Study On The Key Technology Of Red Clay Subgrade Filling In Hunan

Red clay is a kind of special roadbed filling material.With high natural water content, poor water stability and many other bad properties. In addition, it is difficult to reach the heavy compaction standards, which make it a poor engineering soil when in subgrade filling. Red clay is widely distributed in the west of China, such as Guizhou, Hunan, Guangdong, Guangxi, Yunnan and many other places, with a total area of about 200000 square kilometers.Abandon this kind of adverse soil and replac it with other good roadbed filler need new requisition of spoil ground and soil. With environmental protection requirements continue to improve, simple ways to waste replacement will become less viable, make full use of adverse soil subgrade is inevitable trend of the development. In order to save the cost of construction, ensure the red clay subgrade construction quality, this paper carried out the research on red clay subgrade.The main contents of the study include:1.In the summary of numerous scholars studies in the foundation,and through the red clay soil sample soil test, The physical and mechanical properties and pavement performance of red clay were studied, discovered that the red clay has a better compaction, higher strength and so on. Wet method is more consistent with the actual construction process.The higher CBR value and better water stability can be obtained under higher water content, which can improve the construction quality of roadbed2.Experimental studies on compressive properties of cement modified red clay were carried out with the support of the project. Obtained the compressive properties of red clay and modified red clay under different conditions.Results show that the compression properties of red clay and its water sensitivity were significantly decreased.3.Through analyzing the compression law of improved and non-improved samples under different degrees of compaction and evaluating the compressibility of the sample by its compression coefficient, found that soil sample from S18 is medium compression soil while S19 is medium-high compressibility soil.,after improvement, soil sample from S18 become low compression soil and S19 medium compression soil.4.The influence of moisture content, mechanical combination and thickness of uncompacted layer on the compaction degree of subgrade is studied through the field test, which optimized the construction process, ensured the main parameters and put forward the controlling indexes and methods of red clay construction quality.The research results obtained in this paper guided the construction of red clay subgrade filling and have an important engineering reference value.