Despite increasing interests in various aspects of expansive soil behavior such as the structure of the expansive soil

properties of expansion and shrink

treatment measures

little is known about the nature and magnitude of secondary compression of the distinct sediment. However

long-term stabilization of subgrade and underground structures as tunnel excavation promotes the study of secondary compressibility of expansive clay. The secondary compression behavior of a typical expansive soil in Nanning was investigated. A series of long-term compressibility tests were conducted. The influence of compression pressure and water content on compression index Cc and coefficient of secondary compression Ca is discussed respectively as well as the relation between Cc and Ca. Moreover

the influence of precompression or lime-added dispose on secondary compressibility is studied to seek the best measure to reduce secondary compressibility. Some useful conclusions are drawn. The relation between Cc and Ca is linear. The secondary compressibility of Nanning expansive clay appears little compared with other clays. The secondary compression can be minished effectively by precompression or lime-added dispose. Specially

the secondary compressibility of lime-added expansive soil becomes less if precompressed simultaneously.