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.

摘要

珊瑚砂中桩基及上部结构的抗震安全性值得关注。为了探索地震期间珊瑚砂-桩-上部结构的特殊动力相互作用，使用快速拉格朗日连续体分析 (FLAC3D) 建立了完全非线性的 3D 数值模型。采用磁滞阻尼来表征珊瑚砂的特定应力应变关系和剪切模量衰减。结果表明，增加桩径可减少上部结构沉降，但会增大桩及上部结构的弯矩。具体来说，当桩半径从0.05 m增加到0.25 m时，上部结构沉降减少了30.0%，而桩和上部结构的弯矩平均分别增加了993.9%和29.5%。虽然当珊瑚砂渗透率增加时，超孔隙水压力比减小，但桩弯矩随着渗透率的增加而增加。珊瑚砂抗震时应考虑有效平衡上部结构沉降、桩弯矩和珊瑚砂液化。