Case studies of lightweight treated soil method in seaport and airport construction project

A lightweight treated soil (LWTS) method has recently been developed to reuse dredged soils as an artificial geomaterial, the density of which ranges from 1.0 to 1.2 g/cm(3) for coastal construction projects. There are two types of lightweight soils, foam-treated soil and bead-treated soil. The slurry of dredged soil or waste soil is mixed with cement and air foam, or cement and expanded polystyrol beads, respectively. Since 1996, LWTS has been applied to several seaport and coastal airport projects in Japan. The slice method was developed to calculate the earth pressure at earthquake when LWTS is used as a backfill of quaywall. In this paper, four cases of field application in Kobe Port, Kumamoto Port, Ishikari Bay New Port and Tokyo International Airport were presented, where lightweight soil was used to reduce the earth pressure or consolidation settlement.