挤扩支盘桩-土相互作用的机理研究

Study on the Mechanism of Squeezed Branch Pile-Soil Interaction

为揭示静荷载作用下挤扩支盘桩-土相互作用机理,采用室内模型试验和理论分析的方法研究了扩大盘盘径对桩体工作性能和桩周土体附加应力分布的影响。研究表明:挤扩桩的静承载力比等直径直孔桩高2倍以上,承载力随盘径的增大而增大;扩大盘盘阻贡献率随着盘径和外荷载的增大均增大,同时,盘阻的增大可引起桩侧阻力的提高;在盘底以下2D深度处附加土压力主要分布在桩周2D范围内,附加土压力沿竖向的分布范围主要为盘底以下2.5D深度内。

In order to reveal the interaction mechanism between squeezed branch pile and soil under static load,the influence of expanded plate diameter on the working performance of pile and the additional stress distribution of soil around pile was studied by means of model test and theoretical analysis.The research shows that the static bearing capacity of the squeezed branch pile is 2 times higher than that of straight hole pile of the equal diameter,and the bearing capacity increases with the increase of the plate diameter;the contribution rate of the expanded plate resistance increases with the increase of the plate diameter and load.Meanwhile,the increase of the plate resistance can cause the increase of the pile side resistance;The additional stress at the 2D depth below the bottom of the plate is mainly distributed in the 2D range of the pile,and the distribution of the additional stress in the vertical direction is mainly within 2.5D depth below the bottom of the plate.