桩土界面荷载传递双曲线模型的改进及其应用

 首先，在总结前人土–结构相互作用试验研究成果的基础上，改进反应桩土界面荷载传递性状的双曲线模型，改进后的模型能够描述随着地基土固结、桩侧土初始剪切刚度随时间增长以及桩土界面的分阶段加/卸载循环剪切特性。然后，利用改进模型对文献中的算例进行分析，计算结果与文献结果比较接近，验证了改进模型的合理性。最后，利用该模型分析大面积荷载下，在桩顶作用大小不同的竖向荷载以及桩侧土达到不同固结度时再打桩情况下，桩身摩阻力、中性点位置及桩承载力的发展变化规律。研究结果表明，桩身中性点位置、桩身负摩阻力随地基土的固结逐渐变化；在地基土固结过程中，桩承载力逐渐减小。该研究成果可为桩基工程设计提供有益的参考。

AN IMPROVED LOAD TRANSFER HYPERBOLIC MODEL FOR PILE-SOIL INTERFACE AND ITS APPLICATION

An improved load transfer hyperbolic model for the pile-soil interface is developed based on the conventional hyperbolic model and the results of soil structure interface(SSI) tests，which considers the increase of initial shear stiffness with the surrounding soil consolidation and loading/unloading behavior of the interface. The validity of the proposed model is proved by the good agreement between the computed results and the documental results. Further studies of the negative skin friction of single piles under different pilehead loadings and pile capacities are also conducted. The results show that the location of neutral point and distribution of skin friction of pile shaft and pile capacity vary with the surrounding soil consolidation and the pilehead loading conditions. The conclusions drawn from the study can provide valuable references for the practice.