The Research On Physical Properties And Classification And Identification Method Of Expansive Soil In Nan Yang Region

Expansive soil is composed of a great deal of strong hydrophilic clay minerals, such as montmorillonite and illite. The study of expansive soil is one of the most complicated world subjects. The distribution of expansive soil in China is very wide, especially in NanYang, expansive soil area occupies 65 percent of the total area. Because behavior of expansive soil has not been enough identified, and which has extensive distributing, engineering accident has occurred continually, the studies on expansive soil have been increasingly noticed.The first issue during construction in expansive soil region is to determine whether the soil is of expansive behavior or not. The work is very important in Nan Yang.In this paper research on expansive specialty of expansive soil is introduced, properties of expansive soil distributing in Nan Yang has been discussed, some physical, mechanical parameters of the expansive soil in Nan-Yang are measured, specialty index of judgment and classification for expansive soil are ascertained, these three performance indexes indirectly reflect the expansion and shrink of soil, such as liquid limit, shrink limit, Swelling rates under load applying and two directly relative indexes, namely expansive force and shear strength parameter of unsaturated soil, the standard of judgment and classification are obtained, engineering practice through examples and disposal methods of foundation of expansive soil are illuminated, and advices on design and construction are put forward.The evidence of judgment and classification of expansive soil could be obtained by conclusion above.