Centrifuge modelling of sand embankments and islands in earthquakes

The bumpy road shaking table system at the Cambridge geotechnical centrifuge was used to conduct an experimental investigation into the effects of earthquakes on sand embankments and islands. The results of the study show that, when a loose or medium dense embankment or island is subjected to an earthquake, positive pore pressures are generated, particularly at the crest. This pore pressure generation softens the embankment and lowers its resonance frequency, resulting in liquefaction and decoupling of surcharge motions from crest motions in the extreme case. When a dense embankment or island is subjected to a strong earthquake, spiky acceleration records are observed at the shoulders of the embankment or island. These records may be attributed to the propagation of dilation fronts through the sand which is in a state of cyclic mobility. If a rigid surcharge is present on the crest, the interaction of the embankment or island with the rigid surcharge gives rise to surcharge accelerations which are charact...