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The Liquefaction Experiments and Analysis Project (LEAP) is a joint international project that pursues the verification, validation and uncertainty quantification of numerical liquefaction models. As part of this project, eight centrifuge models were developed at the facilities of Kyoto University, to simulate the dynamic behavior of a submerged, uniform-density, 20 m long, 4 m deep and 5° sloping deposit of Ottawa F-65 sand. The results are intended to compose part of a reliable database in the development of current and future V&V processes of liquefaction models. This paper presents the main characteristics of the model preparation and testing process, and an analysis of: (1) the validity of the “Generalized Scaling Law” for centrifuge modeling (2) the consistency and repeatability of the tests by means of the development of an additional repeatability-test, and numerical modelling, and (3) the importance of the viscosity of the fluid in liquefaction modelling.

Twenty-four centrifuge model tests have been conducted at nine different geotechnical centrifuge facilities around the world as part of the international LEAP effort (liquefaction experiments and analysis projects). All of the centrifuge models represent a 4 m deep 5 degree sloping submerged sand deposit. The mean effective PGA of the input motion for all of the experiments was approximately 0.15 g and the mean relative density was approximately 65%, but the effective PGA's varied between about 0.07 g and 0.3 g, and the relative densities varied between about 40% and 75%. The test matrix was designed to enable experimental quantification of not only the median response but also the trend and sensitivity of the model response to density and shaking intensity. Quantification of the sensitivity of the response to initial conditions is a prerequisite for objective evaluation of the quality of the model test data. In other words, a discrepancy between two experiments should be evaluated after accounting for the uncertainty in the initial conditions and the sensitivity of the response to initial conditions. For the first time, a sufficient number of experiments has been performed on a similar problem to provide meaningful quantitative evaluation of the trend between PGA, density, and displacement. The sensitivity is quantified by the gradient of the trend and the uncertainty of the trend is quantified from the residuals between the fitting data and the trend.