不同变截面桩竖向承载特性的数值分析

基于现场试验，采用Abaqus有限元软件对等截面桩及变截面桩单桩竖向承载力测试实验过程进行数值模拟。结果表明:弹性变形阶段，竖向荷载-沉降曲线呈线性变化趋势，等截面桩比变截面桩桩身沉降较小；塑性屈服阶段，等截面桩与变截面桩单桩承载力几乎一致。变截面位置对桩侧摩阻力沿深度的分布有一定影响，最大侧摩阻力位置根据变截面的位置而变化。变截面桩的平均侧摩阻力较等截面桩的平均侧摩阻力大，变截面桩侧摩阻力效果较等截面桩更有优势。在相同承载力条件下，变截面桩所耗费的材料较等截面少，对于竖向承载特性，变截面桩与等截面桩表现基本一致，因此使用变截面桩能节约工程成本。

Experimental Analysis of Vertical Bearing Characteristics of Piles with Different Variable Sections

The numerical simulation of the experiment process of the vertical bearing capacity of single pile with constant section and variable section was performed with Abaqus finite element software based on field test. The results indicated that the vertical load-settlement curve shows a linear trend at the elastic deformation stage，and the settlement of constant section pile of the constant cross-section pile is smaller than that of the variable section pile. In the plastic yield stage，the bearing capacity of single variable cross-section pile is almost same with that of constant cross-section pile. The position of variable section has influences on the distribution of lateral friction along the depth，and the position of maximum lateral friction varies with the position of variable section. Compared with the constant section pile，the average lateral friction of variable section pile is larger than that of constant section pile，and the variable section pile exhibits more advantages than the uniform section pile in the aspect of exerting the effect of lateral friction. Under the condition of the same bearing capacity，the variable section pile consumes less material than the constant section pile. For the vertical bearing characteristics，the variable section pile performs nearly the same as the constant section pile. Thus it is concluded that the use of variable section pile can save the construction cost.