Three-dimensional numerical simulation of earthquake damage to group-piles in a liquefied ground

Dynamic behavior of group-piles in liquefied ground is discussed using numerical analyses. The process of damage to a group-pile foundation in reclaimed land is simulated using three-dimensional soil-water-coupled analysis with a soil-pile-building model. This study analyzed a five-story building that tilted northeastward because of serious pile damage during the 1995 Kobe earthquake. Analyses showed that the piles yielded immediately before complete liquefaction in the reclaimed layer, when the horizontal displacement of the building reached several tens of centimeters. In the early period before complete liquefaction of the reclaimed layer, inertial effects of superstructure on pile curvatures are apparent at both the pile head and at the bottom of the reclaimed layer. In contrast, after complete liquefaction of the reclaimed layer, the kinematic effect of connected footings on curvatures of piles is considerable at the bottom of the reclaimed layer.