Centrifuge modelling of liquefaction-induced effects on shallow foundations with different bearing pressures

Abstract

Liquefaction-induced effects are a major threat to shallow foundations built on saturated sand deposits, in seismically active regions. This type of structure is frequently used to support different structures, namely bridges, buildings, gravity walls, etc. Currently, there are few procedures in practice with limited scientific basis for estimation of the liquefaction-effects on foundations built on liquefiable soil. Therefore it is very important to develop more reliable predictions of the performance of shallow foundations built on liquefiable ground and, even more importantly, to develop more efficient techniques to improve that performance. This paper aims at describing a preliminary investigation carried out as part of a research project- SERIES- involving dynamic centrifuge modelling of seismic liquefaction effects and mitigation in shallow foundations. The observations from a centrifuge model test performed at Cambridge University Engineering Department’s Schofield Centre are used to evaluate the settlements of two shallow foundations applying different bearing pressures to the soil. Also, the results presented aim at evaluating the development of excess pore pressures during the seismic simulations, post-earthquake response to the high transient hydraulic gradients, and the propagation of the accelerations under the footings and free-field during the seismic motion. The results obtained enhance current understanding on liquefaction effects and provide valuable information that can be used to examine current design procedures. This will hopefully contribute to design safer and cheaper structures built on shallow foundations in regions prone to earthquake-induced liquefaction.