挤扩支盘桩抗拔承载特性的模型试验研究  

Model test study on uplift bearing characteristicof squeezed branch pile

作　　者：马宏伟[1] 杨玉琪 何青睿 王丽娜 MA Hong-wei;YANG Yu-qi;HE Qing-rui;WANG Li-na(School of Civil Engineering&Architecture,Anhui University of Science&Technology,Huainan 232001,China)

机构地区：[1]安徽理工大学土木建筑学院,安徽淮南232001

出　　处：《河南城建学院学报》2023年第3期1-7,共7页Journal of Henan University of Urban Construction

基　　金：国家自然科学基金项目(51408006);安徽省博士后基金项目(2016B01)。

摘　　要：基于模型试验分析了上拔力作用下挤扩支盘桩的荷载-位移曲线特征、轴力分布特点和抗拔承载力的构成,研究盘径对承载特性的影响规律。结果表明:挤扩支盘桩比直孔桩具有更高的抗拔承载力和抗拔刚度,其拔出破坏具有脆性破坏的特征,同时盘径对挤扩支盘桩Q-s曲线的影响主要在加载后期体现;挤扩支盘桩发生脆性拔出破坏的原因是承力盘引起的土体突发剪切失效,而挤扩支盘桩的抗拔极限承载力主要由挤扩盘压力引起的土体滑移面强度和盘上直孔段的桩土接触面强度决定;上拔力作用下挤扩支盘桩的抗拔承载过程由盘上土体挤密阶段、弹性锚固阶段、塑性锚固阶段构成;盘阻在挤扩支盘桩抗拔承载力中的占比随着盘径的增大而增大,加载后期的盘阻贡献率相对于加载初期可以提升6%~8%。Based on the model tests,the characteristics of load-displacement curve,the axial force distribution and the tensile capacity composition of the squeezed branch pile under the uplift force are analyzed,and the influence of the expanded plate diameter on the characteristics is investigated.The results show that the squeezed branch pile has a higher uplift bearing capacity and stiffness than the straight pile,and its failure is abrupt.At the same time,the effect of the expanded plate diameter on the Q-s curve of the squeezed branch pile is mainly reflected in the late loading period.The reason of pile’s brittle pull-out failure is the soil burst shear failure caused by the expanded plate,and the ultimate pull-out capacity of the pile is mainly determined by the strength of the soil slip surface caused by the plate pressure and the strength of the pile-soil contact surface of the pile straight section over the plate.Under the action of uplift force,the bearing process of the pile consists of a soil compaction phase,an elastic anchoring phase and a plastic anchoring phase.The proportion of plate resistance in the pile uplift capacity increases with the increase of expanded plate diameter,and it can be increased by 6%~8%during the late loading period compared with the initial loading period.

关 键 词：挤扩支盘桩 上拔力 承载特性 模型试验 

分 类 号：TU473.1[建筑科学—结构工程]