Dynamic interaction of coral sand-pile-superstructure during earthquakes: 3D numerical simulations

Abstract

The seismic safety of piles and superstructures in coral sand deserves attention. To explore the particular dynamic interaction of the coral sand–pile-superstructure during earthquakes, fully nonlinear, 3 D numerical models were established using the Fast Lagrangian Analysis of Continuum (FLAC3D). Hysteresis damping was adopted to indicate the particular stress–strain relationship and shear modulus attenuation of coral sand. The results show that increasing the pile diameter reduces the superstructure settlement but amplifies the bending moment of the piles and superstructures. Specifically, when the pile radius increases from 0.05 m to 0.25 m, the superstructure settlement is reduced by 30.0%, while the moments of the piles and superstructures are increased by an average of 993.9% and 29.5%, respectively. Although the excess pore pressure ratio decreases when the coral sand permeability increases, the pile bending moment increases with an increase in permeability. Effectively balancing the superstructure settlement, pile bending moment and coral sand liquefaction should be considered in the earthquake resistance of coral sand.