Twenty nine years of experience with physical modelling of geotechnical problems in port structures

At present, centrifuge model testing has become an important tool for investigation of complex geotechnical natures. In 1980, the Port and Harbour Research Institute (PHRI) constructed the Mark I geotechnical centrifuge, whose effective radius was 3.8 m. Since then, the PHRI carried out many tests on fundamental and practical research projects. Unfortunately, since 1989, undesirable vibrations of the concrete pit floor had frequently occurred during the operation of the Mark I centrifuge. Therefore the maximum operative acceleration had to be limited below 50 g for safety reason, which in fact led to serious limitations to research projects to be studied. Consequently, the PHRI had decided to construct a new centrifuge, namely the Mark II. Based on the statistical studies on the actual operation, the major dimensions and capacities of the new centrifuge was decided to be the same as the Mark I. In 1989, the PHRI had started the construction and completed in 1994. In 2001, the PHRI became an independent administrative institution in the administrative reorganization of Japanese Government, and the name of the institute was changed to the Port and Airport Research Institute (PARI). The PHRI and the PARI have conducted more than 1,300 centrifuge operations on various research subjects mainly regarding to ground improvements. Some of them were related to fundamental research topics, while the research subject also included practical research projects associated with specific prototypes. The test results have been applied and reflected to the constructions of various port, harbor and airport facilities in Japan and overseas. This report briefly reviews the summary of the Mark I and the Mark II geotechnical centrifuge facilities and the centrifuge operations experienced in 29 years. Some research subjects studied so far are reviewed to demonstrate usefulness of this modelling technique and the ability of the centrifuge facilities.