桩基础被广泛应用于高层建筑物地基建设中，但传统方桩通常因需要抵抗竖向荷载的作用而采用大尺寸和密集布置，导致成本不够经济。鉴于此，设计了一种新的适用于高层建筑的异形截面桩，通过扩大桩与土体的接触面积来提升桩的极限承载力。基于桩基承载力理论，分析了内凹边数和内凹角度对异形桩几何特性的影响。针对异形桩在不同内凹边数和内凹角度下对竖向承载性能的影响规律开展了有限元数值模拟。结果表明，异形桩的截面周长和桩侧面积随内凹边数和内凹角度的增加而增大，达到等截面积方桩的1.01 ~ 1.78倍，其中内凹角度对截面周长的影响最显著。异形桩的截面最大惯性矩随内凹边数的增加呈现先增后减的趋势，而随内凹角度的增加持续增加。在相同内凹角度下，两个内凹边的异形桩截面最大惯性矩最大。增加桩截面的内凹边数和内凹角度可有效提升桩的侧摩阻力和极限承载力，其中极限承载力是等截面方桩的1.05 ~ 1.92倍。研究结果可为解决异形桩选型及优化设计等相关问题提供参考。

Pile foundations are widely used in the construction of foundations for high-rise buildings, but traditional square piles are often not economical enough due to the need to resist vertical loads by using large sizes and dense arrangements. In view of this, a new special-shaped pile suitable for high-rise buildings was to enhance the ultimate bearing capacity of the pile by means of expanding the contact area between the pile and the soil. Based on the theory of pile bearing capacity, the influence of the number of concave sides and concave angle of the section parameters on the geometric characteristics of the section of the shaped pile was analyzed. And the finite element software ABAQUS was used to simulate the influence of different number of concave edges and concave angle on its vertical bearing performance. The results show that the cross-section perimeter of the special-shaped pile increases with the increase of the number of concave edges and the concave angle, which is 1.01 ~ 1.78 times that of the square pile with same cross-section area, and the influence of the concave angle on the cross-section perimeter is the most significant. The maximum moment of inertia of the cross-section of the special-shaped pile shows a tendency of increasing and then decreasing with the increase of the number of concave sides, and increasing with the increase of the angle of concavity, and when the angle of concavity is the same, the maximum moment of inertia of the cross-section of the special-shaped pile with two concave sides is the largest. Increasing the number of concave sides and concave angle of pile section can effectively improve the lateral friction resistance and ultimate bearing capacity of the pile, and the ultimate bearing capacity is 1.05 ~ 1.92 times of the ultimate bearing capacity of the square pile with same cross-section area. The results of this paper can provide a reference for solving the problems related to special-shaped pile selection and optimal design.