Verification of Scientificity and Rationality of Three Indices for Classification of Expansive Soil Filler

The three indices for classification of expansive soil used as filler was the key and core of the physical treatment technique which was a major breakthrough in expansive soil embankment engineering. Test on soil properties, strength and deformation of road performance were performed for three kinds of expansive soil in Bai-Long Expressway in Guangxi Zhuang Autonomous Region in order to verify its rationality. In terms of testing results and the new classification criteria of expansive soil used as embankment filler determined by modified CBR strength, modified CBR swelling rate and consistency, it is concluded that the indices for the three kinds of expansive soils all satisfy the requirements. Therefore, the Bai-se expansive soils can be directly used as embankment filler. Accordingly, the applicability of the three indices for classification of expansive soils as embankment filler is verified by the laboratory tests and practical projects.