某大型哑铃型承台群桩基础与土体共同作用竖向承载变形特性数值模拟分析

Numerical analysis of interaction between group piles and dumbbell shaped cap in a super large bridge

用ANSYS对某特大桥索塔哑铃型承台群桩基础与土体共同作用进行了三维弹塑性有限元分析。利用桩土界面间水平方向位移相容,桩土界面间竖向设置双曲线本构方程的弹簧,能较好模拟竖向荷载作用下特大型群桩基础桩土间相互作用。分析结果表明,数值分析所得承台沉降与承台荷载的关系曲线、桩顶轴力分布、桩顶轴力随承台荷载变化的关系曲线,与其离心模型试验实测成果较一致。在用离心模型试验成果验证数值分析的正确性下,用其数值分析成果进一步深入分析群桩基础的承载变形特性。

Interaction between group piles and dumbbell shaped cap in a super large bridge was analyzed with ANSYS software of 3-D elasto-plastic finite element method. Spring was used in hyperbolic constitutive equation to model the pile-soil-pile interaction under the vertical load assuming consistency of horizontal displacement on the interface between pile and soil. It could be seen that the curve of settlement and load of pile, the distribution of axial force on the pile top, the curve of load on cap and axial force on the top pile obtained with numerical analysis were agreed with those measured in centrifugal model test. Bearing capacity and settlement of super large pile-cap and pile foundation were thoroughly analyzed with numerical analytical results validated by centrifugal model test.