基于桩-土软化模型的单桩荷载传递规律

Load Transfer Law of Single Pile Based on Pile-soil Softening Model

桩身侧摩阻力是桩基设计非常重要的参数指标;而桩侧摩阻力的软化行为会引起桩承载能力的降低。基于桩-土软化模型推导出了单桩荷载传递规律的解析解。通过单桩静载荷试验,对比分析了解析解和桩荷载试验结果之间关系,结果表明桩的轴向力和桩-土界面应力应变吻合良好,验证了所提解析解的合理性。传统的解析解是通过经验法将桩端承载力当作已知边界条件使用,而提出的解析解可以通过不同的外加荷载和侧摩阻力来计算桩端承载力。由于考虑了桩侧土体的软化特性,在桩基加载过程中,从桩身归一化的侧摩阻力分布图中可以观察到桩身摩阻力的软化行为,桩基承载力有所下降。

The skin friction of pile draft is important and esential during its design and analysis. M o r e and more attentions have been paid on the softening behavior of skin friction because it results in the reduction of tlie bearing capacity. In order to investigate the load transfer m e c h a n i s m in this condition,an analytical analysis withsoftening model is derived. Moreover,a series of pile load tests are carried out to verify the proposed analyticalsolutions. The comparison results between analytical analysis and pile load tests shows results on pile axial force and stress-strain relationship of pile-soil interface are obtained. analysis calculates the end bearing by the difference between the applied load and its skin friction, whereasconventional analytical method set the end bearing as a known boundary condition by experience m e t h o d. D u e to the use of tlie softening m o d e l,softening behavior of skin friction could be observed in the skin friction profile whensubjected to large load.