Insights into Settlement Mechanisms of Shallow Foundations on Liquefiable Layers

Buildings with shallow foundations form the bulk of the structures at risk due to liquefaction during a seismic event. Predictions of their potential settlement are often performed using methodologies that correspond to the free-field. However, these methods often prove insufficient, as they fail to capture the mechanisms that contribute to the settlement of a building. In an effort to offer insight regarding these mechanisms, centrifuge tests were performed, examining the seismic response of a shallow foundation on liquefiable soil. The main parameter investigated was the ratio of the width of the structure’s foundation over the depth of the liquefiable layer on which it rests. Velocity vector fields in combination with excess pore pressure distributions were used to identify settlement-generating processes. Mechanisms that are not accounted for by current methodologies, such as the mobilisation of bearing capacity and soil-structure interaction induced displacements proved to be prominent.