竖向荷载作用下大直径钻孔灌注桩承载特性研究  

Study on Bearing Characteristics of Large Diameter Bored Piles Under Vertical Loading

作　　者：沈川 SHEN Chuan(No.1 Engineering Co.,Ltd.of China Railway 18th Bureau Group Co.,Ltd.,Baoding,Hebei 072750,China)

机构地区：[1]中铁十八局集团第一工程有限公司,河北保定072750

出　　处：《施工技术(中英文)》2025年第7期88-96,共9页Construction Technology

基　　金：中铁十八局集团有限公司科研课题(CR18GK-24-S-p-11);中铁十八局集团有限公司荥密高速XMSG-1标项目经理部科研课题(1-JF-2024荥密高速-0-003)。

摘　　要：为明确黄河中下游流域密实粉细砂地层中长大桩基承载特性及荷载传递机理,探讨承压桩在竖向循环堆载作用下的沉降特性,设计拉压锚法加载反力装置开展3根长大钻孔灌注桩静载试验,并结合数值模拟研究了桩顶、桩端在有限次循环堆载下的沉降规律。结果表明:大直径长钻孔灌注桩桩身的侧摩阻力和桩端阻力发挥不同步,且桩侧摩阻力发挥程度与桩顶荷载、土层性质、埋深以及桩基施工工艺均有一定的关系;密实粉细砂地层中长大桩基呈现出纯摩擦桩性状;计算长大桩基承载力时,应对基于规范取值的勘察报告参数乘以相应的修正系数;密实粉细砂层中桩身侧摩阻力并未充分发挥,“永临结合”梁场有限次加卸荷并不能引发桩基发生明显变形,梁场运营对桩基承载性能的影响较弱。To clarify the bearing characteristics and load transfer mechanism of long and large pile foundations in dense silty fine sand strata in the middle and lower reaches of the Yellow River,and to explore the settlement characteristics of pressure-bearing piles under vertical cyclic loading,the static load tests of three long and large drilled grouting piles were carried out by designing tension-compression anchor method loading with reaction devices,and the settlement law of pile top and pile end under finite cyclic loading was studied by numerical simulation.The results indicate that the side friction resistance and pile end resistance of large diameter and long bored piles are not synchronized,and the degree of pile side friction resistance is related to the pile top load,soil properties,buried depth,and pile foundation construction technology.The long pile foundation in dense fine sand stratum shows the characteristics of a pure friction pile.When calculating the bearing capacity of a long and large pile foundation,the survey report parameters based on the standard value should be multiplied by the corresponding correction coefficient.The side friction resistance of the pile body in the dense silty fine sand layer is not fully utilized.The finite loading and unloading of the permanent-temporary combination beam yard cannot cause obvious deformation of the pile foundation,and the influence of the beam yard operation on the bearing capacity of the pile foundation is weak.

关 键 词：桩基础 梁场 钻孔灌注桩 静载试验 数值模拟 沉降 

分 类 号：TU753.3[建筑科学—建筑技术科学]