支盘桩承载力特性及变形破坏模式研究

Bearing capacity and deformation failure mode study of squeezed branch pile

为了深入揭示支盘桩与土相互作用的内在机理,利用基于数字图像相关技术的模型试验及三维数值模拟方法对单桩、单支盘桩及双支盘桩的承载特性、桩周土体位移场分布特征进行研究。研究结果表明:单桩及单支盘桩荷载-沉降曲线呈现陡降型,而双支盘桩呈缓降型,且随着支盘数量增加,支盘桩承载力近似线性增长;单支盘桩在极限荷载阶段支盘下及桩端土体位移较大,而双支盘桩桩周土体位移较大部位主要集中在支盘周围土体;单支盘桩基础破坏面由支盘下土体的剪切滑动破坏面及桩端刺入破坏面构成,而双支盘桩基础破坏面由双支盘构成的连续滑动面组成,桩端刺入破坏特征不明显。研究结果为支盘桩承载力及破坏模式的合理确定提供了重要依据。

In order to further reveal the interaction mechanism of squeezed branch pile and soil, model test using digital image correlation technique and three-dimensional numerical simulation method were used to study the bearing capacity and soil displacement field distribution characteristics of single pile, one branch pile and two branch pile. The study results showed that the load-settlement curves of single pile and single branch pile is steep drop type, the two branch pile is slow down type, and the branch pile bearing capacity is approximately linear growth with the increase of branches number. The displacement is bigger under branch and pile tip for one branch pile, and the soil displacement larger sites are mainly concentrated around branches for two branch pile. One branch pile foundation is damaged by soil shear slip under branch and pile tip penetration, and the two branch pile foundation is damaged by continuous soil slip around two branch, but the pile tip penetration failure characteristics is not obvious. The findings provide the important basis for the determining of bearing capacity and the destruction pattern to branch pile.