Numerical study on the effect of rotation radius of geotechnical centrifuge on the dynamic behavior of liquefiable sloping ground

For a small-size geotechnical centrifuge, it is well known that a uniform gravity field, which is position independent, cannot be achieved in a model ground due to finite lengths of rotating radius: a gravity field in the centrifuge becomes radial. However, little works have been done related to the radial gravity effect on seismic responses of the model ground. This paper presents finite element simulation results for dynamic centrifuge model tests of a liquefiable sloping ground conducted at two centrifuge facilities having different small-radial arms with the shaking direction being tangential to the axis, aiming to show the importance of considering the radial gravity effect in numerical simulation. The simulations are performed in the centrifuge model scale by using a strain space multiple mechanism model; the radial gravity field is applied to the model ground at the stage of self-weight analyses before seismic response analyses are carried out. Comparison of the simulated seismic response with the centrifuge test results demonstrates that the experimental deformation mode due to lateral spreading during shaking is simulated with higher accuracy, particularly near the side boundaries, by considering the small-radius effect (i.e., the radial gravity field instead of the uniform gravity field) in an appropriate manner.