1--Soil Erosion Caused by Highway Construction in Expansive.pdf

Liu, Dengand Chu (eds)? 2008 Science PressBeijingand Springer-Verlag GmbHBerlinHeidelberg Geotechnical Engineering for DisasterMitigation and Rehabilitation SOIL EROSION CAUSED BY IDGHWAY CONSTRUCTION IN EXPANSIVE SOILS DISTRICTS AND ITS PREVENTION MEASURES Heping Yang, Liping Lin and Yingxi He School ofHighway Engineering, Changsha University ofScience and Technology, Changsha, China Because of special geological engineering characteristics of expansive soil, cut slopes and embankments ofexpansive soils used to be bound to damage and slide. According to Chinese Specifications for Design of Highway Subgrades, it is not appropriate to fill embankment with expansive soils, so replacing expansive soils by non-expansive materials is usually adopted, as a result serious soil erosions and damages to environments are caused frequently by highway construction in expansive soils districts. Taking Guangxi Nanning-Youyi Guan Expressway as an example, this paper analyses the influence and damages to ecological environment in the construction period of Ningming expansive soil section and introduces scientific researches and technical innovation carried out by the research group of Changsha University of Science and Technology, and how to solve the difficult problem of directly building embankment with expansive soils and develop a new environmental protection technology for stabilizing cut slopes of expansive soils. It is clearly suggested that the geological disaster problem of soil erosion caused by highway construction in expansive soils areas can only be solved by adopting effective engineering treating measures. INTRODUCTION Soil erosion is currently the greatest ecological environmental problems, and the soil erosion area all over the world is 25,000,000 square kilometers. Our country is one of the countries in which there is the most serious soil erosion in the world, and soil erosions occur in almost all provinces. The statistics in 1989 showed that the soil erosion area