E-Defense Facility: A Frontier in Geotechnical Physical Modeling

Recently, a great attention has been devoted to performance based design in geotechnical engineering, and many design codes have initiated applying its concepts. As a result, estimation of deformation of structures subjected to intense loading, earthquake, is becoming more important. In this regard, physical modeling in geotechnics is a key measure to study the behavior of different structures including pile foundation and quay wall. 1-g shaking model test is one of the most common tools in the field of experimental geotechnical engineering. However, limitation of the size of model decreases its efficiency. To overcome the disadvantage of low confining stress, the world's largest shaking table, 20m x 15m, which is called E-Defense, was established in the National Research Institute for Earth Science and Disaster Prevention (NIED), Japan where full-scale tests on engineering structures including RC building, quay wall, pile foundation, and masonry house are run. This paper aims to illustrate E-Defense facility by giving an example of a full-scale test on pile group and sheet pile quay wall which was subjected to the liquefaction-induced large ground deformation. The quay wall was displaced laterally, and the pile group, which was placed behind it, was damaged extensively. Over 880 channel data of various parameters were recorded and some of the results are presented in this paper mainly on rate dependency behavior of liquefied sand.