竖向抗压桩承载机理与受力特性分析方法

Bearing mechanism and response analysis method of vertically loaded piles

桩基础具有竖向承载力高,基础沉降小,调节不均匀沉降能力强等优点,成为大型建构筑物的主要基础型式。桩基承载力与沉降分析是桩基设计中的主要内容。本研究基于桩身布设钢筋应力计的单桩现场静载试验结果,分析了竖向抗压单桩荷载-沉降关系、桩身轴力分布规律、桩侧摩阻力和桩端摩阻力发挥特性等,总结了不同桩侧和桩端荷载传递模型,明确了荷载传递模型中各参数的意义和取值方法。以桩侧和桩端荷载传递双曲线模型为例,考虑群桩中各基桩间的相互作用,提出了群桩中各基桩的双曲线荷载传递函数,结合荷载传递法形成了考虑桩-土体系渐进变形的桩基承载特性迭代计算方法。

Pile foundations have been commonly used in large construction projects due to their large vertical bearing capacity,small settlemeat,and easy adjustment on differential settlement.In the design of pile foundation,it is importment to consider the analyses on bearing capacity and settlement.Based on the field test results of single piles equipped with strain gauges along pile shaft,in this paper,the load-displacement relationship of vertically loaded single piles,the distribution of axial force,and the mobilization of skin friction and end resistance were analyzed.Moreover,different load-transfer models of skin friction and end resistance were summarized,and the meaning and evaluation method of each parameter related to the load-transfer models were given.With the hyperbolic model of skin friction and end resistance as an example,the hyperbolic load-transfer function of individual piles in pile groups was proposed by considering the interactive effects among individual piles.An iterative method considering progressive deformation of pile-soil system was developed by using the load-transfer method.