Shake Table Modeling of Pile Foundation Performance in Laterally Spreading Frozen Ground Crust Overlying Liquefiable Soils

Abstract

One of the most important lessons learned from Alaska’s major earthquakes is that lateral spread of frozen ground crust overlying liquefiable soils induced extensive bridge foundation damage. A shake table experiment was performed to study the interaction mechanisms of frozen soil-pile foundation in this scenario. Data collected from the shake table experiment were presented and analyzed. Three plastic hinges formed on the model pile: one at the ground crust surface, one at the ground crust-loose sand interface induced by strong confinement of the stiff ground crust, and one within the partially liquefied medium dense sand layer induced by laterally spreading ground crust. The failure mechanisms of single piles revealed in this experiment corresponded well with pile-pile cap connection failures observed in previous earthquakes and the frozen ground crust can be thought of as acting like a natural pile cap that restricts the rotation of the single pile head. This study provided data for computer model calibration and helped gain insight into the frozen ground crust impact on the seismic performance of piles under lateral spread induced by liquefaction.