桩土作用下缺陷大管桩单桩极限承载力理论计算

码头大管桩出现的不同类型缺陷，如混凝土脱落和钢筋锈蚀，会造成码头承载能力下降。基于完整桩-土体系的荷载传递理论，推导获得缺陷桩剩余极限承载力的计算公式。依托工程实践，考察混凝土剥落和钢筋锈蚀这两种缺陷类型对单桩极限承载力的影响，并得出相应结论：混凝土剥落位置对单桩竖向极限承载力和单桩抗拔极限承载力有影响，混凝土剥落位置位于土层内部会减小单桩竖向极限承载力和单桩抗拔极限承载力，单桩竖向极限承载力减小0.07%，单桩抗拔极限承载力减小1.72%；但对桩身竖向承载力却不同，混凝土缺损对桩身轴心受压承载力减小25.65%，钢筋损失对桩身竖向承载力减小20.95%。混凝土缺损比钢筋缺损对桩身各项承载力的影响要大得多。

Theoretical calculation of ultimate bearing capacity of defect large pipe pile in pile-soil condition

There are different types of defects of large pipe piles,such as concrete shed and steel corrosion,which have an unfavorable influence on the bearing capacity of the dock.Based on the complete pile-soil load transfer system theory,the formula of the remaining bearing capacity of the defect pile is derived.The influence of defects like concrete spalling and steel corrosion on the ultimate bearing capacity of a single is studied.The result reveals that the position of concrete spalling has an influence on the vertical compress ultimate capacity and the vertical uplift ultimate capacity.When it is inside the soil layer,the vertical compress ultimate capacity will have a decrease of 0.07%,while the vertical uplift ultimate capacity will have a decrease of 1.72%.The axial-compression capacity is different,the impact of the defect on the concrete pile on axial-compression capacity is a decrease of 25.65% and that for the steel cohesion on axial-compression capacity reaches a decrease of 20.95%.The concrete defect on the capacity is much greater.