基于二维离散元软件PFC2D模拟多级旋扩桩在单桩竖向受荷条件下的静载试验,揭示多级旋扩桩的承载特性以及桩-土相互作用规律。研究结果表明:①在加载过程中,随着荷载的增大,上部桩身侧摩阻力、桩身扩径段阻力、桩端阻力是依次发挥承载能力作用的;②在加载过程中,当荷载较小时,荷载主要由桩身侧摩阻力承担,随着荷载逐步增大,桩身扩径段分担荷载的比例快速增大,当荷载继续增大,荷载增加的部分主要由桩端阻力承担,此时桩端阻力分担荷载的比例快速增大;③在加载过程中,随着荷载的增大,桩周土体的孔隙率、土颗粒之间的配位数、土体水平向应力、土体竖直向应力,以及桩周土颗粒的位移均呈有规律的变化。
Abstract
Multistage rotated-expanded pile carrying vertical load are simulated using DEM software PFC2D to reveal the bearing behaviors and the interaction between pile and soil. Test results show that: (1) With the increase of load in the process of loading, the side friction of the upper part of pile, the friction of diameter-expanding segment of pile, and the pile tip resistance plays the role of bearing in turn. (2) When the load is small, load is mainly composed of side friction of pile; with the increasing of load, the diameter-expanding segment of pile undertakes a rapidly increasing rate of the load; and when the load continues to increase, the increment is mainly and increasingly undertaken by pile tip resistance. (3) With the increase of load in the process of loading, the porosity of surrounding soil, the coordination number between the levels of soil, the horizontal and vertical stresses of pile, and the soil particle displacement surrounding pile are in regular changes.
关键词
多级旋扩桩 /
颗粒流 /
承载特性 /
细观研究 /
二维离散元
Key words
multistage rotated-expanded pile /
particle flow /
bearing behaviors /
meso-study /
2D discrete element
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参考文献
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