中文摘要：

楔形桩是一种可以有效发挥桩侧摩阻力，提高单位材料利用率的纵向变截面异形桩；然而针对其沉桩施工过程的研究却相对较少。基于PFC数值分析软件，建立楔形桩沉桩施工过程模拟的数值模型；为了对比分析，建立等体积混凝土用量的常规等截面桩沉桩施工过程模拟的数值模型；通过与楔形桩和等截面桩沉桩模型试验及圆孔扩张理论计算结果的对比分析，验证了本文所建立的数值模型的准确性和可靠性；系统对比分析楔形桩沉桩过程中桩周土体位移场、应力场以及沉桩阻力等变化规律。研究结果表明：楔形桩静压沉桩效应与等截面桩沉桩效应规律基本类似；本文数值模型条件下，楔形桩静压沉桩施工桩端阻力、桩侧摩阻力和整体沉桩阻力分别是等截面桩的1．0倍、1．82倍和1．37倍。

英文摘要：

Tapered pile is one of variable cross - section pile, which can improve the friction of pile shaft and the unit material utilization. However, there are relative little studies focused on the tapered pile driving process. Based on PFC numerical simulation software, comparative numerical models on pile driving process of traditional equal section pile and tapered pile with the same concrete usage were built. The accuracy and reliability of varia- ble pile driving numerical models was verified by comparing with tapered pile and equal section pile driving mod- el test results and cavity expansion theoretical calculation method results. Then, the displacement field, stress field, and pile driving resistance were systematically discussed and analyzed. The results show that pilling effects of tapered pile are similar with those of traditional equal section pile. The results also show that the pile driving tip resistance, pile shaft and total resistance of tapered pile equal 1.0 times, 1.82 times and 1.37 times of those of equal section pile respectively.