Tapered piles have superior benefits over traditional cylindrical piles in resisting axial and lateral loads, being an economical alternative to cylindrical piles. When designing the tapered pile in soft or liquefiable soil, it is necessary to identify its buckling strengths. Notwithstanding, the buckling analysis of tapered piles considering nonlinear pile-soil interactions with geometric imperfections under combined loads has not been well established. This paper presents a non-prismatic beam-column element for nonlinear buckling analysis, considering nonlinear pile-soil interactions, combined external loads, and geometric imperfections, to robustly and efficiently simulate the buckling response of tapered piles. Unlike the discrete-spring stepped element (DSSE) model using an approximate stepwise modeling approach, analytical expressions for considering the axial and flexural rigidity of tapered section members are derived in the proposed element formulations to explicitly model the tapered sections. Several examples of buckling analysis are provided to validate the accuracy and efficiency of the proposed method. Parametric studies are performed to investigate the influences of Young’s modulus, taper ratio, initial geometric imperfection, and horizontal load on the buckling behavior of tapered piles with different boundary conditions. The critical buckling load of tapered piles is found to increase with increasing Young’s modulus and decreasing initial geometric imperfection and horizontal load. An optimal taper ratio of the tapered pile can be determined to carry the maximum axial load.

锥形桩在抵抗轴向和横向载荷方面比传统圆柱桩具有优越的优势，是圆柱桩的经济替代品。在软土或可液化土壤中设计锥形桩时，必须确定其屈曲强度。尽管如此，考虑到非线性桩土相互作用和组合载荷下几何缺陷的锥形桩屈曲分析还没有得到很好的建立。本文提出了一种用于非线性屈曲分析的非棱柱梁柱单元，考虑了非线性桩土相互作用、组合外部载荷和几何缺陷，以稳健有效地模拟锥形桩的屈曲响应。与使用近似逐步建模方法的离散弹簧阶梯元件 (DSSE) 模型不同，考虑到锥形截面构件的轴向和弯曲刚度的解析表达式是在所提出的单元公式中推导出来的，以明确地模拟锥形截面。提供了屈曲分析的几个例子来验证所提出方法的准确性和效率。进行参数研究以研究杨氏模量、锥度比、初始几何缺陷和水平载荷对具有不同边界条件的锥形桩的屈曲行为的影响。发现锥形桩的临界屈曲载荷随着杨氏模量的增加和初始几何缺陷和水平载荷的减小而增加。可以确定锥形桩的最佳锥度比以承受最大轴向载荷。