大直径阶梯型变截面桩竖向承载力计算方法研究

Study on Calculation Method of Vertical Bearing Capacity of Large Diameter Staircase Variable Cross-section Pile

通过分析阶梯型变截面桩-土体系的荷载传递过程,综合考虑桩侧土体侧摩阻力及端桩承载力的发挥情况,并考虑一定的安全储备,提出了基于变形协调原则的变截面桩基竖向承载力和沉降的计算理论和公式,该方法克服了规范法中桩基竖向承载力和沉降不相关的缺陷,并以某深水大跨度桥梁大直径阶梯型变截面桩为例,分别采用变形协调原则法和规范法对该桩基进行计算和对比分析,结果表明:变形协调原则法计算出来的桩基竖向承载力小于规范法计算值。

By analyzing the load transfer mechanism of staircase variable cross-section pile-soil system, comprehensively considering the side friction and end bearing capacity of the pile-end soil on the pile side, and considering sufficient safety storage, this paper put forward the calculation theory and formula of vertical bearing capacity and settlement of pile foundation with variable cross-section based on deformation coordination principle. This method overcomes the defect that the vertical bearing capacity and settlement of pile foundation are not related in the code method. Taking a large-diameter staircase variable cross-section pile of a deep-water long-span bridge as an example, the deformation coordination principle method and the code method are used to calculate and compare the pile foundation. The results show that the vertical bearing capacity calculated by the deformation coordination principle method is smaller than the value calculated by the code method.