Abstract
Sand compaction pile ground improvement method (SCP method) has been applied for soft clay layer beneath gravity-type quay walls in order to increase the ground stability. In the improvement method, solidified iron-and-steel slag is considered to be used as ground improvement material instead of exhaustible sand. In this study, a series of centrifuge model tests and circular slip analyses were conducted to investigate the stability of ground using iron-and-steel slag. Some types of soil materials were chosen as the improvement material for the backfill loading model tests. The model grounds using sand and slag showed the same ground deformation mode to the failure state. In addition, the displacement in the slag case was found to be smaller than that in the sand case.