The proposed Nanning outer ring expressway crosses the distribution area of expansive soil

the stability of cut slope is difficult to be ensured if using rigid retaining; while the design method of replacement will to considerably increase the construction investment and seriously damage the ecological environment because more than 2.4 million cubic expansive soils will be abandoned. Therefore

the new treatment technology of expansive soil is discussed. The feasibility of building expansive soil sabgrade by the physical treatment technique is demonstrated through the series of soil and filler quality tests. The stability of cut slope by implementing flexible support is analyzed by the fast Lagrangian Analysis of Contihu(FLAC) and limit equilibrium method. Based on the laboratory tests and theoretical analysis and referenced the successful research experience of West China traffic of expansive soil project

two methods of the treatment with the characteristics of “enveloping and wrapping” for Nanning expansive soil subgrade and design of flexible supporting for cut slope under different boundary conditions are proposed

so as to provide the basis for the rational use of Nanning expansive soil

and for the construction of highways with a low-carbon and environmental mode