【摘要】 基于黏弹性人工边界,建立上部结构-桩-土的共同作用三维有限元模型,分析地震作用下预应力混凝土管桩的运动响应特性。分别针对预应力混凝土管桩的桩径、双层软硬土剪切波速比值、上覆土层厚度、上部结构荷载等影响因素进行数值计算。参数分析表明:在地震作用下,桩径的增大会导致桩身整体弯矩相应增加,特别是桩身土层分界面处增大明显;软硬土层剪切波速比及上覆土层厚度的增加,引起土层分界面处桩身峰值弯矩增加;固定桩头条件下,桩头与桩身软硬土层分界面处均会产生较大的运动弯矩;上部结构的惯性荷载对固定桩头的内力有着较大影响,对桩身深处段弯矩影响较小。本文研究结论可为预应力混凝土管桩抗震设计提供有益的理论参考。更多还原

【Abstract】 During earthquakes,piles undergo stresses due to both the motion of the superstructure(inertial interaction)and that of the surrounding soil(kinematic interaction).Based on the artificial viscoelastic boundary,a 3Dnumerical model of seismic performance for superstructure-pilesoil interaction was developed to analyze the kinematic response of PHC pile(prestressed high concrete pipe pile)during earthquakes.The kinematic seismic interaction of single piles embedded in soil was evaluated by focusing on the bending moments induced by the transient motion.Considering the conditions of layered soil,factors influencing the analysis included PHC pile diameter,the ratio of shear wave velocities between two soil layers,the depth of embedded soil,and the inertial loading of the superstructure.The results indicated that pile diameter affects the amplitude of bending moments at the pile head.Specifically,at the interface between layers for a given soil deposit,the bending moment increased as the pile diameter increased,especially at the interface of two soil layers.In soil profiles where the transition between layers was distinct,the bending moments in the pile were significant,especially near the interface of soil layers with highly contrasting stiffness.The bending moment at the interface between two soil layers of soil increased when the ratio of shear wave velocities increased.An increase in the depth of overlying soil in two soil layers would also cause an increase in the pile bending moment at the interface between the two layers.The fixed head of a pile and the interface of two soil layers would increase the bending moment.The superstructure had an important influence on the bending moment of the pile head,but not for the deep section of the pile.The conclusions of this study will lead to recommended reference criteria for the seismic design PHC piles更多还原