ABSTRACT
Liquefaction-induced settlement is continuing to be a cause of significant damage in earthquakes across the world. Research is currently ongoing at the University of Cambridge to investigate the effect of the presence of a basement structure on a building sited on liquefiable soil. The inclusion of basements can provide uplift forces during the liquefied period thereby reducing overall settlement of the structures. During the dynamic centrifuge tests conducted, oscillations of excess pore pressure ratio (r u ) with peak values notably greater than one were recorded. The pore pressures generated resulted in the soil body no longer being in vertical equilibrium, and the resultant vertical accelerations were calculated using the data obtained from the pore pressure transducers. These were found to be in close agreement to the vertical accelerations measured by piezoelectric accelerometers orientated vertically in the soil body. Whilst liquefaction was found to cause horizontal accelerations to be progressively attenuated, vertical accelerations were found to be amplified. It should become common practice to measure vertical accelerations in the soil body in liquefaction problems being investigated using dynamic centrifuge testing.
