Study On Soil Strength Indexes And Its Test And Analysis Method Of Highway Embankment

With rapid development of communications industry in China, traffic volume of expressway and axle load of vehicle increased speedily. As a result, the requirement on subgrade strength and quality improved gradually. However, the examination methods for different strength indices are not compatible generally at present and conversion formulas among them are absent. Therefore, subgrade strength analysis only can be done by single index, which has limitation to some extent, and it is difficult to evaluate subgrade strength comprehensively. Actually, the tester for some targets is extremely large and testing work is very hard. Hence, it has great significance on projects and will bring potential benefits to study on how to find value of subgrade strength indices and relationship between each index.In this paper, the author studied on expressway subgrade with a research task about subgrade construction technology, which is used at special section covered with red sandstone in Xiangtan-Leiyang Expressway and belongs to key tasks in Ministry of Communications during the Ninth-Five Year Plan stage. Firstly, the author made analysis about subgrade earth deformation property and impacting factors, probed into strength theory and relationship between stress and strain on the basis of existing research outcome home and broad. Secondly, discussed roundly about different examination methods and their limitations, collected and analyzed a lot of tests information and records from expressways construction sites in Hunan Province. Then, established conversion formulas between some indices such as earth resistance, dense, loading capacity, CBR, resilience modulus, rebound deflection, compactness etc. And finally, improved examination method and calculation way of CBR test and falling weight test in site, found effective coefficient C for class 1 and class 2 red sandstone on the foundation of research work at trial red sandstone section in Xiangtan-Leiyang expressway.The base of this paper's study work is a great deal of experiment data collected from site, consequently, the results connected with projects closely and could be referenced by design and research departments for their work on expressway in Hunan Province and similar section.