【摘要】 目的 为探究粉砂地基中刚性与弹性阶梯型变截面桩的水平承载机理和变径因素对水平承载性能的影响，进行室内和数值模拟实验。方法 分别对刚、弹性阶梯型变截面桩和常截面桩进行水平加载，并利用有限元软件建立不同变径比和变径长度的数值模型。结果 研究结果表明，下半段桩径减小阶梯型变截面形式对弹性桩的水平承载性能影响较小，考虑材料利用率情况下，刚性阶梯型变截面桩的单位体积水平承载力比常截面桩提高6.4%，弹性阶梯型变截面桩提升33.28%；水平荷载相同条件下，刚性阶梯型变截面桩的浅层土抗力大于常截面桩的，弹性阶梯型变截面桩的浅层土抗力小于弹性常截面桩的；阶梯型变截面桩的水平承载力随变径比和变径长度的增加而增大，单位体积水平承载力随变径比增加而减小。变径比为0.8，变径长度占比为50%时，弹性阶梯型变截面桩的水平承载力接近于弹性常截面桩；与弹性常截面桩相比，当弹性阶梯型变截面桩变径比为0.8，变径长度占比为40%时，单位体积水平承载力提升最大。结论 与常截面桩相比，阶梯型变截面桩的单位水平承载力更高，合理设置变径长度和变径比可以节约成本。研究结果为实际工程中阶梯型变截面桩的应用提供参考。更多还原

【Abstract】 Objectives This study aims to investigate the horizontal bearing mechanism of rigid and elastic stepped variable cross-section piles in silty sand foundations and to evaluate the impact of variable diameter factors on horizontal bearing capacity. Indoor and numerical simulation experiments were conducted. Methods Horizontal loading tests were performed on rigid and elastic stepped variable cross-section piles as well as constant cross-section piles. Finite element software was used to develop numerical models with different variable diameter ratios and lengths for analysis. Results The results indicate that reducing the diameter of the lower half of the pile, using the stepped variable cross-section design, has a minimal impact on the horizontal bearing capacity of the elastic piles. Considering material efficiency, the unit volume horizontal bearing capacity of the rigid stepped variable cross-section pile is 6.4% higher than that of the constant cross-section pile, while the elastic stepped variable cross-section pile shows a 33.28% increase. Under the same horizontal load conditions, the shallow soil resistance of the rigid stepped variable cross-section pile is higher than that of the constant cross-section pile, while the shallow soil resistance of the elastic stepped variable cross-section pile is lower than that of the elastic constant cross-section pile. The horizontal bearing capacity of the stepped variable cross-section pile increases with higher variable diameter ratios and lengths, while the unit volume horizontal bearing capacity decreases as the variable diameter ratio increases. When the variable diameter ratio is 0.8 and the variable diameter length is 50% of the pile length, the horizontal bearing capacity of the elastic stepped variable cross-section pile is close to that of the elastic constant cross-section pile. Compared to the elastic constant cross-section pile, the unit volume horizontal bearing capacity is maximized when the variable diameter ratio is 0.8 and the variable diameter length is 40% of the pile length. Conclusions The unit horizontal bearing capacity of the stepped variable crosssection pile is higher than that of the constant cross-section pile. Reasonable optimization of the variable diameter length and ratio can help reduce project costs. The findings provide valuable insights for the application of stepped variable cross-section piles in practical engineering.更多还原