ABSTRACT
The first use of lightweight treated soil as a ground material in the history of port or airport construction projects in Japan was for quaywall improvement work in the Port of FushikiToyama in 1992 [1],[2]. The quaywall was a wharf type structure, but during the nearly 30 years since its construction, the corrosion of its steel pipe piles and steel sheet piles had caused it to deteriorate to such a degree that it could no longer satisfy the allowable stress during an earthquake. Therefore, as shown in Figure 6.1, the quaywall was reconstructed and air foam treated soil was used as a backfill material in one part of the reconstructed section. This material was used in order to reduce the earth pressure behind the quaywall and to secure the stability at the front of the quaywall under the action of waves. It was a small-scale work with only approximately 900 m3 placed. Photograph 6.1 shows a view of the placing. Approximately one year after the construction, some specimens were sampled to study its density and strength. The results showed that the strength and density satisfied the design conditions, as shown in Figure 6.2, thus verifying the applicability of the method.
