Abstract: The experimental studies and railway operations observations of the use of modified expansive soils as embankment backfill materials in Hefei Nanning Railway project are presented in this paper. The feasibility of modified expansive soils as railway embankment backfills are studied through laboratory limesoil mixing ratio, field backfill trial test, quality assurance test and dynamic measurement and deformation observations. The embankment with modified expansive soils was minored throughout four years of operation. The results indicate that the embankment with modified materials is successfully constructed. The expansive soil modification design, embankment construction procedure and its quality assurance standard are also proposed in the paper.

Key words: Expansive Soils, Backfill Materials, Soil Modification