DYNAMIC MODEL TESTS IN CENTRIFUGE OF QUAY WALLS MODELING K-VALUE INCREASED BY GROUND IMPROVEMENT

Abstract

 In recent years, dynamic numerical analyses are often used to design harbor structures subjected to earthquakes. In the analyses, the ground improved by the sand-compaction-pile method (SCP method) causes excessive deformation. On the other hand, the SCP-improved ground has not been reported on damage in the past earthquake, and it demonstrates the improvement effectiveness. The reason for the difference between this calculation and the real phenomenon would be that the stress state of the SCP-improved ground, which was a composite ground of sand piles and ground, was complicated and difficult to evaluate. It is difficult to properly model the state in analyses. Especially, the increase of the static earth pressure coefficient K-value, which was confirmed on the actual modified ground, is not considered in the current analyses. In this study, the K-value increase was reproduced in the ground behind the caisson in centrifuge model tests, and the improvement effectiveness was examined. As a result, high improvement effectiveness could be confirmed by taking into consideration the K-value increase in addition to density increase.