Physical treating techniques of highway embankments filled with expansive soils

Chemical improvement is used as the main studied and recommended technique to build embankment in expansive soil areas, especially in foreign countries. However, it cannot be widely applied due to complicated technology, high requirements for construction equipments and diseconomy. On the other hand, the method of soil replacement is often adopted during the construction of expansive soil subgrades in the west areas of China, which results in serious soil erosion, damages to ecological environments along highways and greatly increasing engineering investment. Therefore, with regard to the the research program of western expansive soils of Ministry of Communications, Nanning-Youyiguan expressway in Guangxi Province is taken as the main trial section on the site, and experience of building several trial sections of embankments successfully filled with expansive soils with different types and grades of shrinking and expansion in different districts is summarized. The physical treating techniques of filling embankments with expansive soils are firstly put forward. By the site tracing monitoring of trial projects and the laboratory large-scale model tests as well as carrying out modifying tests to evaluate road performance of expansive soils, the moisture content, the strength of expansive soil fill and the stability of embankments after physical treating are analyzed and evaluated, and the rationality and effectiveness of the new technique are validated. Based on the above, the main points and methods of techniques for treating expansive soils physically are summarized and put forward, which can be referred to and applied in practical engineering projects.