竖向荷载作用下大直径钢管桩承载力特性分析

近年来,新型大直径钢管桩基的承载力特性备受关注,为此,以湛江某新建油码头工程大直径钢管桩测试桩Z2桩为研究对象,采用有限元三维数值静载试验方法,对竖向荷载作用下大直径钢管桩的桩径、桩长、桩侧土摩擦系数及桩端土压缩模量对其承载力特性的影响规律进行研究。结果表明:钢管桩桩径增大,则其极限承载力和桩侧摩阻力随之提高,桩端沉降与桩顶沉降之比逐渐减小,同时桩端阻力随着桩径的增加而减小;钢管桩桩长增加,钢管桩的极限承载力和桩侧摩阻力都显著提高,桩端阻力与桩顶荷载之比逐渐减小;桩侧土摩擦系数增大,则桩的极限承载力增大而桩端沉降量显著减小,尤其在摩擦系数从0.3增加到0.4时,沉降量减小幅度较大;桩端土压缩模量增加,则钢管桩竖向极限承载力和桩端阻力增大,而桩端沉降量减小。研究结果可对类似工程大直径钢管桩的设计和施工提供参考。

Load bearing capacity of the large-diameter steel pipe piles under vertical loads

In recent years,the load bearing capacity of large-diameter steel pipe piles has attracted more and more attention from researchers.Taking Z2 pile,a large-diameter steel pipe test pile of the newly-built oil terminal in Zhanjiang Port as the research object,and employing the static loading test given by finite element simulation,the influence of pile diameter,pile length,pile-soil friction coefficient and pile-soil compressive modulus on the load bearing capacity of large-diameter steel pipe piles was studied.The results show that the ultimate load and lateral friction resistance of the pile are increased respectively with the increment of pile diameter,the ratio between pile tip resistance and pile top settlement is gradually decreased,and the pile tip resistance is decreased as the increase of pile diameter.The ultimate load bearing capacity and lateral friction resistance of the pile are significantly increased respectively with the increment of the pile length,however,the ratio between pile tip settlement and pile top settlement is gradually decreased;if the friction coefficient of pile side soil is increased,the ultimate load bearing capacity of the pile will be significantly increased,and especially when the friction coefficient is increased from 0.3 to 0.4,the pile top settlement is decreased largely;the ultimate vertical load bearing capacity of the pile is significantly increased with the increment of the pile-soil compression modulus.These results are instructive for the design and construction of similar projects.