Centrifuge Modelling Influence of Various Integration Schemes of Retaining Walls on Seismic Behaviour Using Tilting Table Test

More than 4000 retaining walls were damaged during the Kumamoto earthquake in 2016. Among them, approximately 60% were masonry retaining walls. There are mainly two types of masonry retaining walls in Japan. One is an air masonry retaining wall, which is unfilled with mortar, and the other is an integrated stone masonry retaining wall, which is filled with mortar. In addition, there is another type of retaining wall which is filled with mortar only on its surface so that the entire masonry retaining walls are not integrated and many of this type of retaining walls were damaged during the Kumamoto earthquake. The purpose of this study is examining how the integration of retaining walls affects their earthquake resistance. In this report, in order to confirm it from the deformation behaviour during an earthquake, we modelled the different types of retaining walls and conducted centrifuge tilting experiments. A series of centrifuge model tests were carried out under 20G, where a model retaining wall ground was tilted using a tilting table, a horizontal seismic force during an earthquake was reproduced, and the deformation behaviours of different types of model retaining walls during an earthquake were confirmed. Three types of model retaining walls made of plaster were reproduced including an air masonry retaining wall which is not integrated, a simple reinforced air masonry retaining wall which is integrated only on its surface, and a gravity retaining wall.