Influence of Centrifuge Test Soil-Container Friction on Seismic Sheet-Pile Wall Response in Liquefiable Deposit: Insights from Numerical Simulations

As part of the LEAP (Liquefaction Experiments and Analysis Projects), many centrifuge model tests on a sheet pile retaining wall were conducted at six different centrifuge facilities around the world. Each centrifuge facility used containers of different W/H (width of container/height of wall) ratios to model the same plane strain prototype retaining wall. Predictions of the centrifuge tests that neglected wall friction, assumed plane strain conditions, and used the CycLiq constitutive model, exhibit reasonable general agreement with tests in terms of liquefaction response. However, an overprediction of the median response of sheet pile wall displacement was observed. The study presented in this paper was motivated by a concern that friction on the side walls might be biasing results from model containers with different W/H. A numerical simulation parametric study using FLAC3D is presented to illustrate the potential effects of interface friction and container geometry on the LEAP retaining wall test results. The results show that incorporation of appropriate container geometry and soil-container friction can reduce the error between simulated and experimental sheet pile wall displacements. Soil-container friction is also shown to affect the total earth pressure and especially its distribution on the sheet pile wall, causing the actual tests to deviate from the intended plane strain conditions. For the assessed liquefaction related cases, soil-container friction has the additional effect of significantly restricting the local development of excess pore pressure and subsequent soil deformation, further contributing to its influence on the centrifuge tests. The parametric study indicates that an interface friction angle of 17.6° and W/H>1, 2, and 3 reduced horizontal wall displacements by 50%, 20%, and 10% respectively, compared to simulations neglecting wall friction. Use of containers with large W/H is therefore recommended for future centrifuge experiments.