Comparision Analysises Of Expansive Rock/soil Properties And Treatment Technologies Of Cutting Slope For Guangxi And Beijing Areas

Based on the knowledge of engineering geological characteristics, cutting slope failure properties and laws for Ningming expansive soil during the construction of Nanyou expressway in Guangxi, the flexible supporting treatment technology developed by Changsha University of Science and Technology overcome the problem of frequent landslide of expansive soil cutting slope. The generalization of this technology was performed on the Baise residual expansive soil. However, whether this technology is suitable to treat the sedimentary expansive rock/soil or not is focused by the engineers. The successful application of flexible supporting treatment technology for Beijing western sixth ring highway in 2009 was a good example for the comparative researches. In this paper, the expansive rock/soil engineering properties and flexible supporting technology of cutting slope for engineering in Baise and Beijing mentioned above were compared to generalize the new treatment technology. According to the investigation of existing relative researches, the major origin, distribution characteristics, geological properties and degree of engineering damage of Northern and Southern expansive rock/soil and the engineering treatment technology measures of expansive soil cutting slope and its effects, main advantages and disadvantages are discussed.The major differences of chemical composition, physicochemical properties and swelling-shrinkage characteristics between Southern residual and Northern sedimentary expansive rock/soils are obtained according to the field geological structure investigation, drilling sampling, engineering geology analogy and systematical laboratory testing of expansive rock/soil properties. The geological structures of expansive rock/soil in Southern areas are binary, but that in Northern areas are horizontal interlayer. Therefore, the failures of excavated slopes are different for Southern and Northern expansive rock/soils. The effective content of montmorillonite of Southern expansive rock/soil with montmorillonite/illite mixed layer mineral is less than 18% but that of Northern expansive rock/soil with mono-montmorillonite mineral is more than 40%. The engineering characteristics differences between them are analyzed.According to the cutting slope failure characteristics and the research on its development rule, the deformation, failure rule of expansive rock/soil cutting slope with different origins, climate conditions and soil properties are achieved. It is found that the differences of cutting slope failures are existed but the most cutting slope failures considerably affected by climate are shallow.Finally, the design scheme and construction method of flexible supporting treatment measures for Southern and Northern expansive rock/soil cutting slopes are compared. The new treatment measures are suitable for various expansive rock/soil cutting slopes. However, the technology scheme should change according to the specific conditions to obtain the satisfactory results.