Model test of all the physical phenomena must be based upon the rational verification of similarity conditions between a model and a prototype. Unfortunately, however, gravitational force which cannot be modeled in a scaled model in earth's gravity is dominant in the behavior of soils and foundations. The significance of model testing has been very much limited. Use of geotechnical centrifuge in the model study reduces this limitation.
　A large scale centrifuge was installed in the Port & Harbour Research Institute (PHRI), Ministry of Transport, for geotechnical studies in the March of 1980. An
cillary equipments including various data acquisition system, photo-instrumentation system, loading equipments, and etc. were completed in the following two years. This is the largest centrifuge amoung eight geotechnical cnetrifuges existing in Japan. In the present article, outline of the similitude of geotechnical modeling, details of the PHRI centrifuge, current research projects, and scope of the future studies are described.