.In the summary numerous scholars study in the foundation,and through the red clay soil sample soil test, the relevant experimental design, discovered that the red clay has a better compaction, higher strength and so on. Wet method is more consistent with the actual construction process, at higher moisture content and ensure that cases of Subgrade compaction, to obtain a higher CBR value, good water stability, can improve the quality of roadbed construction; Wet and dry cycle can cause structural damage of the red clay, and causes the roadbed intensity and the stability drops, causing Red Clay is the main disease, it is primary cause that Creates the red clay roadbed plant disease. Proposed the classification system of red clay-filler, the Filling Method of red clay roadbed, the construction craft and the construction quality control of red clay roadbed.Classification of red clay filler which indicators include: water sensitivity, strength, compressibility, swelling, particle analysis and consistency; Red clay roadbed principle of design: First, to improve the subgrade soil properties and compaction characteristics. Second, to ensure that the requirements of compactness of road shoulder,to lower the evaporation of soil water content in edge. Third, to separate the impact of water on the subgrade ,to reduce wetting and drying cycle, to ensure embankment stability. the most important is control water rate (consistency) of compaction, and select the appropriate compaction process, and distinction classification of filler,and do well roadbed drainage and anti-cracking measures in the red clay roadbed construction.