A centrifuge study on the effect of the water cover on the ground motion of saturated marine sediments

Abstract

The dynamic characteristics and ground motion of saturated marine sediments in the sea area play an important role in the assessment of seismic safety and risk in geotechnical and marine engineering. Current engineering practices usually adopt a simplified approach by neglecting the effect of the overlying seawater. In the present study a centrifuge experiment is conducted to simulate the response of the ground motion of saturated marine sediments to explore the effect of the overlying water cover. Two models, one without the overlying water and the other under the overlying water are subjected to different base inputs. Their acceleration time histories, peak values and the response acceleration spectra are examined. The results of the acceleration time histories show that the seismic waveforms in the model with the overlying water are denser than those without overlying water. Overall the acceleration response spectra of the two models are considerably different and the differences are especially substantial under the base inputs of moderately high to high acceleration.